A Computational Analysis of Supported and Unsupported Group 6 Transition Metal-Metal Bonds Based on the Natural Orbitals for Chemical Valence (NOCV) and the Extended Transition State (ETS) Techniques
Date
2013-02-14
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
A computational study has been carried out on the nature of the metal-metal bond of group 6 transition metal complexes based on the extended transition state (ETS) and natural orbitals for chemical valence (NOCV) methods. The analysis of the unsupported triple (M2L6) and quadruple (M2L2L´2; M=Cr,Mo,W; L,L´=π-acceptor/σ-donor ligands) metal-metal bonds demonstrated that the M-M bond strength follows the trend Cr<<Mo<W, a trend that is influenced largely by the higher steric repulsion between metal fragments that diminish down the triand with increasing M-M distances.
The five bonding components of the putative Cr-Cr quintuple (σ2,π2,π´2,δ2,δ´2) bond in Ar´CrCrAr´ (Ar´=C6H3-2,6(C6H3-2,6-Pri2)2) are also presented in this thesis. It is shown that the presence of isopropyl (Pri) groups stabilizes the system by 20kcal/mol through van der Waal dispersions. Finally, the ETS-NOCV is applied on the analysis of the shortest (1.73Å) fully supported Cr-Cr bond in Cr2(Ar´NC(NMe2)NAr´)2 (Ar´= C6H3-2,6(C6H3-2,6-Pri2)2) and the quadruply (σ2, π4, δ2) bonded paddlewheel complexes.
Description
Keywords
Chemistry--Inorganic
Citation
Ndambuki, S. W. (2013). A Computational Analysis of Supported and Unsupported Group 6 Transition Metal-Metal Bonds Based on the Natural Orbitals for Chemical Valence (NOCV) and the Extended Transition State (ETS) Techniques (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/24675