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(a) Absorption spectra of H4L in DMF solution upon the addition of Ni²⁺. (b) Absorption spectra of the Ni(ii) complex in DMF solution upon the addition of Ca²⁺. (c) Absorption spectra of the Ni(ii) complex in DMF solution upon the addition of Sr²⁺. (d) Absorption spectra of the Ni(ii) complex in DMF solution upon the addition of Ba²⁺
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Three heterometallic Ni(II)–M(II) (M = Ca, Sr and Ba) complexes, two discrete heterotrinuclear complexes [Ni2(L)Ca(OAc)2(CH3OH)2]·2C2H5OH·2CHCl3 (1) and [Ni2(L)Sr(OAc)2(CH3OH)2]·2CH3OH·2CH2Cl2 (2) and a discrete heterohexanuclear dimer [Ni2(L)Ba(OAc)2(CH3OH)2(H2O)]2·2CH3OH (3), were synthesized with a naphthalenediol-based acyclic bis(salamo)-type...
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Four homo/heterometallic complexes [Cu3(L)(μ2-OAc)9(CH3OH) 9]·3CHCl3 (1), [Cu2(L)Ca(μ2-NO3)9] (9), [{Cu2(L)Sr(μ2-NO3)9}9]·CH3CH2OH (11) and [Cu2(L)Ba(μ2-OAc)9(OAc)] (14), containing an acyclic naphthalenediol-based ligand H4L, were synthesized and characterized by elemental analyses, IR, UV-Vis, fluorescence spectra, TG-DTA and X-ray crystallograph...
Citations
... The complex formation between the Zn(II) and HDPBA results in bathochromic shift of n-π* transition of the C=N functional group in HDPBA. Similar shifts of n-π* transition absorption band of other ligands upon complex formation with other metals have also been reported [32,33,34,35]. ...
In this study, a new carbon paste electrode modified with a laboratory-synthesized ligand, N 1-hydroxy-N 1 ,N 2-diphenylbenzamidine (HDPBA) and multi-walled carbon nanotubes (MWCNTs) (HDPBA-MWCNTs/CPE) has been developed. The modified electrode was applied for pre-concentration and voltammetric determination of zinc ions (Zn(II)) by square wave anodic stripping voltammetry (SWASV). The preconcentration of Zn(II) on the electrode surface was performed in 0.1 M Brinton Robinson (B-R) buffer solution (pH 6) at an applied potential of − 1.30 V versus Ag/AgCl for 120 s, followed by stripping in the positive potential scan of the SWASV after a quit time of 10 s. Under optimized experimental conditions, the proposed electrode exhibited a wider linear dynamic response for Zn(II) in a concentration range of 0.02-10.00 μM with a detection limit of 2.48 nM. This is due to the excellent metal-chelation property of the ligand, and the good conductivity and large surface area of MWCNTs which significantly improved the sensing performance of the nanocomposite modified electrode. The selectivity of the electrode was studied by evaluating the interference effects of various foreign ions on the peak current of Zn(II). The method exhibited high reproducibility with a relative standard deviation (RSD) of 3.1%. The present method was applied for the determination of zinc ions in water samples. The recovery values in the tested samples were found to be 98.50-106.0%, indicating a good accuracy of the proposed electrode. Furthermore, the electrochemical behavior of HDPBA in acetonitrile and aqueous solutions has been studied.
... These hetero-metallic Salamo-like coordination compounds have been studied for their catalytic activities [29,30], biological activities [31], and fluorescence properties [32][33][34]. Meanwhile, supra-molecular chemistry has become increasingly prominent in the coordination chemistry, for Salamo-like derivatives, supra-molecular structures are formed mainly with the help of hydrogen bonding interactions [35][36][37][38]. In our previous studies, a number of Salamo-type derivatives and their hetero-nuclear coordination compounds have been synthesized [39][40][41][42]. ...
A hetero-hexanuclear Zn(II)-La(III) coordination compound, [{(ZnL)2La}2(bdc)2](NO3)2 (H2bdc = terephthalic acid) has been synthesized with a symmetric Salamo-like bisoxime, and characterized by elemental analyses, IR, UV-Vis, fluorescent spectroscopy, and single-crystal X-ray diffraction analysis. All of the Zn(II) ions are pentacoordinated by N2O2 donator atoms from the (L)2− unit and one oxygen atom from one terephthalate anion. The Zn(II) ions adopt trigonal bipyramidal geometries (τZn1 = 0.61, τZn2 = 0.56). The La(III) ions are decacoordinated in the Zn(II)-La(III) coordination compound and has a distorted bicapped square antiprism geometry. Meanwhile, the photophysical property of the Zn(II)-La(III) coordination compound was also measured and discussed.
