Molecular Mimics of Heterogeneous Metal Phosphides: Thermochemistry, Hydride-Proton Isomerism, and HER Reactivity.

A new series of low-valent dinuclear molybdenum complexes bearing phosphido or phosphinidene bridging ligands was synthesized as a structural model of heterogeneous metal phosphide catalysts. Addition of acid to a monocationic Mo -μ-P complex results in phosphide protonation, affording a dicationic Mo -μ-PH species. Alternatively, reaction of an isoelectronic Mo -μ-P precursor with LiBEt H gives a Mo H-μ-P complex. Mixing these species, one bearing a Mo-H and the other a P-H bond, results in facile H production at room temperature.