PRESSURE-TUNING INFRARED AND RAMAN-SPECTROSCOPIC STUDY OF (2,2'-BIPYRIDINE)TETRACARBONYLCHROMIUM(O)

Pressure-tuning infrared and Raman spectroscopic studies were performe d on (2,2'-bipyridine)tetracarbonylchromium(0), Cr(CO)(4)(bpy). Previo us bpy ring mode assignments were confirmed with new assignments offer ed by examination of the pressure-induced alterations in the vibration al spectra. The electron-density distribution of the bipyridyl ligand (and consequently, the electron-donating ability to the central metal) is modulated by the application of pressure. The pressure dependence of the carbonyl moieties reveals that the bipyridyl ligand can accommo date a significant portion of the molecular compressibility at higher pressures.