THEORETICAL-STUDIES OF ORGANONICKEL COMPOUNDS .1. A DENSITY-FUNCTIONAL AND AB-INITIO HF STUDY

The pi-allylic organonickel compounds are considered to be key structu res in the catalytic reactions of butadiene. Bis(eta(3)-allyl)nickel, bis(eta(3)-methallyl)nickel, and the syn-crotyl-cyclooctadiene-nickel cation have been calculated with DZ and TZ basis sets in all-electron and pseudopotential (ECP) Hartree-Fock (HF) methods and compared with experimental structures. In the second part, we report a systematic in vestigation of these compounds by density functional theory (DFT). The DFT-optimized structures are generally in better agreement with exper imental data than are the HF results. (C) 1995 John Wiley & Sons, Inc.