... favorable reaction will allow to obtaining ligands that are extremely difficult to separate by classical anionic organic chemistry under conventional conditions. This, in turn, will allow the synthesis of novel-innovative metal complexes that are pre-restricted by ligand design [8][9][10][11][12][13][14][15][16][17]. Based on this, the transition metal Mn ion has become our target of choice due to its various oxidation states and Lewis acidity [18], which acts as a potential promoter to study the extent of the in situ aldol reaction of acetone and salicylaldehyde derivatives. ...
... This favorable reaction will allow to obtaining ligands that are extremely difficult to separate by classical anionic organic chemistry under conventional conditions. This, in turn, will allow the synthesis of novel-innovative metal complexes that are pre-restricted by ligand design [8][9][10][11][12][13][14][15][16][17]. Based on this, the transition metal Mn ion has become our target of choice due to its various oxidation states and Lewis acidity [18], which acts as a potential promoter to study the extent of the in situ aldol reaction of acetone and salicylaldehyde derivatives. ...
Three polyhydroxyl-bridged tetranuclear MnIII complexes [Mn4(L1a)2(μ3-OMe)2(μ2-OMe)2(MeOH)2] (1), [Mn4(L2a)2(μ3-OMe)2(μ2-OMe)2(H2O)2] (2), and [Mn4(L3a)2(μ3-OMe)2(μ2-OMe)2(H2O)2] (3) derived from Mnn+-promoted reactivity of Schiff base ligands (HL1 = 1-(4-{[(E)-3,5-dichlorine-2-hydroxybenzylidene]amino}phenyl)ethanone O-benzyloxime, HL2 = 1-(4-{[(E)-3-bromine-5-chloro-2-hydroxybenzylidene]amino}phenyl) ethanone O-benzyloxime, and HL3 = 1-(4-{[(E)-3,5-dibromine-2-hydroxybenzylidene]amino}phenyl)ethanone O-benzyloxime) have been synthesized and characterized. In the MnIII complexes 1, 2, and 3, the newly formed ligands (L1a)4−, (L2a)4−, and (L3a)4− are derived from the chemoselective cleavage of the C=N bond in the original Schiff base ligands HL1, HL2, and HL3 to form corresponding halogenated salicylaldehyde, 3,5-dichlorosalicylaldehyde, 3-bromine-5-chlorosalicylaldehyde, and 3,5-dibrominesalicylaldehyde, respectively. Then, the further addition of acetone to two halogenated salicylaldehyde molecules in situ α,α double aldol reaction promoted by Mnn+ ions in the presence of base to give the new ligands ((Lna)4−. X-ray crystallographic analyses of the MnIII complexes 1, 2, and 3 show that the three complexes are all tetranuclear structure and crystallizes in the triclinic system, space group P-1. The four MnIII ions and bridging alkoxido groups are arranged in a face-shared dicubane-like core with two missing vertices. In the three MnIII complexes, the asymmetric unit contains two kinds of different MnIII ions (Mn1 and Mn2), where the MnIII ions are all hexacoordinated with slightly distorted octahedral geometries. Simultaneously in the synthesis of multinuclear Mnn+ complexes above, we explored the crystal structure, spatial configuration, and spectroscopic properties of the multinuclear MnIII complexes with different halogen substituents.
... The latter, salamo-like ligands, are more attractive candidates for metal-binding sites to be involved into metallohosts. Salamo-like ligands could coordinate to different transition metal ions in a tetradentate N 2 O 2 -type fashion to form stable metal coordination compounds, some of which are often as organic reaction catalysts [16], metal enzyme reaction center models [17,18], nonlinear optical and magnetic molecular materials [19][20][21][22][23][24][25][26][27], supramolecular architectures and host-guest chemistries [28][29][30][31][32][33][34], electrochemistries [35][36][37] and so on. ...
