COMPLETE ASSIGNMENT AND ADDITIVITY RULE FOR H-1 AND C-13 CHEMICAL-SHIFTS OF NONPLANAR, NONACYCLIC AROMATIC-HYDROCARBONS

Complete assignments of H-1 and C-13 NMR spectra were made for heptacy clic peropyrene and five isomers of dibenzoperopyrenes, using 2D corre lation spectroscopic techniques of homonuclear HH-COSY and NOESY and h eteronuclear CH-COSY and HMBC methods. New additivity rules of H-1 and C-13 chemical shift values were established for compounds having two types of benzene ring condensation. All H-1 chemical shifts were satis factorily interpreted by a very simple magnetic point dipole model. Th is model includes net contributions from each constituent benzene ring due to the ring current anisotropy and permits some ring planes to de viate from the mean molecular plane. The conjugated ring currents are consistent with the chemical shifts. Thus, the aromatic properties are normal even if the molecular skeleton is considerably deformed and be comes non-planar.