Jump to main content
Jump to site search

Issue 30, 2009
Previous Article Next Article

Metal fragment isomerisation upon grafting a d2 ML4perhydrocarbyl Os complex on a silica surface: origin and consequence

Author affiliations

Abstract

Grafting of Os bisalkylidene complexes, [Os([double bond, length as m-dash]CHtBu)2(CH2tBu)2], on a silica partially dehydroxylated at 700 °C selectively yields an alkylidyne complex [([triple bond, length as m-dash]SiO)Os([triple bond, length as m-dash]CtBu)(CH2tBu)2] according to mass balance analysis, IR and solid state NMR spectroscopies, but 70% of the silanols remains unreacted. Grafting corresponds to a replacement of one alkyl by a siloxy ligand and induces the isomerisation of the metal fragment from a bis-alkylidene to an alkyl alkylidyne. Molecular (B3PW91) and periodic DFT-calculations show that the bis-alkylidene is the energetically favoured isomer for the perhydrocarbyl complex, while the alkyl alkylidyne isomer is more stable when one of the alkyl ligands is replaced by a siloxy ligand. The change of the nature of the ligand is accompanied with a change of geometry: from a distorted tetrahedral structure for [Os([double bond, length as m-dash]CHtBu)2(CH2tBu)2] to a butterfly-geometry with apical siloxy and alkylidyne ligands for [([triple bond, length as m-dash]SiO)Os([triple bond, length as m-dash]CtBu)(CH2tBu)2]. Finally, DFT calculations show that grafting occurs via a σ-bond metathesis between the silanol and a metal–alkyl bond and not through the typical addition of the silanol onto the alkylidene ligand.

Graphical abstract: Metal fragment isomerisation upon grafting a d2 ML4perhydrocarbyl Os complex on a silica surface: origin and consequence

Back to tab navigation

Supplementary files

Publication details

The article was received on 26 Jan 2009, accepted on 20 Feb 2009 and first published on 17 Mar 2009


Article type: Paper
DOI: 10.1039/B901669D
Citation: Dalton Trans., 2009,0, 5879-5886

  •   Request permissions

    Metal fragment isomerisation upon grafting a d2 ML4perhydrocarbyl Os complex on a silica surface: origin and consequence

    R. Berthoud, N. Rendón, F. Blanc, X. Solans-Monfort, C. Copéret and O. Eisenstein, Dalton Trans., 2009, 0, 5879
    DOI: 10.1039/B901669D

Search articles by author

Spotlight

Advertisements