Isolated CH stretching frequencies and bond properties in some organo-germanes and methyl arsines

Abstract

Infrared spectra in the CH stretching region have been obtained from partially deuterated methyl, dimethyl and trimethyl germanes and arsines, ethyl germane, MeGeH 2X, where X = F, Cl, Br, I and MeGeHCl 2. In general, the isolated CH stretching frequencies show patterns of behaviour with respect to the α and β substituent effects of CH 3, GeH 3 and halogen groups similar to these found in the corresponding carbon compounds, although on a smaller scale. However, the trans effect of halogen is almost independent of the nature of the halogen, and a CH bond trans to GeH 3 is weaker than one trans to CH 3. In methyl arsine, an anomalous lone pair trans effect occurs, as previously found in methyl phosphine. CH bond lengths and dissociation energies, and average HCH angles are predicted for these compounds.