Synthesis and X-ray crystal structure of the novel hydridocarbonyl cluster [NEt4][Re4(µ-H)5(CO)14]

Abstract

The reaction between [Re₃(µ-H)₃(CO)₁₀(NCMe)₂] and [ReH₂(CO)₄]^– affords the novel hydridocarbonyl cluster [Re₄(µ-H)₅(CO)₁₄]^–. Its NEt₄⁺ salt has been investigated by X-ray analysis; the crystals are monoclinic, space group P2₁/n, with a= 14.038(6), b= 15.152(5), c= 15.501(6)Å, β= 101.79(3)°, and Z= 4. The structure was solved and refined on the basis of 3 169 significant counter data, to a final R value of 0.031. The anion contains a butterfly metallic skeleton [Re–Re bond lengths 3.206(1)–3.247(1)Å] with all the edges bridged by hydride ligands. The most unusual feature is the absence of ligands bridging the wing tips of the butterfly cluster.