N-ヘテロ芳香族の電子的性状(第10報) : アミノピリンと安息香酸誘導体との相互作用の機構について新吸收帯の検討

抄録

Spectrophotometric and molecular orbital studies have been made on the mode of interaction between aminopyrine and benzoic acid derivatives. The following findings mentioned below were revealed through examination of the absorption bands which appeared in the spectra of the mixtures of two components : (1) complexes were formed between undissociated species of both interactants, (2) the new absorption bands were ascribable to n→π^* transitions, (3) for the equilibration of the complex formation reaction, it required about 48 hr., (4) no interaction was taken place when the carboxyl group of benzoic acid was esterified, and (5) linear relationship existed between Hammett's σ-values of o-, m- and p-substituted benzoic acid derivatives in the complex formation. Localized charge transfer between an oxygen atom of carbonyl group of aminopyrine and a carbon atom of carboxyl group of aminopyrine and a carbon atom of carboxyl group of benzoic acid derivatives was also deduced from computation of frontier-electron density of the interactant molecules by the simple LCAO MO method. It was assumed that hydrogen bonding and charge transfer forces might work cooperatively in stabilizing complexes.