THE CONJUGATION AND EFFECTIVE CHARGES OF THE ATOMS AT THE TRIPLE BONDIN GERMYLACETYLENES

The integrated extinction coefficients (A) of the C=C stretching modes in the IR spectra of 12 germylacetylenes Me3GeC=CR are determined by the resonance interactions of substituents with the triple bond. The A (1/2) values change linearly with change in the difference between the effective pi-electron charges on the atoms at the triple bond and sig ma(R)(0) constants of organic substituents R The average value of the sigma(R)(0) constant of the Me3Ge substituent in the compounds studied is +0.06. The resonance acceptor effect of the Me3Ge substituent towa rd the triple bond (d,pi-conjugation) is stronger than the donor effec t (sigma,pi-conjugation).