James E. Babin

Cluster synthesis—XXIII. The synthesis, structure and bonding of Fe4(CO)10(μ-CO)(μ4-S)2

Abstract The compound Fe4(CO)10(μ-CO)(μ4-S)2 (1) was synthesized in 38% yield by the UV induced decarbonylation of Fe(CO)5 in the presence of Fe3(CO)9(μ3-S)2. Compound 1 was characterized by a single-crystal X-ray diffraction analysis. Space group: Pccn, a = 6.603(1), b = 15.429(3), c = 17.292(4) A, Z = 4. The structure was solved by direct methods and was refined (807 reflections) to the final values of the residuals R = 0.043 and Rw = 0.054. The molecule consists of a planar array of four iron atoms with a quadruply bridging sulphido ligand on each side of the plane. The shortest metal-metal bond, 2.489(3) A, contains a bridging carbonyl ligand. Semi-bridging carbonyl ligands bridge the two adjacent metal-metal bonds, 2.532(2) A. The longest metal-metal bond, 2.605(2) A, has no carbonyl bridge. Compound 1 is unsaturated (by EAN rule) by the amount of two electrons. The two semi-bridged carbonyl-metal bonds in 1 are significantly shorter than those in the saturated cluster Fe2CO2(CO)11(μ4-S)2. A molecular orbital description which explains the differences in bonding between the two compounds is proposed.

Clusters containing carbene ligands—VI. The synthesis of higher nuclearity metal carbene cluster complexes by carbene ligand transfer. The synthesis and structures of [Ru4(CO)10{C(Ph)NMe2}(μ4-S)2] and [Ru4(CO)10{C(Ph)NMe2}(μ4-S)(μ5-S){W(CO)5}]

Abstract UV irradiation of a solution of [Ru4(CO)11(μ4-S)2] (1) and [W(CO)5{C(Ph)NMe2}] yielded the two new higher nuclearity carbene-containing cluster complexes [Ru4(CO)10{C(Ph)NMe2}(μ4-S)2] (2) 20%, and [Ru4(CO)10{C(Ph)NMe2}(μ4-S)(μ5-S){W(CO)5}] (3) 1%, by transfer of the carbene ligand from the tungsten complex to a ruthenium atom of the cluster. Compound 3 was obtained in 50% yield by UV irradiation of solutions of 2 and W(CO)6. Compounds 2 and 3 were both characterized by single-crystal X-ray diffraction methods. Crystal data for 1: Ru4S2O10NC19H11, M = 881.7, P21/n, (No. 14), a = 11.847(1), b = 11.773(2), c = 19.310(2) A, β = 104.685(8)°, V = 2597(1) A3, Dc = 2.26 g cm−3, Z = 4, λ(Mo-Kα) = 0.71069 A (graphite monochromator), μ = 24.3 cm−1. Methods: MITHRIL, difference Fourier, full-matrix least-squares. Refinement of 3383 reflections (F2 ⩾ 3σ(F2)), (1 ⩽ 2θ ⩽ 47°), gave R and Rw values of 0.032 and 0.043. Data/parameters ratio = 10.4, highest peak in final difference Fourier = 0.82 e A−3. Crystal data for 2: WRu4S2O15NC24H11, M = 1205.6, monoclinic, P21/n (No. 14), a = 15.268(1), b = 11.451(1), c = 19.121(2) A, β = 99.731(8)°, V = 3295.0(6) A3, Dc = 2.43 g cm−3, Z = 4, λ(Mo-Kα), graphite monochromator, μ = 56.2. Methods: MITHRIL, difference Fourier, full-matrix least-squares. Refinement of 4444 reflections (F2 ⩾ 3σ(F2)), (1 ⩽ 2θ ⩽ 48°), yielded R = 0.026, Rw = 0.032. Data/parameters ratio = 10.5. Compound 2 consists of a square-planar cluster of four ruthenium atoms with two quadruply bridging sulphido ligands and one terminally coordinated phenyl(dimethylamino)carbene ligand. Compound 3 consists of a cluster of 2 with a W(CO)5 group added to one of the quadruply bridging sulphido ligands.

Cluster condensations. The decarbonylation and dimerization of the sulphur-bridged cluster complexes Ru3(CO)8L(μ3-HC2Ph)(μ3-S) (L = CO and PMe2Ph). X-ray crystal structures of Ru3(CO)8(PMe2Ph)(μ3-HC2Ph)(μ3-S), [Ru3(CO)8(μ3-HC2Ph)(μ4-S)]2 and two isomers of [Ru3(CO)7(PMe2Ph)(μ3-HC2Ph)(μ4-S)]2

Abstract The compounds Ru3(CO)9(μ3-HC2Ph)(μ3-S) (1) and Ru3(CO)8(PMe2Ph)(μ3- HC2Ph)(μ3-S) (2) are decarbonylated when heated to 68°C and condense to form the dimers [Ru3(CO)8(μ3-HC2Ph)(μ4-S)]2 (3) and two isomers of [Ru3(CO)7(PMe2Ph)(μ3-HC2Ph)(μ4-S)]2 (4) and (5), respectively. Compounds 2, 3, 4 and 5 were characterized by single-crystal X-ray diffraction. Compounds 1 and 2 are open clusters that have a triply bridging sulphido ligand and a triply bridging HC2Ph ligand. Compounds 3, 4 and 5 are dimers of the decarbonylated forms of 1 and 2 that are joined by two S → Ru donor-acceptor bonds, one from each cluster to the other. Compounds 3 and 4 are centrosymmetric and were formed by the combination of enantiomers of the cluster precursors. Compound 5 is chiral but has overall C2 symmetry and was formed by the combination of enantiomerically similar monomeric units. Compound 5 is converted to 4 when heated, but the reverse does not occur.

