REACTION OF POLYNUCLEAR ACETYLIDE CLUSTERS - MIXED-METAL COMPLEXES DERIVED FROM REACTIONS OF CPWOS3(CO)11(C=CR) (R = PH, NBU) WITH DISUBSTITUTED ALKYNES

Reaction of CpW(CO)3(C=CR) with Os3(CO)10(CH3CN)2in refluxing toluene produces tetranuclear mixed-metal acetylide complexes, CpWOs3(CO)u(C=CR) (R = Ph (la), nBu (lb)). Reaction of la with excess ditolylacetylene in refluxing toluene effects the scission of acetylide ligand to give CpWOs3-(CO)8(β3-CPh)[β4- η5-C(C2Tol2)2] (3). In contrast, treatment of complexes la and lb with alkynes containing electron-withdrawing groups produces the tetranuclear alkyne-acetylide coupling products CpWOs3-(CO)10[CR’CR’CCR] (R = Ph, R’ = CO2Me (4a), CO2Et (4b); R =nBu, R’ = CO2Et (4c)) and CpWOs3-(CO)9[CCRCR’CR’] (R = Ph, R’ = CO2Me (5a), CO2Et (5b); R =nBu, R’ = CO2Et (5c)). The structures of complexes la, 3, 4c, and 5a have been determined by single-crystal X-ray diffraction studies. Crystal data for la: space group P21/c; a = 9.057 (2), b = 9.197 (1), c = 29.065 (4) Å; β = 95.77 (1)°; Z-4; final R-0.055, Rw- 0.060, and GOF = 2.757. Crystal data for 3: space group PI; a = 10.351 (3), b = 12.576 (3), c = 18.098 Å; α = 94.44 (2), β = 91.07 (2), γ = 96.00 (2)°; Z = 2; final R = 0.041, Rw= 0.042, and GOF = 2.397. Crystal data for 4c: space group P21/n; a = 10.025 (2), b = 9.550 (5), c = 34.708 Å; β = 91.19 (2)°; Z = 4; final Rw= 0.070, R = 0.072, and GOF = 2.77. Crystal data for 5a: space group PI; a = 9.203 (3), b-11.580 (3), c = 14.937 Å; α = 91.57 (2), β = 100.85 (2), γ-102.23 (2)°; Z = 2; final R-0.033, Rw= 0.034, and GOF = 1.928. © 1990, American Chemical Society. All rights reserved.