High resolution optical spectroscopy of mer-[Cr(dpt)(Gly-Gly)]ClO4

try. Especially the sharp-line splittings are very sensitive to the exact bond angles around the metal. Thus it is possible to extract structural information from sharp-line electronic spectroscopy without a full X-ray structure determina-tion.17,18 In this study the low temperature absorption and emission spectra, and the room temperature infrared spectra of mer-[Cr(dpt)(Gly-Gly)]ClO4·H2O have been measured. The pure electronic origins were assigned by analyzing the vibrational and absorption spectra. Using the observed electronic transi-tions, a ligand field analysis have been performed to deter-mine the metal-ligand bonding properties for the coordinat-ed atoms toward chromium(III) ion. Experimental Section Synthesis. The chemicals were of reagent grade or better quality and used without further purification. The complex Results and Discussion Infrared and Emission Spectra. The infrared spectros-copy is frequently useful in elucidating structures and deter-mining the number of functional groups involved in coordination by a multidentate ligand. In some cases stretch-ing and bending modes of amino groups in metal-amino acid complexes are sensitive to the stereochemistry of the com-plexes. Meridional coordinated ligands have different stretching, bending and rocking frequencies in the infrared region than facially coordinated ligands. Figure 1 presents the mid-infrared spectrum recorded at room-temperature of mer-[Cr(dpt)(Gly-Gly)]ClO4·H2O. A sharp absorption peak at 3590 cm–1 can easily assigned to the O-H stretching of H2O molecule in the hydrate com-plex. The strong bands in the regions of 3100-3300 cm–1 an