Figure 3 - available via license: Creative Commons Attribution 4.0 International
Content may be subject to copyright.
![Proton-nuclear magnetic resonance ( 1 H NMR) spectra for (A) [Sn(GMFX)(Gly)]Cl2, (B) [Zn(GMFX)(Gly)]Cl2•H2O, and (C) [Ce(GMFX)(Gly)]SO4•H2O.](publication/325158918/figure/fig1/AS:626737897562112@1526437367406/Proton-nuclear-magnetic-resonance-1-H-NMR-spectra-for-A-SnGMFXGlyCl2-B.png)
Proton-nuclear magnetic resonance ( 1 H NMR) spectra for (A) [Sn(GMFX)(Gly)]Cl2, (B) [Zn(GMFX)(Gly)]Cl2•H2O, and (C) [Ce(GMFX)(Gly)]SO4•H2O.
Source publication
Three novel mixed ligand metal complexes have been synthesized by the reaction of Zn(II), Sn(II), and Ce(III) with gemifloxacin (GMFX) in the presence of glycine (Gly) (1:1:1 molar ratio). The coordination possibility of the two ligands toward metal ions has been proposed in the light of elemental analysis, molar conductance, spectral infrared (IR)...
Contexts in source publication
Context 1
... suggested molecular structures of the complexes were also proved by nuclear magnetic resonance (NMR) spectroscopy. The 1 H NMR spectra of the ligands and their metal complexes in CD3OD displayed distinct signals with appropriate multiplets; the signal assignments are shown in (Figure 3). The 1 H NMR spectrum obtained for GMFX shows peaks in the range δ = 8.02-8.72 ppm The decrease or increase of the absorption bands and the appearance of new bands upon coordination could be caused by the following effects: (1) the expected increase of the metal ion mass upon coordination; (2) the increase of the electron density on the metal ions by ligand, and (3) the decrease of the electron density on oxygen and nitrogen donor atoms. ...
Context 2
... suggested molecular structures of the complexes were also proved by nuclear magnetic resonance (NMR) spectroscopy. The 1 H NMR spectra of the ligands and their metal complexes in CD 3 OD displayed distinct signals with appropriate multiplets; the signal assignments are shown in (Figure 3). The 1 H NMR spectrum obtained for GMFX shows peaks in the range δ = 8.02-8.72 ppm for the protons of an aromatic ring, a multiplet at δ = 1.14-1.33 ...
Similar publications
The yield, composition and fungicidal activity of essential oils obtained from fennel fruits cultivated in Poland (FEOPOL) and Egypt (FEO-EG) were compared. The influence of the duration of hydrodistillation using a Clevenger apparatus on the essential oil yield was studied. The composition of the fennel essential oils was determined by GC-MS metho...
Citations
... 25 Moreover, mixed ligand complexes of Gemifloxacin as primary ligand and glycine or various N-donor heterocyclic ligands as secondary ligands showed significant action against some bacterial species and antitumor activity against several human cancers. 26 Silver complexes with gemifloxacin have a specific feature because the silver binding occurs at the nitrogen atom of the gemifloxacin N4'-piperazine, different from most other metal complexes that coordinate via 3-carboxyl and 4-oxo groups. Compared with other metal complexes, the antitumor activity of silver complexes is still very poor, although a lot of Ag(I) complexes were found to display higher cytotoxic activity than cisplatin. ...
