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1.
Complexes of the type [M(bssdh)]Cl and [M(dspdh)]Cl, where M = Co(II), Ni(II), Cu(II), Zn(II) and Cd(II); Hbssdh = benzil salicylaldehyde succinic acid dihydrazone, Hdspdh = diacetyl salicylaldehyde phthalic acid dihydrazone have been synthesized and characterized with the help of elemental analyses, electrical conductance, magnetic susceptibility measurements, electronic, ESR and IR spectra and X–ray diffraction studies. Magnetic moment values and electronic spectral transitions indicate a spin free octahedral structure for Co(II), Ni(II) and Cu(II) complexes. IR spectral studies suggest that both the ligands behave as monobasic hexadentate ligands coordinating through three > C = O, two > C = N– and a phenolate group to the metal. ESR spectra of Cu(II) complexes are axial type and suggest as the ground state. X–ray powder diffraction parameters for [Co(bssdh)]Cl and [Co(dspdh)]Cl complexes correspond to an orthorhombic crystal lattice. The ligands as well as their metal complexes show a significant antifungal and antibacterial activity against various fungi and bacteria. The metal complexes are more active than the parent ligands. 相似文献
2.
Graham A. Bowmaker Effendy Brian W. Skelton Allan H. White 《Inorganica chimica acta》2005,358(14):4307-4326
The meagre (structurally defined) array of 1:2 silver(I) (pseudo-)halide:unidentate nitrogen base adducts is augmented by the single-crystal X-ray structural characterization of the 1:2 silver(I) thiocyanate:piperidine (‘pip’) adduct. It is of the one-dimensional ‘castellated polymer’ type previously recorded for the chloride: ?Ag(pip)2(μ-SCN)Ag(pip)2? a single bridging atom (S) linking successive silver atoms. By contrast, in its copper(I) counterpart, also a one-dimensional polymer, the thiocyanate bridges as end-bound SN-ambidentate: ?CuSCNCuSCN? A study of the 1:1 silver(I) bromide:quinoline (‘quin’) adduct is recorded, as the 0.25 quin solvate, isomorphous with its previous reported ‘saddle polymer’ chloride counterpart.Recrystallization of 1:1 silver(I) iodide:tris(2,4,6-trimethoxyphenyl)phosphine (‘tmpp’) mixtures from py and quinoline (‘quin’)/acetonitrile solutions has yielded crystalline materials which have also been characterized by X-ray studies. In both cases the products are salts, the cation in each being the linearly coordinated silver(I) species [Ag(tmpp)2]+, while the anions are, respectively, the discrete [Ag5I7(py)2]2− species, based on the already known but unsolvated [Cu5I7]2− discrete, and the polymeric, arrays, and polymeric . The detailed stereochemistry of the [Ag(tmpp)2]+ cation is a remarkably constant feature of all structures, as is its tendency to close-pack in sheets normal to their P-Ag-P axes.The far-IR spectra of the above species and of several related complexes have been recorded and assigned. The vibrational modes of the single stranded polymeric AgX chains in [XAg(pip)2](∞|∞) (X = Cl, SCN) are discussed, and the assignments ν(AgX) = 155, 190 cm−1 (X = Cl) and 208 cm−1 (X = SCN) are made. The ν(AgX) and ν(AgN) modes in the cubane tetramers [XAg(pip)]4 (X = Br, I) are assigned and discussed in relation to the assignments for the polymeric AgX:pip (1:2) complexes, and those for the polymeric [XAg(quin)](∞|∞) (X = Cl, Br) compounds. The far-IR spectra of [Ag(tmpp)2]2[Ag5I7(py)2] and its corresponding 2-methylpyridine complex show a single strong band at about 420 cm−1 which is assigned to the coordinated tmpp ligand in [Ag(tmpp)2]+, and a partially resolved triplet at about 90, 110 and 140 cm−1 which is assigned to the ν(AgI) modes of the [Ag5I7L2]2− anion. An analysis of this pattern is given using a model which has been used previously to account for unexpectedly simple ν(CuI) spectra for oligomeric iodocuprate(I) species. 相似文献
3.
