共查询到20条相似文献,搜索用时 15 毫秒
1.
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
2.
Four related ruthenium(III) complexes, with the formula mer-[RuCl3(dmso)(N−N)] (dmso = dimethyl sulfoxide; N−N = 2,2′-bipyridine (1), 1,10-phenantroline (2), dipyrido[3,2-f:2′,3′-h]quinoxaline (3) and dipyrido[3,2-a:2′,3′-c]phenazine (4)), have been reported. Complexes 3 and 4 are newly synthesized and characterized by X-ray diffraction. The hydrolysis process of 1-4 has been studied by UV-vis measurement, and it has been found that the extension of the N−N ligands can increase the stability of the complexes. The binding of these complexes with DNA has been investigated by plasmid cleavage assay, competitive binding with ethidium bromide (EB), DNA melting experiments and viscosity measurements. The DNA binding affinity is increased with the extension of the planar area of the N−N ligands, and complex 4 shows an intercalative mode of interaction with DNA. The in vitro anticancer activities of these compounds are moderate on the five human cancer cell lines screened. 相似文献
3.
Vitalie Stavila Aurelian Gulea Sergiu Shova Peter Petrenko Fabrice Riblet 《Inorganica chimica acta》2004,357(7):2060-2068
Two novel cobalt(III)-bismuth(III) heterometallic compounds [Co(NxH)2(An)2]2[Bi(EDTA)(H2O)]2 · 7H2O (1) and [Co(NxH)2(p-Tol)2][Bi(EDTA)] · 4H2O (2) [An-aniline, p-Tol-para-toluidine, NxH-1,2-cyclohexanedionedioximate-ion, EDTA-ethylenediaminetetraacetate-ion] have been synthesized and characterized by NMR, thermogravimetry and single X-ray crystallography. Substitution of the aniline by para-toluidine molecules leads to radical changes in the anionic sub-lattice: from monomeric form to polymeric one. The coordination number of bismuth is 7+1 in 1, and 8 in 2; Bi coordination polyhedron in 1 can be described as a two-capped trigonal prism, while in 2 as a dodecahedron. The Co atoms in 1 and 2 have an octahedral coordination. NMR spectroscopy in DMSO solution confirms the trans-configuration of the complex cations in 1 and 2 by observation of a broad singlet of two symmetric hydrogen bonds. The NCH2CH2N component of EDTA ligand is in the domain of the fast exchange and the signal from this group is a singlet, while four acetate methylene protons give rise to an AB quartet system. It was shown that thermolysis of 1 and 2 occurs in three successive stages, via the dehydration, pyrolysis of the ligands and, finally, the formation of a sillenite-type phase Bi26−xCoxO40−δ and small quantities of Co3O4. 相似文献
4.
A novel Ru(III) complex, mer-[RuCl(3)(CH(3)CN)(dpq)] (1), has been synthesized and characterized by X-ray diffraction, where dpq=dipyrido[3,2-d:2',3'-f]quinoxaline. Its chemical and biological properties have been intensively compared with those of mer-[RuCl(3)(DMSO)(dpq)] (DMSO=dimethyl sulfoxide) (2). It has been found that the stability in buffered solutions and the reduction potential for the Ru(III)/Ru(II) couple can be modulated by changing the small molecule bonded to the Ru(III) center. Interactions of 1 with DNA have been investigated by DNA melting experiments, DNA competitive binding with EB (ethidium bromide), plasmid DNA cleavage experiments and viscosity measurements. The interaction of 1 and 2 with BSA (bovine serum albumin) has also been studied using fluorescent quenching method. The experimental results show that 1 exerts higher affinity towards DNA and BSA than 2 does. The cytotoxicity of 1 has been evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) method, and 2 shows slightly higher anticancer potency than 1 does against all the cell lines screened. Attempts are made to clarify the possible antitumor mechanisms of these two complexes by analyzing the experimental results presented. 相似文献
5.
Metal complexes of d-glucose (d-Glc) from large cation containing dibromo-dichloro salts of dipositive metals [NEt4]2[MBr2Cl2] (M = Mn, Co, Ni, Cu and Zn) and the disodium salt of glucose were synthesized from a MeOH:MeCN mixture. The complexes were characterized by UV-vis absorption, circular dichroism, IR and proton magnetic resonance spectroscopies, and by elemental analysis, and were found to be Na[M(d-Glc)(OMe)Cl]. Cyclic voltammetric studies of these complexes, in the acidic to neutral pH range, indicated no dissociation, even in highly acidic conditions.This paper is dedicated to Professor Richard H. Holm (Harvard University) on the occasion of his 60th birthday. 相似文献
6.
