Aminoborane σ Complexes: Significance of Hydride Co-ligands in Dynamic Processes and Dehydrogenative Borylene Formation

Systems of the type [(p-cym)Ru(PR3)(H)-((H2BNPr2)-Pr-i)](+) (R = Cy, Ph) can be synthesized from (p-cym)Ru-(PR3)Cl-2 and (H2BNPr2)-Pr-i/Na[BAr4f] and are best formulated as (hydrido)rutheniurn kappa(1)-aminoborane complexes. VT-NMR measurements have been used to probe the sigma-bond metathesis process leading to Ru-H/H-B exchange, yielding an activation barrier of Delta G(double dagger) = 7.5 kcal mol(-1) at 161 K. Moreover, in contrast to the case for related non-hydride-containing systems, reactivity toward alkenes constitutes a viable route to a metal borylene complex via sacrificial hydrogenation.