Finite-Perturbation Intermediate Neglect of Differential Overlap Molecular Orbital Calculations of Nuclear Magnetic Resonance Spin-Spin Coupling Constants for Polycyclic Aromatic Hydrocarbons and Aromatic Nitrogen Heterocyclics

摘要

The H-H, C-H, and C-C spin-spin coupling constants were calculated by the finite-perturbation, intermediate neglect of differential overlap method using the Fermi contat interaction for benzene, naphthalene, biphenyl, anthracene, phenanthrene, and pyrene. The calculations were made using both the actual and the average molecular geometries. For all six of these molecules, the agreements between the calculated and the experimental coupling constants were comparable to those previously reported for other, predominantly smaller, molecules. The actual molecular geometries always gave the correct relative order of values for the H-H coupling constants, whereas the average molecular geometries did not always do so. The magnitudes, but not the signs, of the calculated coupling constants were sensitive to small changes in molecular geometry. The results were the best (next best) for the H-H (C-H) coupling constants.