Mixed-Metal Cluster Chemistry. 11.1 Reactions of Tungsten-Iridium Clusters with Terminal Alkynes and Tungsten Acetylides: X-ray Crystal Structures of Cp2W2Ir2
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- 作者：Susan M. Waterman ; Mark G. Humphrey ; Vicki-Anne Tolhurst ; Michael I. Bruce ; Paul J. Low ; and David C. R. Hockless
- 刊名：Organometallics
- 出版年：1998
- 出版时间：December 21, 1998
- 年：1998
- 卷：17
- 期：26
- 页码：5789 - 5795
- 全文大小：111K
- 年卷期：v.17,no.26(December 21, 1998)
- ISSN：1520-6041
文摘
Reactions of Cp2W2Ir2(CO)10 (1) with terminal arylalkynes HC
CR afford the complexesCp2W2Ir2(
r.gif">4-
rs/eta.gif" BORDER=0 >2-HC2R)(r.gif">-CO)4(CO)4 [R = Ph (3), C6H4Me-4 (4), C6H4NO2-4 (5)] in excellentyields (56-70%). The analogous adduct with the terminal alkylalkyne HCCBut is obtainedin much lower yield (20%). An X-ray structural study of 3 reveals that the alkynes haveformally inserted into the W-W bond of 1, affording clusters with a pseudooctahedralgeometry. The site of reactivity in 1 is consistent with the lack of reactivity towards terminalalkynes of the isostructural and isolobally related CpWIr3(CO)11 (2). Reaction of 1 with thebuta-1,3-diynyl complex CpW(CO)3(CCCCH) (8) affords the analogous adduct Cp2W2Ir2{r.gif">4-rs/eta.gif" BORDER=0 >2-HC2CCW(CO)3Cp)(r.gif">-CO)4(CO)4 (9), shown spectroscopically to be attached via theCCH unit rather than the WCC group. Attempts at condensing the pendant CpW(CO)3CC unit with the W2Ir2 core in 9 have proven unsuccessful. Reactions of CpWIr3(CO)11 (2)with equimolar amounts of the tungsten acetylides CpW(CO)3(CCR) (R = Ph, C6H4Me-4,C6H4NO2-4, CCPh) afford the products Cp2W2Ir3(r.gif">4-rs/eta.gif" BORDER=0 >2-C2R)(r.gif">-CO)(CO)9 [R = Ph (11), C6H4Me-4 (12), C6H4NO2-4 (13), CCPh (14)] in fair yields (23-45%). Product 12 has beenstructurally characterized, with the structural study revealing an edge-bridged tetrahedralmetal core geometry and an unusual r.gif">4-rs/eta.gif" BORDER=0 >2 (3rs/sigma.gif" BORDER=0 > + rs/pi.gif" BORDER=0 >)-coordinated alkynyl ligand. The reactioncorresponds to formal insertion of the alkynyltungsten reagent into an Ir-Ir linkage of 2.Reactions of 1 with these tungsten acetylides were not successful under the experimentalconditions attempted, a result ascribed to steric constraints.
CR afford the complexesCp2W2Ir2(r.gif">4-rs/eta.gif" BORDER=0 >2-HC2R)(r.gif">-CO)4(CO)4 [R = Ph (3), C6H4Me-4 (4), C6H4NO2-4 (5)] in excellentyields (56-70%). The analogous adduct with the terminal alkylalkyne HCCBut is obtainedin much lower yield (20%). An X-ray structural study of 3 reveals that the alkynes haveformally inserted into the W-W bond of 1, affording clusters with a pseudooctahedralgeometry. The site of reactivity in 1 is consistent with the lack of reactivity towards terminalalkynes of the isostructural and isolobally related CpWIr3(CO)11 (2). Reaction of 1 with thebuta-1,3-diynyl complex CpW(CO)3(CCCCH) (8) affords the analogous adduct Cp2W2Ir2{r.gif">4-rs/eta.gif" BORDER=0 >2-HC2CCW(CO)3Cp)(r.gif">-CO)4(CO)4 (9), shown spectroscopically to be attached via theCCH unit rather than the WCC group. Attempts at condensing the pendant CpW(CO)3CC unit with the W2Ir2 core in 9 have proven unsuccessful. Reactions of CpWIr3(CO)11 (2)with equimolar amounts of the tungsten acetylides CpW(CO)3(CCR) (R = Ph, C6H4Me-4,C6H4NO2-4, CCPh) afford the products Cp2W2Ir3(r.gif">4-rs/eta.gif" BORDER=0 >2-C2R)(r.gif">-CO)(CO)9 [R = Ph (11), C6H4Me-4 (12), C6H4NO2-4 (13), CCPh (14)] in fair yields (23-45%). Product 12 has beenstructurally characterized, with the structural study revealing an edge-bridged tetrahedralmetal core geometry and an unusual r.gif">4-rs/eta.gif" BORDER=0 >2 (3rs/sigma.gif" BORDER=0 > + rs/pi.gif" BORDER=0 >)-coordinated alkynyl ligand. The reactioncorresponds to formal insertion of the alkynyltungsten reagent into an Ir-Ir linkage of 2.Reactions of 1 with these tungsten acetylides were not successful under the experimentalconditions attempted, a result ascribed to steric constraints.