Ruihu Wang Junhua Luo Feilong Jiang Lei Han Zhenzhong Lin Rong Cao 《Inorganica chimica acta》2004,357(1):103-114
Six hydrogen-bonded silver(I) complexes, Ag(4-abaH)2(NO3) (1), [Ag(4-abaH)2(NO3)]n (2), {[Ag(4-aba)(4-abaH)] · H2O}n (3), {[Ag(4,4′-bipy)(H2O)](4-aba)0.5(NO3)0.5 · (H2O)0.5}n (4), [Ag[(3-abaH0.5)2] (5), and {[Ag(3-aba)] · H2O}n (6) (4-abaH=4-aminobenzoic acid, 3-abaH=3-aminobenzoic acid), have been synthesized and characterized by single-crystal X-ray diffraction analyses. In 1, 4-abaH serves as a monodentate ligand coordinating to Ag(I) through its nitrogen atom, while uncoordinated carboxylic group links (4-abaH)-Ag-(4-abaH) into a one-dimensional metallic carboxylic synthon. 2 may be regarded as an extension of 1 into a two-dimensional carboxylic synthon through NO3 − bridging two adjacent Ag(I) centers. In 3, 4-abaH in a monodentate mode and 4-aba in a μ-N,O bridging mode link three-coordinated Ag(I) to form a one-dimensional swallow-like chain, which is further extended into a two-dimensional layer structure through inter-chain hydrogen bonding interactions. The alternating Ag(I) and 4,4′-bipy in 4 give rise to a slightly distorted linear chain, which is further extended into a two-dimensional layer through the completely overlapping and off-set stacking interactions. The hydrogen bonds involving in weakly coordinated aqueous molecules and 4-aba further extend it into a three-dimensional framework. In 5, the inter-molecular hydrogen bonding and π-π stacking interactions extend Ag[(3-abaH0.5)2] into a two-dimensional supramolecular architecture. In 6, 3-aba in a μ3-N,O,O′ coordination mode links three three-coordinated Ag(I) into a two-dimensional network. Uncoordinated aqueous molecules and the adjacent 3-aba oxygen atoms form intermolecular hydrogen bonds. 相似文献
4.
Santini C Pellei M Papini G Morresi B Galassi R Ricci S Tisato F Porchia M Rigobello MP Gandin V Marzano C 《Journal of inorganic biochemistry》2011,105(2):232-240
Hydrophilic, monocationic [M(L)4]PF6 complexes (M = Cu or Ag; L: thp = tris(hydroxymethyl)phosphine, L: PTA = 1,3,5-triaza-7-phosphaadamantane, L: thpp = tris(hydroxypropyl)phosphine) were synthesized by ligand exchange reaction starting from [Cu(CH3CN)4]PF6 or AgPF6 precursors at room temperature in the presence of an excess of the relevant phosphine. The related [Au(L)4]PF6 complexes (L = thp, PTA or thpp) were synthesized by metathesis reactions starting from [Au(L)4]Cl at room temperature in the presence of equimolar quantity of TlPF6. The three series of complexes [M(L)4]PF6 were tested as cytotoxic agents against a panel of several human tumour cell lines also including a defined cisplatin resistant cell line. These investigations have been carried out in comparison with the clinically used metallodrug cisplatin and preliminary structure-activity relationships are presented. The best results in terms of in vitro antitumour activity were achieved with metal-thp species and, among the coinage metal complexes, copper derivatives were found to be the most efficient drugs. Preliminary studies concerning the mechanism of action of these [M(L)4]PF6 species pointed to thioredoxin reductase as one of the putative cellular targets of gold and silver complexes and provided evidence that copper derivatives mediated their cytotoxic effect through proteasome inhibition. 相似文献
5.
