Acid-assisted reductive elimination of hydrogen from Tp'PtH3 and of methane and hydrogen from Tp'PtMeH2 (Tp' = hydridotris(3,5-dimethylpyrazolyl)borate) is examined herein. Loss of H-2 is observed from solutions containing platinum(IV) complexes of the type Tp'Pt(R)(H)(2) (R = Me, H) upon protonation and addition of a ligand such as CO. Results of kinetic studies on reductive elimination of H-2 and formation of [kappa(2)-(HTp')Pt(R)(L)][BAr`(4)] products from intermediates derived from Tp'Pt(R)(H)(2) precursors are described. Elimination appears to occur from cationic 6-coordinate [kappa(2)-(HTp')Pt(R)(H)(2)(L)][BAr'(4)] species.