AB-INITIO STUDY OF HYPERCONJUGATION EFFECTS ON CHARGE-DISTRIBUTION INREPRESENTATIVE POLYCYCLIC ALCOHOLS

Ab initio calculations using fully optimized geometries are used to ge neralize hyperconjugation effects in a representative series of eight polycyclic alcohols. The systems studied include tetra-, penta- and he xa-cyclic structures with varying degrees of tension, due to compressi on and stretching of carbon-carbon and carbon-hydrogen bonds, and of d istortion from normal bond angles as well to differences in van der Wa als interactions. These findings indicate, in general, that carbon and hydrogen atoms with the proper spatial alignment relative to a nonbon ding oxygen lone pair follow the same general trends as small acyclic alcohols. Results from minimum STO-3G basis-set calculations and the h yperconjugation model can generally distinguish clearly the subtleties of charge and bond length distributions observed in the various confo rmations of all the polycyclic alcohols investigated.