Ru–η6‐Arene Cations [{(Ph2PC6H4)2B(η6‐Ph)}RuX]+ (X=Cl,H) as Lewis Acids |
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Authors: | Dr. Michael P. Boone Prof. Dr. Douglas W. Stephan |
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Affiliation: | Department of Chemistry, University of Toronto, 80 St.?George Street, Toronto, Ontario, M5S 3H6 (Canada) |
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Abstract: | The reactivity of [{(Ph2PC6H4)2B(η6‐Ph)}RuCl][B(C6F5)4] ( 1 ) as a Lewis acid was investigated. Treatment of 1 with mono and multidentate phosphorus Lewis bases afforded the Lewis acid–base adducts with the ortho‐carbon atom of the coordinated arene ring. Similar reactivity was observed upon treatment with N‐heterocyclic carbenes; however, adduct formation occurred at both ortho‐ and para‐carbon atoms of the bound arene with the para‐position being favoured by increased steric demands. Interestingly treatment with isocyanides resulted in adduct formation with the B‐centre of the ligand framework. The hydride‐cation [{(Ph2PC6H4)2B(η6‐Ph)}RuH] [B(C6F5)4] was prepared via reaction of 1 with silane. This species in the presence of a bulky phosphine behaves as a frustrated Lewis pair (FLP) to activate H2 between the phosphorus centre and the ortho‐carbon atom of the η6‐arene ring. |
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Keywords: | carbon‐based acids frustrated Lewis pairs hydrogen activation Lewis acid– base adducts ruthenium |
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