σ‑SiH Complexes of Copper: Experimental Evidence and Computational Analysis

Copper and gold complexes 2–4 of the diphosphine-hydrosilane [Ph2P­(o-C6H4)]2MeSiH ligand 1 have been prepared, and their bonding situation has been analyzed experimentally (NMR, IR, X-ray diffraction) and computationally (geometry optimizations, NBO analyses). The σ-SiH bond remains pendant in the gold complex 4 but engages into a weak side-on coordination to copper. This bonding interaction slightly strengthens when the metal becomes more electron deficient, consistent with essentially pure σ-SiH-to-copper donation. Complexes 2 and 3 provide very rare examples of σ-bond coordination to a coinage metal.