Synthesis and characterization of the [Cu(Cin2bda)2]ClO4 and [Cu(Ncin2bda)2]ClO4 complexes: Crystal structure of [Cu(Ncin2bda)2]ClO4

Two copper(I) complexes [Cu(Cin₂bda)₂]ClO₄ (I) and [Cu(Ncin₂bda)₂]ClO₄ (II) have been prepared by the reaction of the ligands N²,N²′-bis(3-phenylallylidene)biphenyl-2,2′-diamine (L¹) and N²,N²′-bis[3-(2-nitrophenyl)allylidene]biphenyl-2,2′-diamine (L²) and copper(I) salt. These compounds were characterized by CHN analyses, ¹H NMR, IR, and UV-Vis spectroscopy. The C=N stretching frequency in the copper(I) complexes shows a shift to a lower frequency relative to the free ligand due to the coordination of the nitrogen atoms. The crystal and molecular structure of II was determined by X-ray single-crystal crystallography. The coordination polyhedron about the copper(I) center in the complex is best described as a distorted tetrahedron. A quasireversible redox behavior was observed for complexes I and II. The article is published in the original.     

Recyclization of ethyl 1-alkyl-5-benzoyl-6-methylsulfanyl-2-oxo-1,2-dihydropyridine-3-carboxylates into Bicyclic <Emphasis Type="Italic">N</Emphasis>-alkyl-5-benzoyl-2-oxo-1,2-dihydropyridine-3-carboxamide derivatives by the action of nitrogen-containing 1,4- and 1,5-binucleophiles

Reactions of ethyl 1-alkyl-5-benzoyl-6-methylsulfanyl-2-oxo-1,2-dihydropyridine-3-carboxylates with nitrogen-containing 1,4- and 1,5-binucleophiles (o-phenylenediamine, o-aminobenzenethiol, ethane-1,2-diamine, and propane-1,3-diamine) involved recyclization, leading to the formation of fused N-alkyl-5-benzoyl- 2-oxo-1,2-dihydropyridine-3-carboxamides, diethyl 6,6′-oxybis(1-alkyl-5-benzoyl-2-oxo-1,2-dihydropyridine-3-carboxylates), and diethyl 6,6′-[ethane-1,2-diyl(or propane-1,3-diyl)diimino]bis(1-alkyl-5-benzoyl-2-oxo-1,2-dihydropyridine-3-carboxylates), depending on the reactant ratio. The sequence of formation of intermediate recyclization products was determined.     

Synthesis,structure and DNA-binding studies of tetranuclear copper(II) complexes bridged by asymmetrical<Emphasis Type="Italic"> N</Emphasis>,<Emphasis Type="Italic">N′</Emphasis>-bis(substituted)oxamides

Two tetranuclear copper(II) complexes bridged by asymmetrical N,N′-bis(substituted)oxamides have been synthesized and characterized as [Cu₄(dmapob)₂(Me₂bpy)₂](pic)₂·6H₂O (1) and [Cu₄(oxbe)₂(dabt)₂](pic)₂ (2), where H₃dmapob and H₃oxbe denote N-benzoato-N′-[3-(dimethylamino)propyl]oxamido and N-benzoato-N′-(2-aminoethyl)oxamide, respectively; and Me₂bpy, dabt, and pic represent 4,4′-dimethyl-2,2′-bipyridine 2,2′-diamino-4,4′-bithiazole, and 2,4,6-trinitrophenol, respectively. Complex 1 was characterized by elemental analyses, IR and electronic spectra, and single-crystal X-ray diffraction. Its structure consists of two asymmetrical binuclear copper(II) units linked by carboxyl bridges into a circular tetranuclear copper(II) complex with an embedded center of inversion. The copper(II) centers are in square-planar and distorted square-pyramidal environments. Hydrogen bonds and aromatic stacking interactions link the tetranuclear copper(II) fragments into a 3D supramolecular structure. The interactions of complexes 1 and 2 with herring sperm DNA (HS-DNA) were investigated by electronic and fluorescence spectra and viscosity measurements. Both complexes bind to HS-DNA via the intercalative mode, and complex 2 displays a significant binding propensity to HS-DNA.     

