Basicities and structures of 2-(N-arylaminomethylene)-3(2H)-benzo[b]thiophenones,-benzo[b]furanones,and -benzo[b]selenophenones

The ionization constants of the conjugate acids of the reaction series 2-(N-arylaminomethylene)-3(2H)-benzob]thiophenones,-benzob]furanones, and -benzob]selenophenones were determined by potentiometric titration in anhydrous acetonitrile. The electronic and vibrational spectroscopic data showed that the protonation center in the molecules of these compounds is the carbonyl oxygen atom. It was established by correlation analysis that N-aryl substituents affect the protonation center primarily via an induction mechanism.Communication XVIII from the series Basicities and structures of azomethines and their structural analogs. See 1] for communication XVII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. pp. 619–623, May, 1977.