This study tends to accomplish the sustainable development goal, which calls for all healthy lives. Antibiotic resistance, cancer, and severe acute respiratory syndrome coronavirus all showed high death rates in recent years. Our approach is to make better medications available to fight these feared health issues. In this context, three silver(I) complexes (1–3) based on the antibiotic gemifloxacin (HGMF) were synthesized and thoroughly examined using analytical, spectral, and thermal methods. The density functional theory suggested that complex 1 has a bent coordination environment while 2 and 3 have a distorted trigonal planar geometry. The optimal donor and acceptor centers were determined by the natural‐bond orbital analysis. Interaction of complexes with calf‐thymus DNA has been investigated and their binding constants were ordered as 3 > 2 > 1. The antimicrobial activity against 10 pathogenic microorganisms demonstrated that complex 3 exhibited superior activity compared with standard antibiotics. Testing against mammalian cell lines, liver carcinoma, breast carcinoma, and colon carcinoma revealed that complex 3 showed remarkable cell growth inhibition activity with IC50 values ranging from 3.0 to 9.3 μg/mL. Studies of Molecular docking against SARS‐CoV‐2 main protease Mpro (ID: 6 WTT) proved a powerful type of interaction at the active site. Complex 3 exhibits a potent inhibition effect with a total binding energy of −12.58 kcal/mol compared with the reference ligand inhibitor K36 suggesting its ability to block viral protease. This study presents promising bioactive candidates that have a practical impact on various medicinal fields.
... Also, complex 123 ( Figure 1) showed enhanced antifungal activity against M. fructicola, (62.5 mm) and P. digitatum (62.5 mm) compared to both the free Schiff base ligand (36.0 and 28.0 mm, respectively) and the standard antifungal agent azoxystrobin (45.3 and 58.1 mm, respectively) and can be considered as an antifungal drug candidate. The microbicide impact of the investigated compounds may result from the chemical structure of the free ligand as well as the toxicity of the investigated metal ions [67,68]. The increased antimicrobial activity of freshly synthesized metal chelates was explained by the principle of cell permeability of the microbes [35]. ...
Organometallic drug development is still in its early stage, but recent studies show that organometallics having iron as the central atom have the possibility of becoming good drug candidates because iron is an important micro-nutrient, and it is compatible with many biological systems, including the human body. Being an eco-friendly Lewis acid, iron can accept the lone pair of electrons from imino(sp2)-nitrogen, and the resultant iron–imine complexes with iron as a central atom have the possibility of interacting with several proteins and enzymes in humans. Iron–imine complexes have demonstrated significant potential with anticancer, bactericidal, fungicidal, and other medicinal activities in recent years. This article systematically discusses major synthetic methods and pharmacological potentials of iron–imine complexes having in vitro activity to significant clinical performance from 2016 to date. In a nutshell, this manuscript offers a simplistic view of iron complexes in medicinal inorganic chemistry: for instance, iron is presented as an “eco-friendly non-toxic” metal (as opposed to platinum) that will lead to non-toxic pharmaceuticals. The abundant literature on iron chelators shows that many iron complexes, particularly if redox-active in cells, can be quite cytotoxic, which can be beneficial for future targeted therapies. While we made every effort to include all the related papers, any omission is purely unintentional.
... It, however, was inactive against C. acutatum (not shown in the table). The microbicide impact of the investigated compounds may result from the chemical structure of the free ligand as well as the toxicity of the investigated metal ions [67,68]. The increased antimicrobial activity of freshly synthesized metal chelates was explained by the principle of cell permeability of the microbes [35]. ...
Organometallic drug development is still in its early stage, but recent studies show that organometallics having iron as the central atom have the possibility of becoming good drug candidates because iron is an important micro-nutrient, and it is compatible with many biological systems, including the human body. Being an eco-friendly Lewis acid, iron can accept the lone pair of electrons from imino(sp2)-nitrogen, and the resultant iron-imine complexes with iron as a central atom have the possibility of interacting with several proteins and enzymes in humans. Iron-imine complexes have demonstrated significant potential as anticancer, bactericidal, fungicidal, and other medicinal activities in recent years. This article systematically discusses major synthetic methods and pharmacological potentials of iron-imine complexes having in vitro activity to significantly affect clinical performance from 2016 to date. In a nutshell, this manuscript offers a simplistic view of iron complexes in medicinal inorganic chemistry: for instance, iron is presented as an "eco-friendly non-toxic" metal (as opposed to platinum) that will lead to non-toxic pharmaceuticals. The abundant literature on iron chelators shows that many iron complexes, particularly if redox-active in cells, can be quite cytotoxic, which can be beneficial for future targeted therapies. While we made every effort to include all the related papers, any omission is purely unintentional.
