Metal-assisted transformation of N-benzoyldithiocarbazate to 5-phenyl-1,3,4-oxadiazole-2-thiol in the presence of ethylenediamine,and its first row transition metal complexes

The reaction of metal complexes of the type [M(HL)Cl] or [M(HL)₂] [where M = Cu(II), Ni(II), Mn(II), Co(II) and Zn(II) and H₂L = N-benzoyldithiocarbazate] with an excess of ethylenediamine (en) in CHCl₃–MeOH medium leads to ring closure by desulfurisation to yield unique mixed-ligand complexes 1–4, [Cu(en)₂](pot)₂(pot = 5-phenyl-1,3,4-oxadiazole-2-thiol), [M(en)₂(pot)₂] [M = Ni(II), Mn(II)] and [Zn(en)(pot)₂]. The metal complexes have been characterized by various physicochemical methods. The molecular structure of [Cu(en)₂](pot)₂ has been determined by a single crystal X-ray diffraction study. In the centrosymmetric unit of [Cu(en)₂](pot)_2, the metal ion has a square planar arrangement of four symmetry related N-atoms of two en groups and is ionically bonded to two pot anions. Weak interaction studies on the complex reveal the presence of a hydrogen-bonded network in the molecule involving non-coordinating donor atoms of the pot anion with en resulting in the formation of an extended three-dimensional network. The arrangement of the [Cu(en)₂]²⁺ units, at a dihedral angle of 49.43° to pot⁻, provides a network of intermingled chains leading to a π–π stacked 3-dimensional framework.     

Synthesis,crystallographic and spectroscopic studies,evaluation as antimicrobial and cytotoxic agents of a novel mixed-ligand nickel(II) complex

A new mononuclear mixed-ligand complex of Ni(II) has been synthesized and structurally characterized by single-crystal X-ray diffraction as [Ni(4-Cl-pydc)(apym)(H₂O)₂], where 4-Cl-pydc and apym are 4-chloropyridine-26-dicarboxylate and 2-aminopyrimidine, respectively. Spectroscopic studies such as FT-IR, UV-vis, ¹H-NMR, and thermal analysis (TGA/DTA) were carried out. The fluorescence properties were studied in solvents with different dipole moments. Antimicrobial activities of 4-chloropyridine-26-dicarboxylic acid (1), 2-aminopyrimidine (2), complex (3), and nickel(II) nitrate hexahydrate (4) were investigated by disk diffusion and broth microdilution methods against three Gram-positive bacteria, Staphylococcus aureus, Bacillus subtilis, Staphylococcus epidermidis and three Gram-negative bacteria, Escherichia coli, Pseudomonas aeruginosa, S. marcescens; also antifungal effect was evaluated on Aspergillus niger and Saccharomyces cerevisiae in vitro. The highest antibacterial activity of complex was observed nearly equal to gentamicin as a standard drug toward S. epidermids with IZD of 18 mm. The in vitro antiproliferative activity of 1–4 on H1299 (a human non-small cell lung carcinoma), HepG2 (a human liver hepatocellular carcinoma), and β-TC3 (a mouse beta pancreatic) cell lines was evaluated by MTT (3-(45-dimethylthiazol-2-yl)-25-diphenyl-2H-tetrazolium bromide) assay and, effect of complex on depolarization of mitochondrial membrane (MMP) of all three cell lines was measured by rhodamine 123. The highest cytotoxic effect of complex was exhibited toward H1299 cell line with IC₅₀ value equal to 10 μM.     

高效磷光[Ru(terpy)(phen)X]+配合物结构和光谱性质的理论研究

采用密度泛函方法研究了三个混合配体的Ru(II)配合物[Ru(terpy)(phen)X]⁺ (terpy为2,2',6',20'-三联吡啶,phen为1,10-邻二氮杂菲,X为-C≡CH (1)、Cl (2)和CN(3))的几何结构、电子结构和光谱性质．分别在B3LYP/LanL2DZ UB3LYP/LanL2DZ水平下优化了它们的基态和激发态结构．在TD-DFT计算水平下结合极化连续介质模型得到了它们在CH3CN溶液中的吸收和发射光谱．计算得到的Ru-C、Ru-N和Ru-Cl基态     

Synthesis and spectroscopic characterization of eleven mixed-ligand diorganotellurium(IV) compounds containing dithiocarbamate and dithiophosphate ligands

