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

Abstract

Copper(I) complexes of a new participative triphosphane ligand (<b>2<sup>H</sup></b>) have been prepared and structurally characterized, in particular [Cu(<b>2<sup>H</sup></b>)I] and [Cu(<b>2</b>)]<sub>2</sub>. Hydrogenation of the latter species afforded the trimetallic hydride species [Cu<sub>3</sub>(<b>2</b>)<sub>2</sub>(µ-H)] or in the presence of BEt<sub>3</sub>, [Cu(<b>2<sup>H</sup></b>)(HBEt<sub>3</sub>)]. Their formation evidences transient formation of [Cu(<b>2<sup>H</sup></b>)H] formed by hydrogenolysis of the Cu‒<br>N bond of [Cu(<b>2</b>)]<sub>2</sub>. [Cu(<b>2<sup>H</sup></b>)(HBEt<sub>3</sub>)] behaves like a hydride complex and inserts CO<sub>2</sub> to yield the formate product [Cu(<b>2<sup>H</sup></b>)(O<sub>2</sub>CH)].<br>