Microwave and vibrational spectra, ab initio calculations, conformational stabilities and assignments of the fundamentals of the C s conformer of n-butylgermane

Abstract

The FT-microwave spectrum of n-butylgermane, CH 3CH 2CH 2CH 2GeH 3 has been investigated from 4000 to 18,000 MHz and the microwave spectra have been observed for all of the five naturally occurring germanium isotopologues for the anti–anti (aa) conformer. The dipole moment for the 74Ge containing species has been measured, giving a total dipole moment of 0.881 (26) D. In addition, the vibrational spectrum of n-butylgermane is described. Modestly complete assignments are made for the aa conformer. The relative stabilities of the five conformers are calculated, and the anti–anti (aa) conformer is found to be the most stable in all calculations done. This conclusion is confirmed by the infrared and Raman spectrum of the annealed crystal. The dipole moments of all conformers are calculated to be approximately equal and less than 1 D, ranging from approximately 0.8 to 0.9 D.