Thermal oxidative destruction of cobalt(II)phthalocyanines with oxygen containing substituents

Summary The complexes of the type [M(HDMBG)Cl₃] ((1) M:Co; (2) M:Zn;) and [M(DMBG)Cl₂] ((3) M:Pd; (4) M:Pt; DMBG: N,N-dimethylbiguanide) present in vitro antimicrobial activity. The modification evidenced in IR and 1H NMR spectra (in the case of complex (2)) was correlated with the presence of N,N-dimethylbiguanide ion as unidentate, coordinated through N³ and of N,N-dimethylbiguanide as chelate, coordinated through N¹ and N⁴ respectively. The electronic reflectance spectrum showed the d-d transition for complex (1) characteristic for the tetrahedral surrounding while the spectra for complexes (3) and (4) have the characteristic pattern for square-planar stereochemistry. The cyclic voltammetric data show the characteristic waves for mononuclear complexes of the metallic ions presented below. The thermal analysis has evidenced the thermal intervals of stability and also the thermodynamics effects that accompany them. The different nature of the ligands generates a different thermal behaviour for complexes.     

Anticancer activity of silver(I) cyclohexyldiphenylphosphine complexes toward SNO cancer cells

Silver and its derivatives have been and are currently used as antimicrobial and antibacterial agents. However, their use is rather limited to date as anticancer agents. Thus, this study focuses on the synthesis and characterization of three silver(I) complexes which have the ability to adopt different geometries, and to induce cancer cell death in SNO esophageal cancer cells. Silver thiocyanate was reacted in different ratios with cyclohexyldiphenylphosphine to obtain 1:1 (complex 1), 1:2 (complex 2), and 1:3 (complex 3) molar ratios of silver(I):cyclohexyldiphenylphosphine complexes. These complexes were characterized using conventional spectroscopic techniques, which included ¹H, ¹³C, and ³¹P NMR, FTIR, and microanalysis (%C, H, N, S). In addition, the single-crystal X-ray structures of complexes 1 and 2 were determined. Moreover, all three complexes displayed toxic activity toward the malignant SNO cells with IC₅₀ concentrations below 5 μM as determined with an alamarBlue® viability assay. Morphological and flow cytometric analyses were included to identify the possible mode of cancer cell death. These biochemical assays revealed that all three treatments induced apoptosis due to the presence of specific apoptotic markers.     

Syntheses and characterizations of trinuclear and dinuclear “half-sandwich” zirconocene phosphates and phosphonates

A series of six-coordinate “half-sandwich” zirconocene phosphates and phosphonates have been synthesized by the reaction of Cp₂ZrCl₂ with (diphenyl-, dibenzyl-)phosphate and methylphenylphosphinic acid under different conditions. All of the complexes were characterized by elemental analysis, FT-IR and NMR (¹H, ¹³C) spectroscopy. Except for complex 3, the structures of complexes 1, 2, 4, 5, and 6 were confirmed by X-ray crystallography. The structure analyses reveal that complexes 1, 2, and 3 are trinuclear complexes with fascinating μ₃-oxygen bridging ligands, central to a Zr–O backbone (Cp₂ZrCl₂:ligand is 1:1) while complexes 4, 5, and 6 are centrosymmetric dinuclear complexes built up about the trapezoidal Zr₂(μ₂-OH)₂ unit (Cp₂ZrCl₂:ligand is 1:2).     

Synthesis,characterisation and thermal behaviour of some complexes with ligands having 1,3,4-thiadiazole moieties

Summary The investigations concerning the thermal behaviour of a series of Ni(II) and Cu(II) complexes of type [MLCl_n]·mH₂O ((1) M:Ni, L:L(1), n=1, m=2; (2) M:Cu, L:L(2), n=1, m=2; (3) M:Ni, L:L(3), n=2, m=0; (4) M:Cu, L:L(3), n=1, m=2) are presented in this paper. The ligands L(1)-L(3) have been synthesised by template condensation of 1,2-diaminoethane with formaldehyde and 2-amino-1,3,4-thiadiazole-5-thiole or 2-acetamino-1,3,4-thiadiazole-5-sulfonamide. The bonding and stereochemistry of the complexes have been characterised by IR, electronic and magnetic studies at room temperature. The thermal behaviour provided confirmation of the complex composition as well as the number and the nature of water molecules and the intervals of thermal stability. The different nature of the ligands and/or the metallic ions generates a different thermal behaviour for complexes. The complexes do not show biological activity against HIV virus.     

