Dihydrogen Activation with tBu3P/B(C6F5)3: A Chemically Competent Indirect Mechanism via in Situ-Generated p-tBu2P-C6F4-B(C6F5)2

A chemically competent indirect pathway for the activation of dihydrogen by the nonmetal Lewis acid/Lewis base pair (Bu3P)-Bu-t/B(C6F5)(3) is described. The reaction between (Bu3P)-Bu-t and B(C6F5)(3) produces [(Bu3PH)-Bu-t](+)[FB(C6F5)(3)](-) and the known phosphinoborane p-(Bu2P)-Bu-t-C6F4-B(C6F5)(2) (1-Bu-t) with elimination of isobutylene. At 1:1 stoichiometry, 1-Bu-t is produced rapidly in detectable quantities and can act as a catalyst for the formation of [(Bu3PH)-Bu-t](+)[HB(C6F5)(3)](-) from (Bu3P)-Bu-t and B(C6F5)(3) in the presence of H-2. The extent to which this indirect path competes with the direct path is explored.