Structure and Magnetic Characteristics of New Binuclear Complexes Based on Bisbenzoylhydrazones of 2,6-Diformyl-4-R-phenols and Copper(II) Nitrate

A series of binuclear Cu(II) complexes with bisbenzoylhydrazones of 2,6-diformyl-4-R-phenols (R = OCH₃, CH₃, CH₂Ph, Cl, Br, CO₂CH₃) with H₂LCu₂(NO₃)₂(OCH₃) composition, where H₂L^–are monodeprotonated bishydrazones, was synthesized. The structure of the obtained complexes was established using IR spectro-scopy and conductometric and magnetochemical data. The title complexes were shown to exhibit exchange interaction of the antiferromagnetic type. Results of quantum-chemical calculations of structures modeling the state of a ligand in the complex were used to discuss the effect of substituent R nature on magnetic exchange in the complexes.     

Magnetochemistry of Homo- and Heterobinuclear Complexes with Bis(hydrazones) of 2,6-Diformyl-4-R-Phenols

Data on the magnetochemical properties of binuclear copper(II) complexes with different bishydrazone ligands prepared from 2,6-diformylphenol are surveyed. An attempt to systematize the investigation results by elucidating the magnetostructural dependences that relate the strength of exchange interaction to the structure of the binuclear complex is made. Experimental and theoretical data are presented demonstrating the dependence of the exchange interaction strength on both the geometry of the exchange fragment and the nearest environment and the nature of the nonbridging donor atoms coordinated directly by the metal.     

Fine-Tuning the Electronic Properties of Binuclear Bis(terpyridyl)ruthenium(II) Complexes

Vastly improved photophysical properties of terminal Ru^II terpyridine-based chromophores is achieved by insertion of an ethynylene group between the terpyridine ligand and a covalently linked aromatic nucleus. In the case where the aromatic nucleus possesses vacant coordination sites, as shown in 1 , complexation of certain cations (e. g., Zn²⁺, Cd²⁺, or Ba²⁺) at the central unit gives a further improvement in the photoproperties due to a better blending of the respective LUMO levels.     

Effects of Electronic and Steric Factors on the Magnetic Properties of Novel Homo- and Heterobinuclear Transition-Metal Complexes with Asymmetric 2,6-Diformyl-4-R-Phenol Bis(Hydrazones)

A series of novel homo- and heterobinuclear copper(II), manganese(II), and VO²⁺ complexes with asymmetric 2,6-diformyl-4-R-phenol bis(hydrazones) are synthesized. The values of exchange parameters of these compounds are determined. The comparison of experimental results with the quantum-chemical calculations of the model fragments of binuclear metal chelates allows one to elucidate the main electronic and geometric factors determining the character of changes in the magnetic properties in systematic series of transition-metal complexes with bis(hydrazones).     

Nickel(II) Complexes with Pentane-2,4-dione Bis(4-allylthiosemicarbazone)

Reaction of pentane-2,4-dione with N-(prop-2-en-1-yl)hydrazinecarbothioamide at a 1: 2 molar ratio in ethanol resulted in the formation of a pyrazole derivative. The latter reacted with nickel perchlorate at a 1: 1 molar ratio to form the nickel complex with pentane-2,4-dione bis(4-allylthiosemicarbazone). The same type of nickel complex was obtained as a result of N-(prop-2-en-1-yl)hydrazinecarbothioamide reaction with pentane-2,4-dione and nickel nitrate at a 2: 1: 1 molar ratio. Antimicrobial, antifungal, antioxidant, and anticancer activities of the obtained compounds were studied.     

