Preparation and characterization of mononuclear ni complexes of tetradentate amine-thioether and amine-thiolate ligands

A short route for the preparation of tetradentate amine-thioether and amine-thiolate ligands derived from thiosalen is reported. The ligating properties of several of the svnthesized ligands towards Ni(ll) has been examined. The diamine-dithiophenolate ligands (L6)(2-) [H2L6 = N,N'-dimethyl-NN'-di(2-mercaptobenzyl)-ethane-1,2-diamine] and (L-7)(2-) [H2L7 = N,N'-di(2-mercaptobenzyl)-piperazine] support the formation of four-coordinate (NiN2S2)-N-II complexes [Ni-II(L-6)] (10) and [Ni-II(L-7)] (11). By contrast, the amine-thioethers 2 [A,N ''-bis(2-(tert-butylthio)benzyl)ethane-1,2-diamine], L-2 [8,11- diaza-5,13-dibenzo-1,4-dithia-cyclotetradecane] and its N-methylated derivative L-2,L-M were found to produce the six-coordinate Ni(II) complexes [(NiCl2)-Cl-II(2)(2)] (9), [Ni-2(II)(mu-Cl)(2)(L-2)(2)][ClO4](2) (12), [Ni-II(NCS)(2)(L-2)] (13), and [(NiCl2)-Cl-II(L-2,L-Me)] (14). The results of IR, NMR and UV/vis spectroscopy and the crystal structures of complexes 9-13 are reported.