Cooperative Transition Metal/Lewis Acid Bond-Activation Reactions by a Bidentate (Boryl)­imino­methane Complex: A Significant Metal–Borane Interaction Promoted by a Small Bite-Angle LZ Chelate

The
synthesis of a three-coordinate Pt–borane complex featuring
a bidentate “LZ” (boryl)­imino­methane (BIM)
ligand is reported. Unlike other LZ-type borane ligands featuring
a single-donor buttress, the small bite angle enforced by the BIM
ligand is shown to promote a significant metal–borane reverse-dative
σ-interaction akin to multiply strapped metalloboratranes. The
steric accessibility of the reactive Pt → B bond fostered by
the BIM ligand allows for a rich reactivity profile toward small molecules
that exploit metal–borane cooperative effects. The unligated
(boryl)­imino­methane BIM is also synthetically accessible
and functions as a Frustrated Lewis Pair (FLP). The ability of the
free BIM to effect bond activation reactions is contrasted with the
behavior seen in the corresponding platinum-bound complexes.