Anticarcinogenic effects of hexaamminecobalt(III) chloride in mice initiated with diethylnitrosamine
Hexaamminecobalt(III) chloride ([Co(NH3)6]Cl3) was investigated for its antineoplastic role in relation to tumor marker enzymes, drug metabolizing enzymes, oxidative stress-related
parameters, and histopathological analysis of liver and lung tissues of mice. Initiation was performed using a single intraperitoneal
injection of diethylnitrosamine (DENA) at a carcinogenic dose of 90 mg/kg body weight. The cobalt complex supplementation
at a dose of 100 ppm in drinking water was given ad libitum throughout the experimental period of 14 weeks. In comparison
to lung, the cobalt complex supplementation was found to reverse DENA-induced biochemical changes more effectively in liver.
Histological examination of liver and lung from DENA-initiated and cobalt-complex-supplemented mice showed considerable protection
in the case of liver compared to that of lung. The involvement of the [Co(NH3)6]Cl3 in modulating several factors associated with carcinogenesis induced by DENA thus showed its anticarcinogenic potential against
chemically induced hepatocarcinogenesis. 相似文献
7.
Ahmed Alagha Declan Gaynor Zoya A. Starikova Eimear C. O’Brien Kevin B. Nolan 《Inorganica chimica acta》2011,368(1):58-66
The attempted acetylation of anthranilic hydroxamic acid (2-aminobenzohydroxamic acid) as a possible dual inhibitor of the catalytic sites in prostaglandin-H-synthase (PGHS) gave the cyclic hydroxamic acid 3-hydroxy-2-methyl-3H-quinazolin-4-one (ChaH) which was characterised by spectroscopy and X-ray crystallography. The length of the hydroxamic acid C-N bond, 1.3998(17) Å, in ChaH is longer than normal (∼1.33 Å) indicative of reduced delocalisation of the nitrogen lone pair of electrons into the hydroxamic acid π system. This is confirmed by the appearance of the ν(CO) band at a considerably higher wavenumber in the IR spectrum than normal. The complexes Fe(Cha)2(Cl)(H2O)·7/2H2O, Co(Cha)2(EtOH)2, Ni(Cha)2(EtOH)2, Cu(Cha)(H2O)(Cl) and Zn(Cha)2(H2O), have been synthesised and their structures determined by X-ray crystallography. The X-ray data confirmed coordination by Cha- through the carbonyl and deprotonated hydroxamate oxygen in all cases. The M-O (hydroxamate) bonds are shorter than the M-O (carbonyl) bonds by between 0.0930 Å for the Co(II) complex and 0.0448 Å for the Ni(II) complex. The geometries of all complexes conform to the coordination requirements of the particular metal ion involved. Speciation studies for ChaH and its complexes with Ni(II) and Zn(II) were carried out using pH-metric methods. The results show that ChaH is much more acidic than related acyclic hydroxamic acids and that its metal complexes are correspondingly less stable. 相似文献
8.
The preparation and variable temperature-magnetic investigation of three squarate-containing complexes of formula [Fe2(OH)2(C4O4)2(H2O)4]·2H2O (1) [Cr2(OH)2(C4O4)2(H2O)4]·2H2O (2) and [Co(C4O4)(H2O)4]n (3) [H2C4O4 = 3.4-dihydroxycyclobutene-1,2-dione (squaric acid)] together with the crystal structures of 1 and 3 are reported. Complex 1 contains discrete centrosymmetric [Fe2(OH)2(C4O4)2(H2O)4] diiron(II) units where the iron pairs are joined by a di-μ-hydroxo bridge and two squarate ligands acting as bridging groups through adjacent oxygen atoms. Two coordinated water molecules in cis position complete the octahedral environment at each iron atom in 1. The iron-iron distance with the dinuclear unit is 3.0722(6) Å and the angle at the hydroxo bridge is 99.99(7)°, values which compare well with the corresponding ones in the isostructural compound 2 (2.998 Å and 99.47°) whose structure was reported previously. The crystal structure of 3 contains neutral chains of squarato-O1,O3-bridged cobalt(II) ions where four coordinated water molecules complete the six-coordination at each cobalt atom. The cobalt-cobalt separation across the squarate bridge is 8.0595(4) Å. A relatively important intramolecular antiferromagnetic coupling occurs in 1 whereas it is very weak in 2, the exchange pathway being the same [J = −14.4 (1) and −0.07 cm−1 (2), the spin Hamiltonian being defined as ]. A weak intrachain antiferromagnetic interaction between the high-spin cobalt(II) ions occurs in 3 (J = −0.30 cm−1). The magnitude and nature of these magnetic interactions are discussed in the light of their respective structures and they are compared with those reported for related systems. 相似文献
9.
