Electronic transitions and ligand field analysis of mer-(N-(2-aminoethyl)-1,2-ethanediamine)(glycylglycinato) chromium(III) perchlorate

The emission and excitation spectra of mer-(Cr(dien)(glygly))ClO4(glygly=glycylglycinate;dien=N-(2-aminoethyl)-1,2 -ethanediamine taken at 77 K are reported. The infrared and visible spectra at 298 K are also measured. The twelve electronic bands due to spin-allowed and spin-forbidden transitions are assigned. Using the observed transitions, a ligand field analysis has been preformed to determine the bonding property of coordinated atoms in the chromium(III) complex. It is confirmed that the amine nitrogen atoms of the dien and glygly have strong σ-donor characters, but the peptide nitrogen of glygly has weak π-donor property toward chromium(III) ion