Synthesis and crystal structure of a group of phenoxo-bridged heterodinuclear [NiIIHgII] Schiff base complexes

Synthesis, Characterization, Analytical Application, and Theoretical Studies of a Schiff Base, (E)-2-(2-aminophenylthio)-N-(Thiophen-2-yl-methylene) Benzenamine

In this study, a new Schiff base, (E)-2-(2-aminophenylthio)-N-(thiophen-2-yl-methylene) benzenamine was synthesized for selective detection of Hg2+. This Schiff base was characterized by proton nuclear magnetic resonance (1HNMR), carbon-13 nuclear magnetic resonance (13CNMR), and Fourier-transform infrared (FTIR) spectroscopy. Binding interaction between (E)-2-(2-aminophenylthio)-N-(thiophen-2-yl-methylene)benzenamine and various metal ions has been studied by UV-Vis spectroscopic measurements and shows promising coordination towards Hg2+ and almost no interference from other metal ions (Ag+, Mn2+, Fe3+, Al3+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Fe2+ and Cr3+).This Schiff base exhibiting detection limit of 3.8 × 10- 8 M. The Schiff base newly synthesized in this study was successfully applied to the determination of Hg2+ in water samples. In addition to the experimental study, a theoretical study was conducted using Gaussian 09 program to support the experimental findings. FTIR, NMR, bond angle, bond length, torsional angles, and structural approximation were studied using theoretical consideration.

Two new heterodinuclear Schiff base complexes: synthesis, crystal structure and thermal studies

Two new heterodinuclear Schiff base complexes, [Hg(L)NiCl2(DMF)2] 1, and [Zn(L)NiCl2(DMF)2] 2, where H2L = N,N'-bis(salicylidene)-1,3-diaminopropane and DMF = dimethylformamide have been synthesized and characterized using elemental analysis, IR spectroscopy, thermal analysis and X-ray diffraction. Structural studies on 1 and 2 reveal the presence of a heterodinuclear [Ni(II)Hg(II)] unit and [Zn(II)Ni(II)] in which the central metal ions are connected to each other by two phenolate oxygen bridges. For complex 1 the Ni(II) ion adopts an elongated octahedral geometry (NiN2O4) while the Hg(II) ion assumes a distorted tetrahedral arrangement (HgO2Cl2) whereas for complex 2 the Zn(II) ion adopts an elongated octahedral geometry (ZnN2O4) while the Ni(II) ion assumes a distorted tetrahedral arrangement (NiO2Cl2). There are intermolecular C-H···Cl-M interactions among the dinuclear complexes which are interconnected for 1 and 2. These intermolecular interactions result in the formation of a three dimensional structure for 1 and one dimensional zig-zag chains for 2.

Isolation of a metastable intermediate in a heterometallic Cu(II)-Hg(II) 1D polymeric chain: synthesis, crystal structure, and photophysical properties

A metastable heterometallic intermediate, [Cu2(bpy)2(DIPSA)2Hg2(OAc)4(DIPSA)2]n (1, where OAc = CH3COO(-), bpy = bipyridine, and DIPSA = diisopropylsalicylic acid), has been isolated and characterized during the synthesis of 1D polymer [Cu2(bpy)2(DIPSA)2(CH3CN)2Hg2(OAc)2(DIPSA)4]n (2) at ambient temperature in acetonitrile. Moreover, recrystallization of 2 in methanol results in monomeric [Cu(DIPSA)(bpy)(CH3OH)]·CH3OH (3). Complexes 1-3 have been characterized by elemental analysis, Fourier transform infrared, and UV-vis spectroscopy as well as by their single-crystal X-ray structures. The photophysical study suggests the quenching of fluorescence of DIPSA upon complexation.

Synthesis, Spectral, and In Vitro Antibacterial Studies of Organosilicon(IV) Complexes with Schiff Bases Derived from Amino Acids

The present work stems from our interest in the synthesis, characterization, and antibacterial evaluation of organosilicon(IV) complexes of a class of amino-acid-based Schiff base which have been prepared by the interaction of ethoxytrimethylsilane with the Schiff bases (N OH) in 1 : 1 molar ratio. These complexes have been characterized by elemental analysis, molar conductance, and spectroscopic studies including electronic IR and NMR ((1)H, (13)C, and (29)Si) spectroscopy. The analytical and spectral data suggest trigonal bipyramidal geometry around the silicon atom in the resulting complexes. The ligands and their organosilicon complexes have also been evaluated for in vitro antimicrobial activity against bacteria (Bacillus cereus, Nocardia spp., E. aerogenes, Escherichia coli, Klebsiella spp., and Staphylococcus spp.). The complexes were found to be more potent as compared to the ligands.