Crossed-Beam Reaction of Boron Atoms, B (2Pj), with Dimethylacetylene, CH3CCCH3 (XA1g): Untangling the Reaction Dynamics to Form the 1,2-Dimethylene-3-bora-cyclopropane Molecule

Abstract

The reaction of ground-state boron atoms, B (2Pj), with dimethylacetylene, CH3CCCH3 (X1A1g), was studied at a collision energy of 17.9 kJ mol-1 using the crossed molecular beam approach. It was found that the reaction follows indirect scattering dynamics. B (2Pj) attacks the carbon−carbon triple bond of the dimethylacetylene molecule to form a cyclic BC4H6 intermediate that undergoes hydrogen transfer from the methyl group to the boron atom. This complex then rotates around the A/B axis and fragments to atomic hydrogen plus a cyclic BC4H5 isomer, 1,2-dimethylene-3-bora-cyclopropane, via a tight transition state.