Synthesis,characterization, and thermal decomposition of fluorinated salicylaldehyde Schiff base derivatives (salen) and their complexes with copper(II)

Trifluoromethoxy functionalized copper(II) Schiff base complexes N,N′-bis(5-trifluoromethoxysalicylaldehyde)cyclohexanediiminatodiaquacopper(II) and N,N′-bis(5-trifluoromethoxysalicylaldehyde)phenylenediiminatocopper(II) were synthesized and characterized. Thermal decompositions of the synthesized complexes were studied by thermogravimetry in order to evaluate their thermal stability and thermal decomposition pathways. Three similar decomposition steps occurred for the two copper complexes. Mass losses and evolved gasses were characterized by TG/DTA-MS. Kinetic parameters were calculated and the results showed that the values obtained are comparable.     

Synthesis, crystal structure and antibacterial activity of a group of mononuclear manganese(II) Schiff base complexes

Five mononuclear complexes of manganese(II) of a group of the general formula, [MnL(NCS)₂] where the Schiff base L = N,N′-bis[(pyridin-2-yl)ethylidene]ethane-1,2-diamine (L¹), (1); N,N′-bis[(pyridin-2-yl)benzylidene]ethane-1,2-diamine (L²), (2); N,N′-bis[(pyridin-2-yl)methylidene]propane-1,2-diamine (L³), (3); N,N′-bis[(pyridin-2-yl)ethylidene]propane-1,2-diamine (L⁴), (4) and N,N′-bis[(pyridin-2-yl)benzylidene]propane-1,2-diamine (L⁵), (5) have been prepared. The syntheses have been achieved by reacting manganese chloride with the corresponding tetradentate Schiff bases in presence of thiocyanate in the molar ratio of 1:1:2. The complexes have been characterized by IR spectroscopy, elemental analysis and other physicochemical studies, including crystal structure determination of 1, 2 and 4. Structural studies reveal that the complexes 1, 2 and 4 adopt highly distorted octahedral geometry. The antibacterial activity of all the complexes and their respective Schiff bases has been tested against Gram(+) and Gram(−) bacteria.     

Synthesis,Characterization, and an ab initio Study of a Manganese(II) Macrocyclic Schiff-Base Complex with Two 2-Aminoethyl Pendant Arms

The cyclocondensation of 2,6-diformylpyridine with N,N,N,N-tetrakis(2-aminoethyl)ethane-1,2-diamine (pentene) in the presence of Mn^II forms the [1 + 1] pendant arm Schiff-base macrocyclic complex, [MnL³]²⁺. The ligand is a 15-membered pentaaza macrocycle having two 2-aminoethyl pendant arms {L³= 6,9-bis(aminoethyl)-3,6,9,12,18-pentaazabicyclo[12.3.1]octadeca-1(18),2,12,14,16-pentene}. The complex, investigated by analytical, spectroscopic and magnetic techniques, supports the formation of a highly symmetrical pentagonal bipyramid complex with the Mn^II ion located within a pentaaza macrocycle and two pendant amines coordinating on opposite sides of a plane defined by the macrocycle and the metal ion. The structure of the complex was also verified by ab initio HF-MO calculations using a standard 3-21G basis set.     

Mimicking a Superoxide Dismutase (SOD) Enzyme by copper(II) and zinc(II)-complexes

Mimicking the Superoxide Dismutase Enzyme (SOD), several imidazolato-bridged copper(II)-zinc(II) complexes were prepared, characterised by IR spectroscopy and their SOD enzyme activity was determined. 2,2′-Bipyridine, 2,2′:6′,2″-terpyridine and tris(2-aminoethyl)amine molecules were used on both metal sides, as coordinating ligands. The complex, containing the 2,2′:6′,2″-terpyridine ligand on copper side has the smallest SOD activity, which indicates the importance of the rigidity of the copper complex in SOD activity.     