Synthesis,structures, and characterization of copper(II), nickel(II), and cobalt(III) metal complexes derived from an asymmetric bidentate Schiff-base ligand

An asymmetric bidentate Schiff-base ligand (2-hydroxybenzyl-2-furylmethyl)imine (L–OH) was prepared. Three complexes derived from L–OH were synthesized by treating an ethanolic solution of the appropriate ligand with an equimolar amount of metallic salt. Three complexes, Cu₂(L–O^?)₂Cl₂ (1), Ni(L–O^?)₂ (2) and Co(L–O^?)₃ (3), have been structurally characterized through elemental analysis, IR, UV spectra and thermogravimetric analysis. Single crystal X-ray diffraction shows metal ions and ligands reacted with different proportions 1?:?1, 1?:?2 and 1?:?3, respectively, so copper(II), nickel(II), and cobalt(III) have different geometries.     

4-碘吡唑铜配合物的合成、结构及量子化学

分别采用水热反应法和溶液培养法,合成了两个结构新颖的铜配合物[Cu3(Ipz)3](Ipz=4-碘吡唑)(1),[Cu(SO4)(Ipz)4]·2H2O·CH3OH(2)。通过元素分析、红外光谱、紫外光谱和X-ray单晶衍射方法对其结构进行了表征。晶体结构表明,配合物1属于正交晶系,Pnma空间群;配合物2属于三斜晶系,P1空间群。配合物1和2的中心金属铜原子的化合价分别是+1和+2价,金属的配位环境以及配体的配位模式也完全不同。配合物1中金属铜为二配位,与配体相互连接形成一个闭合的九元环结构;配合物2中金属铜为六配位,通过配位的硫酸根分子连接形成一条无限的一维链状结构。此外,对这2个配合物进行了量化计算,同时还对配合物1进行了荧光光谱分析。     

Examining the binding mechanism of 3,4-dihydro-3-(2-oxo-2-phenylethylidene)-quinoxalin-2(1H)-one and its fragments to Cu2+

The structure and stoichiometries of the complexes that could be formed between Cu²⁺ and 3,4-dihydro-3-(2-oxo-2-phenylethylidene)-quinoxalin-2(1H)-one (1) were investigated by various spectral techniques such as IR, fluorescence, UV–vis and electron paramagnetic resonance. The results suggest that initially 3?:?1 and 2?:?1 (1/Cu²⁺) complexes are formed at low Cu²⁺ concentration and upon adding more Cu²⁺, 1?:?1 (preferred) and 1?:?2 complexes are generated. Since 1 possesses two possible binding sites, further exploration was done by testing the binding ability of Cu²⁺ to fragments of 1, namely β-enaminoketone derivatives (2–3) and quinoxaline-2-one (4), and by executing calculations of thermodynamic parameters of the reaction between 1 and Cu²⁺ in ethanol, optimized geometries of the possible complexes, and estimation of stability constants at various stoichiometries. Consequently, a step-by-step binding mechanism is suggested for formation of various complexes between 1 and Cu²⁺.     

基于季戊四胺席夫碱的Ni(Ⅱ)和Cu(Ⅱ)配合物的合成、结构及其抑菌活性

以4-甲氧基水杨醛和季戊四胺进行缩合反应得到席夫碱化合物 H₄L, 然后将配体H₄L分别与Ni(ClO₄)₂·6H₂O、Cu(ClO₄)₂在乙醇溶液中进行配位反应, 得到2个席夫碱配合物[Ni₂(L)]·DMF (1)和[Cu₄(L)₂(DMSO)₃]·2DMSO (2)。并用元素分析、FT-IR和X射线单晶衍射进行了表征。配合物1和2都属于三斜晶系, P1 空间群, 配合物1和2都为双核配合物。初步研究了配体和配合物的体外抑菌活性, 结果表明, 配体及其配合物1和2对金黄色葡萄球菌具有一定的抑菌活性。     

