Some nickel(II) complexes with pentadentate and tridentate heterocyclic N- and S-donor ligands

Abstract

High-spin Ni(II) complexes of the linear pentadentate ligand 2,6-bis([2′-aminophenylthio]methyl)pyridine (Batp) and the tridentate ligands ([2′-aminophenylthio]ethyl)pyridine (Atep) 1,5-bis( N-methylbenzimidazol-2′-yl)-3-oxapentane (Mbeo) have been prepared. Crystal structures of the complexes [Ni(Batp)(H 2O)](CF 3SO 3) 2 ( 2) and [Ni(Atep) 2](ClO 4) 2 ( 4) reveal pseudooctahedral coordination. Tetragonal distortion in [Ni(Mbeo) 2](ClO 4) 2 ( 5) is evident from the longer Ni–O and shorter Ni–N bond lengths. From the electronic spectrum of 5, the tetragonal distortion parameter D t and the in-plane Dq xy and axial Dq z ligand field parameters are calculated. The three Ni(II) complexes exhibit irreversible cathodic electrochemistry.