... According to the chelation idea, chelation could actually make it easier for the complexes to pass through a phospholipid membrane. According to our findings, complexation improves the antibacterial activity [70,71]. The activity indexes for L and its chelates were graphically found from Figure 2. ...
The condensation product of the reaction between aniline and salicylaldehyde was a 2-(2-hydroxybenzylidinemine)—aniline Schiff base bidentate ligand (L). L was used to generate complexes by interacting with the metal ions lanthanum(III), zirconium(IV), yttrium(III), and copper(II), in addition to cobalt(II). Various physicochemical techniques were utilized to analyze the synthesized L and its metal chelates, including elemental analysis (CHN), conductimetry (Λ), magnetic susceptibility investigations (μeff), Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H NMR) spectroscopy, ultraviolet–visible (UV-Vis.) spectrophotometry, and thermal studies (TG/DTG). FT-IR revealed that the L molecule acted as a bidentate ligand by binding to metal ions via both the oxygen atom of the phenolic group in addition to the nitrogen atom of the azomethine group. Additionally, 1H NMR data indicated the formation of complexes via the oxygen atom of the phenolic group. An octahedral geometrical structure for all of the chelates was proposed according to the UV-Vis. spectra and magnetic moment investigations. Thermal analysis provided insight into the pattern of L in addition to its chelates’ breakdown. In addition, the investigation furnished details on the chelates’ potential chemical formulas, the characteristics of adsorbed or lattice H2O molecules, and the water that is coordinated but separated from the structure at temperatures exceeding 120 °C. The thermodynamic parameters utilizing Coats–Redfern in addition to Horowitz–Metzger equations were studied. The antimicrobial effectiveness of L and its chelates against distinct species of bacteria and fungi was studied using the disc diffusion method. Cu(II) and Y(III) chelates had significant antimicrobial activity against Staphylococcus aureus and Micrococcus luteus.
... The permeability of the cell membrane and the lipid composition of the studied microbial cells' cell walls enable the easier passage of soluble compounds through the cell, which is a significant aspect of assessing an antimicrobial agent's efficacy [54,55]. This suggests that chelation may facilitate metal complex diffusion across the lipid layer of the cell membrane to the site of action [56][57][58][59][60]. Table 6 and Figure 2 provide measurements of the compounds' activity indices. ...
Coordination compounds of Co(II), Cu(II), Y(III), Zr(IV) and La(III) ions were synthesized from the N-salicylidene aniline (L) derived from the condensation of aniline with salicylaldhyde and 1,10-phenanthroline (phen) as a secondary mixed ligand. L, phen and their complexes were characterized using various physiochemical methods, such as elemental analyses (CHN), Fourier-transform infrared spectroscopy (FT-IR), molar conductance (Λ), magnetic susceptibility (μeff), proton nuclear magnetic resonance (1H NMR), ultraviolet–visible spectroscopy (UV–Vis) and thermogravimetric analysis (TG/DTG). The analytical and spectroscopic data supporting the chemical formulas of the metal complexes and chelation of L and phen with the metal ions forming octahedral complexes. FT-IR spectra demonstrated that L chelated with metal ions as a bidentate ligand via the oxygen atom of the phenolic group with a band in the range 3378–3437 cm−1 and the nitrogen atom of the azomethine group at 1612 cm−1. In addition, phen chelated through two nitrogen atoms in the range 1525–1565 cm−1. The 1H NMR results confirmed the IR assumption that the ligand connected to the metal ions via the phenolic’s oxygen atom. The molar conductance measurements of the complexes revealed high values of the electrolytic nature of these complexes in the range of 90.40–125.80 S cm2 mol−1. Thermal analysis (TG/DTG) was used to differentiate between coordinated and hydrated water molecules and the thermal stability of the complexes. Finally, the anti-microbial activities of the complexes were investigated against fungi (Candida albicans), Gram-negative bacteria (Escherichia coli and Salmonella typhimurium) and Gram-positive bacteria (Staphylococcus aureus and Micrococcus sp.) using the disc diffusion method. The La(III) complex was significant against C. albicans compared with all other compounds and reference standard control.