Synthesis,spectroscopic and thermal properties of Pt(II) complexes of some polydentate ligands

The new tetradentate symmetrical (2R,2′S)-1,1′-piperazine-1,4-diyldipropane-2-thiol) (L¹), (2S)-1-[bis(2-aminoethyl)amino]propan-2-ol) (L²), and 2-{(E)-[((1R,2S)-2-{[(1Z)-(2-hydroxy phenyl)methylene]amino}cyclohexyl)imino]methyl}phenol (L³) ligands were synthesized and characterized on the basis of FT-IR, ¹H, ¹³C NMR, EI mass, and elemental analysis. Three commercially available ligands, (2,2′-[ethane-1,2-diylbis(thio)]diethanol (L⁴), 2,2′-dithiodiethanenamine (L⁵), and (2,2′-[ethane-1,2-diyldi(imino)] diethanol (L⁶), were also studied. Pt(II) complexes were characterized by FTIR, elemental analysis and thermal methods. Thermal behaviors of these complexes were investigated in the range 10–1000 °C. Magnetic properties were also studied, and the all complexes were found to be diamagnetic. The structures consist of the monomeric units in which the Pt(II) atoms exhibit square planar geometry. N,N′-bis(salicylidene)-1,2-cyclohexane has been synthesized and characterized by X-ray single crystal diffraction measurement. The ligand crystallizes in monoclinic crystal system and space group, Cc.     

Tetradentate nitrogen-containing ligands bis-5-(2-pyridylmethylidene)-3,5-dihydro-4<Emphasis Type="Italic">H</Emphasis>-imidazol-4-ones and their coordination compounds with Cu<Superscript>I</Superscript> and Cu<Superscript>II</Superscript>

Tetradentate N₄-type organic ligands containing two 5-(2-pyridylmethylidene)-2-thio-3,5-dihydro-4H-imidazol-4-one fragments linked by two-, four-, or six-carbon polymethylene bridges between the sulfur atoms were synthesized. Mono- and dinuclear complexes of these ligands with copper(II) chloride, as well as with copper(I) and copper(II) perchlorates, were prepared. The structure of the coordination compound (5Z,5′Z)-2,2′-(butane-1,2-diyl-disulfanyldiyl)bis-5-(2-pyridylmethylidene)-3-phenyl-3,5-dihydro-4H-imidazol-4-one with copper(I) perchlorate was established by X-ray diffraction. The copper atom in this complex is in a distorted tetrahedral coordination formed by four nitrogen atoms of two imidazole and two pyridine rings. The perchlorate anion is located in the outer sphere of the complex and is not involved in the coordination with the copper ion. The electrochemical study of the ligands and the complexes was carried out by cyclic voltammetry and rotating disk electrode voltammetry. The initial reduction of the complexes under study occurs at the metal atom. The length of the polymethylene bridge in the ligand has only a slight effect on the redox properties of the ligands and the complexes.     

Anticorrosion properties of products of N-(2-Vinyloxyethyl)-1,2-ethylenediamine condensation with carbonyl compounds

N-(2-Vinyloxyethyl)-N′-cyclohexylidene-1,2-ethylenediamine and N,N′,N″-tris-[2-(2-vinyloxyethyl)-aminoethyl]hexahydro-1,3,5-triazine were synthesized by reactions of N-(2-vinyloxyethyl)-1,2-ethylenediamine with cyclohexanone and formaldehyde with yields of 91 and 90%, respectively. The IR and ¹H and ¹³C NMR spectral data and the results of studying their anticorrosion properties are given.     

The synthesis and characterization of copper(II)–<Emphasis Type="Italic">p</Emphasis>-aminosalicylate complexes with diamine ligands

The complexes were synthesized by the reaction between sodium salt of p-aminosalicylic acid (PAS) and Cu(II) for 1 and corresponding ethylenediamine (en) or its derivatives for 2–6. The complexes were characterized by using elemental analyses, FT-IR, UV–Vis, magnetic moment measurements, and thermal analyses techniques. In complex 1[Cu₂(PA)₄(H₂O)₂], two Cu(II) ions were found as bridged by four μ-O:O′ p-aminosalicylato (PA) ligands, forming a cage structure, and two aqua ligands to form dinuclear square-pyramidal geometry around Cu(II) ions. In the complexes 2–6, the PA (anionic form of p-aminosalicylic acid) coordinated to Cu(II) ions as monodentate manner by using its oxygen atom of deprotonated carboxylic acid and ethylenediamine derivatives coordinated to the Cu(II) ions in bidentate manner to form mononuclear octahedral complexes [Cu(PA)₂(L)₂] (L = ethylendiamine, N,N-dimethylethylendiamine, N,N′-dimethylethylendiamine, N,N,N′,N′-tetramethylethylendiamine, and 1,3-propanediamine, for complexes 2, 3, 4, 5, and 6, respectively). In all the complexes OH and NH₂ groups of PA ligands were not coordinated to metals.     