Graham A. Bowmaker Effendy Maksum Nitiatmodjo Allan H. White 《Inorganica chimica acta》2005,358(14):4327-4341
Syntheses and room-temperature single crystal X-ray structural characterizations are recorded for a variety of silver(I) oxyanion (perchlorate, nitrate and trifluoroacetate (‘tfa’) (increasing basicity)) adducts, AgX, with a number of pyridine (‘py’) bases, L, functionalized in the 2-position with N- or O-donor groups, namely 2-amino-, 2-amino-6-methyl-, 2-aminomethyl-, 2-hydroxy-, 2-methoxy- and 2-acetyl- pyridines, ‘2np’, ‘nmp’, ‘amp’, ‘ohp’, ‘mop’, and ‘acp’. A variety of stoichiometries and associated structural types are defined: [Ag(chelate)2]X, L/X = amp,acp/ClO4, [XAg(chelate)2], L/X = acp/tfa, of 1:2 AgX:L stoichiometry; for 1:1 stoichiometry, although a discrete mononuclear complex [(chelate)Ag(O2NO)] is defined for AgNO3: acp (1:1), all others are polymers, successive silver atoms being linked by N,N′-bridging ligands singly (L/X = 2np/ClO4 (?HAgHTAgTHAgH?), amp/ClO4, NO3 (?HTAgHTAg?) (‘H’ ≡ head, ‘T’ = tail)) or pairwise, ?L2AgX2AgL2Ag? (L/X = 2np/tfa, nmp/NO3). More complex polymeric arrays are found with L/X = ohp/NO3, tfa, where interaction with the metal takes place via the O-donor only, the py functionality being protonated, and in adducts of more complex stoichiometry AgNO3:mop (2:3) and AgNO3:2np (3:4). 相似文献
6.
Maurizio Casarin Daniel Forrer Federica Garau Claudio Pettinari 《Inorganica chimica acta》2009,362(12):4358-442
Density functional theory has been used to study the electronic structure of [M(tp)] and [M(tpm)]+ conformers (M = Cu, Ag; tp = tris(pyrazol-1-yl)borate anion, tpm = tris(pyrazol-1-yl)methane) and the energetics of their interconversions. Results for the free tp ligand are similar to those of tpm [M. Casarin, D. Forrer, F. Garau, L. Pandolfo, C. Pettinari, A. Vittadini, J. Phys. Chem. A 112 (2008) 6723], indicating an intrinsic instability of the tripodal conformation (κ3-like). This points out that, though frequently observed, the κ3-coordinative mode is unlikely to be directly achieved through the interaction of M(I) with the κ3-like tp/tpm conformer. Analogously to the [M(tpm)]+ molecular ions, the energy barrier for the κ2-[M(tp)] → κ3-[M(tp)] conversion is computed to be negligible. Though κn-[M(tp)] and κn-[M(tpm)]+ (n = 1, 2, 3) have similar metal-ligand covalent interactions, the negative charge associated to the tp ligand makes the M-tp bonding stronger. 相似文献
7.
《Bioorganic & medicinal chemistry》2016,24(16):3649-3656
Novel benzimidazolium salts were synthesized as N-heterocyclic carbene (NHC) precursors, these NHC precursors were metallated with Ag2O in dichloromethane at room temperature to give novel silver(I)–NHC complexes. Structures of these benzimidazolium salts and silver(I)–NHC complexes were characterized on the basis of elemental analysis, 1H NMR, 13C NMR, IR and LC–MS spectroscopic techniques. A series of benzimidazolium salts and silver(I)–NHC complexes were tested against standard bacterial strains: Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and the fungal strains: Candida albicans and Candida tropicalis. The results showed that benzimidazolium salts inhibited the growth of all bacteria and fungi strains and all silver(I)–NHC complexes performed good activities against different microorganisms. 相似文献
8.
The crystal structures of two 1:1 ligand-silver(I) cyanide complexes, [Ag(CN)(en)] (en = ethane-1,2-diamine) (1) and [Ag(CN)(pn)] (pn = propane-1,2-diamine) (2), and of two 2:1 ligand-silver(I) cyanide compounds, [(AgCN)2 · tn] (tn = propane-1,3-diamine) (3) and [(AgCN)2 · bn] (bn = butane-1,4-diamine) (4), were determined from single-crystal X-ray diffraction data, collected at 173 K. In 1 and 2, mononuclear AgCN complexes are formed, in which silver(I) is coordinated by one cyanide and one chelating alkanediamine donor ligand. However, in the dinuclear adducts of 3 and 4, two AgCN units are connected by one alkane-1,n-diamine bridging ligand (n = 3, 4). The resulting molecules of 1-4 are cross-linked via N-H?N hydrogen bonds. Apart from these intermolecular contacts, comparatively short Ag(I)-Ag(I) distances of 3.182(1) Å (in 1), 3.267(1) Å (in 2), 3.023(2) Å (in 3) and 3.050(2) Å (in 4) occur. 相似文献
9.