基于羧苄基紫精配体构筑的三种多重响应配合物

以羧苄基紫精配体1,1''-双（4-羧苄基）-4,4''-联吡啶二氯化物（（H₂Bpybc） Cl₂）为功能主体,引入辅助配体1,3,5-苯三甲酸（H₃BTC）,与不同金属离子自组装反应,合成了3个配合物{[Cd （Bpybc）_0.5（HBTC）（H₂O）]·0.6H₂O}_n （1）、[Ni （Bpybc）_0.5（HBTC）（H₂O）₄]（2）和[Co （Bpybc）_0.5（HBTC）（H₂O）₄]（3）。其中,配合物1为2D结构,而配合物2和3为0D结构。同时,3种配合物表现出不同的变色性能。配合物1是由于产生紫精自由基而具有光致变色行为,而配合物2和3的光致变色行为是光诱导形成紫精自由基及金属离子的氧化反应共同导致的。此外,配合物2还表现出由电子转移而导致的热致变色行为,而配合物3表现出脱水和吸水引起的可逆结构改变而导致的颜色变化。这些结果表明,金属离子对紫精配合物的结构及变色性能具有明显的调控作用。     

基于季戊四胺席夫碱的Ni(Ⅱ)和Cu(Ⅱ)配合物的合成、结构及其抑菌活性

以4-甲氧基水杨醛和季戊四胺进行缩合反应得到席夫碱化合物H_4L,然后将配体H_4L分别与Ni(Cl O_4)_2·6H_2O、Cu(Cl O_4)_2在乙醇溶液中进行配位反应,得到2个席夫碱配合物[Ni_2(L)]·DMF(1)和[Cu_4(L)_2(DMSO)_3]·2DMSO(2)。并用元素分析、FT-IR和X射线单晶衍射进行了表征。配合物1和2都属于三斜晶系,P1空间群,配合物1和2都为双核配合物。初步研究了配体和配合物的体外抑菌活性,结果表明,配体及其配合物1和2对金黄色葡萄球菌具有一定的抑菌活性。     

Regularities in the stabilization by hemoglobin of binuclear iron complexes [Fe<Subscript>2</Subscript>(μ-N—C—SR)<Subscript>2</Subscript>(NO)<Subscript>4</Subscript>] containing benzimidazolylthiol and benzothiazolylthiol ligands

The NO-donor ability of new binuclear tetranitrosyl complexes of the μ-N—C—S type, namely, bis(5-methylbenzimidazol-2-ylthio)- (1), bis(benzimidazol-2-ylthio)- (2), and bis(benzothiazol-2-ylthio)(tetranitrosyl)diiron (3), was studied in aqueous solutions by spectrophotometry. All kinetic regularities obtained for complexes 1–3 are well described in terms of formalism of pseudo-first-order reactions. The apparent first-order reaction rate constants for NO evolution by the complexes to solution were determined. Complexes 1–3 are good donors of NO. The structures of the complexes and the effect of their stabilization by hemoglobin were compared. The stabilization effect is explained by different basicities of the sulfur-containing ligands in the complexes studied.     

Cadmium(II) complexes of 4′-tolyl-2,2′:6′,2′′-terpyridine: synthesis,structures, and antibacterial activities

A straightforward synthetic method has been developed to prepare cadmium(II) complexes of 4′-tolyl-2,2′:6′,2″-terpyridine (ttpy) in good yields. These complexes are formulated as {[Cd(ttpy)(NO₃)₂][Cd₂(ttpy)₂(NO₃)₄]} (1), [Cd₂(ttpy)₂(N₃)₄]0.5CH₃OH?·?0.125H₂O (2), and {[Cd(ttpy)(SCN)(CH₃COO)][Cd(ttpy)(SCN)₂]₂} (3). Intermolecular, intramolecular, hydrogen bonding and π–π stacking interactions were observed in the complexes, and are responsible for the arrangement of complexes in the crystal packing and play essential roles in forming different frameworks of 1–3. The antibacterial activities of the synthesized complexes were tested against three gram positive bacteria and three gram negative bacteria.     

