The molecular structures of the compounds Os3(μ3-S)2(CO)9, I, and Os3(μ3-S)2(CO)8PMe2Ph, II, have been determined by single-crystal X-ray diffraction methods. For I: space group P1, a = 6.745 (2) A, b = 9.503 (2) A, c = 13.592 (3) A, a = 82.42 (2), β = 84.58 (2), γ = 69.61 (2); V = 808.4 (4) A3, Z = 2, ρcalcd = 3.64 g/cm3. The structure was solved by a combination of Patterson and difference Fourier techniques. Full-matrix least-squares refinement on 2137 reflections (F02 ≥ 3.0σ(F)2) yielded the final residuals RF = 0.032 and RwF = 0.038. The molecule contains an open triangular cluster of three metal atoms with two equivalent metal-metal bonds Os(l)-Os(2) = 2.814 (1) A and Os(l)-Os(3) = 2.812 (1) A. There are two inequivalent triply bridging sulfido ligands, and each metal atom has three linear terminal carbonyl ligands. For II: space group P1, a = 9.316 (2) A, b = 11.346 (1) A, c = 13.592 (3), α = 71.65 (1), β = 71.63 (2), γ = 79.67 (1), V = 1164.5 (3) A3, Z = 2, pcaIcd = 2.84 g/cm3. This structure was solved by a combination of Patterson and difference Fourier techniques. Full-matrix least-squares refinement on 2834 reflections (& F02 ≥ 3.0σ(F)2) yielded the final residuals RF = 0.040 and RwF = 0.041. The structure of II is similar to that of I except that a PMe2Ph ligand has been substituted for an equatorially positioned carbonyl ligand on one of the exterior metal atoms of the cluster in a position trans to one of the metal-metal bonds. The two metal-metal bonds are significantly different. The one trans to the phosphine ligand is 2.856 (1) A while the other is 2.770 (1) A. The structures of I and II are compared with that of Os3(μ3-S)2(CO)8CS, III, which shows distortions in the metal-metal bonding that are similar to II. The cause of these distortions is attributed to a trans influence of the substituted ligand and is believed to be largely σ inductive in nature.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry