Aminoborane σ complexes: Significance of hydride co-ligands in dynamic processes and dehydrogenative borylene formation

Abstract

Systems of the type [(p-cym)Ru(PR3)(H)(H2BN iPr2)]+ (R = Cy, Ph) can be synthesized from (p-cym)Ru(PR3)Cl2 and H2BNiPr 2/Na[BArf4] and are best formulated as (hydrido)ruthenium κ1-aminoborane complexes. VT-NMR measurements have been used to probe the σ-bond metathesis process leading to Ru-H/H-B exchange, yielding an activation barrier of ΔG † = 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. © 2013 American Chemical Society.