title: Trends in Homolytic Bond Dissociation Energies of Five- and Six-Coordinate Hydrides of Group 9 Transition Metals: Co, Rh, Ir.
abstract: The homolytic bond dissociation energies of a series of five- and six-coordinate mono- and dihydride complexes of the type HM(diphosphine)2and [H2M(diphosphine)2]+(where M = Co, Rh, and Ir) are calculated and compared with experimental values. This work probes the relationship between the homolytic bond dissociation energies (HMBDEs) of these complexes in these two different coordination environments and formal oxidation states. The results of these calculations and previous experimental observations suggest that for M = Rh the HMBDE of the five-coordinate HM(diphosphine)2species are 0-2 kcal/mol larger than the HMBDE of the corresponding six-coordinate [H2M(diphosphine)2]+species. For M = Ir the bond energies of the five- and six-coordinate complexes are nearly the same and for M = Co the six-coordinate species are 1-5 kcal/mol less than the corresponding five-coordinate species. Simplified models of large and complicated ligands seem to capture the essential trends and give very good estimates of these thermodynamic properties compared with experimentally available data that are difficult to obtain.
authors.affiliation: Basic and Applied Molecular Foundations, ‡Advanced Controls, and §Institute for Integrated Catalysis, Pacific Northwest National Laboratory , MS K1-83, P.O. Box 999, Richland, Washington 99352, United States.
authors.forename: Vassiliki-Alexandra
authors.identifier: http://orcid.org/0000-0001-6028-7021
authors.initials: VA
authors.lastname: Glezakou
authors.affiliation: Basic and Applied Molecular Foundations, ‡Advanced Controls, and §Institute for Integrated Catalysis, Pacific Northwest National Laboratory , MS K1-83, P.O. Box 999, Richland, Washington 99352, United States.
authors.forename: Roger
authors.initials: R
authors.lastname: Rousseau
authors.affiliation: Basic and Applied Molecular Foundations, ‡Advanced Controls, and §Institute for Integrated Catalysis, Pacific Northwest National Laboratory , MS K1-83, P.O. Box 999, Richland, Washington 99352, United States.
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Elbert
authors.affiliation: Basic and Applied Molecular Foundations, ‡Advanced Controls, and §Institute for Integrated Catalysis, Pacific Northwest National Laboratory , MS K1-83, P.O. Box 999, Richland, Washington 99352, United States.
authors.forename: James A
authors.initials: JA
authors.lastname: Franz