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101.
The hydrolytic reactions between various Pt(II) complexes of the type [Pt(L)Cl2] and [Pt(L)(CBDCA-O,O′] (L is ethylenediamine, en; (±)-trans-1,2-diaminocyclohexane, dach; (±)-1,2-propylenediamine, 1,2-pn and CBDCA is the 1,1-cyclobutanedicarboxylic anion) and the N-acetylated l-methionylglycine dipeptide (MeCOMet-Gly) were studied by 1H NMR spectroscopy. All reactions were realized at 37 °C with equimolar amounts of the Pt(II) complex and the dipeptide at pH 7.40 in 50 mM phosphate buffer in D2O. Under these experimental conditions, a very slow cleavage of the Met-Gly amide bond was observed and this hydrolytic reaction proceeds through the intermediate [Pt(L)(H2O)(MeCOMet-Gly-S)]+ complex. In general, it can be concluded that faster hydrolytic cleavage of the MeCOMet-Gly dipeptide was observed in the reaction with the chloride complex than with corresponding CBDCA Pt(II) complexes. The steric effects of the Pt(II) complex on the hydrolytic cleavage of the amide bond in the MeCOMet-Gly dipeptide were also investigated by 1H NMR spectroscopy. It was found that the rate of hydrolysis decreases as the steric bulk of the CBDCA and chlorido Pt(II) complexes increase (en > 1,2-pn > dach). These results contribute to a better understanding of the toxic side effects of Pt(II) antitumor drugs and should be taken into consideration when designing new potential Pt(II) antitumor drugs with preferably low toxic side effects. 相似文献
102.
Two mononuclear Co(II) complexes based upon 2-(1H-benzimidazol-2-yl)phenol, abbreviation Hsalbim ligand, have been prepared and studied. The structure of Hsalbim and [Co(salbim)2] have been confirmed by X-ray structure analysis. The second cobalt(II) complex matches the formula [Co(salbim)2]·(Hsalbim)·MeOH assuming a co-crystallization of one neutral ligand. The electronic spectra are consistent with the tetrahedral pattern. Magnetic susceptibility measurements down to T = 2 K along with the magnetization data until B = 7 T show that the Co(II) complexes are high-spin with a considerable zero-field splitting of the 4B1(D2d) term: D/hc = 67 and 55 cm−1, respectively. 相似文献
103.
Rafael Bou-MorenoSimon A. Cotton Verity HunterKathryn Leonard Andrew W.G. PlattPaul R. Raithby Stefanie Schiffers 《Polyhedron》2011,30(17):2832-2836
The new cobalt(II) phosphine oxide complexes Co(Cy3PO)2Cl2 (1), Co(Cy3PO)2Br2 (2), Co(Cy3PO)2I2 (3), Co(Ph2CyPO)2Cl2 (4), Co(Ph2CyPO)2Br2 (5), Co(Ph2CyPO)2I2 (6), Co(Ph2EtPO)2Br2 (7), Co(Cy3PO)2(NCS)2 (8) and Co(Cy3PO)2(NO3)2 (9) have been prepared mainly by the reaction of anhydrous CoX2 (X = Cl, Br, I, NCS, NO3) with the appropriate phosphine oxide. The complexes were characterised by single-crystal X-ray crystallography supported by IR and UV-Vis absorption spectroscopy. The structural analyses show that the cobalt(II) centre adopts a distorted tetrahedral coordination geometry except for 9 which displays an octahedral geometry. Systematic structural features of these complexes are explained within this paper. 相似文献
104.