A homotrinuclear ZnII bis(salamo) coordination compound, [LZn3(OAc)2(H2O)] of a new bis(salamo)-like ligand, has been synthesized and structurally characterized using elemental analyses, IR, UV-Vis and fluorescent spectra, and Hirshfeld surface analysis. Hirshfeld surface analyses and X-ray crystallography revealed that complexation between ZnII acetate dihydrate and the ligand H4L afforded a 3:1 (ZnII:L) type coordination compound. Moreover, the X-ray crystal structure analysis demonstrated that two μ2-acetate anions bridge three ZnII atoms in a μ2-fashion forming a homo-trinuclear structure. There were two kinds of ZnII atoms coordination geometries (strongly distorted square pyramidal (Zn1) and distorted trigonal bipyramidal (Zn2 and Zn3)) in the ZnII coordination compound. In addition, a 3D supra-molecular structure was constructed by intermolecular C-H···π and π···π interactions in the ZnII coordination compound. Most importantly, the fluorescent and antimicrobial properties of H4L and its ZnII coordination compound were investigated.
... As we know, due to easy preparation and strong coordination abilities, modified Salen-type ligands [1][2][3][4][5][6][7][8] containing tetradentate N 2 O 2 site have been used for the synthesis of metal complexes [9][10][11][12][13] in the past few decades. The potential applications of Salen-type compounds and their corresponding metallic complexes in modern coordination chemistry and organometallic chemistry have attracted considerable attentions, such as optical sensors [14,15], catalyses [16,17], luminescence properties [18][19][20][21][22][23][24], supra-molecular buildings [25][26][27][28][29][30][31][32][33], electrochemistries [34,35], magnetic materials [36][37][38][39][40][41], biological systems [42][43][44][45][46][47][48][49][50][51] and nonlinear optical materials [52], and so forth. In recent years, Salen-type complexes have attracted considerable attention from the viewpoint of the integration effect of multiple functional units. ...
... Recently, some Salamo-type lanthanide complexes have been reported to perform excellent fluorescence properties [21,24,32]. Zn II components have been applied as lanthanide fluorescence sensitizers. ...
Two new hetero-trinuclear 3d-4f complexes [Zn2(L)Ho(μ2-OAc)2(OAc)(MeOH)]·CH2Cl2 (1) and [Zn2(L)Er(μ2-OAc)2]OAc (2), derived from a bis(salamo)-based ligand H4L, were synthesized and characterized via elemental analyses, IR, UV–Vis, fluorescence spectra and X-ray crystallography. The X-ray crystal structure analyses demonstrated that two μ2-acetateanions bridge the ZnII and LnIII (Ln = Ho (1) and Er (2)) atoms in a μ2-fashion forming similar hetero-trinuclear structures, respectively. In complex 1, one methanol molecule as coordinating solvent participates in the coordination, the two ZnII atoms are six-and five-coordinated and have geometries of slightly distorted tetragonal pyramid and octahedron, and the HoIII atom is nine-coordinated and has the geometry of a mono-capped square antiprism. In complex 2, the two ZnII atoms both possess five-coordinated tetragonal pyramid geometries, and the ErIII atom is eight-coordinated with a square antiprism geometry. Furthermore, the fluorescence properties of complexes 1 and 2 were determined.
... Salen-type ligands and their coordination compounds have been extensively investigated [1][2][3][4][5][6][7][8][9][10] for their catalytic activities [11][12][13][14][15], biological activities [16][17][18][19][20][21][22], supramolecular architectures [23][24][25][26][27][28][29][30][31][32], and fluorescence properties [33][34][35][36][37][38]. To improve the properties of Salen-type ligands, in recent years, Nabeshima and our group's researches mostly concentrated on the syntheses of Salamo-type ligands, which are a class of novel Salen-type analogues [39][40][41][42][43][44][45][46][47][48][49][50][51]. These Salamo-type multidentate ligands can self-assemble with transition metals, alkali metals, alkaline earth metals, and rare earth metals to form mononuclear or multinuclear 3d, 3d-s, 3d-4f coordination compounds [52][53][54][55][56][57][58][59][60]. ...