... MIC is the lowest concentration that inhibits visible bacterial growth in liquid media, whereas MBC is the lowest concentration at which no growth occurs in solid media. The MICs and MBCs of the ethanolic extract from T. indica were determined in triplicate by the broth microdilution method [38]. To obtain the appropriate suspensions needed for each experiment, the stock solution of tamarind extract (25 mg/mL) was diluted in nutrient broth to obtain twofold serial dilutions ranging from 0.195 to 12.5 mg/mL. ...
The worldwide crises from multi-drug-resistant (MDR) bacterial infections are pushing us to search for new alternative therapies. The renewed interest in medicinal plants has gained the attention of our research group. Tamarindus indica L. (T. indica) is one of the traditional medicines used for a wide range of diseases. Therefore, we evaluated the antimicrobial activities of ethanolic extract of T. indica. The inhibitions zones, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and fractional inhibitor concentration indices (FICI) against Gram+ve and −ve pathogens were detected. The bioactive compounds from T. indica extract were identified by mass spectroscopy, thin-layer chromatography, and bio-autographic assay. We performed scanning electron microscopy (SEM) and molecular docking studies to confirm possible mechanisms of actions and antivirulence activities, respectively. We found more promising antimicrobial activities against MDR pathogens with MIC and MBC values for Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa), i.e., (0.78, 3.12 mg/mL) and (1.56, 3.12 mg/mL), respectively. The antimicrobial activities of this extract were attributed to its capability to impair cell membrane permeability, inducing bacterial cell lysis, which was confirmed by the morphological changes observed under SEM. The synergistic interactions between this extract and commonly used antibiotics were confirmed (FICI values < 0.5). The bioactive compounds of this extract were bis (2-ethylhexyl)phthalate, phenol, 2,4-bis(1,1-dimethylethyl), 1,2-benzenedicarboxylic acid, and bis(8-methylnonyl) ester. Additionally, this extract showed antivirulence activities, especially against the S. aureus protease and P. aeruginosa elastase. In conclusion, we hope that pharmaceutical companies can utilize our findings to produce a new formulation of T. indica ethanolic extract with other antibiotics.
... [50] The shift in the spectra of the complexes detects that imino nitrogen and oxygen are included in the coordination with the metal ions. [51] All complexes have new bands which dedicated the ligand metal charge transfers in a range of 428-476 nm. [52][53][54][55] The magnetic susceptibilities (μ eff ) of the complexes calculated and supported that the complexes (1), (2), (3) and (4) (1), (2) and (4) were attributed to only the spin value of an odd electron. ...
A new Schiff base, (N,N\‐phenylene‐(bis‐1‐ethyl‐ 6 ‐fluoro ‐7‐ (piperazine‐ 1‐ yl) ‐quinolone ‐ 3 ‐carboxylic acid) & (Nor‐o‐phdn.2H2O) and its derived complexes with nickel (II), cobalt (II), copper (II), iron (III), yttrium (III) , lanthanum (III), zirconium (IV) and uranium (VI) were synthesised and distinguished by different tools such as elemental analyses, magnetic properties, molar conductivity, spectroscopic methods (UV‐Vis., IR and 1H‐NMR), mass‐spectrometry and thermogravimetric analysis. Depending on the spectroscopic data Schiff base Nor‐o‐phdn.2H2O is co‐ordinated to metal centers as a potentially tetradentate ligand via N2O2 atoms. UV‐Vis. and magnetic data suggest an octahedral‐geometry for all mentioned complexes. Thermogravimetric analysis indicated the existence of water molecules inside and outside complex sphere. The thermo‐dynamics‐related parameters were analysed through using Horowitz‐Metzger and Coats‐Redfern formula. Schiff base as well as its metal‐derived complexes were assessed for their antibacterial, antifungal and antiviral bioactivities. As anticipated, Schiff's‐base and its metal complexes showed high anti‐bacterial profile against E. coli and Salmonella typhae. In case of Staphylococcus‐aureus and Bacillus‐cereus, it was observed that metal‐derived complexes exhibited more bactericidal features than the un‐complexed ligands. However, there is no antifungal bioactivities were detected. Regarding to the antiviral bioactivity, we detetermined in an innovative manner the effectiveness of Schiff base and metal‐derived complexes on the replication of human cytomegalovirus (huCMV‐DNA). In this regard, we utilised a humanised mouse model (huNOG‐EXL) that were implanted with human immune system cells and was subsequently infected with huCMV. The infected‐mice divided into drug‐treated mice and the drug‐untreated vehicle control. After post‐infection and during the course of treatment, Fe (III) and Zr (IV) complexes were impactful in obstructing huCMV replication by 10‐15 fold when compared to the vehicle control, concomitantly with inducing the immune recognition of T‐cytotoxic CD8+ cells towards the huCMV. The complexes are believed to be the best nominees for further research and development as huCMV inhibitors.
