Solid-state metal carbonyls. Part 4.—An infrared and far-infrared study of M3(CO)12, M = Ru, Os
Abstract
The ν(CO) region of Ru3(CO)12 has been studied using single-crystal i.r.-reflectance in polarised light. Making use also of extant Raman data and of new low-temperature i.r. spectra, a detailed assignment is offered. Of the seven ν(CO) molecular modes located, only the two E′ modes, ν16 and ν17, show a rise in frequency from solution to solid.
In the δ(MCO), ν(M—C) region the major features of the spectra are readily accounted for on the basis of D3h rules, the same being true of the complex region below 200 cm–1. An essentially complete assignment is deduced. Lattice modes down to 21 cm–1(Raman) and 24 cm–1(i.r.) are found for Ru3(CO)12.