Activation of Carbon−Hydrogen and Hydrogen−Hydrogen Bonds by Copper−Nitrenes: A Comparison of Density Functional Theory with Single- and Multireference Correlation Consistent Composite Approaches
- 19 October 2009
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of Chemical Theory and Computation
- Vol. 5 (11), 2959-2966
- https://doi.org/10.1021/ct900277m
Abstract
The kinetics and thermodynamics of copper-mediated nitrene insertion into C−H and H−H bonds (the former of methane) have been studied using several levels of theory: B3LYP/6-311++G(d,p), B97-1/cc-pVTZ, PBE1KCIS/cc-pVTZ, and ccCA (correlation consistent Composite Approach). The results show no significant difference among the DFT methods. All three DFT methods predict the ground state of the copper−nitrene model complex, L′Cu(NH), to be a triplet, while single reference ccCA predicts the singlet to be the ground state. The contributions to the total ccCA energy indicate that the singlet state is favored at the MP2/CBS level of theory, while electron correlation beyond this level (CCSD(T)) favors a triplet state, resulting in a close energetic balance between the two states. A multireference ccCA method is applied to the nitrene active species and supports the assignment of a singlet ground state. In general, the largest difference in the model reaction cycles between DFT and ccCA methods is for processes involving radicals and bond dissociation.Keywords
This publication has 60 references indexed in Scilit:
- Enthalpy of Formation of the Cyclohexadienyl Radical and the C−H Bond Enthalpy of 1,4-Cyclohexadiene: An Experimental and Computational Re-EvaluationThe Journal of Physical Chemistry A, 2009
- Effects of Electron-Deficient β-Diketiminate and Formazan Supporting Ligands on Copper(I)-Mediated Dioxygen ActivationInorganic Chemistry, 2009
- Bonding and Structure of Copper NitrenesInorganic Chemistry, 2008
- Application of the Correlation Consistent Composite Approach (ccCA) to Third-Row (Ga−Kr) MoleculesJournal of Chemical Theory and Computation, 2008
- Transient Terminal Cu−Nitrene Intermediates from Discrete Dicopper NitrenesJournal of the American Chemical Society, 2006
- Coordination‐Number Dependence of Reactivity in an Imidoiron(III) ComplexAngewandte Chemie, 2006
- Transition metals in organic synthesis: cross-coupling and C–H activation processesAnnu. Rep. Prog. Chem., Sect. B: Org. Chem., 2006
- Accurate Enthalpies of Formation of Alkali and Alkaline Earth Metal Oxides and Hydroxides: Assessment of the Correlation Consistent Composite Approach (ccCA)The Journal of Physical Chemistry A, 2006
- Understanding and exploiting C–H bond activationNature, 2002
- Electron affinities of the first-row atoms revisited. Systematic basis sets and wave functionsThe Journal of Chemical Physics, 1992