Hydrogen atom transfer rates from Tp-containing metal-hydrides to trityl radicals

Abstract

The H• transfer rate constants for a series of group 6 molybdenum and tungsten pyrazolyl borate complexes are described. The rate constants for these complexes were found to span a range over 1 magnitude. Analysis of the H• transfer rate constants suggests that a combination of steric, electronic, and enthalpic factors are important in these reactions. Further analysis of the components suggests that the generated 17 e– radicals of these complexes are less electrophilic than the more commonly used CpCr(CO)3H complexes. General implications for H• transfer reactions are discussed.