John C. Bullinger 《Inorganica chimica acta》2009,362(12):4510-4516
New complexes have been synthesized of scorpionate ligands with cyano substituents in the 4-positions of the pyrazoles and tert-butyl substituents in the 3-positions of the pyrazoles. Reaction of Co2+, Mn2+, and Ni(cyclam)2+ (cyclam = 1,4,8,11-tetraazacyclotetradecane) with Tpt-Bu,4CN in a 1:2 ratio produced new octahedral metal complexes of the form (Tpt-Bu,4CN)2ML4 (L4 = (H2O)4, (H2O)2(MeOH)2, or cyclam). Unlike the sandwich complexes previously isolated with TpPh,4CN, the crystal structures showed none of the pyrazole nitrogen atoms coordinated to the metal. Rather, the metal is coordinated to one CN nitrogen atom from each ligand, with two Tp anions coordinated trans to each other around the metal center. This leaves the Tp pyrazole nitrogen atoms open for another metal to coordinate, which could to lead to heterometallic complexes, new coordination polymers, as well as the framework for supramolecular complexes. 相似文献
10.
Wilson Jacob 《Inorganica chimica acta》2006,359(14):4565-4573
We have prepared and structurally characterized six-coordinate Fe(II), Co(II), and Ni(II) complexes of types [MII(HL1)2(H2O)2][ClO4]2 (M = Fe, 1; Co, 3; and Ni, 5) and [MII(HL2)3][ClO4]2 · MeCN (M = Fe, 2 and Co, 4) of bidentate pyridine amide ligands, N-(phenyl)-2-pyridinecarboxamide (HL1) and N-(4-methylphenyl)-2-pyridinecarboxamide (HL2). The metal centers in bis(ligand)-diaqua complexes 1, 3 and 5 are coordinated by two pyridyl N and two amide O atoms from two HL1 ligands and six-coordination is completed by coordination of two water molecules. The complexes are isomorphous and possess trans-octahedral geometry. The metal centers in isomorphous tris(ligand) complexes 2 and 4 are coordinated by three pyridyl N and three amide O atoms from three HL2 ligands. The relative dispositions of the pyridine N and amide O atoms reveal that the pseudo-octahedral geometry have the meridional stereochemistry. To the best of our knowledge, this work provides the first examples of structurally characterized six-coordinate iron(II) complexes in which the coordination is solely by neutral pyridine amide ligands providing pyridine N and amide O donor atoms, with or without water coordination. Careful analyses of structural parameters of 1-5 along with that reported in the literature [MII(HL1)2(H2O)2][ClO4]2 (M = Cu and Zn) and [CoIII(L2)3] have allowed us to arrive at a number of structural correlations/generalizations. The complexes are uniformly high-spin. Spectroscopic (IR and UV/Vis) and redox properties of the complexes have also been investigated. 相似文献
11.
The crystal structures of the complexes [RuCl(Nap-o-phd)(AsPh3)] and [RuBr(Nap-o-phd)(PPh3)] (where H2-Nap-o-phd = N,N′-bis(2-hydroxy-1-naphthaldehyde) o-phenylenediamine) have been determined by single crystal X-ray diffraction techniques. The antibacterial properties of the complexes have also been examined. 相似文献
12.
Pap JS Kripli B Váradi T Giorgi M Kaizer J Speier G 《Journal of inorganic biochemistry》2011,105(6):911-918
Recently, a series of Fe(II) complexes have been published by our group with 3 N-donor 1,3-bis(2′-Ar-imino)isoindoline ligands containing various Ar-groups (pyridyl, 4-methylpyridyl, thiazolyl, benzimidazolyl and N-methylbenzimidazolyl). The superoxide scavenging activity of the compounds showed correlation with the Fe(III)/Fe(II) redox potentials. Analogous, electroneutral chelate complexes with Mn(II) and Ni(II) in 2:1 ligand:metal composition are reported here. Each Mn(II) complex exhibits one reversible redox wave that is assigned as the Mn(III)/Mn(II) redox transition. The E1/2 spans a 180 mV range from − 98 (Ar = 3-methylpyridyl) to 82 mV (Ar = thiazolyl) vs. the Fc+/Fc depending on the Ar-sidearm. The SOD-like (SOD=superoxide dismutase)activity of all complexes was determined according to the McCord-Fridovich method. The Mn(II) isoindolinates have IC50 values - determined with 50 μM cytochrome c Fe(III) - that range from (3.22 ± 0.39) × 10− 6 (Ar = benzimidazolyl) to (10.80 ± 0.54) × 10− 6 M (Ar = N-methylbenzimidazolyl). In contrast with the Fe(II) complexes, the IC50 concentrations show no significant dependence on the E1/2 values in this narrow potential range emphasizing that the redox potential is not the governing factor in the Mn(II)-containing scavengers. The analogous Ni(II) compounds show no redox transitions in the thermodynamically relevant potential range (− 0.40 to 0.65 V vs. SCE) and accordingly, their superoxide scavenging activity (if any) is below the detection level. 相似文献
13.
