Metal-ion directed synthesis of N2O2 type chelate complexes of Ni(II), Cu(II) and Zn(II): spectral, thermal and single crystal studies.

A set of Ni(II), Cu(II) and Zn(II) complexes of Schiff base have been synthesized by one pot condensation reaction of 2-hydroxy-4-methoxybenzophenone with 1,3-diaminopropane in 1:2:1 molar ratio. They have been characterized by elemental analysis, conductance measurement, thermal analysis (TGA/DTA), FT-IR, (1)H-NMR, EPR spectra, ESI-MS and electronic spectral studies. In order to establish the geometry, a single crystal X-ray structure for [Ni(L)] complex was determined. It crystallizes in monoclinic system having unit cell parameters a=14.015(5)Å, b=13.391(5)Å, c=14.931(5)Å and α=90.000(5)(o), ß=112.237(5)(o), γ=90.000(5)(o) with P 2(1)/c space group. No π-π stacking interaction was obtained in molecular packing diagram. A square-planar geometry has been confirmed for Ni(II) complex. Furthermore, on the basis of elemental analysis, IR, UV-visible and EPR data a square-planar geometry for Cu(II) and a distorted octahedral geometry for the Zn(II) complex has been established. In case of Zn(II) complex NO(3)(-) group was found to be coordinated in monodentate fashion. The low molar conductivity values of the complexes measured in chloroform and DMSO suggest their non-ionic nature.

Resonance Rayleigh scattering, second-order scattering and frequency doubling scattering spectra of copper(II)-Flutamide system with anionic surfactants and its analytical application.

A simple, sensitive, and rapid method based on ion association, for the determination of FLD has been developed. Flutamide (FLD) can react with Cu(II) to form 1:1 cationic chelate at pH 2.2-7.0 Mclivaine buffer medium, which can further react with anionic surfactants (AS) such as sodium dodecyl sulfate (SDS), sodium lauryl sulfonate (SLS) and sodium dodecylbenzene sulfonate (SDBS) to form 1:1 ion-association complexes. As a result, the resonance Rayleigh scattering (RRS), second-order scattering (SOS) and frequency doubling scattering (FDS) were enhanced to the highest degree. The maximum RRS, SOS and FDS wavelengths of three ion-association complexes were located at 345/345 nm, 610/305 nm and 430/860 nm, respectively. The increments of scattering intensity (ΔI) were directly proportional to the concentration of FLD in certain ranges. The detection limits (3σ) of FLD for SDS, SLS and SDBS systems were 1.9 ng ml(-1), 2.1 ng ml(-1) and 2.2 ng ml(-1)(RRS method), 2.4 ng ml(-1), 2.7 ng ml(-1) and 2.6 ng ml(-1) (SOS method) and 2.3 ng ml(-1), 2.4 ng ml(-1) and 2.5 ng ml(-1) (FDS method), separately. The sensitivity of RRS method was higher than those of FDS and SOS methods. The optimum conditions of RRS method and the influence factors, the composition and the reaction mechanism have been discussed. Since the method is highly selective, it does not interference concomitant substances. These methods were applied successfully for the determination of FLD in pharmaceutical formulation and urine samples.

Synthesis, spectroscopic, magnetic and thermal properties of bimetallic salts, [Ni(L)][MCl4] [where M=Co(II), Zn(II), Hg(II) and L=3,7-bis(2-aminoethyl)-1,3,5,7-tetraazabicyclo(3.3.1)nonane]. X-ray structure of [Ni(L)][CoCl4].

New bimetallic complex salts corresponding to the formulation [Ni(L)][MCl(4)] have been synthesized by the facile reaction between [Ni(L)](ClO(4))(2) and [MCl(2)(PPh(3))(2)] in high yields [where M=Co(II), Zn(II), Hg(II) and L=3,7-bis(2-aminoethyl)-1,3,5,7-tetraazabicyclo(3.3.1)nonane]. The complexes were characterized by IR, electronic spectra, TGA/DSC, magnetic moment and conductivity measurements. The X-ray crystal structure for [Ni(L)][CoCl(4)] clearly establishes the cationic-anionic interaction. It crystallizes in the space group P1 with unit cell dimensions a=7.1740(15)A, b=8.1583(16)A and c=8.3102(16)A. A square-planar geometry is evident for the [Ni(L)](2+) cation while the anion is found to be tetrahedral. A two-step thermolytic pattern is observed in the pyrolysis of the bimetallic complex salts.

Interaction of organotin with piperazine derived self-assembled cylindrical bisdithiocarbamates: spectral and thermal investigations.

