Reactivity of triruthenium diphosphine clusters with 3,5-bis(trifluoromethyl)mercaptobenzene: Electronic and steric influence of diphosphines onto coordination modes of thiolate, capping sulfide, and phosphide groups to a Ru3 clusters

Abstract

The bridge diphosphine triruthenium clusters [Ru3(μ-κ2P,P′-diphosphine)(CO)10] 1a–1c [diphosphine = dppe, dfppe and dppm, respectively] react with 3,5-bis(trifluoromethyl)mercaptobenzene under refluxing THF, resulting in the oxidative addition of the thiol, to give isostructural compounds [Ru3(μ-H)(μ-κS-SC6H3(CF3)2)(μ-κ2P,P′-diphosphine)(CO)8] [diphosphine = dppe (2a); dfppe (2b) and dppm (2c)] in moderate yields. The thermal hydrogenation reaction of clusters 2a or 2b gives the bridge diphosphine asymmetric dihydride isomeric compounds [Ru3(μ-H)2(μ3-S)(μ-κ2P2-diphosphine)(CO)7] [diphosphine = dppe (3a) and dfppe (3b)] that promote the formation of chelate diphosphine asymmetric dihydride isomers [Ru3(μ-H)2(μ3-S)(κ2P,P′-diphosphine)(CO)7] [diphosphine = dppe (4a) and dfppe (4b)] respectively. Moreover, the hydrogenation reaction of 2a yielded the chelate diphosphine symmetric dihydride isomer [Ru3(μ-H)2(μ3-S)(κ2P,P′-dppe)(CO)7] (5a). The hydrogenation reaction of 2b also yielded [Ru3(μ-H)(μ3-S){μ-κ2P,P′-P(C6F5)CH2CH2P(C6F5)2}(CO)7] (6b), where a C–P bond rupture promoted the formation of a phosphide group in a 50 electron unsaturated cluster. The new clusters have been characterized by spectroscopic methods, and the molecular structures of 2b, 2c, 3a, 3b, 5a, and 6b have been determined by single crystal X-ray diffraction studies.