Computer augmented modelling studies of Pb(II), Cd(II), Hg(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of L-glutamic acid in 1,2-propanediol-water mixtures

Potentiometric studies of complex equlibria of CaII, MgII and ZnII with 5-sulphosalicylic acid in cationic micelles of CTAB

Formation of metal ligand complex species of 5-sulphosalicylic acid with CaII, MgII and ZnII metal ions have been studied potentiometrically in various composition (0.0, 0.5, 1.0. 1.5, 2.0, and 2.5% w/v) of cetyltrimethylammonium bromide (CTAB). The study has been carried out at 303 K temperature and maintaining 0.16 mol dm-3 ionic strength using NaCl. The dynamic species belongs to 5-sulphosalicylic acid are LH2 - and LH2-. The best fit of complex speciation has been preferred on basis of statistical parameters like skewness, χ 2, Kurtosis and crystallographic R-factor. ML2H, ML2H2 and ML3H3 type complex were formed by the complexation of 5-sulphosalicylic acid with the metal ions. The change in stability of complex species with composition of the surfactant has been illustrated on the basis electrostatic grounds. Distribution of chemical species with respect to pH and various compositions medium and probable complex equilibria are also studied.

A study of novel cobalt(II) octaazamacrocyclic complexes with aminocarboxylates or their derivatives

Four new air-stable mixed-ligand Co(II) complexes having the general formula [Co2(Y)tpmc]Z3?q(H2O/CH3CN) (HY = N-methylglycine/N,N-dimethylglycine, Z = - 4BF , qH2O=4 or 3; HY=S-norvaline/S-valine Z=-ClO4 , qCH3CN = 0.5; qH2O = 0.5; tpmc = N,N',N'',N'''-tetrakis(2-pyridylmethyl)- -1,4,8,11-tetraazacyclotetradecane) were prepared. The composition, some physical and chemical properties and their tentative geometries were evaluated based on elemental analysis (C, H, N), conductometric and magnetic measurements, spectroscopic data (UV/Vis, IR) and cyclic voltammetry. The data were compared with earlier described analogous complexes containing the macrocyclic ligand and aliphatic aminocarboxylates. It is assumed that all complexes are binuclear with an exo coordination mode of the octaazamacrocyclic pendant ligand in the boat conformation. In addition, two -N-(CH2)2-N- portions of the cyclam ring within the tpmc ligand and Co(II) ions in the high-spin state are most probably bridged via oxygen atoms from the anion of the aminocarboxylate/derivatives, whereas nitrogen atoms rest uncoordinated. In all cases, a combined chelate-bridged coordination is proposed as the most probable. The complexes were electrochemically stable in the potential range -1.0 to 1.0 V. They were also preliminary assayed toward some microorganisms together with the ligands, starting simple salts and solvents as test substances. In some cases, certain antimicrobial activity of the complexes was detected.