Electrochemical Synthesis of MII Complexes with a Schiff Base containing an Amido Group. Crystal Structure of a Cobalt(II) Complex with a Reorganised Ligand

Abstract

M(HL)(H2O)n complexes have been obtained by the electrochemical reaction of Fe, Co, Ni, Cu, Zn and Cd anodes with the potentially pentadentate and trianionic asymmetrical Schiff base 3-aza-N-{2-[1-aza-2-(5-nitro-2-hydroxylphenyl)-vinyl]phenyl}-4-(5-nitro-2-hydroxyphenyl)but-3-enamide (H3L), containing a hard amido donor atom. The complexes have been characterized by elemental analysis, mass spectrometry, IR and 1H NMR spectroscopies, magnetic measurements and molar conductivities. Co(HL)(H2O) (2) has been found to rearrange in DMF solution into a crystallographically solved octahedral complex, CoL1(H2O)2 (7) [where H2L1 is the symmetrical Schiff base ligand N,N′-(1,2-phenylene)-bis(5-nitro-3-hydroxysalicylidenimine)]. A hydrolysis mechanism is discussed to explain this rearrangement.