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Synthesis, magnetic, spectral, and antimicrobial studies of Cu(II), Ni(II) Co(II), Fe(III), and UO2(II) complexes of a new Schiff base hydrazone derived from 7-chloro-4-hydrazinoquinoline
Abstract
A new hydrazone ligand, HL, was prepared by the reaction of 7-chloro-4-hydrazinoquinoline with o-hydroxybenzaldehyde. The ligand behaves as monoprotic bidentate. This was accounted for as the ligand contains a phenolic group and its hydrogen atom is reluctant to be replaced by a metal ion. The ligand reacted with Cu(II), Ni(II), Co(II), Fe(III), and UO2(II) ions to yield mononuclear complexes. In the case of Fe(III) ion two complexes, mono- and binuclear complexes, were obtained in the absence and presence of LiOH, respectively. Also, mixed ligand complexes were obtained from the reaction of the metal cations Cu(II), Ni(II) and Fe(III) with the ligand (HL) and 8-hydroxyquinoline (8-OHqu) in the presence of LiOH, in the molar ratio 1:1:1:1. It is clear that 8-OHqu behaves as monoprotic bidentate ligand in such mixed ligand complexes. The ligand, HL, and its metal complexes were characterized by elemental analyses, IR, UV-vis, mass, and 1H NMR spectra, as well as magnetic moment, conductance measurements, and thermal analyses. All complexes have octahedral configurations except Cu(II) complex which has an extra square-planar geometry, while Ni(II) mixed complex has also formed a tetrahedral configuration and UO2(II) complex which formed a favorable pentagonal biprymidial geometry. Magnetic moment of the binuclear Fe(III) complex is quite low compared to calculated value for two iron ions complex and thus shows antiferromagnetic interactions between the two adjacent ferric ions. The HL and metal complexes were tested against one stain Gram positive bacteria (Staphylococcus aureus), Gram negative bacteria (Escherichia coli), and fungi (Candida albicans). The tested compounds exhibited higher antibacterial acivities.
... The ligand scaffolds play an important role in the chemotherapy, and among ligand system, hydrazones consisting of a carbon-nitrogen double bond (R-CO-NH-N=CHR) group [4] belong to special class due to their interesting multidentate chelating properties and form complexes with almost all the metal ions in different oxidation states depending upon the carbonyl group and hydrazide derivatives [5,6]. They possess diverse biological and pharmaceutical activities [7,8] such as antimicrobial [9,10], anticancer [11,12] and antioxidant properties [13]. They also show applications in wastewater treatment [14], catalytical activity [15,16], good magnetic behaviour [17], specific sensors, nonlinear optical devices [18], resin for separation [19] and acting as enzyme inhibitor [20]. ...
... Due to the widespread therapeutic and diagnostic properties of hydrazones and tetralone derivatives, it seemed appealing to investigate compounds that have remarkable applications of both antimicrobial and anticancer activities, so here we have reported the synthesis of hydrazones from condensation of hydrazide derivatives with tetralone and reacted them with transition metal(II) acetates to form complexes. For characterization and structure determination, various spectroscopic analyses (UV-Vis, 1 H NMR, 13 C NMR, FT-IR, mass, ESR and fluorescence), magnetic susceptibility, elemental analysis, molar conductance measurements and thermal (TGA, DTG and DTA) methods were used. Screening of compounds for cytotoxic activity against three cancer cell lines-human breast adenocarcinoma cell line (MCF7), human alveolar adenocarcinoma epithelial cell line (A549), human cervical cell line (HeLa) and Rat myoblast cell line normal (L 6 )-were assayed. ...
... The in vitro anticancer activity of the compounds (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) was tested as given by Mosmann [30]. The cytotoxicity was evaluated against a series of three different human carcinoma cell lines: A549 derived from human alveolar adenocarcinoma epithelial cell lines (ATCC No.CCL-185), HeLa derived from human cervical adenocarcinoma epithelial cell lines (ATCC No. CCL-2), MCF7 derived from human breast adenocarcinoma epithelial cell lines (ATCC No.HTB-22) as well as normal cell line L 6 derived from rat skeletal muscle myoblast cells (ATCC No. CRL-1458), and these cells were cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with 1% gentamicin, 10% foetal bovine serum (FBS) and 10% Pen-Strep. ...
... The ligand scaffolds play an important role in the chemotherapy, and among ligand system, hydrazones consisting of a carbon-nitrogen double bond (R-CO-NH-N=CHR) group [4] belong to special class due to their interesting multidentate chelating properties and form complexes with almost all the metal ions in different oxidation states depending upon the carbonyl group and hydrazide derivatives [5,6]. They possess diverse biological and pharmaceutical activities [7,8] such as antimicrobial [9,10], anticancer [11,12] and antioxidant properties [13]. They also show applications in wastewater treatment [14], catalytical activity [15,16], good magnetic behaviour [17], specific sensors, nonlinear optical devices [18], resin for separation [19] and acting as enzyme inhibitor [20]. ...
... Due to the widespread therapeutic and diagnostic properties of hydrazones and tetralone derivatives, it seemed appealing to investigate compounds that have remarkable applications of both antimicrobial and anticancer activities, so here we have reported the synthesis of hydrazones from condensation of hydrazide derivatives with tetralone and reacted them with transition metal(II) acetates to form complexes. For characterization and structure determination, various spectroscopic analyses (UV-Vis, 1 H NMR, 13 C NMR, FT-IR, mass, ESR and fluorescence), magnetic susceptibility, elemental analysis, molar conductance measurements and thermal (TGA, DTG and DTA) methods were used. Screening of compounds for cytotoxic activity against three cancer cell lines-human breast adenocarcinoma cell line (MCF7), human alveolar adenocarcinoma epithelial cell line (A549), human cervical cell line (HeLa) and Rat myoblast cell line normal (L 6 )-were assayed. ...
... The in vitro anticancer activity of the compounds (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) was tested as given by Mosmann [30]. The cytotoxicity was evaluated against a series of three different human carcinoma cell lines: A549 derived from human alveolar adenocarcinoma epithelial cell lines (ATCC No.CCL-185), HeLa derived from human cervical adenocarcinoma epithelial cell lines (ATCC No. CCL-2), MCF7 derived from human breast adenocarcinoma epithelial cell lines (ATCC No.HTB-22) as well as normal cell line L 6 derived from rat skeletal muscle myoblast cells (ATCC No. CRL-1458), and these cells were cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with 1% gentamicin, 10% foetal bovine serum (FBS) and 10% Pen-Strep. ...
A series of transition metal (II) complexes with general formula [M(L¹⁻⁴)2(H2O)2] (where M = Co(II), Ni(II), Cu(II) and Zn(II)) was synthesized by the reaction of metal(II) acetates with hydrazones [HL¹–HL⁴] obtained from condensation of tetralone with hydrazide derivatives. The characterization of synthesized compounds (1–20) was done by using elemental analysis, different spectral studies (UV–Vis, ¹H NMR, ¹³C NMR, FT-IR, mass, ESR and fluorescence), magnetic susceptibility, molar conductance measurement and thermal (DTA, TGA and DTG) analysis. The characterization results suggested the bidentate nature of the hydrazones, which chelate with the metal ion via nitrogen of (C=N) group and deprotonated carbonyl oxygen in the enolized form, resulting in stable, non-volatile octahedral complexes. The antimicrobial potential of the compounds was evaluated against four bacterial, i.e. (S. aureus, B. subtilis, P. aeruginosa and E. coli), and two fungal species, i.e. (A. niger and C. albicans), by a serial dilution method with complexes 15 and 16 as most active compounds against microbes. All the compounds were also tested for its cytotoxicity (in vitro) against three human cancer cell lines (A549, HeLa and MCF-7) and one normal cell line (L6) by the MTT assay, which focussed on an increased activity of compounds 7 and 15 towards A549, MCF-7 and HeLa cancer cell line with IC50 values ranging from 10.76 to 16.42 μg/mL, and compounds were found to be non-toxic towards L6 cell line as compared to the standard drug doxorubicin. The results demonstrated that complexation enhanced the biological activity of compounds.
Graphic abstract
The synthesized compounds (1–20) were screened for antitumor activities against A549, MCF7, Hela cancer cell lines. Copper complex (7) and (15) was found to be the most active antitumor agent and less toxic against L6—Rat myoblast normal cell line than standard doxorubicin.
... The thermal stability and tenability of metal-organic coordination complexes make them truly suitable for a wide range of catalytic and stoichiometric transformations. These comprise many reactions, including bond activation [18,19], carbon-carbon bond formation [20,21], polymerization [22], production of ammonia from nitrogen and hydrogen [23], organic synthesis [24,25], and supramolecular chemistry [26]. The donor atoms of employed mixed ligands for complex formation are depicted below (violet color): Reduction plays an important role in various organic transformations. ...
... The thermal stability, magnetic susceptibility, spectroscopic, and X-ray diffraction studies are described in the experimental part. All the analytical and spectroscopic features are based on the good judgement of six coordinated complexes [25,45,47,50] in all the cases. The relevant IR spectroscopic and Gas Chromatography Mass Spectrometric (GC-MS) analysis for ester products are interpreted herein. ...
... The bands at about 498-475 cm -1 and 595-531 cm -1 are also attributed to M-N and M-O stretching frequency [53], respectively. The coordination mode of NBpy and NPhe to Ni(II) and Co(II), and OTyr and OPhe atoms to Fe(II) are the agreement with bands observed at 590-485 cm -1 [25,50,54,55]. ...
... analoges shows a wide range of biological applications including, anticonvulsant [3,4], antitubercular [5,6], antioxidant [7,8], antiviral [9,10], vasodilator activity [11], antitumor activity [12,13], antimicrobial [6,14,15], antimycobacterial [16], antidepressant [17,18], antimalarial [2,19], antifungal [20,21], analgesic and anti-inflammatory activities [22][23][24][25]. Furthermore, some hydrazones have also been used as nematicides, herbicides, insecticides, rodenticides and plant growth regulators [26] as well as plasticizers, stabilizers for polymers also [9,27,28]. ...
... analoges shows a wide range of biological applications including, anticonvulsant [3,4], antitubercular [5,6], antioxidant [7,8], antiviral [9,10], vasodilator activity [11], antitumor activity [12,13], antimicrobial [6,14,15], antimycobacterial [16], antidepressant [17,18], antimalarial [2,19], antifungal [20,21], analgesic and anti-inflammatory activities [22][23][24][25]. Furthermore, some hydrazones have also been used as nematicides, herbicides, insecticides, rodenticides and plant growth regulators [26] as well as plasticizers, stabilizers for polymers also [9,27,28]. The hydrazones supported metal complexes exhibit broad spectrum of potential applications such as catalysts [29], luminescent probes [30], radio protective properties [31], enzyme inhibitors [32] and molecular sensors [33]. ...