Studies on Binuclear Co(II) and Cu(II) Complexes of Tridentate N-(2-Carboxyphenyl)Salicylideneimine

Homo Cu(II) and Co(II) binuclear complexes H[MLClMCl₂] formed by using the donor properties of the cis two oxygen atoms of the tridentate N-(2-carboxyphenyl)-salicylaldimine Schiff base derived from salicylaldehyde and anthranilic acid have been synthesized. It was found that the Cu(II) “complexed ligand” readily reacts with CoCl₂ to form mononuclear Co(II) and binuclear oxygen bridged Co(II) complex [Co₂-L₂](H₂O)₂. The structure of the so prepared complexes was investigated using microchemical analysis, molar conductance measurements as well as electronic and vibrational spectral studies. It was concluded that in the Cu(II) binuclear complex, the Cu(II) ion inside the “complexed ligand” has a planar structure while the other Cu(II) ion is distorted away from planarity. In the Co(II) binuclear complex, the Co atom of the “complexed ligand” is distorted from tetrahedral structure when it coordinates to the second Co atom.     

Crystal Structures and Characterizations of Bis(pyrrolidinedithiocarbamato) Cu(II) and Zn(II) Complexes

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅａｂｉｌｉｔｙｏｆｄｉｔｈｉｏｃａｒｂａｍａｔｅ(ｄｔｃ)ｂｉｎｄｉｎｇｔｏｍｅｔａｌｓｈａｓｂｅｅｎｋｎｏｗｎｆｏｒｍａｎｙｙｅａｒｓ .Ｉｔｆｏｒｍｓｃｈｅｌａｔｅｓｗｉｔｈｖｉｒｔｕ ａｌｌｙａｌｌｔｒａｎｓｉｔｉｏｎｍｅｔａｌｓ.1Ｔｈｅｂｉｄｅｎｔａｔｅａｎｉｏｎｉｓａｌｓｏｗｅｌｌｋｎｏｗｎａｓａｂｒｉｄｇｅｂｅｔｗｅｅｎｔｗｏｔｒａｎｓｉｔｉｏｎｍｅｔａｌｃｅｎｔｅｒｓ.2 Ｗａ ｔｅｒ ｓｏｌｕｂｌｅｄｉａｌｋｙｌｄｉｔｈｉｏｃａｒｂａｍａｔｅｃｏｍｐｌｅｘｅｓ…     

Crystal Structures and Characterizations of Bis(pyrrolidinedithiocarbamato)Cu（Ⅱ） and Zn(Ⅱ） Complexes

The structures of [Cu (S₂CN (CH₂)₄)₂] (1) and [Zn₂(S₂CN‐(CH₂)₄)₄] (2) have been determined by X‐ray crystallography analysis. They are all isomorphous and triclinic, space group of P1^?, with Z = 1. The lattice parameters of compound 1 is: a = 0.63483(2) nm, b = 0.74972(3) nm, c=0.78390(1) mn, α = 75.912(2)°, β = 78.634(2)° and γ = 86.845(2)°; compound 2: a = 0.78707(6) nm, b=0.79823(6) nm, c = 1.23246(9) nm, α = 74.813(2)°, β = 73.048(2)° and γ = 88.036(2)°. The copper atom is located on a crystallographic inversion center and zinc atom lies across centers of symmetry. The Cu(II) ion has a square‐planar geometry while Zn(II) has a distorted tetrahedral geometry. The thermal gravity (TG) data indicate that no structural transitions in the two compounds were abserved and the decomposition products can adsorb gas. Also they all have a high thermal stability.     

Binuclear Copper(II) Complexes with Hydrazones Containing Spiropyran Fragment

New hydrazones were prepared by the reaction of new spiropyran of benzoxazine series and aliphatic acid hydrazides; their binuclear complexes were synthesized.     

