Geometrical distortion caused by substituents. III. Hybridization and ring internal angles in benzene derivatives

An extensive survey on hybridization angles, calculated by localized MO analysis, was undertaken through a broad sample of benzene derivatives, as part of a comprehensive theoretical research. The aim was to obtain molecule-independent, substituent-dependent hybridization angles which could account for the distortions from 120° observed In most internal in-plane ring angles in a general interpretation, not to reproduce them accurately. Most calculations were carried out using STO-3G basis. Boys’ localization, and properly chosen geometries. Despite its limitations in other chemical fields, this methodology seemed to be convenient for our research. Some data of alternative methods are discussed for comparison purposes. Results indicate that the hybridization model provides a semiquantitative explanation for in-plane angular distortion. Hybridization angles arising from substitution seem to be almost independent of environment and well predictable in polysubsti l.ul.ed molecules by addition of substituent effects; thus, hybridization parameters are defined. Their correlation with various chemical magnitudes is also investigated