The growing pharmaceutical relevance of drug-resistant pathogens has necessitated the emergence of new treatment medicines. In this scenario, a novel series of N′-(substituted)-2-(4-(3-nitroimidazo[1,2-b]- pyridazin-6-yl)piperazin-1-yl)acetohydrazides and 1-(2-(substituted)-5-((4-(3-nitroimidazo[1,2- b]pyridazin-6-yl)piperazin-1-yl)methyl)-1,3,4-oxadiazol-3 (2H)-yl)ethan-1-ones have been synthesized and characterized by 1H & 13C NMR spectral data and screened for antimicrobial activity, as well as molecular docking studies. The synthesized compounds were tested against Escherichia coli (1668), Bacillus cereus (1272), Candida albicans (854) by using disc diffusion method. Among all the synthesized compounds 3c and 4c exhibit good potent antimicrobial activity against Escherichia coli, 3a, 4c against Bacillus cereus and 4a, 4c against Candida albicans. The Auto-Dock 4.2/ADT application was performed to investigate the binding interaction of the synthesized compounds with BAX protein. Among all the synthesized compounds 4e, 4a, 3e and 3a showed the highest binding affinity (-8.0, -7.5, -7.0 and -6.9 Kcal/mol) with BAX protein.
... The IR spectral data for the ligand (1) and its metal complexes are presented in Table 2. The IR spectrum of the ligand showed bands at3195, 1660 and 1600 cm -1 may be due to (NH), (C=O) and (C=N) groups, respectively [10]. The absence of any signals for hydroxy group indicates that the ligand is present in the keto-form in the solid state.The spectra of solid complexes are compared with those of the ligand in order to know the mode of bonding. ...
... (NH)of one side of the ligand was shifted to higher wave number, while the other one found almost at their original place, iii) the simultaneous appearance of new bands in the 655-634 and 520-549 cm -1 regions are due to the (M-N) and v(M-O) vibrationsrespectively [12]. 2. Neutral tetradentateligand, coordinating through C=O and C=N of both sides of the ligand (complexes2, 7,[9][10][11][12][13][14]16,20,22,23), the mode of coordination was suggested by the following evidence: i)all (C=O)and (C=N) were shifted to lower wave number with decreasing their intensities [11], ii) both (NH)were shifted to higher wave number, iii) the simultaneous appearance of new bands in the 657-637 and 555-530 cm -1 regions are due to the v(M-N) and v(M-O) respectively [12]. 3. Dibasic tetradentateligand, coordinating through C-O and C=N of both sides of the ligand (complexes4, 6,15,18), the mode of coordination was suggested by the following evidence: i)all v(C=N) were shifted to lower wave number with decreasing their intensities [11], ii) all v(C=O) and v(NH)disappeared with the appearance of bands due to new v(C=N) found at higher wave number [13], the disappearance of the formed v(OH) indicates the deprotonation of the ligands prior to coordination through oxygen atom. ...
... They have typical chemical applications, but it is also very popular to obtain compounds of this type, including both Schiff bases and their complexes, and study not only their catalytic properties, but also biological ones, including antifungal, antibacterial, and anti-inflammatory properties, which enables their use in clinical and pharmacological areas [24][25][26][27][28][29][30][31][32]. Schiff base complexes with copper are commonly synthesized and studied [20,[33][34][35][36][37][38]. Compounds of this type were also used in the present study. ...
... PVC. Table 6 compares the basic analytical parameters of the proposed electrode with other previously reported Cu 2+ -selective electrodes [3,8,[34][35][36][37][38][39][40]. The presented data shows that our sensor is superior to most of the other electrodes with regard to detection limit and linear range. ...
The paper describes research on ion-selective electrodes sensitive to copper(II) ions, in which Schiff bases and their Cu(II) complexes were used as active components of ion-selective membranes. The Schiff bases differ in the type and amount of substituents in the benzene ring and/or in the aliphatic chain. A multi-stage process of optimization of the ion-selective membrane composition was carried out. Apart from the selection of the best ionophore, the influence of the type of plasticizer and lipophilic salt as well as the active substance content was also investigated. The best results were obtained for N,N′-bis(5-bromo-2-hydroxy-3-methoxybenzylidene)2-hydroxypropylene-1,3-diamine and its dinuclear copper(II) complex. The ion-selective membrane composition was optimized, resulting in obtaining electrodes with a very good slope of 29.68 mV/decade in a wide measuring range 1 × 10⁻⁶ – 1 × 10⁻¹ mol L⁻¹ and good potential stability and selectivity. The electrodes could successfully work in the pH range of 2.4–5.5 for a minimum period of 2 months.
... The IR spectral data for the ligand (1) and its metal complexes are presented in Table 2. The IR spectrum of the ligand showed bands at3195, 1660 and 1600 cm -1 may be due to (NH), (C=O) and (C=N) groups, respectively [10]. The absence of any signals for hydroxy group indicates that the ligand is present in the keto-form in the solid state.The spectra of solid complexes are compared with those of the ligand in order to know the mode of bonding. ...
... (NH)of one side of the ligand was shifted to higher wave number, while the other one found almost at their original place, iii) the simultaneous appearance of new bands in the 655-634 and 520-549 cm -1 regions are due to the (M-N) and v(M-O) vibrationsrespectively [12]. 2. Neutral tetradentateligand, coordinating through C=O and C=N of both sides of the ligand (complexes2, 7,[9][10][11][12][13][14]16,20,22,23), the mode of coordination was suggested by the following evidence: i)all (C=O)and (C=N) were shifted to lower wave number with decreasing their intensities [11], ii) both (NH)were shifted to higher wave number, iii) the simultaneous appearance of new bands in the 657-637 and 555-530 cm -1 regions are due to the v(M-N) and v(M-O) respectively [12]. 3. Dibasic tetradentateligand, coordinating through C-O and C=N of both sides of the ligand (complexes4, 6,15,18), the mode of coordination was suggested by the following evidence: i)all v(C=N) were shifted to lower wave number with decreasing their intensities [11], ii) all v(C=O) and v(NH)disappeared with the appearance of bands due to new v(C=N) found at higher wave number [13], the disappearance of the formed v(OH) indicates the deprotonation of the ligands prior to coordination through oxygen atom. ...
... The complexes of Cr(III) are high spin paramagnetic compounds as suggested by their magnetic moment values (16)(17)(18)(19)(20). The values of the magnetic moments of these complexes were in the range of 4.3-5.2 as represented in Table 4, which are comparable with the values reported for octahedral chromium(III) complexes (17)(18)(19). ...
... The complexes of Cr(III) are high spin paramagnetic compounds as suggested by their magnetic moment values (16)(17)(18)(19)(20). The values of the magnetic moments of these complexes were in the range of 4.3-5.2 as represented in Table 4, which are comparable with the values reported for octahedral chromium(III) complexes (17)(18)(19). The value of the magnetic moments of these types of complexes was favorable for the formation of an octahedral complex. ...
Two metal-amino acid complexes, Cr(III)-alanine and Cr(III)-valine, were synthesized and characterized by IR spectroscopy, powder X-ray diffraction (XRD) analysis, magnetic susceptibility, and molar conductivity measurements. Molar conductivity measurements indicated that the composition of the metal complexes corresponds to a metal-amino acid ligand ratio of 1:3. The IR spectra indicated that the amino acids act as bidentate ligands with coordination involving the carboxyl oxygen and the nitrogen of the amino group. Magnetic susceptibility measurements revealed a six-coordinate local symmetry around the Cr(III) ions which depicted that the complexes were paramagnetic with magnetic moment values ranging from 5.10 to 6.00 BM. Powder XRD studies confirmed that the amino acid complexes were crystalline with monoclinic crystal structure. The in vitro biological activity of the investigated chromium(III) complexes with alanine and valine was tested against Bacillus subtilis, Staphylococcus aureus, Salmonella typhi, Pseudomonas aeruginosa, and Escherichia coli. All the microorganisms were standardized using 0.5 McFarland standard. The antimicrobial studies showed that the ligands were biologically active with an inhibition zone range of 10-17 mm and their metal complexes showed significantly enhanced antimicrobial sensitivity with an inhibition zone range of 12-21 mm. The standard drug showed slightly better activity with an inhibition zone range of 24-38 mm.
... The use of chelating agents in coordination chemistry such as Schiff base ligands having four (NNOO) donor atoms as in H 2 Salen have been extensively studied in the literature [1][2][3][4][5][6]. In contrast, the similar structures with only two donor atoms commonly known as bidentate Schiff base ligands are generally less studied [7][8][9]. Due to this, a new class of ligands containing two donor sites of coordination with carbon-bromide function (C-Br) has attracted our attention because of their crucial role in chemical reactivity [4,5]. These brominated or chlorinated precursors may play an important role in the synthesis of bidentate Schiff base ligands. ...
... Thus, these compounds could be used as new monomers to elaborate modified electrodes currently applied as materials useful in many domains as in catalysis [12], electrocatalysis [13][14][15][16] and in the detection of biomolecules as biosensors [17,18]. This wide range of applications may also be extended to study the biological activities such as antibacterial [7,19,20], antifungal [8,21], antitumoral activities [9], etc. ...
Herein, we describe the synthesis of novel bidentate Schiff base ligand 2-[(3-bromo-propylimino)-methyl]-phenol (HL) and its Ni(II) complex in 2:1 (ligand:metal) ratio. The synthesized ligand (HL) and its Ni(II) complex were characterized using routine spectroscopic techniques like microanalysis, UV–visible absorption spectroscopy, FT-IR, NMR (¹H and ¹³C). A suitable single crystal of the nickel complex was obtained from acetone solution by slow evaporation and studied by X-ray diffraction to determine its molecular structure. The crystallographic data of the obtained Ni(II)-2L complex revealed that it possesses a monoclinic space group P 21/n with cell dimensions of a = 10.6818(2) Å, b = 7.1071(1) Å, c = 13.7925(3) Å, β = 105.51(1)°, Z = 4. The electrochemical investigation of both ligand and its Ni(II)-2L complex was carried out by cyclic voltammetry. The cyclovoltammograms showed two redox systems, Ni(II)/Ni(I) and Ni(III)/Ni(II). Interestingly, it was revealed that the Ni(II)-2L complex can be polymerized into its poly-[Ni(II)-2L] films, and electrodeposited onto glassy carbon. The resulting Ni(II)/Ni(I) and Ni(III)/Ni(II) redox systems were advantageously used. The first one was used in the electroreduction of bromocyclopentane while the second one Ni(III)/Ni(II) is rather applied to oxidize methanol.
... Different quinoline compounds have been tested against fungi, a range of Grampositive and Gram-negative bacteria, including Staphylococcus aureus and Escherichia coli [14][15][16]. Lam et al. [14] synthesized and characterized various derivatives of 8-hydroxyquinoline and studied their potential antibacterial activity against Gram-positive S. aureus and Gram-negative E. coli. They found that these quinoline compounds had no effect on E. coli, while showing antibacterial effect against S. aureus. ...