Eleven mixed-ligand organotellurium(IV) compounds of composition R₂Te(dtc)(dtp) have been prepared employing two different dithiocarbamate (dtc) and dithiophosphate (dtp) ligands: 1, R₂ = C₄H₈, dtc = S₂CNEt₂, dtp = S₂P(OCH₂)₂CEt₂; 2, R₂ = C₈H₈, dtc = S₂CNEt₂, dtp = S₂P(OCH₂)₂CEt₂; 3, R₂ = C₄H₈O, dtc = S₂CNEt₂, dtp = S₂P(OCH₂)₂CEt₂; 4, R₂ = C₅H₁₀, dtc = S₂CNEt₂, dtp = S₂P(OCH₂)₂CEt₂; 5, R₂ = C₄H₈, dtc = S₂CN(CH₂)₄, dtp = S₂P(OCH₂)₂CEt₂; 6, R₂ = C₈H₈, dtc = S₂CN(CH₂)₄, dtp = S₂P(OCH₂)₂CEt₂; 7, R₂ = C₄H₈O, dtc = S₂CN(CH₂)₄, dtp = S₂P(OCH₂)₂CEt₂; 8, R₂ = C₅H₁₀, dtc = S₂CN(CH₂)₄, dtp = S₂P(OCH₂)₂CEt₂; 9, R₂ = C₄H₈, dtc = S₂CN(CH₂)₄, dtp = S₂P(OCH₂)₂CMeⁿPr; 10, R₂ = C₈H₈, dtc = S₂CN(CH₂)₄, dtp = S₂P(OCH₂)₂CMeⁿPr; 11, R₂ = C₄H₈O, dtc = S₂CN(CH₂)₄, dtp = S₂P(OCH₂)₂CMeⁿPr. 1-11 were characterized by mass spectrometry, IR spectroscopy and multinuclear NMR (¹H, ¹³C, ³¹P, ¹²⁵Te) spectroscopy. The molecular structures of 2, 4 and 6, of which 2 crystallized in form of two different polymorphs (2a and 2b), were analyzed by single-crystal X-ray diffraction analysis. This analysis showed that the coordination mode of both ligand types is anisobidentate. When considering only covalent Te-C and Te-S bonds, the coordination geometry of the tellurium atoms is distorted Ψ-trigonal-bipyramidal, since the lone pair is stereochemically active and occupies an equatorial position together with the carbon atoms of the tellurocycles. If secondary Te?S interactions are considered also, the coordination sphere around tellurium is best described as bicapped Ψ-trigonal-bipyramidal for the complexes with two intramolecular Te?S secondary bonds and monomeric molecular structures, and pentagonal-bipyramidal for the complexes in which neighboring molecules in the crystal lattice are linked through additional weak intermolecular Te?S secondary bonds to form dimeric supramolecular aggregates.     

Four benzimidazole-based ZnII/CdII polymers extended by aromatic polycarboxylate coligands: synthesis,structure, and luminescence

Four benzimidazole (bim)-based metal complexes, {[Zn₂(bim)₄(btec)] · DMF} _n (1), {[Zn(bim)(btc)] · Htea} _n (2), [Zn(bim)₂(bdc)] _n (3), and {[Cd₃(bim)₄(H₂O)₆(btc)₂] ? 2H₂O} _n (4) (H₄btec = 1,2,4,5-benzenetetracarboxylic acid, H₃btc = 1,3,5-benzenetricarboxylic acid, H₂bdc = 1,4-benzenedicarboxylic acid, and tea = triethylamine), have been obtained by the introduction of benzene-based polycarboxylate as coligand and are structurally characterized by single-crystal X-ray diffraction, elemental analysis, IR spectra, thermogravimetric curves, and luminescence spectra. Controlled by the number and position of the carboxylates attached to the aromatic ring, all the four complexes exhibit polymeric structures from 1-D chain or ribbon for 1, 3, and 4 to 2-D layer for 2. In contrast, the neutral bim is a terminal ligand to complete the metal coordination sphere and it also helps to assemble the low-dimensional coordination skeleton into a high-dimensional ordered supramolecular architecture by N–H ··· O hydrogen-bonding and π–π stacking interactions. Additionally, the complexes exhibit strong emissions originating from the bim-based intraligand as well as photo-induced interligand charge transfer upon cation binding, suggesting potential applications as luminescent materials.     

Synthesis and Crystal Structure of a Mixed-Ligand Cobalt(II) Complex with 2-Aminobenzimidazole

Abstract  The cobalt(II) complex, [Co(abz)₂(SCN)₂] 1, has been synthesized by the reaction of cobalt(II) nitrate with ammonium thiocyanate and abz ligands (abz = 2-aminobenzimidazole), and was fully structurally characterized by elemental analysis, IR spectra, X-ray diffraction and thermogravimetric experiments. It crystallizes in the triclinic P-1 space group with a = 8.6316(10), b = 9.3426(10), c = 13.254(2) ?, α = 95.793(2), β = 95.870(2), γ = 115.7380(10), V = 945.1(2) ?³, and Z = 2. The central cobalt(II) atom is four-coordinated to nitrogen donors from two neutral abz ligands and two isothiocyanate anions respectively, adopting a slightly distorted tetrahedral geometry. In addition, the intermolecular N–H···N and N–H···S hydrogen bonds interactions link the discrete mononuclear units into infinite three-dimensional networks. Index Abstract  The essence sentence of the paper: In the mixed-ligand mononuclear complex, [Co(abz)₂(SCN)₂], the four coordinated cobalt(II) atom exhibits a slightly distort tetrahedron, which is further assembled into 3D infinite network by intermolecular hydrogen interactions.      

