Preparation and Characterization of Nitrogen Bonded Nitrile and Amide Complexes of Pentaamminecobalt(III)-Linkage Isomers of Cyanopyridines

Abstract

The preparation, characterization, and properties of pentaamminecobalt(III) complexes with 1,2-dicyanobenzene, 1,3-dicyanobenzene, 1,4-dicyanobenzene; 3-and 4-cyano-benzaldehyde; 4-acetylbenzonitrile; and 2-, 3-, and 4-cyanopyridine are described. The ligands are all bonded to cobalt via the nitrile nitrogen and undergo facile hydrolysis to the corresponding carboxamides according to the equation:[Formula: see text]Production of a carboxamido complex provides a chemical proof for bonding via the nitrile nitrogen. For the ambidentate cyanopyridines this has been used to assign nitrile bonding. For the 4-cyanopyridine ligand the linkage isomer bonded through the pyridine nitrogen has also been prepared and characterized.