The structure, bonding and transformation behaviour of iminium, aminocarbene and aminocarbyne ligands in triosmium cluster complexes

Abstract A summary of recent developments in the study of the reactions of tertiary amines with triosmium cluster complexes is presented. The relationships between iminium ion ligands, dimethylaminocarbene ligands and dimethylaminocarbyne ligands in several series of triosmium carbonyl cluster complexes are described. The transformations are dominated by binuclear CH activation processes. Novel ligand coordination modes were characterized by crystallographic methods.

Cluster synthesis—XX. The synthesis and crystal and molecular structure of Ru6(CO)17(μ4-η2-HC2Ph)(μ4-S)

Abstract The reaction of Ru5(CO)15(μ4-S) with HC2Ph at 68°C has resulted in the formation of the complex Ru5(CO)13(μ-CO)(μ4-η2-HC2Ph)(μ4-S), 1 in 60% yield. Compound 1 was found to react with Ru(CO)5 at 80°C to yield the enlarged cluster Ru6(CO)17(μ4-η2-HC2Ph)(μ4-S), 2 in 53% yield. Compound 2 was characterized structurally. Crystal data : Ru6SO17C25H6, M = 1216.80, monoclinic, P21/c (No. 14), a = 11.050(2), b = 22.503(5), c = 29.26(1) A, β = 90.80(3)°, V = 7276(4) A3, Dc = 2.27 g cm−3, Z = 8, λ(Mo-Kα) = 0.71073 A (graphite monochromator) μ = 24.9 cm−1. Methods: MITHRIL difference Fourier, full-matrix least-squares. Refinement of 4647 reflections (F2 ⩾ 3σ(F2)), (1°

The reactions of Mo2Ru(CO)7Cp2(η3-S) with phenylacetylene and Ru(CO)5

Abstract The reactivity of the heteronuclear cluster complex Mo2Ru(CO)7Cp2(η3-S) (1) toward HC2Ph was investigated and compared with the reactivity of the homonuclear complexes Ru3(CO)10(μ3-S) (2) and [Mo(CO)2Cp]2 (3). The reaction of 1 with HC2Ph yielded the new compound Mo2Ru(CO)2Cp2[μ3-η6-HCC(Ph)CHC(Ph)CHC(Ph)](μ3-S) (6), 15%. The compound contains a 1,3,5-triphenyldimetallahexatrienyl ligand formed by the head-to-tail coupling of three HC2Ph molecules. The C6-chain bridges one face of the triangular cluster. Three of the carbon atoms of the chain are π-bonded to one molybdenum atom. The other three carbon atoms are π-bonded to the ruthenium atom. The two ends of the chain are σ-bonded to the second molybdenum atom. When treated with CO at 100°C/25 atm, 6 eliminates 1,3,5,triphenylbenzene and reforms 1. At 125°C under nitrogen, the C6-chain in 6 is split at the C(3)C(4) bond to yield the two isomeric products Mo2Ru(CO)2Cp2[μ3-η3-HCC(Ph)CH][μ-η3-PhCC(H)CPh](μ3-S) (7) and Mo2Ru(CO)2Cp2[μ3-η3-HCC(Ph)CH][μ-η3-PhCC(Ph)CH](μ2-S) (8). Both products contain two dimetallaallyl ligands. One bridges the face of the cluster. The other bridges the MoMo edge. Compound 7 is converted into 8 at 125°C. When 1 is treated with Me3NO and HC2Ph at 25°C, the compound Mo2Ru(CO)5Cp2[μ-η4-PhCC(H)CC(H)Ph](μ3-S) (9) is formed in 11% yield. Compound 9 consists of an open cluster with a PhCC(H)CC(H)Ph ligand that bridges the open edge of the cluster. The four-carbon chain is π-bonded to a molybdenum atom while one carbon serves as the bridging link by bonding to the ruthenium atom. Compound 9 does not appear to be an intermediate en route to 6. When 1 is treated with Ru(CO)5 at 80°C, two higher nuclearity cluster products Mo2Ru4(CO)13(μ4-η2-CO)Cp2(μ4-S) (10) and Mo2Ru5(CO)14(μ4-η2-CO)2Cp2(μ4-S) (11) are formed. Compound 10 consists of a square pyramidal Mo2Ru4 cluster containing a quadruply bridging sulphido ligand on the square base. An Ru(CO)3 group bridges an RuRu edge of the square base. A dihapto quadruply bridging carbonyl ligand is bonded by its carbon atom to an MoRu2 triangle of the square pyramid and is bonded by its oxygen atom to the Ru(CO)3 group. Compound 11 is similar to 10 but has an additional Ru(CO)3 group bridging the second RuRu basal edge of the cluster and also has a second dihapto quadruply bridging carbonyl ligand. IR spectra show that the two quadruply bridging carbonyl ligands are vibrationally coupled by the appearance of two CO stretching absorptions at 1419 and 1453 cm−1. When 10 is heated to 80°C, it is converted to an isomer 12 by shifting the quadruply bridged carbonyl ligand to a terminal bonding mode. The cluster is transformed from an edge bridging form in 10 to a face capped form in 12.