Reversible formation of organyl(oxo)boranes (RBO) (R = C6H 5 or CH3) from boroxins ((RBO)3): A matrix isolation study

Article abstract of DOI:10.1021/om061057i

Flash vacuum pyrolysis of triphenyl- and trimethylboroxin and subsequent trapping of the gas phase products in a large excess of argon at T < 20 K allows matrix isolation and characterization by IR spectroscopy of phenyl(oxo)borane and methyl(oxo)borane. The nature of the matrix isolated species, monomelic CH₃BO, 1:1 dimer complex of CH₃BO, (CH₃BO)₂, and (CH₃BO)₃, depends strongly on the trapping temperature and matrix host gas (Ar vs Xe) with the boroxin dominating at 30 K (Ar) or 55 K (Xe). An ab initio investigation (second-order Moller - Plesset perturbation theory) of the potential energy surface for trimerization of CH₃BO is in agreement with the experimental observations.