Copper–Ligand Cooperativity in H2 Activation Enables the Synthesis of Copper Hydride Complexes

Copper(I) complexes of a new participative triphosphane ligand (2^H) have been prepared and structurally characterized, in particular [Cu(2^H)I] and [Cu(2)]₂. Hydrogenation of the latter species afforded the trimetallic hydride species [Cu₃(2)₂(µ-H)] or in the presence of BEt₃, [Cu(2^H)(HBEt₃)]. Their formation evidences transient formation of [Cu(2^H)H] formed by hydrogenolysis of the Cu‒
N bond of [Cu(2)]₂. [Cu(2^H)(HBEt₃)] behaves like a hydride complex and inserts CO₂ to yield the formate product [Cu(2^H)(O₂CH)].