Electronic and vibrational spectroscopy of cis-β-[CrCl2(1,4,7,11-tetrazaundecane)chromium(III) perchlorate

The sharp-line absorption spectrum of cis-β-[CrCl2(2,2,3-tet)]ClO4 (2,2,3-tet: 1,4,7,11-tetraazaundecane) has been measured between 13,000 and 16,000 cm−1 at 5 K. The 77 K emission, 298 K infrared and visible spectra have also been measured. The zero-phonon band in the highly resolved absorption spectrum splits into four components. The vibrational intervals of the electronic ground state were determined from the far-infrared and emission spectra. The 10 electronic bands due to spin-allowed and spin-forbidden transitions were assigned. Using the observed transitions, a ligand field analysis has been performed to probe the ligand field properties of coordinated atoms in the title chromium(III) complex. The X-ray crystal structure at low-temperature was determined to help in assigning the sharp-line electronic transitions.