In this paper the oxygenation of HDTHCo homo and heterodinuclear complexes with Cu(II), Ni(II) and Pb(II) in aqueous solution by control of the stoichiometry of metal ions and HDTH as well as p[H] of solution was investigated (HDTH is a dinucleating 28-membered hexaazadiphenol macrocyclic ligand, 3,7,11,19,23,27-hexaaza-33,34-dihydroxy-15,31-dimethyl-tricyclo-tetratriaconta-1(32),13,15,17(34),29(33),30-hexaene). The pH potentiometric method was utilized successfully to determine oxygenation constants and to determine the distribution of species present in the solution as a function of p[H]. Spectrophotometry was used to investigate the oxygenation process of the homo and heterodinuclear complexes. The X-ray crystal structure of homodinuclear complexes of Ni(II) is also reported. These studies suggested autooxidation takes place during the oxygenation of homo and heterodinuclear Co(II) complexes of the macrocyclic ligand. The neighboring effect increases in the order Ni(II)<Cu(II)<Pb(II)<Co(II). Pb(II) stimulates the neighboring Co(II) to accept dioxygen in its sixth vacant position. Ni(II) is not helpful to Co(II) in its oxygenation. 相似文献
10.
Phil J. Cox Paraskevas Aslanidis Petros Karagiannidis Sotiris Hadjikakou 《Inorganica chimica acta》2000,310(2):268-272
Mixed-ligand complexes of the formula [Ag(PPh3)(L)Br]2 were obtained by treatment of various heterocyclic thiones L {L=pyridine-2-thione (py2SH), pyrimidine-2-thione (pymtH), benz-1,3-imidazoline-2-thione (bzimtH2), benz-1,3-thiazoline-2-thione (bztztH), 1-methyl-1,3-imidazoline-2-thione (meimtH) and 5-methoxy-benz-1,3-imidazoline-2-thione (5MeObzimtH2)} with equivalent quantities of silver(I) bromide and triphenylphosphine in dry acetone. The compounds were characterized by their IR, far-IR, UV–Vis and 1H NMR spectroscopic data. The crystal structure of [Ag(PPh3)(pymtH)Br]2 was determined by single-crystal X-ray diffraction methods. The complex exhibits a planar Ag2Br2 moiety in which each of the doubly bromine-bridged Ag(I) centres is further bonded to one phosphine P and one thione S atom. 相似文献
11.
A series of eight new carboxylate complexes of the general type (L)nMOC(O)R (L=PMe3; n=1; M=Ag, Au; R=C2F5. L=PPh3; n=1-3; M=Ag; R=C2F5, t-Bu) have been prepared in high yields. Crystal and molecular structures have been determined for three representative examples. The crystal structure of (Ph3P)AgOC(O)C2F5 contains dimers in which the silver atoms are bridged by the carboxylate oxygen atoms. This bridging resembles the structural motif found in silver carboxylates without ligand support. Usage of the smaller phosphine PMe3 leads to the formation of a polymeric chain structure in (Me3P)AgOC(O)C2F5 with bridging carboxylate anions and short Ag-Ag contacts holding the monomers together. The reaction of (4-Me2N-C6H4)Ph2 PAuCl with two equivalents of C2F5CO2Ag leads to the formation of a mixed metal product containing both gold and silver. The crystal structure analysis of this compound revealed a tetranuclear complex containing a central dimeric silver pentafluoropropionate unit which is chelated by the (triarylphosphine)gold(I) pentafluoropropionate molecules via Ag-Au metallophilic contacts and Ag-O donor/acceptor interactions. 相似文献
12.