Copper(II) complexing with 2′,2′-diethylheptanohydrazide

Acid-base properties of 2′,2′-diethylheptanohydrazide (DEHH) and its complex formation with copper(II) ions in water-isopropanol solutions were studied. Cationic complexes with [Cu²⁺] : [DEHH] ratios of 1 : 1 and 1 : 2 were found to be formed in weak acid media, and an uncharged complex with a [Cu²⁺] : [DEHH] ratio of 1 : 2 was found to be formed in a basic medium. log K _st values were determined. The data obtained were compared with the stability constants of copper(II) 2′,2′-diethylbenzohydrazide complexes.     

Synthesis,spectroscopic studies and crystal structures of Re<Superscript>I</Superscript>(CO)<Subscript>3</Subscript>(NN)Cl complexes with <Emphasis Type="Italic">N,N</Emphasis>′-bis(substituted benzylidene)ethane-1,2-diamine Schiff base ligands

Four new Re(I) tricarbonyl-diimine complexes were prepared by reaction of Re(CO)₅Cl with N,N′-bis(substituted benzylidene)ethane-1,2-diamine Schiff base ligands. These compounds were characterized by physico-chemical methods, and their crystal structures were established by X-ray diffraction. The coordination geometry at the Re atom is that of a distorted octahedron, with three carbonyl ligands in the facial geometry.     

Synthesis and characterization of nickel(II) complexes with three potentially hexadentate Schiff-base ligands and polyamines: X-ray crystal structure determination of one nickel(II) complex

Three new potentially hexadentate N₄O₂ Schiff-base ligands (H₂L¹, H₂L² and H₂L³) were prepared from the reaction of the polyamines N,N′-bis(2-aminophenyl)-1,2-ethanediamine (L¹), N,N′-bis(2-aminophenyl)-1,3-propanediamine (L²) and N,N′-bis(2-aminophenyl)-1,4-butanediamine (L³), respectively with salicylaldehyde. Reaction of the Schiff bases with Ni(II) salts in the presence of N(Et)₃ gave the neutral complexes [NiL⁴], [NiL⁵] and [NiL⁶]. Ni(II) complexes of the polyamines were also prepared. One of complexes [Ni(L¹)(MeCN)₂](ClO₄)₂·MeCN has been characterized through X-ray diffraction methods.     

Physical and chemical properties of N ′, N ′-aliphatic acid dioctylhydrazides and their complexing with copper(II) ions

Some physical and chemical properties of aliphatic acid N′N′-dioctylhydrazides[RC(O)NHN(C₈H₁₇)₂] (DOHs) were studied in comparison to 2-ethylhexanoic acid N′N′-dialkylhydrazides, namely, solubility, acid-base properties, entrainment with an aqueous phase, and partition factors depending on the medium and the acyl radical length. The pH ranges of maximal extraction of copper(II) complexes by DOHs to kerosene and the effect of ammonium salts on copper(II) extraction were determined. The compositions of extracted complexes were determined (Cu(II): DOH = 1: 1 and 1: 2); the extraction constant K _extr was calculated for the CuL₂ complex with butyric acid N′N′-dioctylhydrazide. Original Russian Text ? T.D. Batueva, A.V. Radushev, L.G. Chekanova, V.Yu. Gusev, V.I. Karmanov, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 1, pp. 146–150.     

Synthesis,characterization and crystal structures of a pair of azido-bridged polynuclear Schiff base copper(II) complexes with urease inhibitory activity

