Synthesis, characterization and X-ray crystallographic structural study of copper(II) and nickel(II) complexes of the 2-quinoline carboxaldehyde Schiff base of S-methyldithiocarbazate (Hqaldsme)

Complexes of general formulae, [Cu(qaldsme)(X)(CH3OH)(n)] and [Ni(qaldsme)(2)] (.) 0.5CH(3)CN (qaldsme = anionic form of the 2-quinoline carboxaldehyde Schiff base of S-methyldithiocarbazate; X = NCS-, I-, NO3-; n = 0 or 1) have been synthesized and characterized by magnetic and spectroscopic techniques. X-ray crystal structure determination of [Cu(qaldsme)(ONO2)(CH3OH)] (1), [Cu(qaldsme)(NCS)](2) (2) and [Ni(qaldsme)(2)] (.) 0.5CH(3)CN (4) shows that the nitrato-complex of copper (1) is monomeric and five-coordinate and the thiocyanato-complex (2) has a novel thiolate sulfur-bridged dimeric structure in which each of the copper(II) ions adopts a five-coordinate, approximately square-pyramidal geometry, with a CuN3S2 coordination kernel. The nickel(II) complex (3) has a distorted octahedral geometry with meridional dispositions of the two uninegatively charged tridentate NNS ligands. In all these complexes, the Schiff bases are coordinated in their iminothiolate forms via the quinoline nitrogen atom, the azomethine nitrogen atom and the thiolate sulfur atom. (c) 2006 Elsevier Ltd. All rights reserved

Synthesis, DFT and X-ray Studies of Trans CuCl₂L₂ with L Is (E)-(4-Chlorophenyl)-N-(3-phenyl-4H-1,2,4-triazol-4-yl)methanimine

A novel approach was carried to prepare trans-CuCl2L2 complex with the ligand L, (E)-(4-chlorophenyl)-N-(3-phenyl-4H-1,2,4-triazol-4-yl)methanimine which was formed in situ during the reaction of CuCl2 with 4-(4-chlorobenzylideneamino)-5-phenyl-2H-1,2,4-triazole-3(4H)-thione. The synthesized compounds were characterized by applying various spectroscopic techniques. The crystal structure of the complex was unambiguously determined using X-ray analysis indicating square planar geometry. Intermolecular H-bonds govern the supramolecular structure of the copper complex. Aromatic rings are stacked in an offset packing due to occurrence of π–π interactions. The structure is further corroborated with a detailed computational investigation. A thione–thiol tautomerism for the triazole compound was also studied. The Schiff base 1,2,4-triazole copper chloride complex is expected to have high anticancer activity

Ruthenium-Catalyzed N-Alkylation of Amines and Sulfonamides Using Borrowing Hydrogen Methodology

The alkylation of amines by alcohols has been achieved using 0.5 mol % [Ru(p-cymene)Cl(2)](2) with the bidentate phosphines dppf or DPEphos as the catalyst. Primary amines have been converted into secondary amines, and secondary amines into tertiary amines, including the syntheses of Piribedil, Tripelennamine, and Chlorpheniramine. N-Heterocyclization reactions of primary amines are reported, as well as alkylation reactions of primary sulfonamides. Secondary alcohols require more forcing conditions than primary alcohols but are still effective alkylating agents in the presence of this catalyst

Synthesis of Schiff Base Encapsulated ZnS Nanoparticles : Characterization and Antibacterial Screening

In this study, Schiff bases containing salicylaldehyde moiety(namely salicylaldehyde2-methyl-3-thiosemicarbazone and salicylaldehyde triazole)were synthesized using the conventional refluxing method. The Schiff bases were utilized in the encapsulation of ZnS nanoparticles usingtheco-precipitation method. The nanoparticles were characterized using FTIR, UV-visible absorption spectroscopy, scanning electron microscopy, and energy dispersive X-ray analysis. X-ray diffraction analyses suggest that the Schiff base encapsulated ZnS particles form the cubic crystal phase of ZnS,with the average crystallite sizes being approximately between56 and 60 nm.The interaction between the Schiff bases and ZnS was also evaluated by photoluminescence spectroscopy. The antibacterial activities of the Schiff base encapsulated ZnS nanoparticles were screened against four different gram-positive and gram-negative bacterial strains (i.e.Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa,andStaphylococcus aureus)using the agar diffusion method. The antibacterial activities of the nanoparticles were compared withthose of their respective Schiff bases. Although in the current study the Schiff base encapsulated ZnSnanoparticles were found to be inactive against those bacteria, they could be applicable as multifunctional materials for fluorescence probes, photocatalysts, andother biological applications