CRYSTAL AND MOLECULAR-STRUCTURE OF PYRYLIUM-SALTS .4. CRYSTAL AND MOLECULAR-STRUCTURE OF 2,6-DIPHENYL-4-(4-CARBOXYPHENYL)PYRYLIUM PERCHLORATE - INTERRELATIONS BETWEEN STRUCTURAL PARAMETERS DUE TO SUBSTITUENT EFFECTS

The crystal and molecular structure of 2,6-diphenyl-4-(4-carboxyphenyl)pyrylium perchlorate was solved by x-ray diffraction, yielding structural parameters of high precision (estimated standard deviations for bond length less-than-or-equal-to 0.5 pm, for bond angles less-than-or-equal-to 0.2-degrees). Comparison with other 4-substituted derivatives of 2,6-diphenyl-4(4-carboxytphenylpyrylium) perchlorate shows regularities in the variations of structural parameters following classical views of substituent effects.