... They found that the synthetic 5,7-dibromo-2-methylquinolin-8-ol derivative shows a similar minimum inhibitory concentration (MIC) of 6.25 lg/mL as compared to that of methicillin (3.125 lg/mL) against Staphylococcus aureus. El-Behery et al. [15] synthesized a Schiff base hydrazone derived from 7-chloro-4hydrazinoquinoline and its complexes with Cu(II), Ni(II), Co(II), Fe(III), and UO 2 (II) ions. Also, they tested the Schiff base ligand and its metal complexes against one stain Gram-positive bacteria (S. aureus), Gram-negative bacteria (E. ...
The reaction on 8-hydroxy quinoline-7-aldehyde azo compounds (HLn) (where n= 1-5) with 4-amino-1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one to obtain HLn (where n= 6-10) have been characterized by means of TLC, melting point and spectral data, such as IR, 1H NMR, mass spectra and thermal studies. The X-ray diffraction patterns of two started materials 8-hydroxy quinoline-7-aldehyde (start 1), 4-amino-1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one (start 2) and the ligands (HL5, HL10) are investigated in powder forms. All the ligands have been screened for their antimicrobial activity against four local bacterial species, two Gram positive bacteria (Bacillus cereus and Staphylococcus aureus) and two Gram negative bacteria (Escherichia coli and Klebsiella pneumoniae) as well as against four local fungi; Aspergillus niger, Alternaria alternata, Penicillium italicum and Fusarium oxysporium. The results show that the azo ligands (HLn) (where n = 1-5) have no antimicrobial activity against bacteria and fungi while most azomethine ligands (HLn) (where n = 6-10) are good antibacterial agents against E. coli and K. pneumoniae as well as antifungal agents against P. italicum and A. alternata. The results were compared to standard substances (start 1) and (start 2). Among the azomethine ligands, HL10 was the most effective against the most microorganisms tested. The size of clear zone was ordered as p-(OCH3 < CH3 < H < Cl < NO2) as expected from Hammett’s constant (σR). Also, the ultrastructure study of the affected bacteria confirmed that HL8 is good antibacterial agent against E. coli and Staphylococcus aureus.
... This value corresponds to two unpaired electrons for a Ni(II) ion with an ideal six-coordination configuration. The Cu(II) complex (6) has a magnetic moment equal to 1.81 B, corresponds to a Cu(II) with a single electron and describes an octahedral environment around the Cu(II) ion [29,30]. ...
The reactions of the Schiff base 2,2’-[(2-hydroxypropane-1,3-diyl) bis-(imino-methane diyl)] bis-(4-bromophenol) (H3L), with metal transition ions (Mn(II), Ni(II), Cu(II), Zn(II), and Cd(II),) afforded one type of complex formulated as [M(HL)(H2O)2].nH2O. These compounds have been characterized by elemental analysis, UV–Vis, FTIR, 1H and 13C NMR spectroscopies, molar conductivity and room temperature magnetic measurements. The structure of nickel (II) complex has been determined by X-ray crystallography. The complex crystallizes in the orthorhombic space group Pnma with a = 7.7702(4) Å, b = 23.1921(15) Å, c = 10.6853(5) Å, V = 1925.57(15) Å3, Z = 8, R1 = 0.043 and wR2 = 0.107, Dcalc = 1.893 Mg m−3. The ligand acts in tetradentate fashion in its di-deprotonated form. Two coordinated water molecules complete the coordination sphere. The environment around the Ni(II) center is best described as an octahedral geometry. In the crystal structure of the Schiff base ligand, the existence of a strong intramolecular O-H•••O hydrogen bonding [O2W-H2W 0.80(3) Å, H2W •••O1 1.915(3) Å, O2W••• O1 2.6258(19) Å, O2W-H2W•••O1 148(3)°] and [O1W-H1W 0.73(3), H1W•••O1 2.15(4) Å, O1W•••O1 2.836(2)Å, O1W-H1W•••O1 156(4)°] are observed. Antibacterial activity study shows that the cadmium (II) complex is more active than the free ligand on.
... These compounds have properties of single-molecule magnetism and single-chain magnetism and are used as a precursor for molecular magnetic materials 57 . In the past decades, Cu (II) complexes achieve great interest because of their important role in the field of molecular magnetic [58][59][60][61][62] . The selection of metal ions with suitable Schiff base ligands for bridging between metal ions in multinuclearity complexes is an important factor in causing magnetic behavior in a complex 63 . ...
A new series of Cu (II) complexes were prepared using Schiff base ligand of N-N'-(1,2-diphenyl ethane-1,2-diylidene)bis(3-Nitrobenzohydrazide). The prepared ligand and Cu (II) complex were characterized using various physicochemical investigations such as X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), and Energy dispersive X-ray analysis (EDX), Fourier Transform Infrared (FT-IR), [Formula: see text] Nuclear Magnetic Resonance (NMR), [Formula: see text] NMR, Diffuse Reflectance Spectroscopy (DRS), Vibrating Sample Magnetometer (VSM), and Z-Scan technique (Nonlinear optical (NLO) properties). In addition, the prepared samples have been examined for their NLO characteristics with the help of the Density Functional Theory calculations which proved that the Cu (II) Complex is more polarized than Ligand. According to XRD and FESEM results, the nanocrystalline nature of the samples is confirmed. The metal-oxide bond assigned in the functional studies by FTIR. Magnetic studies demonstrate weak ferromagnetic and paramagnetic nature for Cu (II) complex and diamagnetic nature for the ligand, respectively. DRS spectrum exhibited higher reflectance for Cu (II) than the ligand. The band gap energies of the synthesized samples were estimated by employing the Tauc relation and Kubelka-Munk theory on reflectance data and found to be 2.89 eV and 2.67 eV for Cu (II) complex and ligand, respectively. Extinction coefficient and refractive index values were calculated using the Kramers-Kronig method. The z-scan technique was applied to estimate the NLO properties by a 532 nm Nd:YAG laser.
... Amongst the tested complexes, 76 indicated equipotent activity as reference drug ciprofloxacin against E. coli at 100 % concentration. [114] ...
Antibiotics are becoming gradually ineffective due to drug resistance, leading to greater difficulty in the treatment of infectious diseases. Therefore, the development of new chemical entities with different mechanisms of action is essential in the fight against resistant microorganisms. Various studies have shown that quinoline hydrazide/hydrazone derivatives possess several biological activities, such as antimalarial, antitubercular, anticancer, anti‐inflammatory, and antimicrobial. Among these activities, the antibacterial activity of quinoline hydrazide/hydrazone derivatives is noteworthy. The synthetic flexibility of the quinoline ring has led to the development of a wide range of structurally diverse quinoline hydrazide/hydrazone derivatives, which can act at various bacterial targets such as DNA gyrase, glucosamine‐6‐phosphate synthase, enoyl ACP reductase, and 3‐ketoacyl ACP reductase. This review emphasizes the antibacterial potential of various reported quinoline hydrazide/hydrazone derivatives based on substitution in the quinoline ring. The antibacterial activity of various metal‐quinoline hydrazide/hydrazone complexes is also discussed. The aim of this review is to assemble and scrutinize the latest reports in this promising area of drug development.
... Among them, many heterocyclic hydrazones represent biologically active drug molecules which have attracted attention of medicinal chemists due to their wide ranging pharmacological properties including iron scavenging and antitubercular activities [1][2][3][4][5][6]. The hydrazones have also been used as herbicides, insecticides, nematocides, redenticides, and plant growth regulators [5] as well as plasticizers and stabilizers for polymers [7,8]. Furthermore, some hydrazones are used as quantitative analytical reagents, especially in colorimetric and fluorimetric determination of metal ions [4][5][6]. ...
The recently developed efficient protocol combining implicit and explicit, accurate quantum mechanical modeling of the condensed state [Katsyuba et al., J. Chem. Phys. 155, 024507 (2021)] is used to describe...
... In analytical chemistry, hydrazones find the application by acting as multidentate ligands with metals (usually from the transition group) [8]. Hydrazones derived from the condensation of isonicotinic acid hydrazide with pyridine aldehydes have been found to show better antitubercular activity than isonicotinic acid hydrazide [9,10]. When transitional metals coordinated with hydrazones, they play a significant role in many catalytic reactions such as oxidation, asymmetric cyclopropanation, and polymerization [11]. ...
The transition metal complexes of hydrazones were synthesized by taking two metals, i.e., Cu (II) and Ni (II). The hydrazones were prepared by the hydrazides of three acids, i.e., oxalic acid, malonic acid, and thiomalic acid reacting with the known amount of different aldehydes. Fourier-transform infrared (FTIR) bands in the region of 380–370, 460–450, and 320–300 cm−1 confirm the formation of metal complexes with hydrazones. Synthesized hydrazones and their metal complexes were characterized through analytical techniques, i.e., FTIR, ultraviolet (UV)-visible, and elemental analysis, and the magnetic susceptibility was calculated by Gouy’s method. The magnetic moment of copper complexes was 1.77–2.05 B.M. and for nickel complexes was 3.04–4.50 B.M. The metal complexes of hydrazones were gave encouraging results.
... The ligand was coordinated with Co(II) ion with an amide manner. The separations of C6-N2 and C6-O1 bond respectively are 1.333(7) Å and 1.245(7) Å, these values are similar to that of coordinated hydrazone with an amide fashion [26][27][28]. The H atom in the phenolic group was eliminated in the course of complex generation. ...
A new mononuclear coordination compound based on Co(II), that is [Co(H2L)Cl2] (1), was formed through the reaction between CoCl2·4H2O and H2L in the methanol in which H2L is the tridentate ONO-donor hydrazone ligand [where H2L stands for (E)-Nʹ-(2-hydroxy-5-iodobenzylidene)isonicotinohydrazide]. The reaction between CoCl2·4H2O and H2L in the existence of NaN3 provides [Co2(HL)2(CH3OH)2Cl2]·CH3OH (2), a phenolate bridged binuclear coordination polymer containing Co(II). Their treatment effect of polycystic ovary syndrome was investigated and the relevant mechanism was discussed. At first, the inflammatory cytokines levels in plasma were examined through enzyme linked immunosorbent assay assay kit after specific treatment. Except for this, the nuclear factor kappa-B signaling pathway activation in the ovarian epithelial cells was determined through exploiting real time reverse transcription-polymerase chain reaction. The above experimental results show that compound 1 could be an outstanding candidate to perform polycystic ovary syndrome through adjusting the estrogen receptor expression.
... (90.31% calc.) for L1, 81.02% (80.96% calc.) for L2, and 90% (89.9% calc.) for L3. In the first step, these mass losses could be due to losses of the organic ligands as gases in the indicated temperature ranges; then, the next steps could correspond to the removal of the remaining organic part of the ligands [42]. Thermal analyses of the uranyl complexes indicated three decomposition steps that occurred in [UO 2 (L1) 2 Figure S8. ...
