Infrared study of some specificities of the dπ pπ interaction in organogermanium compounds

Abstract

The analysis is presented for the frequencies of stretching modes ν(GeH) in the IR spectra of organogermanium compounds R 2XGeH, RX 2GeH, RXYGeH, X 2YGeH and XYGeH 2 (where R is a substituent which does not make a d π p π bond with germanium, and X and Y are groups capable of d π p π interaction with germanium). It is shown that ν(GeH) in these compounds is dependent on both the  I effect of R, X and Y, and the d π p π interaction in GeX and GeY bonds. If only one substituent capable of d π p π interaction with germanium is present, the value of such an effect is determined by itsσo Rconstant. However, when germanium is bound to several substituents capable of d π p π interaction its magnitude depends on the effective charge at germanium which is determined by the inductive and mesomeric effects of X and Y. The data obtained are compared to the dependences observed in the IR spectra of similar organosilicon compounds.