Graham A. Bowmaker Effendy Kevin C. Lim Dedek Sukarianingsih 《Inorganica chimica acta》2005,358(14):4342-4370
Synthetic, single crystal X-ray structural characterizations and vibrational spectroscopic studies are recorded for a number of adducts of 1:2 stoichiometry of silver(I) oxyanion salts for oxyanions of differing basicity (perchlorate, nitrate, carboxylate (as trifluoroacetate (≡‘tfa’))), with a variety of pyridine (≡‘py’) or piperidine (≡‘pip’) bases hindered in the 2- (and, sometimes, 6-) position(s) by methyl or non-coordinating functionalities of other types, the ligands employed being 2-methylpyridine (‘2mp’), 2,6-dimethylpyridine (‘lut’), 2,4,6-trimethylpyridine (‘coll’), quinoline (‘quin’), 2,2,6,6-tetramethylpiperidine (‘tmp’), 2-amino-,6-methylpyridine (‘nmp’), 2-methoxypyridine (‘mop’) and 2-cyanomethylpyridine (‘pcn’); studies are also recorded of adducts with the parent, ‘py’, base and with 4-cyanopyridine (‘cnp’). In the majority of the complexes, the NAgN motif predominates, as might be expected, variously distorted from linearity in response to changes in (competing) basicities of the nitrogen base and any nearby anion or solvent molecule; an unusual variation is found in the highly hindered tmp/tfa adduct which is a monohydrate with interacting water displacing the rather basic anion, the converse being the case in the corresponding nitrate, also a monohydrate. With the less-hindered base mpy, both nitrate and trifluoroacetate are binuclear, with O and OCO bridges corresponding to centrosymmetric four- and eight-membered rings, respectively; the quin/nitrate adduct is more complex, also binuclear but with bis(chelating) nitrate. AgNO3:py (1:3) is found to be binuclear, while with Agtfa/py, a 3:2 adduct [Ag(py)2][Ag2(tfa)3](∞|∞) is found with a novel, polymeric, strongly interacting anion. A further pair of 1:3 adducts, AgNO3:2np (2np = 2-aminopyridine) and Agtfa:nmp, both mononuclear [AgL3]+X− are described, differing in the modes of interaction of silver with the three N-bases. In all simple NAgN systems with aromatic ligands, the pair of ligand ‘planes’ is disposed quasi-parallel.The far-IR spectra of [AgL2]Y (L = lut, coll; Y = ClO4, NO3, tfa) and of [Ag(py)n](ClO4) (n = 2,4) have been recorded and the ν(AgN) bands assigned in the range 80-240 cm−1. For the L = lut, coll complexes, there is a clear trend of decreasing ν(AgN) following increasing r(AgN) as the interaction with the counterion increases along the series Y = ClO4, NO3, tfa. 相似文献
13.
Valentin A. Sharnin Alexandra S. Gushchina Konstantin V. Grazhdan 《Inorganica chimica acta》2009,362(2):437-5140
The complex formation between silver(I) and nicotinamide as well as between copper(II) and nicotinamide in water-ethanol and water-dimethylsulfoxide media was studied by means of potentiometric technique. The heat of complex formation was measured using the method of precision calorimetry. The experimental data have been considered from the point of view of thermodynamic characteristics of the reagents and their solvation. 相似文献
14.
Yusaku Suenaga Kouzou KitamuraTakayoshi Kuroda-Sowa Masahiko MaekawaMegumu Munakata 《Inorganica chimica acta》2002,328(1):105-110
Silver(I) complexes of hexakis(tolylsulfanyl)benzene (htsb), [Ag(htsb)](PF6) (1), have been prepared and their molecular structures were determined by X-ray crystallography. In 1, the silver ion prefers a square planar coordination geometry comprized of four S atoms from two different htsb molecules and producing a zigzag chain structure of AgS in the silver coordination polymer. Based on the thermo-gravimetry analysis results, two tolylsulfanyl groups were easily eliminated at approximately 211 °C. However, [Ag(htsb)(2-butanone)] (PF6) (2), which were obtained by the reactions in different solvents, showed a different colors and thermal degradation behaviors. 相似文献
15.