Three novel 2-aminopyrazine Schiff bases derived from salicylaldehyde derivatives and
their uranyl complexes were synthesized and characterized by elemental analysis, UV-vis, FTIR,
molar conductance, and thermal gravimetric analysis (TGA). The proposed structures were optimized
using density functional theory (DFT/B3LYP) and 6–311G �(d,p) basis sets. All uranyl complexes
are soluble in DMSO and have low molar conductance, which indicates that all the complexes are
nonelectrolytes. The DNA binding of those Schiff bases and their uranyl complexes was studied
using UV-vis spectroscopy, and screening of their ability to bind to calf thymus DNA (CT-DNA)
showed that the complexes interact with CT-DNA through an intercalation mode, for which the Kb
values ranged from 1 � 106 to 3.33 � 105 M1. The anticancer activities of the Schiff base ligands
and their uranyl complexes against two ovarian (Ovcar-3) and melanoma cell lines (M14) were
investigated, and the results indicated that uranyl complexes exhibit better results than the Schiff
base ligands. Molecular docking identified the distance, energy account, type, and position of links
contributing to the interactions between these complexes and two different cancer proteins (3W2S
and 2OPZ).
... In the IR spectra of the metal complexes, the appearance of the bands around 866-859 cm −1 referred to the v(H 2 O) stretching of coordinated water, 587-522 cm −1 referred to v(M-O), and 516-432 cm −1 referred to v(M-N) stretching vibrations [30]. The results on the IR spectra of the Schiff base and metal complexes showed that the prepared Schiff base ligand formed coordination bonds with the metal ions with the carboxyl group-O, azomethine-N, and hydroxyl group-O atoms [31]. ...
Schif bases are well-known compounds for having signifcant biological properties. In this study, a new Schif base ligand
and its metal complexes were synthesized, and their antioxidant and enzyme inhibitory activities were evaluated. The new
Schif base ligand was synthesized with the condensation reaction of 6-tert-butyl 3-ethyl 2-amino-4,5-dihydrothieno[2,3-c]
pyridine-3,6(7H)-dicarboxylate and 2-hydroxybenzaldehyde compounds. Fe(II), Co(II), and Ni(II) metal complexes of the
novel Schif base ligand were synthesized and characterized. The purity and molecular formula of the synthesized compounds
were identifed with elemental analysis, infrared, ultraviolet–visible, mass spectrophotometry, powder XRD, magnetic and
thermal measurements. The Schif base acted as a three dentate chelate. The analytical and spectroscopic data suggested
an octahedral geometry for the complexes. The in vitro antioxidant method studies elucidated a more efective antioxidant
character of the Schif base ligand than its metal complexes but a less efective antioxidant potential than the standard antioxidant compounds. The enzyme inhibition potentials of the synthesized compounds for AChE, BChE, and GST enzymes
were determined by in vitro enzyme activity methods. The Schif base ligand was discovered to be the best inhibitor for
the AChE and BChE with the values of 7.13±0.84 µM and 5.75±1.03 µM Ki
, respectively. Moreover, the Fe(II) complex
displayed the best Ki
value as 9.37±1.06 µM for the GST enzyme. Finally, molecular docking studies were carried out to
see the structural interactions of the compounds. The metal complexes demonstrated better binding afnities with the AChE,
... Schiff bases of aliphatic aldehydes are comparatively unstable and easily polymerizable than aromatic aldehyde [10,11]. Schiff base ligands have interesting ligation properties due to the presence of distinct coordination sites and these ligands are able to coordinate with many various metals and they easily form stable complexes [12,13]. Schiff base and its complexes have important biological application such as antimicrobial, antitumor, antioxidant, anti HIV, antiviral, antiallergenic and nematicidal and also play an essential role in agriculture, pharmaceutical and industrial chemistry [14][15][16][17]. ...
A series of metal complexes [Co(HL)2(H2O)2]Cl2.5H2O (A), [Cu(HL)2](CH3COO)2.2H2O (B), [Y(HL)2]Cl3.2H2O (C), [ZrO(HL)2H2O]Cl2.H2O (D), [La(HL)2(H2O)2]Cl3.5H2O (E) and [UO2(HL)2](CH3COO)2 (F) were prepared. The structures of the compounds in solid state were detected by micro analytical, Fourier transform IR, 1H NMR, UV-Vis, mass, X-ray diffraction spectra, molar conductivity, magnetic susceptibility measurements and TG/DTG analysis. The IR spectral data point out that the ligand behaves as tridentate in nature with Cu(II), Y(III), U(VI) and bidentate with Co(II), Zr(IV) and La(III) metal ions. The conductivity values showed that the complexes found as electrolytes and the XRD models of the complexes indicated crystalline nature. The thermodynamic parameters of compounds have been detected using Coats-Redfern and Horowitz-Metzeger methods at n = 1 and n ≠ 1 and values point out more ordered activated complex formation. The nematicidal efficacy of compounds was assessed. KEY WORDS: Schiff base, Spectroscopic analysis, Thermal analysis, XRD, Nematicidal Bull. Chem. Soc. Ethiop. 2021, 35(2), 381-397. DOI: https://dx.doi.org/10.4314/bcse.v35i2.12
... [19] Besides, the new bands in the ranges 598-592 cm −1 and 476-462 cm −1 demonstrated the coordination between the M-O and M-N, respectively. [20] 1 H and 13 C NMR spectral data ...
Cobalt(II) and copper(II) complexes of the (3-methyl-1-phenyl-4-[E-(1iazinyl-2-yl)1iazinyl]-1H-pyrazole-5-ol) ligand were obtained by the diazotization reaction of 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one with 2-amino pyridine. The synthesized compounds were confirmed by analytical, and spectroscopic analyses (like, UV-Visible, FT-IR, NMR, and mass spectroscopy). Calf thymus DNA interaction with metal complexes is inspected by UV-Visible spectra, viscosity measurements, and thermal denaturation techniques. The intrinsic binding constant (Kb) was found to be 1.17 × 10⁶ M⁻¹, and 0.98 × 10⁶ M⁻¹ for Co(II) and Cu(II) complexes respectively. The Cleavage of pUC-19 DNA was monitored by gel electrophoresis. The computerized in silico molecular dockage studies of the composites with the target receptor Glu-6p and results showed that the compounds are potent drugs for the target enzyme. Further, the optimized structure of the azo dye ligand was obtained by the density functional theory (DFT) by Gaussian09 program by the RB3LYP at 6–311 G (++, g, d, p) basis set. Furthermore, screened for the bacterial action in contradiction of pathogenic organism’s gram-negative Klebsiella pneumonia, gram-positive Bacillus subtills by a diffusion method.
Supplemental data for this article is available online at https://doi.org/10.1080/15257770.2021.1991373 .
... (90.31% calc.) for L1, 81.02% (80.96% calc.) for L2, and 90% (89.9% calc.) for L3. In the first step, these mass losses could be due to losses of the organic ligands as gases in the indicated temperature ranges; then, the next steps could correspond to the removal of the remaining organic part of the ligands [42]. Thermal analyses of the uranyl complexes indicated three decomposition steps that occurred in [UO 2 (L1) 2 Figure S8. ...
Three novel 2-aminopyrazine Schiff bases derived from salicylaldehyde derivatives and
their uranyl complexes were synthesized and characterized by elemental analysis, UV-vis, FTIR,
molar conductance, and thermal gravimetric analysis (TGA). The proposed structures were optimized
using density functional theory (DFT/B3LYP) and 6–311G ∗(d,p) basis sets. All uranyl complexes
are soluble in DMSO and have low molar conductance, which indicates that all the complexes are
nonelectrolytes. The DNA binding of those Schiff bases and their uranyl complexes was studied
using UV-vis spectroscopy, and screening of their ability to bind to calf thymus DNA (CT-DNA)
showed that the complexes interact with CT-DNA through an intercalation mode, for which the Kb
values ranged from 1 × 106
to 3.33 × 105 M−1
. The anticancer activities of the Schiff base ligands
and their uranyl complexes against two ovarian (Ovcar-3) and melanoma cell lines (M14) were
investigated, and the results indicated that uranyl complexes exhibit better results than the Schiff
base ligands. Molecular docking identified the distance, energy account, type, and position of links
contributing to the interactions between these complexes and two different cancer proteins (3W2S
and 2OPZ).
... The spectrum of the complex (C 1 ) was exhibited characteristic band of either lattice water appeared at (3395) cm -1 assigned to υ (OH) or coordinated appeared at (800-860) cm -1 and (3350-3450) cm -1 assigned to υ (H 2 O) of complexes (C 2 and C 3 ). 24 Azomethine group shifted to the lower frequency in the complexes appeared at (1540, 1545 and 1535) cm -1 for (C 1 -C 3 ) complexes respectively. 25 υ (C-O) group appeared at (1260, 1269 and 1258) cm -1 for (C 1 -C 3 ) complexes, respectively. ...
New complexes of some transition metal lions [Cr(III),Cu(II) and Zn(II))] with prepared ligand 2-(((4-(1-((4-bromo-2,6-dimethylphenyl)imino)ethyl)phenyl)imino)methyl)phenol were synthesized. The new complexes' structures were characterized by elemental microanalysis (CHN), Fourier transforms infrared (FTIR), ultraviolet-visible (UV-visible) spectra, thermal gravimetric analysis-differential thermal gravimetric, flame atomic absorption, molar conductivity, magnetic susceptibility measurement, and mass spectra. According to the obtained data, the probable coordination geometries of these complexes were suggested as octahedral. All complexes were found to be non-electrolyte.
... Moreover, Schiff base metal complexes are being used as biological models in understanding the structure of biomolecules and biological process. Instead, Schiff base metal complexes are also being explored as catalysts for organic reactions such as hydrogenation of olefins and carbonyl compounds, oxidation of organic compounds, complexing ability toward some toxic elements [11][12][13][14][15]. Schiff base metal complexes are used as growth inhibiting agents for most of microorganisms [5]. ...
Metal complexes of Cu(II), Co(II) and Cd(II) have been synthesized using two new Schiff base ligands, N,N'-bis(4-chlorobenzylidene)ethane-1,2-diamine (L 1) and N,N'-bis(3-nitrobenzylidene) ethane-1,2-diamine (L 2). The Schiff bases were prepared from the condensation reaction of ethylenediamine with benzaldehyde derivatives (4-chlorobenzaldehyde and 3-nitrobenzaldehyde). The complexes have been characterized by elemental analysis, conductivity measurements, UV-visible, FT-IR and magnetic susceptibility measurements. The magnetic susceptibility measurements and UV-visible spectral data revealed that the geometry of Cu(II) and Co(II) complexes are square planar, whereas the geometry of Cd(II) complex is tetrahedral. The molar conductance data showed that the complexes are non-electrolytic in nature. The complexes were screened for antibacterial activities against four human pathogenic bacteria viz. Escherichia coli, Shigella boydii, Bacillus cereus and Staphylococcus aureus. The results indicate that Cd(II) complex of ligand (L 1) has higher antibacterial activity compared to the free ligands, but less than the standard drug, kanamycine. This suggests that the metal ion plays an important role in the antibacterial activities of complexes.
