Low-temperature Raman and Fourier transform infrared spectra of dodecacarbonyldirhenium(0), Re2(CO)10

Abstract

The Raman spectrum of microcrystalline dodecacarbonyldirhenium(0), Re2(CO)10, has been reinvestigated at 67 K using one of the latest fully-computerized spectrometers available. Previously unobserved peaks have been detected mainly in the 13CO-satellite (2150–1900 cm−1), and overtone and combination regions (1300–700 and 4300–3800 cm−1). This is the first time that Raman-active first CO overtones and combinations of a metal carbonyl complex have been reported. They were earlier thought to be too weak to be detected. Assignments are proposed for the majority of these new peaks together with those from a similar low-temperature (~70 K) FT-ir study. In general, the D4d selection rules are obeyed, but the activity of some forbidden bands reveals that the molecule is slightly distorted in the solid state in agreement with its X-ray structure. The similarity of the low-temperature spectra to those obtained at room temperature indicates that no phase change occurs throughout the temperature range investigated.