The newly designed butterfly-shaped hetero-tetranuclear CuII-NaI coordination compound, [Cu3 (HL)2 Na]·Pic (Pic⁻ is abbreviation of picrate) (1) which is derived from a naphthalenediol-based bis(Salamo)-type chelating ligand H4 L have been synthesized and characterized by elemental analyses, UV-vis spectra, IR spectra analysis, and Hirshfeld surface analysis. X-ray crystallographic analyses revealed that the coordination compound 1 is a novel hetero-tetranuclear CuII-NaI bis(Salamo)-type coordination compound and it differs from heterotrinuclear CuII-NaI bis(Salamo)-type coordination compound reported earlier. The Cu1 and Cu3 atoms are tetra-coordinated with geometries of distorted square pyramid, while Cu2 atom are hexa-coordinated with the geometry of a distorted octahedron. The NaI atom is octa-coordinated with the geometry of a distorted hexagonal bipyramid. Furthermore, the supramolecular structure and Hirshfeld surface analyses have been discussed in detail.
... X-ray crystallographic analyses reveal that the structure of the coordination compound 2 is similar to that of the coordination compound 1. The coordination compounds 1 and 2 form novel dinuclear structures, which are different from the common trinuclear structures of bis(salamo)-like metal coordination compounds reported earlier [58][59][60][61][62]. The crystal structures of the coordination compounds 1 and 2 and the coordination polyhedrons of the M II atoms are shown in Figures 1 and 2. Selected bond lengths and angles are listed in Tables 1 and S1. ...
Two unprecedented homometallic CoII and ZnII coordination compounds, [M2(L)(OCH3)][M2(L)(OAc)] (MII = CoII (1) and ZnII (2)), with a novel symmetric bis(salamo)-like tetraoxime ligand H3L were synthesized and characterized by elemental analyses, infrafred (IR), ultraviolet–visible spectroscopy (UV-Vis), fluorescent spectra and single-crystal X-ray diffraction analyses. The unit cell of the two coordination compounds contains two crystallographically and chemically independent dinuclear coordination compounds. In the two coordination compounds, three metal ions are five-coordinated, formed two square pyramidal and a trigonal bipyramidal geometries, and the other metal ion is a hexacoordinate octahedral configuration. In addition, the coordination compound 1 forms a 3D supramolecular structure, and the coordination compound 2 forms a 0D dimer structure by the inter-molecular hydrogen bond interactions. Meanwhile, the fluorescence spectra of the coordination compounds 1 and 2 were also measured and discussed.
... More recently, modified salen-type ligands having imine groups (-C=N-) [1][2][3][4][5][6][7][8], bear the potentially tetradentate N 2 O 2 -donor and can form relatively stable complexes with different metal ions. Salen and its derivatives are extremely attractive and commonly versatile ligands because their metal complexes have been studied in potential application in catalyses [9,10], supramolecular architectures [11][12][13][14][15][16][17][18][19], luminescence properties [20][21][22][23][24][25][26], electrochemical conducts [27,28], biological systems [29][30][31][32][33][34][35][36][37], optical sensor [38,39], magnetic materials [40][41][42][43][44][45] and nonlinear optical materials [46], and so forth. A lot of researches have been fulfilled to design and synthesize mono-nuclear and homo-or hetero-polynuclear metal complexes possessing salen-type or salamo-type ligand or its analogues. ...
A novel heterotrinuclear complex [Cu2(L)Na(µ-NO3)]∙CH3OH∙CHCl3 derived from a symmetric bis(salamo)-type tetraoxime H4L having a naphthalenediol unit, was prepared and structurally characterized via means of elemental analyses, UV-Vis, FT-IR, fluorescent spectra and single-crystal X-ray diffraction. The heterobimetallic Cu(II)–Na(I) complex was acquired via the reaction of H4L with 2 equivalents of Cu(NO3)2·2H2O and 1 equivalent of NaOAc. Clearly, the heterotrinuclear Cu(II)–Na(I) complex has a 1:2:1 ligand-to-metal (Cu(II) and Na(I)) ratio. X-ray diffraction results exhibited the different geometric behaviors of the Na(I) and Cu(II) atoms in the heterotrinuclear complex; the both Cu(II) atoms are sited in the N2O2 coordination environments of fully deprotonated (L)4− unit. One Cu(II) atom (Cu1) is five-coordinated and possesses a geometry of slightly distorted square pyramid, while another Cu(II) atom (Cu2) is four-coordination possessing a square planar coordination geometry. Moreover, the Na(I) atom is in the O6 cavity and adopts seven-coordination with a geometry of slightly distorted single triangular prism. In addition, there are abundant supramolecular interactions in the Cu(II)–Na(I) complex. The fluorescence spectra showed the Cu(II)–Na(I) complex possesses a significant fluorescent quenching and exhibited a hypsochromic-shift compared with the ligand H4L.