... Moreover, Schiff base metal complexes are being used as biological models in understanding the structure of biomolecules and biological process. Instead, Schiff base metal complexes are also being explored as catalysts for organic reactions such as hydrogenation of olefins and carbonyl compounds, oxidation of organic compounds, complexing ability toward some toxic elements [11][12][13][14][15]. Schiff base metal complexes are used as growth inhibiting agents for most of microorganisms [5]. ...
Metal complexes of Cu(II), Co(II) and Cd(II) have been synthesized using two new Schiff base ligands, N,N'-bis(4-chlorobenzylidene)ethane-1,2-diamine (L1) and N,N'-bis(3-nitrobenzylidene) ethane-1,2-diamine (L2). The Schiff bases were prepared from the condensation reaction of ethylenediamine with benzaldehyde derivatives (4-chlorobenzaldehyde and 3-nitrobenzaldehyde). The complexes have been characterized by elemental analysis, conductivity measurements, UV-visible, FT-IR and magnetic susceptibility measurements. The magnetic susceptibility measurements and UV-visible spectral data revealed that the geometry of Cu(II) and Co(II) complexes are square planar, whereas the geometry of Cd(II) complex is tetrahedral. The molar conductance data showed that the complexes are non-electrolytic in nature. The complexes were screened for antibacterial activities against four human pathogenic bacteria viz. Escherichia coli, Shigella boydii, Bacillus cereus and Staphylococcus aureus. The results indicate that Cd(II) complex of ligand (L1) has higher antibacterial activity compared to the free ligands, but less than the standard drug, kanamycine. This suggests that the metal ion plays an important role in the antibacterial activities of complexes.
... The magnetic susceptibility value for the Ni(II) complex at room temperature is 2.69 BM, which confirms two unpaired electrons of a mononuclear octahedral Ni(II) complex [39]. The magnetic moments for the Cu(II) complexes are the 1.63 and 1.65 BM, respectively. ...
In this work, mixed ligand complexes of Co(II) Ni(II) and Cu(II) were synthesized using quercetin and diimine (1,10-phenanthroline or 2,2′-bipyiridine) ligands. The obtained Ni(II) and Co(II) complexes are new and the Cu(II) complexes are synthesized by different method from the literature. The characterization of complexes was performed by elemental analysis, thermogravimetric analysis, ESI–MS, UV–visible and infrared spectral analyses, magnetic susceptibility and molar conductivity measurements. It was found that quercetin, diimine and metal(II) ion form 1:1:1 complexes. Resulting data supported octahedral geometry for Ni(II) and Co(II) complexes and square pyramidal geometry for Cu(II) complexes. The proposed compositions are [Co(queH-1)Cl(phen)(H2O)]∙2H2O (1, queH = quercetin, phen = 1,10-phenanthroline), [Ni(queH-1)Cl(phen)(H2O)]∙2H2O (2), [Cu(queH-1)Cl(phen)]∙2.5H2O (3) and [Cu(queH-1)Cl(bpy)]∙2H2O (4, bpy = 2,2′-bipyiridine). Antioxidant capacity and total phenolic content of complexes measured by Folin–Ciocalteu and ABTS methods. Anti-cancer effect of these compounds were tested against different cancer cells (A549, PC-3, HeLa and MCF-7). Apoptosis identified by the fluorescence imaging, caspase cleaved cytokeratin-18 and flow cytometry analysis (annexin V, caspase 3/7, mitochondria membrane potential and oxidative stress). As a result, Cu(II) complexes are more effective than the other compounds and Complex 3 is a promising anti-cancer compound against breast cancer MCF-7 and MDA-MB-231 cells (IC50 values are 2.4 and 5.4 µM for 48 h, respectively). Flow cytometry analysis exhibited that Complex 3 caused apoptosis in MCF-7 cells. These results support that Complex 3 has anticancer activity and can be a potential anticancer agent especially in breast cancer.
... Scheme 1 Schematic route for synthesis of precursors (PC-I-III), ligands (L 1-6 ) and copper(II) complexes (126) 1996; Khedr et al. 2005;El-Behery and El-Twigry 2007;Guveli and Ulkuseven 2011). ...
A series of N-benzoylated mononuclear copper(II) complexes of the type [Cu(L¹⁻⁶)Cl2] (1–6), where L¹= ethyl 4-benzoyl-5-methyl-7-aryl-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylate, L²= ethyl 4-(4-nitrobenzoyl)-5-methyl-7-aryl-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylate, L³ = ethyl 4-benzoyl-5-methyl-7-(4-methoxyphenyl)-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylate, L⁴ = ethyl 4-(4-nitrobenzoyl)-5-methyl-7-(4-methoxyphenyl)-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylate, L⁵ = ethyl 4-benzoyl-5-methyl-7-(4-chlorophenyl)-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylate and L⁶ = ethyl 4-(4-nitrobenzoyl)-5-methyl-7-(4-chlorophenyl)-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylate have been synthesized and characterized by spectral methods. Electron paramagnetic resonance spectra of complexes show four lines, characteristic of square planar geometry. The binding studies of the complexes with calf thymus DNA (CT–DNA) revealed groove mode of binding, which were further supported by molecular docking studies. Gel electrophoresis experiments demonstrated the ability of the complexes to cleave plasmid DNA in the absence of activators. Further, the cytotoxicity activity of the complexes were examined on three cancerous cell lines (lung (A549), cervical (HeLa) and colon (HCT-15)), and on two normal cells (human embryonic kidney (HEK) and peripheral blood mononuclear cells (PBMC)) by MTT assay.
... The Ni +2 complex revealed three sharp bands at around 11919cm -1 , 15552cm -1 and 25189cm -1 which have been assigned to the 3 A 2 g → 3 T 2 g; 3 A 2 g → 3 T 1 g (F) and 3 A 2 g → 3 T 1 g (P) transitions respectively indicating octahedral geometry. Ni +2 complex showed the magnetic moment value in the range of 2.96-3.28 which is within the range of 3.19BM suggesting consistency with their octahedral environment (El-Behery et al. 2007). ...
New series of Co+2, Ni+2, Cu+2 and Zn+2 complexes have been synthesized using a bio-active hydrazone compound 4-hydroxybenzaldehyde-N-(5-chloro-2-oxo-1,2-dihydro-3H-indol-3-ylidene), abbreviated as [HL]. Complexes were characterized using elemental analysis, FT-IR, UV-visible spectroscopy conductivity and magnetic susceptibility measurements. Results showed that the bi-dentate [HL] coordinated in a square planner manner with Cu+2 while for the rest of the M+2 ions, it coordinated in a octahedral fashion. Free ligand and its metal complexes were also studied for their antioxidant potential by employing two methods i.e. DPPH radical scavenging and reducing power assay. It was observed that the metal complexes were considerably more potent free radical scavenger and had better reducing abilities compared to the free ligand, furthermore, for both in vitro assays, metal complexes turned out to be better DPPH scavengers and had better reducing abilities than the standards used during biological assays.
... The hydrazone ligand and metal complexes were screened for their anti-bacterial activity against gram-negative (E. coli), gram-positive (S. aureus) and antifungal activity against C. albicans [78] (Scheme 66). ...
Heterocyclic compounds are well known for their different biological activity. The heterocyclic analogs are the building blocks for synthesis of the pharmaceutical active compounds in the organic chemistry. These derivatives show various type of biological activity like anticancer, antiinflammatory, anti-microbial, anti-convulsant, anti-malarial, anti-hypertensive, etc. From the last decade research showed that the quinoline analogs plays a vital role in the development of newer medicinal active compounds for treating various type of disease. Quinoline reported for their antiviral, anticancer, anti-microbial and anti-inflammatory activity. This review will summarize the various synthetic approaches for synthesis of quinoline derivatives and to check their biological activity. Derivatives of quinoline moiety plays very important role in the development of various types of newer drugs and it can be used as lead compounds for future investigation in the field of drug discovery process.
... The reaction mixture was refluxed for 2-4 h to ensure the complete precipitation of the formed complexes. The precipitated solid complexes (1)(2)(3)(4)(5) were filtered off, washed several times with methanol to remove any excess of the unreacted starting materials. Finally, the complexes were washed with ether and dried in vacuum desiccators over anhydrous CaCl 2 . ...
The reaction of the isatinic quinolyl hydrazone (H 2 L) with Fe(III), Co(II), Ni(II), Cu(II) and VO(II) ions in presence of LiOH afforded mononuclear as well as dimeric chelates. Due to the presence of LiOH, the ligand used its lactim form in all complexes and showed a variety of modes of bonding viz. (NNO) 2-, (NO)-with or without O-bridging per each metal ion. The mode of bonding and basicity of the ligand depend mainly on the type of the metal ion. The obtained Co(II), Ni(II) and Cu(II)-complexes have the square planar geometry, whereas, Fe(III) and VO(II)-complexes have the octahedral geometry. LiOH behaves as a coligand in case of Fe(III)-complex whereas, it behaves as a deprotonating agent in case of the rest of complexes. The investigated complexes exhibited low to moderate activities against S. aureus bacteria. For clarifying their proposed structures, the complexes were subjected to elemental analysis and spectral studies.
... Since the quinoline ring system is acknowledged, it possesses complex iron properties [42], we envisioned to combine quinolines with different secondary amines to obtain potent antimalarial [43]. Our structural design efforts were mainly dictated by the hypothesis of anti P. falciparum activity might be directly related to the ability of both to bind intracellular iron and to form redox-active iron complexes that generate cytotoxic ligand centered radical species. ...
Objective: Synthesis, antiplasmodial and absorption, distribution, metabolism, excretion and toxicity (ADMET) studies of 4-methylamino-2-phenylquinoline analogs. Methods: The synthesis of 4-methylamino-2-phenylquinoline analogs 7(a-j) by reacting substituted 4-(chloromethyl)-2-phenylquinoline 6(a-c) with secondary amines to explore their antimalarial property against P. falciparum RKL-2 strain and in silico absorption, distribution, metabolism, excretion and toxicity (ADMET) properties using ACD/I-Lab 2.0. The synthesized structures were confirmed by IR, NMR and Mass spectral analysis. Results: The results revealed that at 100 μg/ml, compounds 7a, 7d and 7i were found to be potent with percentage inhibition of 88.0±1.1, 79.1±1.1, 90.2±0.1, respectively. The compounds 7b, 7e, 7f and 7h were moderately active with 59.9±1.2, 48.5±2.0, 35.2±1.1 and 52.0±0.3 and the remaining compounds 7c, 7g and 7j exhibited mild activity 32.2±1.2, 36.8±3.0 and 28.7±2.0. The absorption, distribution, metabolism, excretion and toxicity (ADMET) studies of title compounds were analyzed and found to be obeying the Lipinski rule of five and are non-toxic. Conclusion: The C4 of quinoline ring with morpholine 7a, piperidine 7d and imidazole 7i substitutions were promising enough to be taken as lead molecules in the drug discovery of new antimalarial. The in silico absorption, distribution, metabolism, excretion and toxicity (ADMET) studies of the molecules were found to be obeying the Lipinski rule of five good drug likeliness.