The 57Fe Mössbauer effect in [Fe(pythiaz)2] (BF4)2 (I) and [Fe(pythiaz)2] (C&O4)2 (II) has been studied between 298 and 4.2°K (pythiaz = 2,4-bis(2-pyridyl)thiazole). At 298°K compound I shows a doublet with ΔEQ(5T2) = 1.29 mm sec?1 and δ1S(5T2) = +0.93 mm sec?1 characteristic of a 5T2 ground state. At 236°K, a second doublet, typical for a 1A1 ground state appears. The transition 5T2 å 1A1 progresses as the temperature is lowered but levels off below ≈ 120°K. At 4.2°K, 59% of the intensity is due to the 1A1 state, and ΔEQ(1A1) = 1.59 mm sec?1 and δ1S(1A1) = +0.26 mm sec?1. In an applied magnetic field, Vzz(1A1) < 0 has been determined Similar results have been obtained with compound II.Debye-Waller factors f5T2 and f1A1. were determined from the Mössbauer spectra under the assumption of Curie-Weiss dependence of the magnetism for the 5T2 and constant μeff for the 1A1 ground state. The resulting temperature dependence of f1A1 is highly unusual thus suggesting complicated magnetic behaviour of both ground states in the transition region. Two mechanisms for the nature of the transition are discussed, a “spin-flip” mechanism being the physically more reasonable one. The assumption of a simple Boltzmann distribution (“spin equilibrium”) may be ruled out for the solid but could be encountered in solutions. 相似文献
105.
《印度化学会志》2021,98(8):100097
Two rare hetero-metallic calcium(II)-zinc(II) complexes [CaZn4(OBz)10(μ2-hmt)2]n (1) and [Ca2Zn4(OBz)12(μ2-hmt)2]n (2) have been synthesized using basic zinc carbonate, benzoic acid (HOBz), hydrated calcium chloride and hexamethylenetetramine (hmt) by varying the molar ratio of the reactants. Both the complexes have been analyzed by elemental analysis, IR spectroscopy and X-ray crystallography. The complex 1 is a 1D polymer which contains one calcium ion and four zinc atoms in the asymmetric unit together with ten benzoates and two hmts. The polymer has been constructed by the alternate joining of paddle-wheel Zn2(OBz)4 units and Zn2Ca trinuclear species by μ2-hmt bridging molecules connecting Zn2+ ions. Zinc atoms have five coordinate square pyramidal geometries and four coordinate tetrahedral geometries in Zn2(OBz)4 and Zn2Ca moieties, respectively, whereas calcium atoms have six-coordinate distorted octahedral geometry. Complex 2 is also a 1D polymer but unlike complex 1, it contains four independent zinc and two independent calcium atoms in the asymmetric unit together with twelve benzoates and two hmts. By contrast, the polymeric structure of complex 2 has been formed by the connection of Zn2Ca trinuclear species via μ2 hmt bridging molecules at Zn centers. Complex 2 is also a 1D polymer but unlike complex 1, it contains four independent zinc and three independent calcium atoms in the asymmetric unit together with twelve benzoates and two hmts. All four zinc atoms are four coordinate with tetrahedral environments and the calcium atoms are six coordinated (two are located on a center of symmetry) exhibiting a distorted octahedral geometry. 相似文献
106.
Solvothermal reaction of aromatic terphenyl-2,5,2',5'-tetracarboxylic acid (H 4 qptc) ligand and the transitional metal cation of Mn II in the presence of 3-(2-pyridyl)pyrazole (pp) affords one new coordination polymer, [Mn(qptc)0.5(pp)2]n·n(H2O) (1). The structure has been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR, TGA, and magnetism. The carboxyl groups of qptc 4-exhibit a μ1-η1 :η 0 coordination mode, and the qptc4- acts as a H-shaped ligand linking the Mn Ⅱ centers together to form a 2D polymeric [Mn(qptc) 0.5 ] n layer. The crystal of 1 crystallizes in orthorhombic, space group Pbca with a=9.3119(12), b=20.848(3), c=26.134(3) , V=5073.4(11) 3 , Z=8, C27H19MnN6O5 , Mr=562.42, Dc=1.473 g/cm3 , F(000)=2304 and μ(MoKα)=0.571 mm-1 . The final R=0.0468 and wR=0.1196 for 4429 observed reflections with I > 2σ(I) and R=0.0797 and wR=0.1383 for all data. 相似文献
107.
