VIBRATION-SPECTRA AND NORMAL COORDINATE ANALYSIS OF CF3 COMPOUNDS .23. COMPOUNDS (CF3)3GEX(X=F,CL,BR,I)

The gas phase i.r. and liquid phase Raman spectra of (CF3)3GeF, (CF3)3GeCl, (CF3)3GeBr and (CF3)3GeI are reported and assigned for C3v symmetry. The solid phase Raman spectrum of (CF3)3 GeF is interpreted assuming a dimeric structure with GeFGe bonds. A normal coordinate analysis has been performed, and force constants have been obtained for the monomeric molecules. Comparison of these force constants with those recalculated for CF3GeX3 and (CF3)2GeX2 indicates that the spectral effects of the CF3 group and Br atom are very similar. Furthermore the GeC stretching force constants, ranging from 2,08 to 250[N cm-1] for CF3GeI3 and CF3GeF3 respectively, are much smaller than those of the corresponding methylgermanes. © 1979.