... The hydrazone Schiff bases are handy ligands in coordination chemistry, with easy preparation, diversity and structural variation. In recent years, metal complexes of Schiff bases have attracted considerable attention due to their remarkable biological activity, such as antifungal [1,2], antibacterial [3][4][5], and antitumor [6,7]. It has been shown that the Schiff base complexes derived from o-hydroxyacetophenone/salicylaldehyde and its derivatives with hydrazide have interesting biological activity. ...
Mononuclear hydrazone Schiff base complexes [CrL(Cl)(H2O)2], [MnL(OAc)(H2O)], [FeL(Cl)(H2O)2] and [Zr(OH)2L(CH3OH)], where L is 2,4-dihydroxy-5-nitroacetophenone-2-chlorobenzoylhydrazone (H2L), has been
synthesized and structurally characterized by elemental analysis, reflectance & infrared spectroscopy, magnetic
susceptibility measurements and thermogravimetric study. The physico-chemical studies support that ligand act as dibasic tridentate ONO donor towards all the metal ion forming octahedral geometrical arrangement around Cr(III), Fe(III) and Zr (IV) ion whereas square pyramidal geometry around Mn(III) ion.
... Schiff base complexes have extensive importance as radiotracers [1], biologically active reagents [2][3][4][5], catalysts for oxidation [6,7], epoxidation [8], polymerization [9] and decomposition reactions [10,11]. On the other hand, considerable attention has been paid over the last few decades in establishing substitution reactions, dissociation, hydroxide attack, and reaction with cyanide of low-spin tris-ligand Fe(II) complexes. ...
The reactivity of few novel high spin Fe(II) complexes of Schiff base ligands derived from 2-hydroxynaphthaldehyde and some variety of amino acids with OH- ion has been examined in aqueous mixture at temperature in the range 10–40 Co. Based on the kinetic investigations, the rate law and a plausible mechanism were proposed and discussed. The general rate equation was suggested as follows: rate = kobs [Complex], where kobs.= k1 + k2 [OH-]. Base catalyzed hydrolysis kinetics measurements imply pseudo-first order doubly stage rates due the presence of merand fac-isomers. The observed rate constants kobs are correlated the effect of substituent R in the structure of the ligands. From the effect of temperature on the rate; various thermodynamic parameters have been evaluated. The evaluated rate constants and activation parameters are in a good agreement with the stability constants of the investigated complexes.
... Metal complexes of bidentate Schiff bases have been extensively studied [10,11], because such ligands can bind with one, two, or more metal centers involving various coordination modes and allow synthesis of homo-and heteronuclear metal complexes with interesting stereochemistry [12,13]. A number of papers [14,15] highlight the flexible nature of bidentate ligands, their analytical, and biological properties. Recently, we have studied [16][17][18] various Schiff bases and their metal (II) complexes. ...
Five new nickel (II) complexes, namely, [Ni(L
1
)
2
](ClO
4
)
2
(
1
); [Ni(L
2
)
2
](ClO
4
)
2
(
2
); [Ni(L
3
)
2
](ClO
4
)
2
(
3
); [Ni(L
4
)
2
](ClO
4
)
2
(
4
); [Ni(L
5
)
2
](ClO
4
)
2
(
5
), where L
1
= benzoylhydrazide; L
2
= N-[(1)-1-(2-methylphenyl)ethylidene]benzohydrazide; L
3
=N-[(1)-1-(4-methylphenyl)ethylidene]benzohydrazide; L
4
=N-[(1)-1-(2-methoxyphenyl)ethylidene]benzohydrazide; L
5
= N-[(1)-1-(4-methoxy-phenyl)ethylidene]benzohydrazide, have been synthesized and characterized by various physicochemical and spectroscopic techniques. The synthesized complexes are stable powders, insoluble in common organic solvents such as ethanol, benzene, carbon tetrachloride, chloroform, and diethyl ether, and are nonelectrolytes. The magnetic and spectroscopic data indicate a distorted square planar geometry for all complexes. The superoxide dismutase activity of these complexes has been measured and discussed. Antibacterial and antifungal properties of these complexes were also tested.
A novel series of tetraaza macrocyclic complexes of biological importance was synthesized by “in situ” template reaction between triethylenetetramine and dibenzoylmethane in the presence of trivalent Fe and Cr metal salts in 1:1:1 molar ratio. These complexes are represented by molecular formula [M(C[Formula: see text]H[Formula: see text]N[Formula: see text]X]X 2 ; [Formula: see text](III) and Cr(III); [Formula: see text], NO[Formula: see text], −OAc; C[Formula: see text]H[Formula: see text]N[Formula: see text] ligand. The reported complexes were characterized by using various physicochemical and spectroscopic techniques including elemental analyses, molar conductance, thermo-gravimetric analysis, FTIR, UV–Visible and mass spectral studies. The results obtained from analytical techniques and spectroscopic techniques together suggested the complexes have a square pyramidal geometry. Various computational studies were performed including molecular docking and modeling. Further, macrocyclic complexes were also screened for their “in vitro” antimicrobial activity against selected bacterial and fungal strains. The antioxidant activity of these complexes was also evaluated. Some of the complexes were found to possess remarkable antimicrobial activity and antioxidant activity. However, complex [Fe(C[Formula: see text]H[Formula: see text]N[Formula: see text](NO[Formula: see text]](NO[Formula: see text] was found to be most potent against selected bacterial and fungal strains. On the other hand, complex [Cr(C[Formula: see text]H[Formula: see text]N[Formula: see text](NO[Formula: see text]](NO[Formula: see text] was found to show best antioxidant activity with lowest value of IC[Formula: see text].
Since the last decade, research on quinoline Schiff base metal complexes has risen substantially due to their versatile applications across many significant fields. Schiff bases are also known as azomethines, aldimines, and imines. Quinoline Schiff base-derived metal complexes are intriguing to study topics. These complexes are employed in biological, analytical, and catalytic fields. Researchers have found that Schiff bases are more biologically active when coordinated with metal ions. Research in the biological sciences has shown that heterocyclic compounds like quinoline and its derivatives are important. Because of their broad spectrum of activity, quinoline derivatives have been discovered to be effective therapeutic agents for various disorders. Even though various classical synthetic pathways mentioned in the literature are still in use, there is an urgent need for a new, more effective method that is safer for the environment, has a higher yield, generates less hazardous waste, and is easier to use. This highlights the critical need for a safe, eco-friendly approach to quinoline scaffold synthesis. This review focuses exclusively on Schiff base metal complexes derived from quinoline, fabricated and studied in the past ten years, and having anticancer, antibacterial, antifungal, antioxidant, antidiabetic, antiproliferative, DNA-intercalation, and cytotoxic activities.
FTIR and FT-Raman of the crystallized structure of 2-{3-(4-Chlorophenyl)-5-[4-(propan-2-yl) phenyl]-4, 5-dihydro-1H-pyrazol-1-yl}-1, 3-thiazol-4(5H)-one has been recorded and vibrational contour of the compound was investigated with the succor of density functional theory. Based on the calculated frequencies, the vibrational assignments are found to be good with experimental spectra. The complete vibrational assignments are executed by potential energy distributions (PED) of the vibrational modes. The ground state molecular structure of the compound has been scrutinized by hybrid functional B3LYP with 6-31 G/6-311G basis sets. Molecular geometrical parameters such as bond length, bond angles were calculated with the same method. The energy bandgap of the title molecule was found using HOMO and LUMO calculations. It is evident that the negative charge covers the C = O group and the positive region covers the phenyl rings. Noncovalent interactions like Van der Waals and hydrogen interactions were described from electron delocalization function and these interactions in the title molecule has carried out from reduced density gradient using Multiwfn. Further extended our study to find the eminent hydrophobicity of the compound, binding ability with protein Parathyroid hormone secretion stimulant and neuropeptide protein 1HFF, 3FFD, 3C4M, and 2E7A was predicted through molecular docking analysis and that have good biological activities.
Metal complexes of two general formulae [M(L)(Cl)(H2O)2] [M = Mn(II), Co(II), Ni(II) and Cu(II)] and [M(L)(H2O)] [M = Zn(II) and Cd(II)] with pyrazine-2-carbohydrazone of 2-hydroxy-5-methylacetophenone (H2L) are synthesized and characterized by microanalytical, thermal, magnetic susceptibility measurement, spectroscopic (IR, ¹H NMR, ¹³C NMR), mass, molar conductance, X- ray powder diffraction, ESR and SEM studies. While the molar conductance measurements in DMSO indicated their non-electrolytic nature, the spectroscopic studies confirmed a tridentate ONO donor behaviour of the ligand towards the central metal ion. Based on the physico-chemical studies monomeric octahedral geometry around Mn(II), Co(II), Ni(II) and Cu(II) ions (i.e. for the first series of complexes) whereas tetrahedral to Zn(II) and Cd(II) ions (i.e. for the second series of complexes) are suggested. Based on the thermal behavior of the complexes, various kinetic and thermodynamic parameters were evaluated using Coats-Redfern method. The ligand and its metal complexes were screened for in vitro antibacterial and antifungal activity against Gram +ve S. aureus, B. subtilis and Gram –ve E. coli and S. typhi. and fungal strains, C. albicans and A. niger. The observed data infer promising biological activity of some of these complexes compared the parent ligand against all bacterial and fungal species.
Two Schiff base ligands namely bis-2-((1E)-((Z)-2-(1,2-diphenylethylideneamino) phenylimino)methyl)phenol (L1) and bis-2-((1E)-((E)-2-(1-phenylethylideneamino)phenylimino) methyl)phenol (L2) were synthesized by tailored reaction of o-phenylenediamine with o-hydroxybenzaldehyde and 2-hydroxy-1,2-diphenylethanone/o-hydroxyacetophenone. The reaction of these ligands with Fe(III), Co(II), and Ni(II) salts yielded six complexes. Ligands and their metal derivatives have been characterized by elemental analysis, molar conductance, magnetic susceptibility, FT-IR, UV–Vis, ESI-mass, ¹H NMR, ¹³C NMR and EPR analysis. Using Gaussian 09 molecular modelling, bond lengths, bond angles and Mulliken charge were also evaluated. In addition to this study of HOMO and LUMO molecular orbital have been performed. The FT-IR spectra have suggested that ligand is coordinated with metal through azomethine-N and phenolic-O. Experimental and theoretical IR and NMR spectrum of ligand L1 and complex 2 exhibits quite good correlation. ESR spectrum of complex 2 at LNT suggests octahedral geometry around Co(II). Complexes were studied for their oxygen-binding activity and displayed significant oxygenation reaction. The thermodynamic parameters such were also calculated. The compounds were screened for antibacterial activity against gram-negative bacteria Escherichia coli and compared with Amoxicillin. Complexes have exhibited significant antibacterial activity. The corrosion inhibition effect of ligands and complexes on mild steel in acidic medium was studied for 24, 48 and 72 h using weight loss measurement.