Okan Zafer Ye?ilel Gökhan Ka?ta? ?nci ?lker Orhan Büyükgüngör 《Inorganica chimica acta》2010,363(8):1849-91
Five new silver(I)-saccharinate complexes [Ag2(sac)2(tmen)2] (1), [Ag2(sac)2(deten)2] (2), [Ag2(sac)2(dmen)2] (3), [Ag(sac)(N,N-eten)] (4), and [Ag(sac)(dmpen)]n (5); (sac = saccharinate, tmen = N,N,N′,N′-tetramethylethylenediamine, deten = N,N′-diethylethylenediamine, dmen = N,N′-dimethylethylenediamine, N,N-eten = N,N-diethylethylenediamine and dmpen = 1,3-diamino-2,2-dimethylpropan) have been synthesized and characterized by elemental analyses, IR, thermal analyses, single crystal X-ray diffraction and antimicrobial activities. The crystallographic analyses show that all the complexes crystallize in monoclinic space group P21/c. In 1, the sac ligand acts as a bridge to connect the silver centres through its imino N and carbonyl O atoms forming an eight-membered bimetallic ring in a chair conformation. Complex 2 has also a dimeric structure in which the monomeric [Ag(sac)(deten)] units are linked by Ag?Ag interactions. In 3, saccharinate ligand acts as a bridging bidentate ligand between two silver(I) centres through sulfonyl group and imino N atom, forming an alternating polymeric chain through the direction [0 1 0]. In 4, the inter-molecular N-H?O hydrogen bonds form one-dimensional polymeric chains through the a axis, and these linear chains are inter-connected to each other by N-H?O hydrogen bonds, which produce a chain of edge-fused and rings along [1 0 0]. Complex 5 is a coordination polymer in which the monomeric [Ag(dmpen)(sac)]n units are linked by Ag?Ag interactions, and the dmpen ligand acts as a bridge between the silver(I) ions, forming a two-dimensional network parallel to the (1 0 0) plane. 相似文献
16.
Mixed ligand complexes: [Co(L)(bipy)] · 3H2O (1), [Ni(L)(phen)] · H2O (2), [Cu(L)(phen)] · 3H2O (3) and [Zn(L)(bipy)] · 3H2O (4), where L2− = two -COOH deprotonated dianion of N-(2-benzimidazolyl)methyliminodiacetic acid (H2bzimida, hereafter, H2L), bipy = 2,2′ bipyridine and phen = 1,10-phenanthroline have been isolated and characterized by elemental analysis, spectral and magnetic measurements and thermal studies. Single crystal X-ray diffraction studies show octahedral geometry for 1, 2 and 4 and square pyramidal geometry for 3. Equilibrium studies in aqueous solution (ionic strength I = 10−1 mol dm−3 (NaNO3), at 25 ± 1 °C) using different molar proportions of M(II):H2L:B, where M = Co, Ni, Cu and Zn and B = phen, bipy and en (ethylene diamine), however, provides evidence of formation of mononuclear and binuclear binary and mixed ligand complexes: M(L), M(H−1L)−, M(B)2+, M(L)(B), M(H−1L)(B)−, M2(H−1L)(OH), (B)M(H−1L)M(B)+, where H−1L3− represents two -COOH and the benzimidazole N1-H deprotonated quadridentate (O−, N, O−, N), or, quinquedentate (O−, N, O−, N, N−) function of the coordinated ligand H2L. Binuclear mixed ligand complex formation equilibria: M(L)(B) + M(B)2+ ? (B)M(H−1L)M(B)+ + H+ is favoured with higher π-acidity of the B ligands. For Co(II), Ni(II) and Cu(II), these equilibria are accompanied by blue shift of the electronic absorption maxima of M(II) ions, as a negatively charged bridging benzimidazolate moiety provides stronger ligand field than a neutral one. Solution stability of the mixed ligand complexes are in the expected order: Co(II) < Ni(II) < Cu(II) > Zn(II). The Δ log KM values are less negetive than their statistical values, indicating favoured formation of the mixed ligand complexes over the binary ones. 相似文献
17.
