Use of the 2-Pyridinealdoxime/N,N′-Donor Ligand Combination in Cobalt(III) Chemistry: Synthesis and Characterization of Two Cationic Mononuclear Cobalt(III) Complexes

The use of 2-pyridinealdoxime (paoH)/N,N′-donor ligand (L-L) “blend” in cobalt chemistry has afforded two cationic mononuclear cobalt(III) complexes of the general type [Co(pao)(2)(L-L)](+), where L-L = 1,10-phenanthroline (phen) and 2,2′-bipyridine (bpy). The CoCl(2)/paoH/L-L (1 : 2 : 1) reaction system in MeOH gives complexes [Co(III)(pao)(2)(phen)]Cl·2H(2)O (1·2H(2)O) and [Co(III)(pao)(2)(bpy)]Cl·1.5MeOH (2·1.5MeOH). The structures of the complexes were determined by single-crystal X-ray crystallography. The Co(III) ions are six-coordinate, surrounded by three bidentate chelating ligands, that is, two pao(−) and one phen or bpy. The deprotonated oxygen atom of the pao(−) ligand remains uncoordinated and participates in hydrogen bonding with the solvate molecules. IR data of the complexes are discussed in terms of the nature of bonding and the known structures.