In the present investigation, the bioactive azo-dye ligand 1,5-dimethyl-4-[(3-methyl-5-oxo-1-phenyl-4,5-dihydro-1H-pyrazol-4-yl)diazenyl]-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (L) and its transition metal complexes have been synthesized and characterized by various physical and spectroscopic techniques to elucidate their geometrical structures. The molar conductivity measurements confirmed the non-electrolytic nature of the complexes. EPR spectroscopy indicated that the metal complexes are monomeric in nature and exhibited octahedral geometry. The redox behavior of the copper complex was studied by the cyclic voltammetric technique in DMF solution and the complex showed well-established redox behavior at a scan rate of 0.05 V s⁻¹. The antimicrobial activity of the ligand and its metal complexes were screened against Escherichia coli, Bacillus subtilis, Aspergillus niger, and Candida albicans, and the results indicated increased activity after coordination of the ligand to the metal ions. The metal complexes exhibited enhanced antitubercular activity after chelation against M. tuberculosis. The DNA-binding experiments showed that the ligand and its metal complexes showed effective binding properties through intercalative mode against CT-DNA. All the synthesized molecules showed partial cleavage of supercoiled plasmid pUC18 DNA.
Pillar[5]arene-decorated quartz slides for the direct detection of linear amines and diamines are now available.
The resulted complexes produced between Fe (III) and Co (II) with biological molecules like amino acids play an important role in human life. They can be used as bioactive compounds as well as in industries. Fe (III) and Co (II) complexes are synthesized with Alanine amino acid. The complexes were characterized by X-ray diffraction, magnetic suscetivility, elemental analysis (AAS), molar conductance, melting point, infrared and uv-visible spectrophotometry analyses. The elemental analyses were used to determine the chelation ratio, 1:3(metal: ligands) for iron (III) Alanine and 1:2 ratio for cobalt (II) Alanine. The molar conductivity of the complexes show that the complexes are not electrolytic in nature. The x-ray data suggest monoclinic crystal system for all the complexes with the exception of Co-alanine, which is hexagonal. The magnetic susceptivility and electronic spectra suggest the complexes are high spin with octahedral geometry.The complexes show enhance activity in comparable to the amino acid.
A novel azo dye ligand, namely 1-[(5-mercapto-1H-1,2,4-triazole-3-yl)diazenyl]naphthalen-2-ol (HL), was synthesized. Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺ and UO2²⁺ complexes were also prepared by the treatment of HL with Mn(CH3COO)2⋅4H2O, Co(CH3COO)2⋅4H2O, Ni(CH3COO)2⋅4H2O, Cu(CH3COO)2⋅H2O, CuCl2⋅2H2O, Cu(NO3)2⋅6H2O and UO2(NO3)2⋅6H2O. The structures of these metal chelates were confirmed using elemental, spectral, magnetic moment, molar conductance and thermal analyses. The analytical data confirmed the formation of the chelates in 1:1 (metal-to-ligand) ratio having the formula [ML(H2O)X]Y⋅H2O, where M is Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺ or UO2²⁺; X is Cl⁻, NO3⁻ or CH3COO⁻; and Y is H2O. The azo compound acts in a monobasic bidentate manner via the nitrogen and oxygen atoms of azo and hydroxyl groups, respectively. All complexes were found to have tetrahedral structures, except the UO2²⁺ complex that showed octahedral geometry. The mode of interaction between the synthesized complexes and calf thymus DNA was explored by the aid of absorption spectroscopy and viscosity measurements. The azo dye and its chelates were evaluated against the growth of various bacterial and fungal strains (Escherichia coli, Staphylococcus aureus, Aspergillus flavus and Candida albicans) with insight gained into the effect of type of metal centre, type of coordinated anion and position of the metal in the periodic table on the activity of the complexes. The geometric structure of the complexes was optimized using molecular modelling. The in vitro cytotoxicity of the synthesized compounds was tested against HEPG2 cell line.
Newly synthesized nonlinear optical material is ethyl4-(3-(1,3-dimethyl-1H-pyrazole-5-carboxamido)phenyl)-1,2,3,4-tetrahydro-6-methyl-2-oxopyrimidine-5-carboxylate (DMPC). It has been characterized experimentally by FT-IR, FT-Raman, ¹H and ¹³C-NMR spectrum and theoretically by DFT method using B3LYP/6-31G(d,p) level of theory. A detailed interpretation of the vibrational spectrum was comparable with theoretical wavenumber using single scaling factor. The intra-molecular charge transfers occurring in the molecule have been analyzed by donor-acceptor interaction from natural bonding orbital analysis. The nonlinear optical activity of the compounds has been calculated, and found that the molecule is a good candidate of nonlinear material. The optical response and conduction nature of the title molecule have band gap of frontier edges were calculated by TD-DFT calculation and these results studied with UV-Visible spectrum. Especially the π-π* bonding interactions were interested to study conjugative property of the molecule. Moreover, molecular electrostatic potential surface of DMPC are useful in investigating the stability and reactivity of the molecule
In this study, feasibility of modified multi walled carbon nanotubes for removal of trace amounts of Uranium is studied. Multi walled carbon nanotubes were oxidized with HNO3 and then modified with loading 1-(2-pyridylazo)-2-naphtol. The effects of various parameters like pH, contact time, and other factors influenced on removal efficiency of uranium on adsorbent have been studied. Results showed that the method is simple, fast and environmental friendly and it is unaffected by the other ions present in the natural waters. Equilibrium isotherm studies were used to evaluate the maximum sorption capacity of MMWCNTs and experimental. Results showed this to be around 118 mg g-1. The Freundlich and Langmuir models have been applied and the data correlate well with Langmuir model and that the sorption is chemical in nature. Thermodynamic parameters showed the exothermic heat of adsorption and the feasibility of the process. This method is very applicable for removal of uranium from water.
Fifteen new complexes of transition metals were designed using three Schiff base ligands and aldol condensation of 2,3-diaminopyridine with 5-R-2-hydroxybenzaldehyde (R = F, Cl, Br) in the 1:2 molar ratio. The tetradentate ligands N,N′-bis(5-R-2-hydroxybenzaldehyde) pyridine were acquired with the common formula H2[(5-R-sal)2py] and characterized by IR, UV–Vis spectra, 1H-NMR and elemental analysis. These ligands produce 1:1 complexes M[(5-R-sal)2py] with Fe(III), Ni(II), Co(III), V(IV) and U(VI) metal ions. The electronic property and nature of complexes were identified by IR, UV–Vis spectra, elemental analysis, X-ray crystallography and cyclic voltammetric methods. The catalytic activity of complexes for epoxidation of styrene with UHP as primary oxidant at minimal temperature (10 °C) has been planned. The spectral data of the ligands and their complexes are deliberate in connection with the structural changes which happen due to complex preparation. The electrochemical outcome has good conformability with what suggested for electronic interaction among metal center and ligand by the UV–Vis and IR measurements.
Some new di and tri-organosilicon complexes of type R2Si(L1)Cl, R3Si(L1), and R2Si(L2)/R2Si(L3) (R = Me, Et, Bu, and Ph; L1 = 4-hydroxy-6-methyl-3-[1-(quinolin-8-ylimino)ethyl]pyran-2-one, L2 = 3-[1-(2-aminophenylimino)ethyl]-4-hydroxy-6-methylpyran-2-one, and L3 = 3-[1-(2-amino-4-chlorophenylimino)ethyl]-4-hydroxy-6-methylpyran-2-one) were synthesized from Schiff base ligands derived from 8-aminoquinoline/o-phenylenediamine/4-chloro-o-phenylenediamine with dehydroacetic acid. All the compounds were characterized with the help of molar conductance measurements, elemental analyses, UV–Vis, IR, 1H, 13C, 29Si NMR, and mass spectroscopy. On the basis of all these studies, penta-coordinated environment around central silicon atom in 1:1 molar ratio was proposed. The ligands and their organosilicon complexes were tested in vitro for antibacterial activity against Gram-positive bacteria viz. Staphylococcus aureus, Bacillus subtilis as well as Gram-negative bacteria viz. Escherichia coli and antifungal activity against Aspergillus niger. Antimicrobial activity results indicated that biological activity of ligands was enhanced on complexation with organosilicon group and phenyl derivatives were found to be more effective antimicrobial agents as compared to other complexes. Further, docking simulation of four compounds against E. coli topoisomerase II DNA gyrase B were carried out.
Graphical abstract
Complexes of CoII, NiII, CuII, ZnII and CdII with trifunctional Schiff base derived from 2,4-dihydroxyacetophenone and S-benzyl-dithiocarbazate have been synthesised and characterised by elemental analysis, ir and electronic spectra, magnetic and thermal studies. Kinetic and thermodynamic parameters have been estimated and DC electrical conductivity has been measured (393-520 K).
The reactions of ruthenium(II) complexes, [RuHCl(CO)(PPh3)2(B)] [B = PPh3, pyridine (py) or piperidine (pip)], with bidentate Schiff base ligands derived by condensing salicylaldehyde with aniline, o-, m- or p-toluidine have been carried out. The products were characterised by analytical, i.r., electronic, 1H-n.m.r. and 31P-n.m.r. spectral studies and are formulated as [RuCl(CO)(L)(PPh3)(B)] (L = Schiff base anion; B = PPh3, py or pip). An octahedral structure has been tentatively proposed for the new complexes. The Schiff bases and the new complexes were tested in vitro to evaluate their activity against the fungus Aspergillus flavus.
Stable, crystalline complexes containing the five-coordinate [CoL2X]+ species, where X = Cl, Br, or I and L is one of the bidentate ligands diphenyl(o-methylthiophenyl)phosphine (I, SP), diphenyl(o-methylselenophenyl)phosphine (II, SeP), or diphenyl(o-diphenylarsinophenyl)phosphine (III, AP), have been isolated and characterized by magnetism and conductivity measurements, electronic and infrared spectra, and elemental analyses. All of the complexes are deep red and possess one unpaired electron (μeff = 2.1-2.5 BM). The electronic spectra exhibit three distinct bands below 22,000 cm-1 which may be assigned to ligand-field transitions.