四碘代对苯二甲酸根桥联的双钴(II)配合物的研究

报导了四种新的双核钴（Ⅱ）配合物，即［Co2（4I-TPHA）（L）4］（COl4）（4I-TPHA＝四碘代对苯二甲酸根阴离子，L＝1，10菲咯啉（phen）（1），5-硝基-,10菲咯啉（NO2-phen）（2），2，2′-联吡啶（bpy）（3）和4，4′-二甲基-2，2′-联吡啶（Me2bpy）（4）的合成和表征，配合物的磁性研究表明双核钴（Ⅱ）离子间有弱的反铁磁性自旋交换相互作用。     

New binuclear metal chelate complexes of copper(II) chloride and acetate with bis(hetarylhydrazones) obtained by condensation of 2,6-diformyl-4-R-phenols with 2-hydrazinoquinoline

Bis(hetarylhydrazones) synthesized for the first time were used as ligands to obtain a number of binuclear copper(II) chelates from copper acetate and chloride. The physicochemical and, first of all, magnetic properties of the resulting complexes were studied. Analysis of the calculated exchange parameters showed that they differ significantly from those obtained previously for analogous binuclear metal chelates containing the identical set of donor atoms. Possible reasons for the differences in the magnetochemical behavior of the binuclear complexes obtained are discussed.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 2, 2005, pp. 157–160.Original Russian Text Copyright © 2005 by Lukov, Gevorkyan, Dontsova, Kogan, Popov, Dykov.     

2,6-二甲酰基对甲苯酚的固相合成

以活性纳米γ-MnO2为氧化剂,在无溶剂状态下用2,6-二甲羟基对甲苯酚为原料合成了2,6-二甲酰基对甲苯酚,其结构经^1H NMR,IR和元素分析确证。较适宜的反应条件为：2,6-二甲羟基对甲苯酚0．85g(5mmol),n(2,6-二甲羟基对甲苯酚)：n(活性γ-MnO2)=1：2,间歇性研磨提供充分的自扩散时间(1h～2h),总研磨时间为5h～6h,收率26％。该法与液相合成法相比,反应时间缩短到1／8,产率提高了6％。     

Binuclear caffeine adducts of Cu(II) acetate and Cu(II) chloroacetates with unusually high antiferromagnetic interaction

New caffeine adducts of Cu(II) acetate, monochloro-, dichloro- and trichloroacetate, were prepared. Electronic, IR and EPR spectra as well as magnetic data over the temperature range 81–296 K have been mainly used for the determination of the stereochemistry and electronic structure of the adducts. The available evidence supports a binuclear structure. The EPR spectra, of the powdered solids is consistent with a spin of S = 1. The values of the energy separation (−2J) between the triplet and singlet states, especially in the case of Cu(CH₃COO)₂.caffeine, represent a significantly bigger interaction than is observed in any other well—characterized Cu(II) acetate adducts of binuclear structure. Some correlations between the magnetic and spectral data as well as the acidity of the respective acids are discussed.     

Thermal Decomposition of Cu(II) Complexes with 2-Chloro- and 2,6-Dichlorobenzoic Acid and Imidazole

The reaction products of Cu(II) 2-chlorobenzoate and the imidazole (1), and of Cu(II) 2,6-dichlorobenzoate and the imidazole (2) formulated as CuL’₂⋅2imd⋅2H₂O and CuL”₂⋅2imd⋅2H₂O (L’=C₇H₄ClO₂ ⁻, L”=C₇H₃Cl₂O₂ ⁻, imd=imidazole), were prepared and characterized by means of spectroscopic measurements and thermochemical properties. The blue (1) and green (2) complexes were obtained as solids with a 1:2:2 molar ratio of metal to carboxylate ligand to imidazole. When heated at a heating rate of 10 K min⁻¹ the hydrated complexes, (1) and (2), lose some of the crystallization water molecules and then decompose to gaseous products. This revised version was published online in August 2006 with corrections to the Cover Date.     

