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

Abstract

2,6-Bis(acetyloxime)pyridine, 2,6-C 5H 3N(C 2H 3NOH) 2 ( L 1), reacts with indium(III) chloride in methanol to give the seven-coordinate complex [InCl 3(L 1)(MeOH)]. The structurally similar Schiff base ligand 2,6-bis(1-phenyliminoethyl)pyridine ( L 2), 2,6-C 5H 3N(C 2H 3NC 6H 5) 2, however, forms a six-coordinate indium(III) complex of the composition [InCl 3(L 2)]. The InN bond distances are longer by 0.03–0.12 Å in the seven-coordinate compound compared with those in the Schiff base complex. The MeOH ligand in [InCl 3(L 1)(MeOH)] can be replaced by Cl − or H 2O to give the complex anion [InCl 4(L 1)] − and [InCl 3(L 1)(OH 2)], respectively. The pentagonal-bipyramidal coordination environment of the metal is preserved during these reactions.