Tantalum-gold and tantalum-copper trihydride complexes (Cp'2TaH3MPPh3)(PF6) (Cp' = C5H4C(CH3)3). Structure determination from 1H T1 relaxation studies

Novel mixed tantalum-gold and tantalum-copper trihydrides of the formula (Cp'2TaH3MPPH3)(PF6) where M = Au, Cu and Cp' = C5H4C(CH3)3 with two bridging hydride ligands. Their structures were studied through relaxation measurements and analysis of proton-proton and phosphorus-proton couplings. The hydride-hydride and metal-hydride distances are similar in structure with the related niobium trihydride ((Nb(C5H3RR')2H3)2Au)(PF6) with R = R' = Si(CH3)3. The Ta-H dipole-dipole interactions were found to be valuable in hydride relaxation.