[IR and Raman spectroscopic studies on the complexes of ytterbium with pyran derivatives]

The complexes of ytterbium(Yb) with 3-hydroxy-2-methyl-gamma-pyrone(HL) and 3-hydroxyflavone(HL') have been prepared respectively in the non-aqueous solution by direct electrochemical oxidation of sacrificial metal anodes, and their IR and Raman spectra have been measured. They provided the complemental information for deducing their structure. By comparing the spectra of the ligands and their complexes, the stretching vibrational band of -OH disappeared in the complexes, and the frequency shifts of some relevant bands of the ligands were observed, particularly for the stretching vibration of C=O. In the low frequency region, new bands at 300-500 cm(-1) were detected in YbL3 and YbL'3 respectively, which could be assigned to the stretching vibrational mode of Yb-O. All the obvious change in the IR and Raman spectra revealed that C=O and -OH were coordinated with Yb center through oxygen atoms. Based on the IR and Raman results, the structures of the two complexes were proposed.