NMR-K reduced coupling constant calculations within the CLOPPA-PM3 approach: I. General results

ROSANA LOBAYAN; GUSTAVO A. AUCAR

JOURNAL OF MOLECULAR STRUCTURE THEOCHEM

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 1998 vol. 452 p. 1 - 11

0166-1280

A new version, i.e. PM3, of the CLOPPA model modi®ed to make indirect nuclear spin coupling calculations for molecules containing heavy atoms is presented. Its performance compared with previous CLOPPA-MNDO-RPA and CLOPPA-AM1-RPA calculations is discussed. The PM3 approach gives better results than its predecessors for couplings where one of the coupled nuclei is P or Cl, and permits one to reproduce qualitatively experimental trends for some other nuclei that are not parametrized within the MNDO and AM1 methods; for example As, Sb, Bi, Ga, In and Tl. However, the general performance of the new version does not achieve the level of the two previous ones