Zinc(II) complexes of N3O-donor tripodal ligands, 2,4-di(tert-butyl)-6-{[bis(2-pyridyl)methyl]aminomethyl}phenol (HtbuL), 2,4-di(tert-butyl)-6-{[(6-methyl-2-pyridyl)methyl]-(2-pyridyl)methylaminomethyl}phenol (HtbuLMepy), and 2,4-di(tert-butyl)-6-{[bis(6-methyl-2-pyridyl)methyl]aminomethyl}phenol (HtbuL(Mepy)2), [Zn(tbuL)Cl] · CH3OH (1), [Zn(tbuLMepy)Cl] (2), and [Zn(tbuL(Mepy)2)Cl] (3), respectively, were prepared and structurally characterized by the X-ray diffraction method. All the complexes were found to have a mononuclear structure with a coordinated phenolate moiety, the geometry of the Zn(II) center being 5-coordinate trigonal-bipyramidal. The Zn(II) binding ability of the ligands with and without 6-methyl-2-pyridylmethyl moieties was evaluated for similar ligands, which lacked the t-butyl groups at the 2- and 4-positions of the phenol moiety, by the stability constants determined by potentiometric titration at 25 °C (I = 0.1 M (KNO3)). The stability of the complexes was found to be in the order L > LMepy > L(Mepy)2, reflecting the steric hindrance of the 6-methyl group of the pyridine ring. Complexes 1, 2, and 3 were converted to the phenoxyl radicals upon oxidation with Ce(IV), giving a phenoxyl radical π-π∗ transition band at 394-407 nm. ESR and resonance Raman spectra established that the radical species had a Zn(II)-phenoxyl radical bond. The cyclic voltammograms showed similar quasi-reversible redox waves with E1/2 = 0.68, 0.67, and 0.63 V (versus Ag/AgCl) for 1, 2, and 3, respectively, corresponding to the formation of the phenoxyl radical, which displayed a first-order decay. The half-lives, 58.6, 25.8, and 15.6 min at −40 °C for 1, 2, and 3, respectively, follow the order of the stability constants of the complexes, indicating that the metal(II)-phenoxyl radical stability is in close relationship with the complexation properties of the present series of N3O-donor ligands. 相似文献
18.
Susmita Bandyopadhyay G.N. Mukherjee Andrea Cantoni Siddhartha Chaudhuri 《Inorganica chimica acta》2004,357(12):3563-3573
Combined pH-metric, UV-Vis, 1H NMR and EPR spectral investigations on the complex formation of M(II) ions (M=Co, Ni, Cu and Zn) with N-(2-benzimidazolyl)methyliminodiacetic acid (H2bzimida, hereafter H2L) in aqueous solution at a fixed ionic strength, I=10−1 mol dm−3, at 25 ± 1 °C indicate the formation of M(L), M(H−1L)− and M2(H−1L)+ complexes. Proton-ligand and metal-ligand constants and the complex formation equilibria have been elucidated. Solid complexes, [M(L)(H2O)2] · nH2O (n=1 for M = Co and Zn, n=2 for M = Ni) and {Cu (μ-L) · 4H2O}n, have been isolated and characterized by elemental analysis, spectral, conductance and magnetic measurements and thermal studies. Structures of [Ni(L)(H2O)2] · 2H2O and {Cu(μ-L) · 4H2O}n have been determined by single crystal X-ray diffraction. The nickel(II) complex exists in a distorted octahedral environment in which the metal ion is coordinated by the two carboxylate O atoms, the amino-N atom of the iminodiacetate moiety and the pyridine type N-atom of the benzimidazole moiety. Two aqua O atoms function as fifth and sixth donor atoms. The copper(II) complex is made up of interpenetrating polymeric chains of antiferromagnetically coupled Cu(II) ions linked by carboxylato bridges in syn-anti (apical-equatorial) bonding mode and stabilized via interchain hydrogen bonds and π-π stacking interactions. 相似文献
19.