Mixed-ligand complexes of palladium(II) involving propane 1,2,3-triamine as primary ligand and amino acids,peptides, or DNA units as secondary ligands

Summary The acid-base equilibria of propane 1,2,3-triamine (PTA) and the formation equilibria of binary and ternary complexes of palladium(II) withPTA as primary ligand and amino acid, peptide, and DNA subunits as secondary ligand have been investigated. Pd(II) is found to form a 1:1 complex withPTA. The ternary complexes are formed in a stepwise mechanism, wherebyPTA first binds to Pd(II) and then ligates to the secondary ligand. The hydrolysis of the Pd-PTA complex and the deprotonation of the amide residues in the peptide complexes are discussed in relation to physiological conditions.

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Gemischte Palladium(II)-Komplexe mit Propan-1,2,3-triamin als Primärligand und Aminosäuren, Peptiden oder DNA-Einheiten als Sekundärliganden

Zusammenfassung Das Säure-Basen-Gleichgewicht von Propan-1,2,3-triamin (PTA) und die Bildungsgleichgewichte von binären und ternären Komplexen von Pd(II) mitPTA als Primärligand und Aminosäuren, Peptiden und DNA-Einheiten als Sekundärliganden wurden untersucht. Pd(II) bildet mitPTA einen 1:1-Komplex. Die ternären Komplexe werden stufenweise gebildet, wobeiPTA zuerst an Pd(II) koordiniert; dann erfolgt die Bindung an den Sekundärliganden. Die Hydrolyse des Pd-PTA-Komplexes und die Deprotonierung der Amide in den Peptidkomplexen werden im Zusammenhang mit physiologischen Bedingungen diskutiert.

     

Synthesis and crystal structure of a mixed-ligand compound di-n-butyl(4-chlorobenzoxy)(4-chlorobenzohydroxamato)tin(IV)

Reaction of dibutyltin dichloride with 4-chlorobenzohydroxamic acid and 4-chlorobenzoic acid in 1:1:1 stoichiometry yields the new title compound di-n-butyl(4-chlorobenzoxy)(4-chlorobenzohydroxamato)tin(IV) 1, which had been characterized by IR and ¹H, ¹³C, ¹¹⁹Sn NMR. Single X-ray crystal structure analysis has been determined for 1, which crystallizes as the five-coordinate mixed-ligand dibutyltin(IV) complex containing both monodentate and bidentate ligands. The crystal structure of the compound reveals that the tin atom adopts distorted trigonal bipyramidal geometry with the Bu groups trans to each other. The C-Sn-C angle is 145.9(3)°, and the Sn-O bonds are 2.083(4) and 2.158(4) Å in one ligand and 2.242(4) Å in the other. An unusual feature of the structure is the presence of a kind of intermolecular hydrogen bonding which serves to stabilize the crystal structure.     

Synthesis and spectroscopic Investigation of Mixed-Ligand Copper Chelates containing 2-hydroxyaryloximes and N-disubstituted dithiocarbamates. Crystal and molecular structure of trans-bis[propanone, 1-(2-hydroxy-phenyl)oximato] copper(II)

A series of mixed-ligand copper(II) chelates containing the anion of 2-hydroxyaryloxime(oxime) and N,N-disubstituted dithiocarbamate(dtc), [Cu(dtc)(oxime)], was prepared and characterised. The spectra (IR, ESR, electronic excitation) indicate that the CuNOS₂ chromophore attains square planar geometry. The ESR observables suggest appreciable covalency. In the case of [Cu(Et₂dtc)(oxime)] chelates, however, the observed data suggest distortion from square planar arrangement to a square pyramidal, indicative of a possible dimerism. In addition, the structure of the trans-bis[propanone, 1-(2-hydroxyphenyl)-oximato]copper(II), Cu(C₉H₁₀NO₂)₂ was determined by X-ray diffraction (monoclinic, space group P2₁/n, a = 12.072(7) Å, b = 5.204(2) Å, c = 13.571(6) Å, β = 103.72(1)°, Z = 2). The molecule consists of discrete Cu(ppox)₂ monomeric units, where the Cu atom is in the equatorial plane bonded to two nitrogen atoms and two oxygen at distances of 1.949(2) and 1.882(2) Å, respectively.