... It is significant to find appropriate substituted groups forthe moieties of the ligands to enhance the properties of these metallic coordination compounds [31][32][33]. Lately, a number of Salen-like compounds [34][35][36][37][38][39] (Salamo and its derivatives) has been exploited using O-alkyloxime units (-CH=N-O-(CH 2 ) n -O-N=CH-) rather than the non O-alkyloxime (-CH=N-(CH 2 ) n -N=CH-) units, and the larger electronegativity of oxygen atoms is desired to strongly influence the electronic behavior of the N 2 O 2 coordination environment, which can give rise to novel structures and different properties of the resulting coordination compounds [40][41][42][43][44][45][46][47]. In addition, metallic ions play important roles in different biological processes and the interaction of the metallic ion with drugs employed for therapeutic reasons [48]. ...
Newly designed three trinuclear coordination compounds [Ni3(L1)2(OAc)2(CH3OH)2] (1), [Ni3(L1)2(OAc)2(CH3CH2CH2OH)2]·2CH3CH2CH2OH (2) and [Ni3(L1)2(OAc)2(DMF)2]·1.71DMF (3) and one mononuclear coordination compound [Cu(L2)2] (4) have been synthesized by H2L1 and nickel(II) and copper(II) acetate hydrates in different solvents. Single-crystal X-ray structure determinations revealed that the coordination compounds 1–3 have analogous molecular structures. The coordination compounds 1, 2, and 3 were affected by the coordinated methanol, n-propanol, and N,N-dimethylformamide molecules, respectively, and the various coordinated solvent molecules give rise to the formation of the representive solvent-induced NiII coordination compounds. All the NiII atoms are six-coordinated with geometries of slightly distorted octahedron. Obviously, in the coordination compound 4, the expected salamo-like mono- or tri-nuclear CuII coordination compound has not been obtained, but a new CuII coordination compound [Cu(L2)2] has been gained. The Cu1 atom is four-coordinated and possesses a geometry of slightly distorted planar quadrilateral. Furthermore, the fluorescence properties of coordination compounds 1–4 and magnetic behavior of coordination compound 1 were investigated.
... Metal complexes bearing Salen-like ligands or their derivatives are now a significant research subject [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15], and could be of ubiquitous use in biological systems [16][17][18][19][20][21][22][23][24], fluorescent sensors [25][26][27][28][29][30][31][32][33][34][35][36][37], magnetic properties [38][39][40][41][42], optical materials [43][44][45][46][47][48][49][50][51] and building blocks for supramolecular features [52][53][54][55][56][57][58][59][60][61][62]. Though a number of advances have been obtained in the researches of Salen-like Ni II complexes [63][64][65][66][67][68][69], there might be novel applications for such a group of unique compounds. Compared with the symmetric Salen-like ligands, the unsymmetric Salen-like ligands are uncommon because electronic and steric effects of unsymmetric configurations with Salen-like ligands or their derivatives would provide more structural changes and coordination compounds [70][71][72][73][74][75] and would be expected to acquire new features [76]. ...
Solvent-induced trinuclear NiII complexes, [{Ni(L)(MeOH)}2(OAc)2Ni]·2MeOH (1), [{Ni(L)(EtOH)}2(OAc)2Ni]·2H2O (2), [{Ni(L)(n-PrOH)}2(OAc)2Ni]·2H2O (3) and [{Ni(L)(i-PrOH)}2(OAc)2Ni] (4), have been prepared with an unsymmetric Salamo-like ligand H2L, and characterized via X-ray crystallography, FT-IR, UV-Vis and fluorescence spectra. In complexes 1, 2, 3 and 4, there are two ligand (L)2− moieties, two acetato ligands, two coordinated methanol, ethanol, n-propanol or i-propanol molecules, respectively, as well as other crystallizing solvent molecules. Two acetato ligands coordinated to the three NiII ions via usual Ni-O-C-O-Ni bridges, and four µ-phenoxo oxygen atoms coming from two [NiL(solvent)] units coordinate to the central NiII ions. Although different solvents are induced in the complexes, all the NiII ions are six-coordinated and adopt geometries of distorted octahedron. Magnetic measurements were performed on complex 2, an intramolecular antiferromagnetic interaction was observed between NiII ions and a simulation of the experimental data gives J = −2.96 cm−1 and g = 2.30.
