Low oxidation state hydride species of heavier main-group elements are notoriously elusive due to their intrinsic instability and rapid decomposition, generating hydrogen. Nevertheless, they offer significant potential for small-molecule activation and catalysis. Herein, we report the synthesis and characterization of the first stable, crystalline, low oxidation state indium hydride, supported by bis(N-heterocyclic carbene)borate ligands and featuring a covalent In-In bond. This compound has been comprehensively characterized by NMR spectroscopy, FT-IR, single-crystal X-ray diffraction, and computational calculations. Experimental and theoretical studies reveal key features that underpin its exceptional stability. Preliminary reactivity investigations demonstrate that this discrete In(II) hydride acts as a nucleophile, opening new avenues for bond activation involving hydrides derived from the heaviest p-block elements.
Mouriki et al. (2026) studied this question.