Browsing by Author "UDDIN, Md. NAZIM"

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    New Triruthenium and Triosmium Clusters Bearing Small Organic Ligands
    (JAHANGIRNAGAR UNIVERSITY SAVAR, DHAKA, 2008-02) UDDIN, Md. NAZIM; Dr. Shariff Enamul Kabir
    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.