Room-Temperature Activation of H by a Surface Frustrated Lewis Pair.

Surface frustrated Lewis pairs (SFLPs) have been implicated in the gas-phase heterogeneous (photo)catalytic hydrogenation of CO to CO and CH OH by In O (OH) . A key step in the reaction pathway is envisioned to be the heterolysis of H on a proximal Lewis acid-Lewis base pair, the SFLP, the chemistry of which is described as In⋅⋅⋅In-OH + H → In-OH ⋅⋅⋅In-H . The product of the heterolysis, thought to be a protonated hydroxide Lewis base In-OH and a hydride coordinated Lewis acid In-H , can react with CO to form either CO or CH OH. While the experimental and theoretical evidence is compelling for heterolysis of H on the SFLP, all conclusions derive from indirect proof, and direct observation remains lacking. Unexpectedly, we have discovered rhombohedral In O (OH) can enable dissociation of H at room temperature, which allows its direct observation by several analytical techniques. The collected analytical results lean towards the heterolysis rather than the homolysis reaction pathway.