... The TGA-50H Shimadzu was also applied for TG-DTG measurements in an N2 atmosphere in the temperature range of room temperature to 1000 °C. The M percentage was evaluated using complex metric titration, thermogravimetric analysis (by changing the solid products into metal oxide) and atomic absorption using a spectrometer of type PYE-UNICAM SP 1900 [83,84] fitted with the correspondent lamp was utilized for this intentional [18]. A Perkin Elmer 2400 CHN elemental analyzer was used to accomplish the analyses. ...
Condensation of the reaction between enrofloxacin and ethylenediamine in the existence of glacial acetic acid produced a new N,N-ethylene (bis 1-cyclopropyl-7-(4-ethylpiperazin-1-yl)-6-fluoro-1,4-dihydroquinoline-3-carboxylic acid Schiff base (H2Erx-en). H2Erx-en was used as a tetra-dentate ligand to produce novel complexes by interacting with metal ions iron(III), yttrium(III), zirconium(IV), and lanthanum(III). The synthetic H2Erx-en and its chelates had been detected with elemental analysis, spectroscopic methods, mass spectrometry, thermal studies, conductometric and magnetic measurements experiments. The calculated molar conductance of the complexes in 1 × 10−3 M DMF solution shows that iron(III), yttrium(III) and lanthanum(III) are 1:1 electrolytes, however the zirconium(IV) complex is non-electrolyte. The infrared spectra of H2Erx-en chelates indicated that the carboxylic group is deprotonated and H2Erx-en is associated with metals as a tetra-dentate through nitrogen and oxygen atoms. The disappearance of the carboxylic proton in all complexes corroborated information concerning H2Erx-en deprotonation and complexation with metal ions, according to 1H NMR data. Thermal analysis revealed the abundance of H2O particles in the chelates’ entrance and outlet spheres, indicating the disintegration pattern of H2Erx-en and their chelates. The Coats–Redfern and Horowitz–Metzeger approaches were utilized to calculate the thermodynamic items (Ea, ΔS *, ΔH *, and ΔG *) at n = 1 and n ≠ 1. The resulting data reveal better organized chelate building activation. Density functional theory (DFT) was created to properly grasp the optimal architecture of the molecules. The chelates are softer than H2Erx-en, with estimates varying between 95.23 eV to 400.00 eV, compared to 31.47 eV for H2Erx-en. The disc diffusion technique was utilized to assess H2Erx-en and their chelates in an antimicrobial assay against various food and phytopathogens. The zirconium(IV) chelate has the most potent antibacterial action and is particularly efficient against Salmonella typhi.
... The increased biological activity of metal chelates can be explained by the concept of cell permeability and chelation theory [22,23]. The chelation reduces the polarity of the metal ion due to partial sharing of its positive charge with donor ligands and delocalization of π electrons over the chelate ring [14,24]. ...