Few organotin complexes of the type R4Sn2L2 where R=CH3 (2), C4H9 (3), C6H5 (4), and Sn2L2Cl4 (5) (L=bis(2,2'-dithiopiperazinato-2,2'-diaminodiethylamine)) have been synthesized and suitably characterized by FT-IR, UV-vis, 1H NMR, 119Sn NMR, ESI-MS, TGA/DSC, microanalysis and room temperature molar conductivity data. On the basis of FT-IR spectral studies, a symmetrical bidentate coordination has been proposed for all the complexes while the absence of any higher peak in the ESI-MS may be corroborated with the formation of binuclear complexes. On the basis of 119Sn NMR spectroscopy, six-coordinate geometry has been observed for the Sn-center in all the complexes. The TGA/DSC profile of the complexes implies their higher stability than its precursor. However, on the basis of IDT values the stability order of the organotin complexes was found to be 4>3>2. The room temperature conductivity values of the 1 mM solution of the ligand and its complexes are found to be comparable with that of non-ionic complexes.

Synthesis and characterization of transition metal 2,6-pyridinedicarboxylic acid derivatives, interactions of Cu(II) and Ni(II) complexes with DNA in vitro.

Mononuclear complexes M(L)Cl(2) where M=Mn(II), Fe(II), Co(II), Ni(II) and Cu(II) and (L=N,N-diethylpiperazinyl,2,6-pyridinedicarboxylate), have been synthesized and characterized by elemental analysis, FT-IR, (1)H NMR spectroscopy, UV-vis, magnetic moment, TGA/DSC, cyclic voltammetry and conductivity measurement data. The spectral data suggests that the dipicolinic acid acts as a bidentate ligand and is coordinated to the metal ion through the carboxylate oxygen. The cyclic voltammogram for Cu(L)Cl(2) complex was found to display two reversible Cu(II)/Cu(I) and Cu(II)/Cu(III) redox couple. The ligand exhibits a two-step thermolytic pattern while the complexes decompose in three stages respectively. An octahedral geometry has been proposed for both the complexes. The investigation of the interaction of the complexes with calf thymus DNA has been performed with absorption spectroscopy and fluorescence quenching experiments, which showed that the complexes are avid binders of calf thymus DNA. Also the interaction of the Cu(II) and Ni(II) complexes with plasmid DNA (pUC 19) was studied using agarose gel electrophoresis. The results revealed that these complexes can act as effective DNA cleaving agents resulting in the nicked form of DNA (pUC 19) under physiological conditions. The gel was run both in the absence and presence of an oxidizing agent (H(2)O(2)). The ligand and its complexes have also been screened against microbes in order to study their antibacterial action. The results revealed that the Cu(II) complex has activity comparable with the reference drugs gentamycin and flucanzole.

Synthesis, spectroscopic and thermal studies of transition metal complexes derived from benzil and diethylenetriamine.

A macrocyclic ligand, bdta (where bdta=3,6,9,12,15,18-hexaaza-1,2,10,11-tetraphenyl-2,9,11,18-tetraenecyclododecane) has been prepared by cyclocondensation of benzil with diethylenetriamine which efficiently encapsulates transition as well as pseudo-transition metal ions leading to the formation of M(bdta)Cl2 type complexes [where M=Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)]. The analytical, spectroscopic and magnetic moment data suggests an octahedral geometry for all the complexes. EPR spectra of Mn(II) and Cu(II) show considerable exchange interaction in the complex. They are non-conducting in DMSO. The TGA profile of the ligand and its complexes are identical and consists of two discreet stages. The voltammogram of Cu-complex exhibits a quasi-reversible one-electron transfer wave for Cu(II)/Cu(I) couple.

Polynuclear transition metal complexes with thiocarbohydrazide and dithiocarbamates.

Sn(tch)2{MCl2}2 was prepared from the precursor Sn(tch)2 and MCl2. It was subsequently allowed to react with diethyldithiocarbamate which yielded the trinuclear complexes of the type Sn(tch)2{M2(dtc)4}, where tch=thiocarbohydrazide, M=Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and dtc=diethyldithiocarbamate. They were characterized on the basis of microanalytical, thermal (TGA/DSC), spectral (IR, UV-vis, EPR, (1)H NMR) studies, conductivity measurement and magnetic moment data. On the basis of spectral data a tetrahedral geometry has been proposed for the halide complexes, Sn(tch)2{MCl2}2 except for Cu(II) which exhibits a square planar coordination although the transition metal ion in Sn(tch)2{M2(dtc)4} achieves an octahedral geometry where the dithiocarbamato moiety acts as a symmetrical bidentate ligand. The bidentate nature has been established by the appearance of a sharp single nu(C-S) around 1000 cm(-1). A downfield shift observed in NH(a) and NH(b) protons on moving from Sn(tch)2 to Sn(tch)2{MCl2}2 is due to the drift of electrons toward metal atoms. A two-step pyrolysis has been observed in the Sn(tch)2{MCl2}2 complexes while their dithiocarbamato derivatives exhibit a three-stage degradation pattern. Finally, the in vitro antibacterial activity of Sn(tch)2{M2(dtc)4} and the mononuclear Sn(tch)2 has been carried out on bacterial strains Escherichia coli and Salmonella typhi. The compounds were found to be active against the test organisms. The activity of the complexes is enhanced with increasing concentration. The maximum activity in both the strains was achieved by cobalt(II) dithiocarbamate complex. Minimum activity was found for Sn(tch)2 which generally increases with the introduction of transition metal ion in the complex.