Nickel(II) complexes with mono(imino)pyrrole ligands: preparation,structure and ethylene polymerization behavior

A series of unsymmetrical mono(imine)pyrroles (L1–L3) were synthesized by microwave irradiation from 2-acetylpyrrole and a series of dimethylanilines with two methyl groups at different positions on the aniline ring. A simplified synthetic method was initiated to prepare the corresponding nickel complexes NiL₂ (1–3) with direct condensation of mono(imine)pyrrole and nickel chloride. The compounds were determined using a suite of techniques (i.e. ¹H NMR, ¹³C NMR, IR, EA, MS). L1–L3 and 3 were further characterized by X-ray crystal diffraction. The structure of 3 showed that the ligand chelated to nickel with 2?:?1 M ratio, in spite of a 1?:?1 rate of charge. Application of 1–3 in ethylene polymerization indicated that mono(imino)pyrrole nickel complexes showed low activities. The polymerization reaction time and temperature, as well as the ligand structure, influenced the catalytic performance to some extent. Experimental data showed higher activity as –CH₃ on the aniline ring is closer to the imine group.     

Square planar complexes of Cu(II) and Ni(II) with N<Subscript>2</Subscript>O donor set of two Schiff base ligands: synthesis and structural aspects

Abstract Two new square planar Cu(II) and Ni(II) complexes, [CuL¹(NCO)] (1) and [NiL²(N₃)] (2) have been synthesized with two different tridentate N₂O donor Schiff base ligands L ¹ H (1:1 condensation product of benzoylacetone and 2-diethylaminoethylamine) and L ² H (1:1 condensation product of benzoylacetone and 2-dimethylaminoethylamine), respectively. Both the complexes 1 and 2 have been characterized by elemental analysis, IR, UV-Vis spectroscopy, room temperature magnetic susceptibility measurement, electrochemical, thermal, and single crystal X-ray diffraction studies. Structural studies reveal that in both the complexes metal centers have square planar environment with N₂O donor set of Schiff base ligands and terminal pseudohalide anions (isocyanate for 1 and azide for 2) at four coordination sites of square plane. Graphical abstract Square planar complexes of Cu(II) and Ni(II) with N ₂ O donor set of two Schiff base ligands: synthesis and structural aspects Subhra Basak, Soma Sen, Samiran Mitra, C. Marschner, W. S. Sheldrick Two new square planar Cu(II) and Ni(II) complexes, [CuL¹(NCO)] (1) and [NiL²(N₃)] (2) have been synthesized with two different tridentate N₂O donor Schiff base ligands L ¹ H and L ² H respectively. Both the complexes 1 and 2 have been characterized by elemental analysis, IR, UV-Vis spectroscopy, room temperature magnetic susceptibility measurement, electrochemical, thermal and single crystal X-ray diffraction studies.      

钴、镍多齿吡啶-胺配合物的制备及晶体结构

设计合成了4个新的钴、镍多齿吡啶-胺配合物,[M(L1)](BF₄)₂(L1=N,N,N',N'-四(2-吡啶甲基)-1,2-乙二胺;C1,M=Co;C2,M=Ni)和 [M(L2)](BF₄)_n(L2=N,N,N',N'-四(2-吡啶甲基)-1,3-丙二胺;C3,M=Co,n=3;C4,M=Ni,n=2)。利用红外光谱、元素分析和X-射线单晶衍射方法对这些配合物的组成及结构进行了分析和表征。这4个配合物的单晶结构均属于单斜晶系,空间群有所不同(C1为Cc空间群,C2为P2₁/n空间群,C3为C2/c空间群,C4为P2₁/c空间群),并且4个配合物具有不同的三维堆积结构。     

Synthesis and characterization of two Cu(II) complexes with a new pyrazole-based Schiff base ligand: crystallography,DNA interaction and antimicrobial activity of Ni(II) and Cu(II) complexes

