LAUSR

(Dimesitylphosphino)ferrocene (FcPMes2) (1) reacted with HB(C6F5)2 (2 equiv) by disproportionation to give adduct FcPMes2·H2B(C6F5) (4) plus B(C6F5)3, whereas 1-(dimesitylphosphino)-1′-vinylferrocene (2) was cleanly hydroborated with HB(C6F5)2 to afford [Fe(η5-C5H4PMes2)(η5-C5H4CH2CH2B(C6F5)2)] (7). Compound 7 adopted an open non-interacting P/B frustrated Lewis pair (FLP) structure in the crystal state as well as in a solution. This frustrated Lewis pair heterolytically cleaved dihydrogen under mild conditions to give the respective zwitterionic [P]H+/[B]H– phosphonium/hydroborate product, [Fe(η5-C5H4PHMes2){η5-C5H4CH2CH2BH(C6F5)2}] (8), which served as a catalyst for the hydrogenation of the electron-rich π-systems (imine, enamine) as well as the electron-deficient carbon–carbon double and triple bonds in some enones and an ynone under more forcing conditions (50 bar H2 pressure, 50 °C).