Modified Carbon Pseudopotentials for Use in ONIOM Calculations of Alkyl-Substituted Metallocenes

Lewin, J. L.; Cramer, C. J.
J. Phys. Chem. A 2008, 112, 12761.

Non-relativistic carbon 1s core pseudopotentials are optimized for substituted cyclopentadienide ring carbons for use in integrated-molecular-orbital-molecular-orbital (IMOMO) and integrated-molecular-orbital-molecular-mechanics (IMOMM) calculations where the Cp ring substituents are not included in the high-level IMOMO or IMOMM subsystem. Use of the optimized pseudopotential within the IMOMO framework leads to significant improvements in predicted carbonyl stretching frequencies for a series of Cp-ring-methylated zirconocenes compared to using a standard carbon pseudopotential. The technology is less successful in the IMOMM implementation.