New Mononuclear and Binuclear Cu(II), Co(II), Ni(II), and Zn(II) Thiosemicarbazone Complexes with Potential Biological Activity: Antimicrobial and Molecular Docking Study

Herein, we report the synthesis of eight new mononuclear and binuclear Co²⁺, Ni²⁺, Cu²⁺, and Zn²⁺ methoxy thiosemicarbazone (MTSC) complexes aiming at obtaining thiosemicarbazone complex with potent biological activity. The structure of the MTSC ligand and its metal complexes was fully characterized by elemental analysis, spectroscopic techniques (NMR, FTIR, UV-Vis), molar conductivity, thermogravimetric analysis (TG), and thermal differential analysis (DrTGA). The spectral and analytical data revealed that the obtained thiosemicarbazone-metal complexes have octahedral geometry around the metal center, except for the Zn²⁺-thiosemicarbazone complexes, which showed a tetrahedral geometry. The antibacterial and antifungal activities of the MTSC ligand and its (Co²⁺, Ni²⁺, Cu²⁺, and Zn²⁺) metal complexes were also investigated. Interestingly, the antibacterial activity of MTSC- metal complexes against examined bacteria was higher than that of the MTSC alone, which indicates that metal complexation improved the antibacterial activity of the parent ligand. Among different metal complexes, the MTSC- mono- and binuclear Cu²⁺ complexes showed significant antibacterial activity against Bacillus subtilis and Proteus vulgaris, better than that of the standard gentamycin drug. The in silico molecular docking study has revealed that the MTSC ligand could be a potential inhibitor for the oxidoreductase protein.     

Physicochemical Study of New Mono- and Binuclear Copper(II) Complexes with Sterically Hindered Acylhydrazones and Azomethines

Series of new binuclear copper(II) complexes with acylhydrazones and azomethines of substituted derivatives of salicylaldehyde containing bulky tert-butyl substituents were synthesized. The target dimerization of the monomeric fragments of the complexes caused by the steric factors was shown to predetermine the specific features of their magnetochemical behavior. The calculated exchange parameters for the complexes based on acylhydrazones range from –110 to –138 cm^–1 and those for the complexes based on azomethines lie in the interval from –400 to –500 cm^–1.     

Crystal Structure and Magnetic Properties of Copper(II) and Nickel(II) Binuclear Complexes with Bisacylhydrazones Based on 2,6‐Diformyl‐4‐methylphenol

The series of binuclear Cu(II) and Ni(II) complexes with an asymmetrical exchange fragment based on 2,6‐diformyl‐4‐methylphenol bishydrazone has been synthesized for the first time. The compositions and structures of both ligands and its complexes have been established with the data of IR, ¹H NMR, and extended X‐ray absorption fine structure (EXAFS) spectroscopical studies as well as magnetic measurements. The structure of [Ni₂L₃(μ‐Pz)] · 2CH₃OH (L = triply deprotonated form of bishydrazone, Pz = pyrazol) was confirmed by X‐ray crystallographic analysis. In this complex, the coordination environment of two nickel ions is quite different, one nickel atom is square‐planar and the other is distorted octahedral coordinated. The values of exchange parameter calculated in terms of HDVV theory have been compared with the features of an asymmetrical exchange fragment's electronic and geometrical structure.     

4-Aminopyridine Adducts of Cu(II) 2-Chloro- and 2,6-Dichlorobenzoate

Reaction products of Cu(II) 2-chlorobenzoate and 4-aminopyridine (1), and of Cu(II) 2,6-dichlorobenzoate and 4-aminopyridine (2) formulated as CuL′₂(4-apy)₂ and CuL″₂(4-apy)₂((L′ =C₇H₄ClO^? ₂,L″ =C₇H₃Cl₂O^? ₂, 4-apy = 4-aminopyridine), were prepared and characterized by structural and spectroscopic measurements, thermochemical properties and magnetic susceptibilities. Compound (1) crystallizes in the orthorhombic space group Pbca, a = 8.875(2), b = 13.236(4), c = 21.603(3) Å, V = 2537.7(10) ų, Z = 4, and the Compound (2) crystallizes in the monoclinic space group P2₁/c, a = 11.516(2), b = 8.749(2), c = 13.469(3) Å, β = 103.36(3)°, V = 1320.3(5) ų, Z = 2. Complexes (1) and (2) decomposes to gaseous products at 473 and 513 K, respectively.