The reactions of a self-assembled silver(I) coordination polymer, [Ag2{μ-PriN(PPh2)2}(μ-NO3)2]n (1) with various bidentate N-donor ligands such as DABCO, 2,2′-bipyridyl and 1,10-phenanthroline yield 1-D helices or π-π stacked polymers, depending on the chelate vector of the N-donor ligand. The molecular structures of the resultant complexes, [Ag2{μ-PriN(PPh2)2}(DABCO)(NO3)2]n (2), [Ag2{μ-PriN(PPh2)2}(2,2′-bipy)2(NO3)2] (3) and [Ag2{μ-PriN(PPh2)2}(1,10-phen)2](NO3)2 (4) have been confirmed by single-crystal X-ray diffraction. Complex 2 exists as an infinite helical polymer because of the exo-bidentate nature of DABCO. Complex 3 assumes a 2D grid motif as a result of intermolecular π-π stacking among adjacent bipyridine moieties. The phenanthroline complex 4 exhibits strong inter- and intramolecular π-π stacking interactions. 相似文献
20.
Hadjikakou SK Ozturk II Xanthopoulou MN Zachariadis PC Zartilas S Karkabounas S Hadjiliadis N 《Journal of inorganic biochemistry》2008,102(5-6):1007-1015
An overview of our work on the synthesis and biological activity of a series of tin(IV), silver(I) and antimony(III) complexes with thioamides is reported. Organotin(IV) complexes of formulae (n-Bu)2Sn(MBZT)2 (1), Me2Sn(CMBZT)(2) (2), {(Ph3Sn)2(MNA) (Me2CO)} (3), Ph3Sn(MBZT) (4), Ph3Sn(MBZO) (5), Ph3Sn(CMBZT) (6), Ph2Sn(CMBZT)2 (7) and (n-Bu)2Sn(CMBZT)2 (8), Me2Sn(PMT)2 (9), (n-Bu)2Sn(PMT)2 (10), Ph2Sn(PMT)2 (11), Ph3Sn(PMT) (12) {where MBZT=2-mercapto-benzothiazole, CMBZT=5-chloro-2-mercapto-benzothiazole, H2MNA=2-mercapto-nicotinic acid, MBZO=2-mercapto-benzoxazole and PMTH=2-mercapto-pyrimidine} were characterized by spectroscopic (NMR, IR, Mossbauer, etc.) and X-ray diffraction techniques and their influence on the peroxidation of oleic acid was studied. They were found to inhibit strongly the peroxidation of linoleic acid by the enzyme lipoxygenase. In addition, organotin(IV) complexes were found to exhibit stronger cytotoxic activity in vitro, against leiomyosarcoma cells, than cisplatin. The antiproliferative activity of the organotin complexes studied, against leiomyosarcoma cells follow the same order of LOX activity inhibition. This is, 3>12>7>6 approximately 8 approximately 10>5 approximately 4>2>9. Thus, among organotin(IV)-CMBZT complexes, 7 exhibits higher activity than the others and this is explained by a free radical mechanism, as it is revealed by an EPR study. The results are compared with the corresponding ones found for the silver(I) complexes of formulae complexes {[Ag6(mu3-HMNA)4(mu3-MNA)2](2-).[(Et(3)NH)+]2.(DMSO)2.(H2O)} (13), {[Ag4Cl4(mu3-STHPMH2)4]n} (14), {[Ag6(mu2-Br)6(mu2-STHPMH2)4(mu3-STHPMH2)2]n} (15), {[Ag4(mu2STHPMH2)6](NO3)4}(n) (16), {[AgCl(TPTP)]4} (17), [AgX(TPTP)3] with X=Cl (18), Br (19), I (20) (where STHPMH2=2-mercapto-3,4,5,6-tetrahydro-pyrimidine, TPTP=tri(p-toly)phosphine) and those of antimony(III) complexes {[SbCl2(MBZIM)4](+).Cl(-).2H2O.(CH3OH)} (21), {[SbCl2(MBZIM)4]+.Cl(-).3H2O.(CH3CN)} (22), [SbCl3(MBZIM)2] (23), [SbCl3(EMBZIM)2] (24), [SbCl3(MTZD)2] (25), {[SbCl3(THPMT)2]} (26) and {[Sb(PMT)3].0.5(CH3OH)} (27) (where MBZIM is 2-mercapto-benzimidazole, EMBZIM=5-ethoxy-2-mercapto-benzimidazole and MTZD is 2-mercapto-thiazolidine), which they have characterized with similar techniques as in case of organotin(IV) complexes. Silver(I) and antimony(III) complexes were found to be cytotoxic against various cancer cell lines. 相似文献