... It should be noted that the calculated logP value for the zinc sulfate molecule [37] turned out to be −4.16. Therefore, the received data confirms that upon chelation, the polarity of a metal ion is reduced due to the partial sharing of the positive charge with the donor groups of the ligand and as a consequence of overlap with the ligand orbitals [22]. ...
... Thus, the results of the biological experiment coincided with the prediction data, showing on one hand the strict relation between biological activity ( obs Ea) and lipophilicity, while on the other hand indicating the ability of Balaban distance-based index to be used for the description of chelate structures. Finally results obtained using the QSAR-analysis and Spirotox-method made it possible to discover and prove that zinc methionine complex has higher biological activity than zinc glycinate, for which the antibiotic effect was previously proven [22,[41][42][43]. ...
The complexation of biogenic molecules with metals is the widespread strategy in screening for new pharmaceuticals with improved therapeutic and physicochemical properties. This paper demonstrates the possibility of using simple QSAR modeling based on topological descriptors for chelates study. The presence of a relationship between the structure (J) and lipophilic properties (logP) of zinc complexes with amino acids, where two molecules coordinate the central atom through carboxyl oxygen and amino group nitrogen, and thus form a double ring structure, was predicted. Using a cellular biosensor model for Gly, Ala, Met, Val, Phe and their complexes Zn(AA)2, we experimentally confirmed the existence of a direct relationship between logP and biological activity (Ea). The results obtained using topological analysis, Spirotox method and microbiological testing allowed us to assume and prove that the chelate complex of zinc with methionine has the highest activity of inhibiting bacterial biofilms, while in aqueous solutions it does not reveal direct antibacterial effect.
... Quinolones are a group of synthetic antibacterial agents now in clinical use for over thirty years [13,14]. There are several reports about the proposed mechanism of the interaction between fluoroquinolones and metal cations, which have indicated chelation formed between the metal ions and the 4-oxo and the adjacent carboxyl group [15][16][17][18][19][20][21] or piperazine nitrogen atom [22][23][24]. Ciprofloxacin hydrochloride (CIP) (Scheme 1-I) is a second-generation fluoroquinolone that was synthesized for the first time in [25]. ...
Coumarin is highly distributed in nature, notably in higher plants. The biological features of coumarin include antibacterial, anticancer and antioxidant effects. It is well known that metal ions present in complexes accelerate the drug action and the efficacy of organic therapeutic agents. The main aim of the current study is the synthesis of different complexes of the interaction between ciprofloxacin hydrochloride (CIP) and coumarin derivative 7-hydroxy-4-methylcoumarin (HMC) with Zr(IV). The chelates of CIP with Zr(IV) were prepared and characterized by elemental analysis, melting point, conductance measurements, spectroscopic techniques involving IR, UV-Vis, 1H NMR, and thermal behavior (TG-DTG) in the presence of HMC, dimethylformamide (DMF), pyridine (Py), and triethylamine (Et3N). Results of molar conductivity tests showed that the new synthesized complexes are electrolytes with a 1:1 or 1:2 electrolyte ratio, with the chloride ions functioning as counter ions. According to IR spectra, CIP acts as a neutral bidentate ligand with Zr(IV) through one carboxylato oxygen and the carbonyl group, HMC as a monodentate through the carbonyl group, and DMF through the oxygen atom of the carbonyl group and the N atom of Py and Et3N. The thermal behavior of the complexes was carefully investigated using TG and DTG techniques. TG findings signal that water molecules are found as hydrated and coordinated. The thermal decomposition mechanisms proposed for CIP, HMC, and Zr(IV) complexes are discussed and the activation energies (Ea), Gibbs free energies (∆G*), entropies (∆S*), and enthalpies (∆H*) of thermal decomposition reactions have been calculated using Coats–Redfern (CR) and Horowitz–Metzeger (HM) methods. The studied complexes were tested against some human pathogens and phytopathogens, including three Gram-positive bacteria (Bacillus subtilis, B. cereus, Brevibacterium otitidis) and three Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae), and compared to the free CIP and HMC parent compounds.
