STRUCTURES AND PROPERTIES OF FLUORINATED PYRIDINES - ASSIGNMENT OF THE 2 HOMOS OF PYRIDINE

Structures and properties of fluorinated pyridines have been studied by microwave spectroscopy and theoretically by the MINDO/3 and MNDO methods. While both MINDO/3 and MNDO reproduce the geometries of fluorinated pyridines within their experimental limits of accuracy, MINDO/3 does better in predicting the small changes in geomeyry due to substitution of hydrogen by fluorine in pyridine. Both MINDO/3 and MNDO give rotational constants in quite good agreement with experiment, but the errors in MINDO/3 are somewhat smaller. Both methods give acceptable estimates of heats of formation of pyridines. MNDO gives better estimates of ionization energies and dipole moments, the results agreeing quite well with experiment. Whereas 14N nuclear quadrupole coupling constants are calculated satisfactory by both methods. MNDO does better in predicting the changes in constants caused by fluorine substitution. © 1979.