THEORETICAL STIMULATION OF ROTATION BY HY DROGEN-BOND OF 2,2-BIQUONINE IN THE GROUND-STATE

Application of the semi-empirical AMI method gives significant evidenc e of the conformation of the isolated 2,2'-biquinoline (2,2'-BQ) in it s ground state. The results obtained on the one hand by Fraga's method in which the molecule is simulated by the hydrogen bonding between a water molecule and the 2,2'-BQ, and on the other hand by CNDO calculat ions using Mataga's model, are in good agreement with the experimental results. They indicate that the spectral changes of 2,2'-BQ in its gr ound state in protonic media are caused by a trans-cis transformation resulting from a rotation around the single C-C bond which links the t wo quinoline rings of the molecule