The reaction of [Re2(CO)8(MeCN)2] with thiols. Formation of hydrido sulfido bridged dirhenium cluster complexes [Re2(µ-H)(µ-SR)(CO)8] (R = H, n-Bu, Cy, Ph, C6H4F-p, C6F5 or 2-naphthyl)

Abstract

The complex [Re₂(CO)₈(MeCN)₂] 1 reacted with thiols or H₂S, respectively, by SH oxidative addition in toluene at 80 °C to give hydrido sulfido bridged dirhenium complexes of the general formula [Re₂(µ-H)(µ-SR)(CO)₈] (R = H 2a, n-Bu 2b, Cy 2c, Ph 2d, C₆H₄F-p 2e, C₆F₅ 2f or 2-naphthyl 2g) in 60 to 80% yield. Complexes 2c and 2g have been characterised by crystal structure analysis. Complex 2a undergoes reaction with another equivalent of 1 to form the novel spirocyclic complex [{Re₂(µ-H)(CO)₈}₂(µ₄S)] 3. In order to demonstrate the acidity of the µ-H ligand 2g was deprotonated by the base 1,8-diazabicyclo[5.4.0]undec-7-ene to give the anion [Re₂(µ-S(2-naph))(CO)₈]^– 4^– (naph = naphthyl) which can be isolated as its PPh₄⁺salt. This reacts with one equivalent of [MCl(PPh₃)] (M = Au, Ag or Cu) to give the novel heteronuclear cluster complexes [Re₂(MPPh₃)(µ-S(2-naph))(CO)₈] (M = Au 5a, Ag 5b or Cu 5c) and PPh₄Cl. The molecular structures of 5a and 5b have been established by single crystal X-ray analysis.