Phosphine–Borane Frustrated Lewis Pairs Derived from a 1,1′-Disubstituted Ferrocene Scaffold: Synthesis and Hydrogenation Catalysis

Abstract

Dimesitylphosphino)ferrocene (FcPMes 2 ) (1) reacted with HB(C 6 F 5 ) 2 (2 equiv) by disproportionation to give adduct FcPMes 2 • H 2 B(C 6 F 5 ) (4) plus B(C 6 F 5 ) 3 , whereas 1-(dimesitylphosphino)-1′-vinylferrocene (2) was cleanly hydroborated with HB(C 6 F 5 ) 2 to afford [Fe(η 5 -C 5 H 4 PMes 2 )(η 5 -C 5 H 4 CH 2 CH 2 B(C 6 F 5 ) 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 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 H 2 pressure, 50 °C).

Pendulum-like hemilability in a Ti-based frustrated Lewis Trio

“…5. [40][41][42] This also resulted in the formation of complex 5 based on NMR analysis (see Fig. S62-S63 †), conrming the speciation in the solution matched that observed in the solid-state.…”

Application of nonmetallic frustrated cations in the activation of small molecules

“…To date, among cationic species, the concept of frustrated Lewis pairs has been limited to transition metal cations, in particular to Zr(IV) compounds. [22][23][24][25][26][27][28][29][30] To the best of our knowledge, no previous reports on nonmetallic frustrated cations (NFCs) are available; to fill this gap, we aimed to synthesize these reactive and ambiphilic species.…”

Application of nonmetallic frustrated cations in the activation of small molecules

“…To date, among cationic species, the concept of frustrated Lewis pairs has been limited to transition metal cations, in particular to Zr(IV) compounds. [22][23][24][25][26][27][28][29][30] To the best of our knowledge, no previous reports on nonmetallic frustrated cations (NFCs) are available; to fill this gap, we aimed to synthesize these reactive and ambiphilic species. Experimental, crystallographic, spectroscopic and computational details.…”