Bis(phosphine)hydridorhodacarborane Derivatives of 1,1'-Bis(ortho-carborane) and Their Catalysis of Alkene Isomerization and the Hydrosilylation of Acetophenone

Antony P Y Chan; John A Parkinson; Georgina M Rosair; Alan J Welch

doi:10.1021/acs.inorgchem.9b03351

Bis(phosphine)hydridorhodacarborane Derivatives of 1,1'-Bis(ortho-carborane) and Their Catalysis of Alkene Isomerization and the Hydrosilylation of Acetophenone

Inorg Chem. 2020 Feb 3;59(3):2011-2023. doi: 10.1021/acs.inorgchem.9b03351. Epub 2020 Jan 16.

Authors

Antony P Y Chan¹, John A Parkinson², Georgina M Rosair¹, Alan J Welch¹

Affiliations

¹ Institute of Chemical Sciences , Heriot-Watt University , Edinburgh EH14 4AS , United Kingdom.
² Department of Pure and Applied Chemistry , University of Strathclyde , Glasgow G1 1XL , United Kingdom.

PMID: 31944690
DOI: 10.1021/acs.inorgchem.9b03351

Abstract

Deprotonation of [7-(1'-closo-1',2'-C₂B₁₀H₁₁)-nido-7,8-C₂B₉H₁₁]^- and reaction with [Rh(PPh₃)₃Cl] results in isomerization of the metalated cage and the formation of [8-(1'-closo-1',2'-C₂B₁₀H₁₁)-2-H-2,2-(PPh₃)₂-closo-2,1,8-RhC₂B₉H₁₀] (1). Similarly, deprotonation/metalation of [8'-(7-nido-7,8-C₂B₉H₁₁)-2'-(p-cymene)-closo-2',1',8'-RuC₂B₉H₁₀]^- and [8'-(7-nido-7,8-C₂B₉H₁₁)-2'-Cp*-closo-2',1',8'-CoC₂B₉H₁₀]^- affords [8-{8'-2'-(p-cymene)-closo-2',1',8'-RuC₂B₉H₁₀}-2-H-2,2-(PPh₃)₂-closo-2,1,8-RhC₂B₉H₁₀] (2) and [8-(8'-2'-Cp*-closo-2',1',8'-CoC₂B₉H₁₀)-2-H-2,2-(PPh₃)₂-closo-2,1,8-RhC₂B₉H₁₀] (3), respectively, as diastereoisomeric mixtures. The performances of compounds 1-3 as catalysts in the isomerization of 1-hexene and in the hydrosilylation of acetophenone are compared with those of the known single-cage species [3-H-3,3-(PPh₃)₂-closo-3,1,2-RhC₂B₉H₁₁] (I) and [2-H-2,2-(PPh₃)₂-closo-2,1,12-RhC₂B₉H₁₁] (V), the last two compounds also being the subjects of ¹⁰³Rh NMR spectroscopic studies, the first such investigations of rhodacarboranes. In alkene isomerization all the 2,1,8- or 2,1,12-RhC₂B₉ species (1-3, V) outperform the 3,1,2-RhC₂B₉ compound I, while for hydrosilylation the single-cage compounds I and V are better catalysts than the double-cage species 1-3.