《Journal of Coordination Chemistry》2012,65(1):35-45
Abstract Reactions of the monofunctional platinum(II) complex, [PtCl(dien)]+, with different thiols and thioethers, including biologically important molecules, have been studied as a function of temperature (288.2–308.2K) using conventional electronic spectrophotometry in 0.10 M aqueous hydrochloric acid and by 1H NMR spectroscopy. The second-order rate constants, k2, are similar, varying between 1.43 × 10?3 and 46.1 × 10?3 M?1s?1 at 25°C. The reactivity follows the sequences: D-penicillamine ≤ L-cysteine ≤ glutathione ≤ thiodiglycolic acid ≤ thioglycolic acid ≤ L-methionine ≤ S-methylthioglycolic acid ≤ glycyl-D,L-methionine. However, variation in size, bulkiness and solvation of the entering ligands reflect in their properties as nucleophiles. Large negative values of the entropy of activation (ΔS≠), between ?140 and ?190 J K?1 mol?1, indicate that all thiols and thioethers react via the same associative mechanism. Results have been analyzed in relation to the antitumor activity and toxicity of platinum(II) complexes. 相似文献
108.
109.
《Journal of Coordination Chemistry》2012,65(12):2171-2183
Synthesis of two new asymmetric ligands: 1-(2-ethoxyphenyl)-3-(2-methoxycarbonylphenyl)triazene (HL) (1) and 1-(2-methoxyphenyl)-3-(2-methoxycarbonylphenyl)triazene (HL′) (2) are reported. The prepared triazenes are functionalized by ethoxy and methoxy groups in the ortho positions, respectively. The related monomeric complexes, [HgL2] (3) and [HgL′2] (4), were prepared by the reacting of the corresponding ligands with Hg(NO3)2 salt in methanol as solvent. All compounds were characterized by CHN analysis, FT-IR, 1H NMR, and 13C NMR spectroscopy. According to the crystal structures of 1 and 2, the N–N bond distances indicate the presence of alternating single and double bonds, and hence the –N=N–NH– moiety. On coordination, each triazene was deprotonated and as a result, a resonance structure is formed between nitrogens which let them to be a tridentate ligand. In the crystal structure of 3, [HgL2], the central Hg(II) is surrounded by two N atoms from interlocked L forming linear geometry, in which the other four Hg–N and Hg–O bonds are longer and can only be regarded as weak secondary bonds. An interesting feature of 3 is also the presence of π?π [centroid–centroid distance of 3.744(3)?Å] and C–H?π interactions. The results of solution studies for the formation of 3 in methanol support its solid-state stoichiometry. 相似文献
110.
《Journal of Coordination Chemistry》2012,65(14):2377-2392
Two copper(II) complexes, [Cu(L)2](ClO4)2] and [Cu(L)(bipy)](ClO4)2, were prepared and characterized by the spectroscopic and analytic methods, where L is N-butylbenzimidazole and bipy is 2,2′-bipyridine. Single crystals of [Cu(L)(bipy)](ClO4)2 suitable for X-ray diffraction study were obtained by slow diffusion of diethyl ether into a DMF solution of the complex and the complex was found to crystallize as [Cu(L)(bipy)](ClO4)2·DMF. The asymmetric unit contains one [Cu(L)(bipy)]2+, two uncoordinated perchlorates, and one DMF solvate. Coordination geometry around Cu(II) is distorted square pyramidal with τ value of 0.31. Thermal properties of the complexes were examined by thermogravimetric analysis, indicating that the complexes are thermally stable to 310?°C. The metal complexes were screened for their in vitro antibacterial and antifungal activities Bacillus subtilis and Bacillus cereus (as Gram(+) bacteria), Escherichia coli, Enterobacter aerogenes, and Klebsiella pneumoniae (as Gram(–) bacteria), and Saccharomyces cerevisiae, Candida utilis, and Candida albicans (as yeasts). The complexes show antibacterial and antifungal activities against bacteria and yeasts. 相似文献