Reaction of Cu(II) nitrate with a new pyrazole-based Schiff base ligand, 5-methyl-3-formylpyrazole-N-(2′-methylphenoxy)methyleneimine (MPzOA), afforded two types of Cu(II) complexes at different reaction temperatures, [Cu(MP_zOA)(NO₃)]₂ (1) and [Cu(3,7,11,15-tetramethylporphyrin)(H₂O)](NO₃)₂ (2), reported together with a Ni(II) complex, [Ni(MPzOA)₂(H₂O)₂]Br₂ (3). The compounds are characterized by single crystal X-ray structure analyses along with several physico-chemical and spectral parameters. Complex 1 is authenticated as a bis(μ-pyrazolato)dicopper(II), while 2 is a porphyrinogen and 3 is a distorted octahedral complex. Structural analyses of the complexes reveal that 1 crystallized in monoclinic P2₁/n space group while 2 and 3 crystallized in monoclinic C2/c space group. DNA-binding studies of the complexes have shown that the complexes interact with CT-DNA. DNA-cleavage studies with plasmid DNA have shown that 1 and 2 induce extensive DNA cleavage in the presence of H₂O₂ as an additive, whereas there is no change in degradation of super-coiled DNA by 3 in the presence of additive. The antimicrobial studies of the complexes against Escherichia coli DH5α bacteria strain indicated that all the complexes were capable of killing E. coli with different LD50 values.     

DFT studies of temperature effect on coordination chemistry of Cu(II)-trimethoprim complexes

The computational analysis of geometrically different copper-trimethoprim complexes, experimentally formed at two different temperatures, was performed using Density Functional Theory (DFT) method. Initial geometries of copper-trimethoprim complexes 1, 2, and 3 were obtained from crystallographic data. These three geometries of complexes 1, 2, and 3 were fully optimized using B3LYP/BLYP hybrid density functional methods along with 6-31G and LANL2DZ basis sets at two temperatures, 298 and 352 K. The results obtained were compared with the experimental data and show that complex 1 is the most stable geometry while complex 3 is unstable/intermediate geometry and can be converted to stable form after the recrystallization process. Moreover, LANL2DZ basis set gives more accurate (with respect to experimental) results as compared to 6-31G.     

Thermal behaviour of new N,N-dimethylbiguanide complexes having selective and effective antibacterial activity

The complexes of the type M(HDMBG)₂(CH₃COO)₂·nH₂O ((1) M:Mn, n=1.5; (2) M:Ni, n=0; (3) M:Cu, n=2; (4) M:Zn, n=2; DMBG: N,N-dimethylbiguanide) present in vitro antimicrobial activity. The thermal analysis has evidenced the thermal intervals of stability and also the thermodynamics effects that accompany them. The different nature of the ligands generates a different thermal behaviour for the complexes. The thermal transformations are complex processes according to TG and DTG curves including dehydration, oxidative condensation of –C=N– units as well as thermolysis processes. The final products of decomposition are the most stable metal oxides.     

Rare earth complexes [Ln(EDBP)<Subscript>2</Subscript>(DME)Na(DME)<Subscript>3</Subscript>] as catalysts for the polymerization of 2,2-dimethyltrimethylene carbonate

The biphenol based discrete ion-pair rare earth complexes,[Ln（EDBP）₂（DME）Na（DME）₃][Ln=Er（1）,Yb（2）, Sm（3）],were prepared and used as catalysts for the ring-opening polymerization（ROP）of 2,2-dimethyltrimethylene carbonate（DTC）.Three complexes show moderate activities for the polymerization,and the catalytic activities increase in the following sequence:（Yb2 elimination was prepared.     

Structure of Dibenzocrown Ethers and their H-Bonded Adducts.1. [1.5]Dibenzo-18-Crown-6 and Biphenyl-20-Crown-6: Complexes with Amidosulfuric Acid

The interaction of the amidosulfuric acid NH ₃ SO ₃ with 15 distal and proximal dibenzocrown ethers, including diphenyloxide, diphenylsulfide and biphenyl ones leads to the stable (1:1) complexes only in the case of [2.4]- and [1.5]dibenzo-18-crown-6 and biphenyl-20-crown-6. According to the data of the X-ray analysis, in the two last adducts the amidosulfuric acid coordinates to hexadentate crown ethers in a zwitterion form through a near-ideal ‘tripod’ arrangement to alternate crown oxygen atoms. The conformations of crown molecules are different in complexes and in initial macrocyclic ligands.This revised version was published online in July 2005 with a corrected issue number.