Studies of Binary Complexes of Tripodal Ligand cis,cis-1,3,5-tris(methylamino)cyclohexane with Cr(III) and Fe(III)

Abstract

The formation of binary complexes of Cr(III) and Fe(III) with a tripodal ligand cis,cis-1,3,5-tris(methylamino)cyclohexane (tmach) (L) has been investigated in solution. The overall stability constants of tmach with Cr(III) and Fe(III) were determined by potentiometric method at an ionic strength of 0.1 M NaClO4 at 25±1°C in aqueous medium. The formation of species like MLH25+, MLH4+, ML3+, ML(OH)2+ and ML(OH)3 were observed. Fe(III) was found to form more stable complexes than Cr(III). Molecular mechanics calculations were performed to explain the mode of coordination in solution.