title: Reaction of H2 with a Binuclear Zirconium Dinitrogen Complex - Evaluation of Theoretical Models and Hybrid Approaches.
abstract: Molecular orbital and hybrid ONIOM (both IMOMO and IMOMM) calculations have been carried out on the important reaction of H2 with a binuclear zirconium dinitrogen complex to test the efficacy of several structural models of the ancillary ligand. The complete experimental ligand, PhP(CH2SiMe2NSiMe2CH2)2PPh, in the zirconium complex has been treated at the IMOMM level, while two smaller approximations of the ligand, HP(CH2SiH2NSiH2CH2)2PH and (PH3)2(NH2)2, have received the full molecular orbital treatment. The mechanism of dihydrogen addition has been compared with our earlier study (Basch, Musaev, and Morokuma J. Am. Chem. Soc. 1999, 121, 5754-5761). We find that the substituent effects do cause some small changes in both the structures of the complexes studied and the activation energies of the transition structures. However for the most part the potential energy profiles are very similar to our earlier study and lend support to our use of simple theoretical models to represent moderately large experimental structures.
authors.affiliation: School of Chemistry, University of Tasmania, Private Bag 75, Hobart TAS 7001, Australia, Department of Chemistry, Bar Ilan University, Ramat Gan, Israel, and Cherry L Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322.
authors.forename: Brian F
authors.initials: BF
authors.lastname: Yates
authors.affiliation: School of Chemistry, University of Tasmania, Private Bag 75, Hobart TAS 7001, Australia, Department of Chemistry, Bar Ilan University, Ramat Gan, Israel, and Cherry L Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322.
authors.forename: Harold
authors.initials: H
authors.lastname: Basch
authors.affiliation: School of Chemistry, University of Tasmania, Private Bag 75, Hobart TAS 7001, Australia, Department of Chemistry, Bar Ilan University, Ramat Gan, Israel, and Cherry L Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322.
authors.forename: Djamaladdin G
authors.initials: DG
authors.lastname: Musaev
authors.affiliation: School of Chemistry, University of Tasmania, Private Bag 75, Hobart TAS 7001, Australia, Department of Chemistry, Bar Ilan University, Ramat Gan, Israel, and Cherry L Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322.
authors.forename: Keiji
authors.initials: K
authors.lastname: Morokuma