Successful application of the spin-delocalization substituent constant ?. to the correlation of the UV spectra of some model compounds withpara-Y-substituted phenyl groups

UV spectra of 16 p-Y-substituted phenylacetylenes (I-Ys), nine p-Y-substituted acetophenones (2-Ys) and six p-Y-substituted-p′-methylsulphonylstilbenes (3-Ys) were measured and correlated against spin-delocalization substitutent constants (σ.) with confidence levels above 99·9%. UV spectra of five ethyl 3-hydroxy-3-(p-Y-substituted-phenyl)-propanates (4-Ys) and five 1-(p-Y-substituted-phenyl)-3-butyn-1-ols (5-Ys) were also measured. Correlation analysis results are discussed. Some literature UV data were also successfully correlated by the dual-parameter equation.