Expanded ring N-heterocyclic carbene complexes of zero valent platinum dvtms (divinyltetramethyldisiloxane): Highly efficient hydrosilylation catalysts

The synthesis and characterisation of a series of new 6- and 7-membered NHC (N-heterocyclic carbene) complexes 7–12 of zero valent platinum dvtms (divinyltetramethyldisiloxane), [Pt(NHC)(dvtms)] are reported. A number of the complexes were investigated as catalyst precursors in the hydrosilylation of a range of unsaturated substrates, including alkynes, alkenes and a ketone with triethylsilane and bis(trimethylsiloxy)methylsilane (MD’M), at low catalyst loading (0.005 mol %); in general, the activity, and the selectivity for 1-functionalised product was found to be high.

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► Catalytic hydrosilylation; addition of H-SiR3 to carbon-element multiple bonds.
► Large-ring NHC-Pt(dvtms) complexes, efficient catalysts at low catalyst loadings.
► Highly active catalysts with excellent regioselectivity; up to 99:1 in some cases.
► XRD study of large-ring NHC-Pt(dvtms) complexes: structure reactivity relationship.