4-ジアルキルアミノスチルベン誘導体の塩基性に対するアルキル基の立体効果

抄録

In hydroxylic solvents, 4-diethylaminostilbenes are much stronger base than the corresponding dimethylaminostilbenes. In acetonitrile, however, the difference, ApKa, between the basicities of these two series of compouns is very small. Furthermore, in the excited state the ilpKa value is considerably smaller even in hydroxylic solvents. The anomalously high base strength of 4-diethylaminostilbene in hydroxylic solvents can be explained in terms of the steric inhibition to hydrogen bonding between the free base and the solvent.