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Syntheses and structures of rhodium-osmium clusters derived from the reaction of (μ-H)2Os3(CO)10with (η5-C5H5)Rh(CO)2

Journal of Organometallic Chemistry
Publication Date
DOI: 10.1016/0022-328x(90)85146-p


Abstract The reaction between (μ-H) 2Os 3(CO) 10 and (η 5-C 5H 5)Rh(CO) 2 in toluene at 90°C produces (η 5-C 5H 5)RhOs 2(CO) 9 (I) and (μ-H) 2(η 5-C 5H 5)RhOs 3(CO) 10 (II), as the principal products while the pentanuclear cluster (μ-H) 2(η 5-C 5H 5)RhOs 4(CO) 13 (III) is obtained in low yield. When added hydrogen is present during the reaction, replacement of the cyclopentadienide ligand by toluene occurs and the principal product is (μ-H) 3(η 6-C 6H 5CH 3)RhOs 3(CO) 9 (VI). Also produced in this reaction are (μ-H) 2(η 5-C 5H 5) 2Rh 2Os 2(CO) 7 (IV) and cluster II, but in low yields. In benzene in the presence of H 2, an analogous reaction occurs. The cyclopentadienide ligand is replaced by benzene to give (μ-H) 3(η 6-C 6H 6)RhOs 3(CO) 9 (VII) as the main product and clusters II and (μ-H) 4(η 5-C 5H 5)RhOs 3(CO) 9 (V) are formed in small yields. Conversion of clusters I and II to clusters IV and V, respectively, was achieved by bubbling H 2 through toluene solutions of I and II at 90°C. Cluster V is moderately unstable in solution, with significant decomposition occurring during the reaction. The molecular structures of clusters II, III, IV, and VII have been determined by single crystal X-ray diffraction studies. Clusters II, IV, and VII have tetrahedral metal cores, while the pentanuclear cluster III has an Os tetrahedral core which is edge bridged by a Rh atom. For compound II: space group P2 1/ n, a 8.120(3), b 14.932(3), c 16.277(3) Å, β 91.29(4)°, V 1972.9 Å 3, Z = 4, mol wt = 1020.73, ρ calcd 3.434 gm cm −3, and μ calcd 201.5 cm −1 for Mo- K α; 3885 independent reflections ⩾ 3σ( I); 4 ⩽ 2θ ⩽ 55° obtained at −35°C; final R f 5.7%, R wf 7.4%. For compound III: space group P2 1/ c, a 11.134(2), b 16.649(2), c 14.015(2) Å, β 109.98(1)°, V 2441.6 Å 3, Z = 4, mol wt = 1294.95, ρ calcd = 2.773 gm cm −3, and μ calcd 162.6 cm −1 for Mo- K α; 5695 independent reflections ⩾ 3σ( I); 4 ⩽ 2θ ⩽ 50° at −30°C; final R f 2.95%, R wf 4.0%. For compound IV: space group P2 1/ c, a 8.186(3), b 15.651(5), c 15.723(2) Å, β 97.32°, V 1998.25 Å 3, Z = 4, mol wt = 914.49, ρ calcd 3.038 gm cm −3, and μ calcd 143.34 cm −1 for Mo- K α; 3619 independent reflections ⩾ 3σ( I); 4 ⩽ 2θ ⩽ 55° at 25°C; final R f 3.3%, R wf 4.5%. For compound VII: space group R , a = b = c = 10.003(4) Å, α = β = γ = 92.16(3)°, V = 998.3 Å 3, Z = 2, mol wt = 1006.5, ρ calcd 3.34 gm cm −3, and μ calcd 214.8 cm −1 Mo- K α; 3017 independent reflections ⩾ 3σ( I); 4 ⩽ 2θ ⩽ 50° at 25°C; Final R f 4.4%, R wf 6.3%.

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