Synthetic and
characterization studies of manganese(11) complexes with
tetrahydro-l,4-thiazin-3-one (tht) and
thiazolidine-2-thione (ttz) are reported. The methods
used for the characterization of the compounds include elementary analyses,
molar conductances, magnetic moments and electronic and
infrared spectroscopy. Assignments for the metal-ligand modes have also been
made; the tht derivatives are coordinated through the
oxygen atom, while the ttz derivatives are
nitrogen-bonded in all the complexes. By use of infrared spectroscopy it has
been possible distinguish whether or not the polyanions
present in these derivatives are coordinated to the metal ion or are present as
free ions.The wavelengths of the
principal absorption peaks have been accounted for quantitatively in terms of
the crystal field theory. The values of B and C obtained are significantly
lower than the corresponding value for the free gaseous ion.
A series of biologically active complexes of cobalt(II), copper(II) and nickel(II) with nicotinoylhydrazine derived compounds having the same metal ion but different anions, such as sulphate, nitrate, oxalate and acetate, have been synthesised and characterised on the basis of their physical, analytical and spectral data. In order to understand the possible role of anions on the antibacterial properties, these synthesised compounds and their metal complexes with various anions have been screened against the bacterial species Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. These title studies have indicated a decisive role of anions in increasing the antibacterial properties.
The new ligands 1,4-diformylbenzene bishydrazone (DFBH) and 1,4-diacetylbenzene bishydrazone (DABH) have been prepared. DFBH forms complexes with transition metal(II) ions of types MX2(DFBH) (M = Co, Ni, Mn, Zn or Cd, X = Cl; M = Co or Ni, X = SCN; M = Ni, X = Br) and MX2(DFBH)2 (M = Co, Ni, Mn, Zn, Cd or Hg, X = Cl; M = Ni or Mn, X = Br). DABH forms complexes of types MX2(DABH)2 (M = Co, Ni or Zn, X = Cl or Br; M = Co or Ni, X = Cl, Br or SCN) and MX2(DABH)3 (M = Co, X = Br or SCN; N = Ni X = Cl or SCN; M = Zn, X = Cl, Br or SCN). Electronic spectra, magnetic moments and IR spectra have been used to deduce probable structures of the complexes. All contain six co-ordinated metals in high-spin configurations except ZnCl2(DFBH) and possibly CdCl2(DFBH) which are tetrahedral. The reactions between cobalt(II) halides and DABH in acetone yield the tetrahedral complexes CoX2 (DABAZ), where DABAZ = the acetone azine of 1,4-diacetylbenzene hydrazone.
Cu(II) complexes with aroyl hydrazones have been prepared in ethanol medium and characterised by elemental analysis. They have 1:1 stoichiometry. I. R. results show that the hydrazones exist in the enol form in the complexes. These Cu(II) complexes show subnormal magnetic moments and the electronic spectra agree with the square planar configuration. In view of the magnetic and electronic spectral evidence, the dimeric square planar configuration is suggested in which CuCu interaction exists.
The detailed synthesis is reported for a series of bi- and tri- nuclear complexes formed by using the donor properties of the two cis-oxygen atoms in metal (M) complexes of tetradentate Shiff bases (TSB) derived from salicylaldehyde or o-hydroxyacetophenone. The “complex ligands” [MTSB, M Cu(II), NiU(II) or Zn(II)] readily react with metal halides M′X2[M′ Cu(II) or Zn(II)] or metal perchlorates M′(ClO4)n [M′ Cu(II), Ni(II), Fe(II), Al(III), Mg(II), Ca(II), Sr(II), Ba(II), Na(I), or Ag(I) to form the complexes of the general types [MTSB) M′X2] and M′(MTSB)2(ClO4)n, many of which are hydrated. The low magnetic moments of a number of the compounds are due to an antiferromaagnetic interactions between the metals. While a number of complexes of type [(MTSB)M′Xn] have previously been reported to be non-ionic, the complexes M′(MTSB)2(ClO4)n are found to have the expected electrical conductivities in nitrobenzene solution.
Coordination polymers of Cu(II), Ni(II), Co(II), Zn(II), Cr(III), Fe(III), oxovanadium (IV), and dioxouranium (VI) with salicylic acid (S)-thiourea (T)-trioxane (T) (STT) polymer were prepared. The analytical data agree with 1:1 metal-ligand stoichiometry. Elemental analyses, magnetic, spectral, and thermal properties, and electrical conductivities of STT and its chelates have been studied and probable structures are assigned to the coordination polymers. All the chelates are amorphous powders, insoluble in common organic solvents, and showing slight solubility in DMF.
A review with 172 refs. [on SciFinder(R)]
The complexes [(UO2)2(saladph)(H2O)4].2H2O (1), [(UO2)2 (saladphH)-(CH3COO)2(H2O)2].6H2O (2), [(UO2)3 (saladph) (CH3COO)2(H2O)2].4H2O (3) [(UO2)3 (saladphH2)(CH3COO)2(C2H5OH)2]3.3C2H5OH (4) and [(UO2)2 (saladph) (PY)2 (H2O)2].xH2O (where pY = pyridine, or, α-, β-or γ-picoline, × = 0, 1) (5–8) have been synthesized by the reaction of uranyl acetate dihydrate with disalicylaldehyde adipoyldihydrazone (saladphH4) in water or ethanol. The complexes have been characterized by physicochemical data, IR, H NMR and electronic spectral studies. It is suggested that the complexes involve 6, 7, 8 and 9-coordinated uranium atoms.
Two new Schiff bases (1a)-(2a) derived from 2,3-diaminopyridine (DAPY) with pyrrole-2-carboxaldehyde (Pyrr) and 2-hydroxy-1-naphthaldehyde (NaphH), and new copper(II), iron(III), nickel(II), ruthenium(II) and zinc(II) complexes (1b)-(1e), (2b)-(2f) and (3b)-(3d) derived from these two new Schiff bases, and the bis-condensed Schiff base of 2,3-diaminopyridine and salicylaldehyde (SalH) were synthesized. They were characterized by a combination of elemental analyses, magnetic susceptibility measurements, IR and NMR spectra. The two new Schiff bases and some of the metal complexes show antibacterial activity. The iron(III) and Ru(II) complexes display catalytic activity in the oxidation of alcohols in the presence of N-methylmorpholine-N-oxide as co-oxidant.
Ruthenium(II) carbonyl complexes have been synthesised by reacting [RuH2(CO)(PPh3)3] or [RuHCl(CO)(PPh3)2(Z)] (Z = PPh3, pyridine (py) or piperidine (pip)) with tridentate Schiff base ligands derived by condensing salicylaldehyde, o-vanillin or o-hydroxyacetophenone with N(4)-phenylsemicarbazide. These complexes have been characterised by analytical, IR, electronic, 1H NMR and 31P NMR spectral studies. The complexes of the general formula [Ru(L)(CO)(PPh3)(Z)] (L = Schiff base anion; Z = PPh3, py or pip) tentatively have been assigned an octahedral structure. Some of the complexes have been tested for in vitro growth inhibitory activity against the bacteria Escherichia coli, Bacillus sp. and Pseudomonas sp.
Ultraviolet and visible absorption spectra are reported for bisacetylacetoneethylenediimine, bisacetylacetone-1,2-propylenediimine, bisbenzoylacetoneethylenediimine, bisbenzoylacetone-1,2-propylenediimine and bistrifluoroacetylacetone-ethylenediimine and many of the corresponding Cu(II), Ni(II) and Pd(II) chelate compounds. The strong absorption bands of the ligands in the ultraviolet region are attributed to the hydrogen-bonded conjugate chelate rings, and the double peaks of these bands are discussed in relation to the vibrational frequencies. An additional band at 244 mμ of the ligands derived from benozylacetone is employed in a determination of the structure of these compounds. Absorption spectra of metal chelate compounds are classified into two groups, one of which is characteristic of the metal ions, while the other is characteristic of both the metal ions and the ligands.
Adducts as well as deprotonated complexes of N-(picolinamido)salicylaldimine (H2PIS) of the types MCl2·2H2PIS [M = Mn(II), Co(II), Ni(II)], M(HPIS)2 [M = Mn(II), Co(II), Ni(II), Cu(II), Zn(II)], and M(PIS)·nH2O [M = VIVO, Mn(II), Co(II), Ni(II), Cu(II), Zn(II); n = 1 for VIVO, 2 for other metal ions] have been prepared. In the case of Cu(II) a partially deprotonated Cu(HPIS)Cl·H2O has also been obtained. Molar conductivities indicate nonelectrolytic behavior of deprotonated complexes and some ionic dissociation of the adducts in 10-3 M DMF solution. Magnetic and electronic spectral studies suggest octahedral geometry for all the complexes except those of Cu(II), which are distorted octahedra. The distorted octahedral geometry for Cu(II) complexes is further shown by the solid-state ESR spectra. X-ray powder diffraction studies of Cu(PIS)·2H2O suggest that this complex belongs to the tetragonal crystal system with a = 8.6059 Å, c = 17.7 Å, and Z = 4. The infrared spectral studies indicate that H2PIS acts as a bi-, ter-, or quadridentate ligand in the complexes.
In a sequence to out earlier reports of transition metal complexes with benzoyl- and chlorobenzoyldi -(2-pyridyl)ketohydrazone, we here report the isolation of palladium(II), platinum(II) and rhodium- (III) complexes with the same ligands and their characterization by chemical analysis, as well as magnetic and spectral studies, in order to evaluate the stereochemistry of the ligand around the metal ions. In these complexes the ligands behaved as terdentate, coordination occurring through the carbonyl and azomethine groups, as well as the nitrogen atom of the pyridyl group. Consequently, the Pd(II) and Pt(II) complexes are formulated as square-pyramidal monomers, whereas in Rh(III) complexes an octahedral environment around the metal is proposed.
The lanthanide(III) perchlorato complexes of hydrazones of isonicotinic acid hydrazide, viz. N-isonicotinamido-p-dimethylaminobenzalaldimine (INH-PDAB) and N-isonicotinamido-3-methoxy-4-hydroxybenzalaldimine (INH-VAN) of the type Ln(ClO4)3·4(INH-PDAB) or Ln(ClO4)3·4(INH-VAN) (Ln = La, Pr, Nd, Sm, Gd, Tb or Dy) have been synthesized and characterized by analytical, magnetochemical, IR and UV-vis spectral methods. The thermal stabilities of these compounds have also been investigated.
A series of 4-quinolylhydrazones were synthesized and tested against Mycobacterium tuberculosis H37Rv. Preparation of the title compounds was achieved by reaction of 4-quinolylhydrazine and aryl- or heteroaryl-carboxaldehyde. For the most of derivatives interesting antitubercular properties were showed; two compounds (3(2) and 3(25)), identified as the most active, were tested also against Mycobacterium avium.
Nine condensation products of isomeric three aldehydes and three acid hydrazides of pyridine group were prepared and their tuberculostatic activity against virulent human tubercle bacillus, strain H37Rv, was examined on Kirchner's medium containing 10% of bovine serum. The most active compounds were the condensation products of isonicotinic acid hydrazide with aldehydes and stronger than isonicotinic acid hydrazide in vitro.