The acid-base and coordination properties towards Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) of four polyamino-phenol macrocycles 15-hydroxy-3,6,9-triazabicyclo[9.3.1]pentadeca-11,13,115-triene L1, 18-hydroxy-3,6,9,12-tetraazabicyclo[12.3.1]octadeca-14,16,118-triene L2, 21-hydroxy-3,6,9,12,15-pentaazabicyclo[15.3.1]enaicosa-17,19,121-triene L3 and 24-hydroxy-3,6,9,12,15,18-hexaazabicyclo[18.3.1]tetraicosa-20,22,124-triene L4 are reported. The protonation and stability constants were determined by means of potentiometric measurements in 0.15 mol dm−3 NMe4Cl aqueous solution at 298.1 K. L1 forms highly unsaturated Co(II), Cu(II), Zn(II) and Cd(II) mononuclear complexes that are prone to give dimeric dinuclear species with [(MH−1L1)2]2+ stoichiometry, in solution. L2 forms stable Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) mononuclear complexes that can coordinate external species as OH− anion, giving hydroxylated complexes at alkaline pH. L3 forms stable Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) mononuclear complexes and Co(II), Ni(II), Cu(II) and Zn(II) dinuclear [M2H−1L3]3+ species. L4 forms stable mono- and dinuclear Co(II), Cu(II), Zn(II) and Cd(II) complexes, but only mononuclear species with Pb(II). The effect of macrocyclic size is considered in the discussion of results. 相似文献
14.
B. Sreekanth G. Krishnamurthy H.S. Bhojya Naik T. K. Vishnuvardhan B. Vinaykumar N. Sharath 《Nucleosides, nucleotides & nucleic acids》2013,32(2):83-96
The two complexes containing bioactive ligands of the type and [Fe(L)] (PF6)2 (1) (where L = [1-{[2-{[2-hydroxynaphthalen-1-yl)methylidine]amino}phenyl)imino] methyl}naphthalene-2-ol]) and [Co(L1L2)] (PF6)3 (2) (where L1L2 = mixed ligand of 2-seleno-4-methylquinoline and 1,10-phenanthroline in the ratio 1:2, respectively) were synthesized and structurally characterized. The DNA binding property of the complexes with calf thymus DNA has been investigated using absorption spectra, viscosity measurements, and thermal denaturation experiments. Intrinsic binding constant Kb has been estimated at room temperature. The absorption spectral studies indicate that the complexes intercalate between the base pairs of the CT-DNA tightly with intrinsic DNA binding constant of 2.8 × 105 M?1 for (1) and 4.8 × 105 M?1 for (2) in 5 mM Tris-HCl/50 mM NaCl buffer at pH 7.2, respectively. The oxidative cleavage activity of (1) and (2) were studied by using gel electrophoresis and the results show that complexes have potent nuclease activity. 相似文献
15.
The 4-hydroxysalicylidenechitosan Schiff-base (2CS-Hdhba) was prepared by the condensation of 2,4-dihydroxybenzaldehyde with chitosan, and its metal complexes, [M(2CS-dhba)Cl2(H2O)2] (M(III) = Fe, Ru, Rh), [M′(2CS-dhba)(AcO)(H2O)2] (M′(II) = Co, Ni, Cu, Zn), [Pd(2CS-dhba)Cl(H2O)] and [Au(2CS-dhba)Cl2], are reported. These complexes were characterized by elemental analysis, by spectral data (FTIR, solid-phase 13C NMR, UV–vis and ESR spectroscopy), by morphological observations (SEM and XRD), and by magnetic and thermal measurements. The Schiff base (2CS-Hdhba) behaves as a bidentate chelate with a single negative charge. The azomethine nitrogen and the deprotonated 2-hydroxy centres with the pendant glucosamine hydroxy functionality play no role in coordination. The dissociation constants of 2CS-Hdhba and the stability constants of some of its metal complexes have been determined pH-metrically. 相似文献
16.
