New Triruthenium and Triosmium Clusters Bearing Small Organic Ligands

Abstract

This thesis describes the synthesis, structures and reactivity of some new triruthenium and triosmium clusters containing phosphorus, sulfur and oxygen donor ligands. Treatment of [Ru3(CO))2] with thianthrene in refluxing toluene afforded [(p4-S)Ru4(pCO)a(CO)o(Ha-17-CeHy)] 2-1, [(Hs-S)Rug(4~CO)2(CO)is(u-1?-Ci2HgS)] 2.2, and [(UsS)Rus(u-CO)2(CO);1(u-7°-C1zHgS)(W4-1)?-C6H4)] 2.3 respectively. Thermolysis of 2.2 in refluxing heptane gave compounds 2.1 and 2.3. A similar thermolysis of 2.3 in refluxing toluene gave 2.1. Treatment of 2.3 with neat MeCN afforded the labile compound [(sS)Rus(p-CO)2(CO)10(-1?-C12HsS)(p4-7)2-C6Hs)(MeCN)] 2.4. The reaction of 2.4 with P(OMe)3 gave the substitution product [(\1s-S)Rus(p-CO)2(CO)10(p-1?-C12HsS)(p4-717- CH.) {P(OMe)3}] 2.5. Compound 2.1 contains a p14-capping sulfido and a py-1n-benzyne ligand, whereas 2.3, 2.4, and 2.5 contain j1s-sulfido and g-1?-benzyne ligands. The latter three compounds provide rare examples of ys-sulfido and metal-assisted opening of the thianthrene ligand on polynuclear centers. In compounds 2.1, 2.3, and 2.4 the 4-1’- benzyne ligand is perpendicular to the Ruy face of the clusters and represents a previously uncharacterized bonding mode for benzyne. Reaction of [Ru3(CO):0(u-dppm)] 3.1 with P(C4H3S)3 gave the simple substitution product [Ru3(CO)o(u1-dppm){P(C4H3S)3}] 3.2, in which the P(C4H3S)3 ligand is monocoordinated through the phosphorus atom. Thermolysis of 3.2 afforded [Ru3(uH)(CO)7(u1-dppm)(113-17’-C4HpS) {u-P(C4H3S)2}] 3.3 and [Rus(CO)s(4-CO)(u-dppm)(H1s1n°>-SCH=CH-CH=C){1-P(C4H3S)2}] 3.4. Compound 3.3 is formed by the C-P and C—-H bonds activation of the coordinated ligand, thus forming a o, x, n':n':n?-vinyl type bridge among the ruthenium atoms. Compound 3.4 contains an unprecedented example of a coordinated metal assisted ring open p1s-7°-1-thia-1,3-butadiene ligand on a triruthenium cluster surface. Treatment of 3.3 with PPh; afforded the equatorially coordinated phosphine substituted compound [Ru3(u-H)(CO)6(p1-dppm)(t3-7?-C4HoS){- P(C4H3S)2}PPh3] 3.5. Reaction of 3.3 with HBr gave [Ru3(y-H)(CO)¢(u-Br)(q'-Br)(pdppm)(is-1)”-CaH2S){H-P(CsH38)2}] 3.6. Il Treatment of [Ru3(CO)j0(u-dppm)] 3.1 with P(C4H30)3 gave the simple substitution product [Ru3(CO)9(u-dppm){P(C4H30)3}] 4.1, in which the P(C4H30) ligand is monocoordinated through the phosphorus atom. Thermolysis of 4.1 in refluxing dichloromethane in the presence of Me3NO furnished the novel compound [Rus(uH)(CO);(u-dppm)(p13-1)':79':1?-C4H20){1-P(C4H30)}] 4.2. Thermolysis of compound 4.2 gave [Ru3(CO)7(u-dppm)(p3-7':79':97-C4H20){13-P(C4H30)}] 4.3. The reaction of [Ru3(-H)(CO)7(p-dppm)(p13-7n':9)':9?-C4H20){-P(C4H3O)2}] 4.2 with PPh3 afforded the PPh; derivative [Ru3(u-H)(CO)(u-dppm)(p13-1)':9':1?-C4H20){1-P(C4H30)2}PPhs] 4.4. Treatment of compound 4.2 with HBr furnished [Ru3(u-H)(CO)¢(p-Br)(n'-Br)(pdppm)(113-n7-C4H20) {u-P(C4H30)2] 4.5. Reaction of the unsaturated cluster [Os3(u-H)(CO)g{p-Ph2PCH2P (Ph)CsH4}] 5.3 with P(C4H3S)3 at room temperature afforded the new compound [Os3(CO)g(u-dppm)(PTh3)2] 5.17. Thermolysis of [Os3(CO)g(u1-dppm) {P(C4H3S)3)}2] 5.17 in toluene at 80 °C gave two new compounds [Os3(CO)o(u-dppm){P(C4H3S)3}] 5.18 and [Os3(u-H)(CO)7{pPh)PCH>P(Ph)C¢H4} {P(C4H3S)3}] 5.19 whereas a similar reaction of 5.3 with P(C4H30)3 furnished three new compounds [Os3(u-H)(CO)s3 {Ph2PCH2P(Ph)C¢H4}P(C4H30)3] 5.19, [Os3(CO)o(u-dppm) {P(C4H30)3}] 5.20 and [Os3(CO)s(u-dppm){P(C4H30)3}2] 5.21. Compound 5.19 contains a unique example of an electronically unsaturated triosmium cluster in which the phenyl ring of the orthometalated diphosphine ligand is bound to the cluster via a three-center two electron bond.