Crystal and molecular structure of pyrylium salts. Part 1. Crystal and molecular structure of 2,6-diphenyl-4-(2-phenylpropan-2-yl)pyrylium perchlorate and aromaticity of the pyrylium ring

Abstract

The crystal structure of 2,6-diphenyl-4-(2-phenylpropan-2-yl)pyrylium perchlorate has been solved by direct methods and refined to R= 0.069. The aromatic character of the pyrylium ring has been described in terms of the HOMA parameter indicating its properties as intermediate between typical aromatic and non-aromatic systems. Relatively good dependence between HOMA and Bird's I₆ indices of aromaticity has been found.