Feiyue WuRandolph P Thummel 《Inorganica chimica acta》2002,327(1):26-30
The ligands 3,3′-dimethylene-2,2′-bibenzo[g]quinoline and bisbenzo[2,3:9,8]-1,10-phenanthroline have been coordinated with Ru(II) to form both tris- and mixed ligand complexes. These species are highly congested about the metal center but can be formed through the use of microwave irradiation. Shielding and deshielding effects on the chemical shifts of the aryl as well as the bridge protons reveal important conformational effects. Bathochromic shifts are observed in the electronic absorption spectra, associated with increased delocalization of the ligand and lowering of the π*-energy level. Similar effects are observed for the reduction potentials while the oxidation potentials are much less sensitive to ligand structure. 相似文献
17.
Three binuclear Co(III) complexes with 5,5′-(buta-1,3-diyne-1,4-diyl)bis(3-tert-butylcatechol) (L1), 5,5′-(2,5-dimethoxy-1,4-phenylene)bis(ethyne-2,1-diyl)bis(3-tert-butyl-catechol) (L2) and 5,5′-(4,4′-(buta-1,3-diyne-1,4-diyl)bis(2,5-dimethoxy-4,1-phenylene))bis(ethyne-2,1-diyl)bis(3-tert-butyl-catechol) (L3) have been prepared. The triple bond-containing L1, L2 and L3 ligands were synthesized by a cross-coupling reaction. These complexes were characterized by elemental analyses, electrochemical measurements, 1H NMR and UV-Vis spectra. In [Co2(bpy)4(L1)]2+, electrochemical oxidation of the complexes occurs at the bridges as two closely spaced one-electron couples. UV-Vis spectra reveal that chemical oxidation of [Co2(bpy)4(L1)]2+ using Ag+ occurs as a two-electron process forming [Co2(bpy)4(L1Cat,SQ)]3+ or [Co2(bpy)4(L1SQ,SQ)]4+. On the other hand, [Co2(bpy)4(L2)]2+ and [Co2(bpy)4(L3)]2+ exhibit different oxidation behavior under the same experimental conditions. In this report we discuss the role of the distance between the two metal atoms on the oxidative behavior of binuclear Co(III) complexes. 相似文献
18.
Yamilet Mejia-RadilloAnatoly K. Yatsimirsky 《Inorganica chimica acta》2002,328(1):241-246
Potentiometric titrations of hydrogen peroxide in the presence of Y(III) revealed formation of dinuclear Y2(O2)2 2+ and Y2(O2)2(OH)2 complexes. Kinetics of the cleavage of bis(4-nitrophenyl) phosphate (BNPP) in the presence of Y(III) and H2O2 was studied at 25 °C in pH range 6-8 and at variable metal and H2O2 concentrations. Comparison of the pH-dependence of the reaction rate with the species distribution diagram shows that Y2(O2)2(OH)2 is the reactive species. The reaction kinetics is second-order in Y(III) at low metal concentration, but is of a ‘saturation’ type at high metal concentrations. A reaction mechanism, which agrees with such kinetics, involves intermediate reversible dimerization of Y2(O2)2(OH)2 to a tetranuclear complex capable to bind BNPP anion and to cleave it intramolecularly. 相似文献
19.
The high-energy intraconfigurational spin-forbidden bands expected in the region of 20 000 cm−1 have been uncovered in the spectra of a number of trans-diacidobis(ethylenediamine) chromium(III)complexes. These bands have been fitted to the quadrate components of the cubic transition 4A2g → 2T2g including spin-orbit interaction. Two interconfigurational spin-forbidden bands in the spectrum of trans-[Cr(en)2(dmf)2](ClO4)3 have been uncovered and interpretted. 相似文献
20.
Two complexes of the formula [MH3L](ClO4)2 [M = Cu(II) (1), Ni(II) (2)] have been prepared by the reaction of M(ClO4)2 · 6H2O with the ligand (H3L) formed by the Schiff base condensation of tris(2-aminoethyl)amine (tren) with three molar equivalents of 4-methyl-5-imidazolecarboxaldehyde and structurally and magnetically characterized. The structures of 1 and 2 are isomorphous with each other and with the iron(II) complex of H3L which has been reported previously. The ligand, while potentially heptadentate, forms six coordinate complexes with both metal centers forming three M-Nimine and three M-Nimidazole bonds. The tren central N atom is at a nonbonded distance from M of 3.261 Å for 1 and 3.329 Å for 2. The neutral complex CuHL 3 was prepared by reaction of H3L with Cu(OCH3)2 and the ionic complex Na[NiL] 4 was prepared by deprotonation of 2 with aqueous sodium hydroxide. Magnetic measurements of 1-3 are consistent with the spin-only values expected for S = 1/2 (d9, Cu(II)) and S = 1 (d8, Ni (II)) systems. 相似文献