A pair of azido-bridged Schiff base copper complexes, [CuL1(μ_1,3-N₃)] _n · nClO₄ (1) and [Cu₂(L2)₂(μ _1,1-N₃)₂] · 2ClO₄ (2) (L1 = N,N-diethyl-N′-(1-pyridin-2-ylmethylidene)ethane-1,2-diamine, L2 = N-isopropyl-N′-(1-pyridin-2-ylmethylidene)ethane-1,2-diamine) have been obtained by the same synthetic procedures, but with slightly different Schiff bases. The structures of the complexes have been characterized by IR spectra, elemental analysis, and single crystal X-ray determination. Each Cu atom in the complexes is five-coordinate in a square pyramidal configuration involving the three N atoms of the Schiff base ligand and two N atoms from two bridging azide ligands. The azide ligands adopt end-to-end bridging mode in (1), and end-on bridging mode in (2). The different coordination modes of the azide ligands in the two complexes are assigned to the steric effects of the terminal groups (two ethyl groups for (1) and one isopropyl group for (2)) in the Schiff base ligands. The urease inhibitory activities of the complexes were evaluated. Both of them showed potent inhibition against jack bean urease. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Synthesis,crystal structures,and fluorescence properties of two dinuclear cadmium(II) complexes derived from <Emphasis Type="Italic">N</Emphasis>-isopropyl-<Emphasis Type="Italic">N</Emphasis>′-(1-pyridin-2-ylethylidene)ethane-1,2-diamine

A new tridentate pyridyl Schiff base, N-isopropyl-N′-(1-pyridin-2-ylethylidene)ethane-1,2-diamine (L), was used to synthesize two dinuclear cadmium(II) complexes, [Cd₂L₂(μ _1,1-N₃)₂(N₃)₂] (1) and [Cd₂L₂(μ _1,3-NCS)₂(NCS)₂] (2). X-ray single crystal structure determination reveals that in both centrosymmetric complexes, the Cd atom is in a distorted octahedral coordination. In the crystal structures of 1 and 2, the dinuclear cadmium(II) complex molecules are linked, respectively, through intermolecular N–H···N and N–H···S hydrogen bonds to form infinite 1D chains. The preliminary fluorescence properties of the complexes were investigated.     

Synthesis and characterization of a new fluorene ligand and its complexes with cobalt(II), copper(II), and ruthenium(II)

A new fluorene ligand, benzo[15-crown-5]-5H-pyrido[3′,2′:4,5]cylopenta[1,2-b]pyridin-5-ylidenehydrazone (bph), has been synthesized from the reaction of 4,5-diazafluoren-9-one with 4′-formylbenzo-15-crown-5. The Co(II), Cu(II), and Ru(II) complexes of the ligand were prepared and characterized. The metal-to-ligand ratio of the Co(II) and Cu(II) complexes was found to be 2:1 and that of the Ru(II) complex was found to be 1:1. The ligand and complexes have been characterized by FTIR, UV–visible, ¹H NMR and fluorescence spectra, as well as elemental analyses and mass spectra.     

Palladium-catalyzed amination in the synthesis of macrocyclic compounds containing 1,3-disubstituted adamantane fragments

Palladium-catalyzed amination of 1,3-dibromobenzene, 2,6-dibromopyridine, 3,3′-dibromobiphenyl, 2,7-dibromonaphthalene, and 1,8-dichloroanthracene with an equimolar amount of 2,2′-(adamantane-1,3-diyl)diethanamine resulted in the formation of macrocyclic compounds containing one or several adamantane and one or several aromatic fragments. The reactions of 2,2′-(adamantane-1,3-diyl)diethanamine with excess 1,3-dibromobenzene, 2,6-dibromopyridine, 1,8-dichloroanthracene, and 1,8-dichloroanthraquinone gave the corresponding N,N′-diaryl derivatives. Polyaza macrocycles incorporating adamantane, aromatic, and 4,7,10-trioxatridecane-1,13-diamine fragments, were obtained by palladium-catalyzed amination of the N,N′-diaryl derivatives with 4,7,10-trioxatridecane-1,13-diamine.     

Extraction of copper(II) from weakly acid and ammonia media with <Emphasis Type="Italic">N</Emphasis>′,<Emphasis Type="Italic">N</Emphasis>′-dialkylhydrazides of aliphatic carboxylic acids

Dependence of physicochemical properties of N′,N′-dialkylhydrazides of aliphatic carboxylic acids (solubility in kerosene, acid-base properties) on the length of hydrocarbon radicals in the functional group was studied. The extraction capacity for copper(II) salts in weakly acid and ammonia media was examined in the range from pH 5–11 to a NH₃ content of 2.7 M. The capacity of the organic phase for copper(II) and re-extraction conditions were determined for the example of N′,N′-dibutylhydrazide of octanoic acid.