The Simplest Amino-borane H2 B=NH2 Trapped on a Rhodium Dimer: Pre-Catalysts for Amine-Borane Dehydropolymerization

Amit Kumar; Nicholas A Beattie; Sebastian D Pike; Stuart A Macgregor; Andrew S Weller

doi:10.1002/anie.201600898

The Simplest Amino-borane H2 B=NH2 Trapped on a Rhodium Dimer: Pre-Catalysts for Amine-Borane Dehydropolymerization

Angew Chem Int Ed Engl. 2016 Jun 1;55(23):6651-6. doi: 10.1002/anie.201600898. Epub 2016 Apr 21.

Authors

Amit Kumar¹, Nicholas A Beattie², Sebastian D Pike¹, Stuart A Macgregor³, Andrew S Weller⁴

Affiliations

¹ Department of Chemistry, Chemistry Research Laboratories, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
² Institute of Chemical Sciences, Heriot Watt University, Edinburgh, EH14 4AS, UK.
³ Institute of Chemical Sciences, Heriot Watt University, Edinburgh, EH14 4AS, UK. S.A.Macgregor@hw.ac.uk.
⁴ Department of Chemistry, Chemistry Research Laboratories, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK. andrew.weller@chem.ox.ac.uk.

Abstract

The μ-amino-borane complexes [Rh2 (L(R) )2 (μ-H)(μ-H2 B=NHR')][BAr(F) 4 ] (L(R) =R2 P(CH2 )3 PR2 ; R=Ph, (i) Pr; R'=H, Me) form by addition of H3 B⋅NMeR'H2 to [Rh(L(R) )(η(6) -C6 H5 F)][BAr(F) 4 ]. DFT calculations demonstrate that the amino-borane interacts with the Rh centers through strong Rh-H and Rh-B interactions. Mechanistic investigations show that these dimers can form by a boronium-mediated route, and are pre-catalysts for amine-borane dehydropolymerization, suggesting a possible role for bimetallic motifs in catalysis.

Keywords: DFT; amino-borane; catalytic mechanisms; dehydrocoupling; rhodium dimers.

Publication types

Research Support, Non-U.S. Gov't