Indium(III) complexes with tridentate nitrogen donor ligands. Synthesis, characterization and crystal structure of complexes with pyridine-2,6-bis(acetyloxime) and 2,6-bis (1-phenyliminoethyl)pyridine

Article abstract of DOI:10.1016/S0277-5387(96)00553-0

2,6-Bis(acetyloxime)pyridine, 2,6-C₅H₃N(C₂H₃NOH)₂ (L¹), reacts with indium(III) chloride in methanol to give the seven-coordinate complex [InCl₃(L¹)(MeOH)]. The structurally similar Schiff base ligand 2,6-bis(1-phenyliminoethyl)pyridine (L²), 2,6-C₅H₃N(C₂H₃NC₆H ₅)₂, however, forms a six-coordinate indium-(III) complex of the composition [InCl₃(L²)]. The In - N bond distances are longer by 0.03-0.12 A in the seven-coordinate compound compared with those in the Schiff base complex. The MeOH ligand in [InCl₃(L¹)(MeOH)] can be replaced by Cl^- or H₂O to give the complex anion [InCl₄(L¹)]^- and [InCl₃(L¹)(OH₂)], respectively. The pentagonal-bipyramidal coordination environment of the metal is preserved during these reactions.