Dppm-substituted ruthenium clusters with capping sulfido and selenido ligands derived from thiourea, tetramethylthiourea and elemental selenium

Treatment of [Ru3(CO)10(μ-dppm)] (4) [dppm = bis(diphenylphosphido)methane] with tetramethylthiourea at 66 °C gave the previously reported dihydrido triruthenium cluster [Ru3(μ-H)2(μ3-S)(CO)7(μ-dppm)] (5) and the new compounds [Ru3(μ3-S)2(CO)7(μ-dppm)] (6), [Ru3(μ3-S)(CO)7(μ3-CO)(μ-dppm)] (7) and [Ru3(μ3-S){η1-C(NMe2)2}(CO)6(μ3-CO)(μ-dppm)] (8) in 6%, 10%, 32% and 9% yields, respectively. Treatment of 4 with thiourea at the same temperature gave 5 and 7 in 30% and 10% yields, respectively. Compound 7 reacts further with tetramethylthiourea at 66 °C to yield 6 (30%) and a new compound [Ru3(μ3-S)2{η1-C(NMe2)2}(CO)6(μ-dppm)] (9) (8%). Thermolysis of 8 in refluxing THF yields 7 in 55% yield. The reaction of 4 with selenium at 66 °C yields the new compounds [Ru3(μ3-Se)(CO)7(μ3-CO)(μ-dppm)] (10) and [Ru3(μ3-Se)(μ3-η3-PhPCH2PPh(C6H4)}(CO)6(μ-CO)] (11) and the known compounds [Ru3(μ-H)2(μ3-Se)(CO)7(μ-dppm)] (12) and [Ru4(μ3-Se)4(CO)10(μ-dppm)] (13) in 29%, 5%, 2% and 5% yields, respectively. Treatment of 10 with tetramethylthiourea at 66 °C gives the mixed sulfur-selenium compounds [Ru3(μ3-S)(μ3-Se)(CO)7(μ-dppm)] (14) and [Ru3(μ3-S)(μ3-Se){η1-C(NMe2)2}(CO)6(μ-dppm)] (15) in 38% and 10% yields, respectively. The single-crystal XRD structures of 6, 7, 8, 10, 14 and 15 are reported.

Graphical abstractSulfur-capped and mixed sulfur/selenium-capped triruthenium clusters have been synthesised by treatment of [Ru3(CO)10(μ-dppm)] with thiourea, tetramethylthiourea or elemental selenium. Bis(dimethylamino)methylidyne ligands are formed in addition to sulfur caps by cleavage of CS bonds of tetramethylthiourea. The crystal structures of six new compounds are reported.Figure optionsDownload full-size imageDownload as PowerPoint slide