Colin R. Eady

Improved syntheses of the hexanuclear clusters [Ru6(CO)18]2–, [HRu6-(CO)18]–, and H2Ru6(CO)18. The X-ray analysis of [HRu6(CO)18]–, a polynuclear carbonyl containing an interstitial hydrogen ligand

The X-ray analyses of two crystalline modifications, (I) and (II), of [N(PPh3)2][HRu6(CO)18] are reported, together with improved synthetic routes to this and the related clusters [Ru6(CO)18]2– and H2Ru6(CO)18. Crystals of (I) are triclinic, space group P1–, with a= 18.083(4), b= 19.101(4), c= 19.238(5)A, α= 117.70(4), β= 78.13(2), γ= 97.05(2)°, and Z= 4. Crystals of (II) are monoclinic, space group P21/n, with a= 33.82(8), b= 52.55(10), c= 9.832(2)A;, β= 92.66(2)°, and Z= 12. Least-squares refinement using diffractometer data (Mo-Kα) has given an R of 0.068 1 for 9 165 reflections for (I) and an R of 0.23 (Ru only) for 1 485 reflections for (II). The unit cell in (I) contains two independent molecules of [HRu6(CO)18]–, cluster (1) which is ordered and cluster (2) which is disordered between two sites (2A) and (2B) that are related by a non-crystallographic two-fold axis. The combined evidence of the X-ray analyses, 1H n.m.r. studies, i.r. [v(CO)] spectra, and variable-temperature 13C n.m.r. is only consistent with the hydrogen ligand lying inside the Ru6 octahedron.

The preparation of Ru5C(CO)15 and Os5C(CO)15

Abstract The carbido carbonyl complexes Ru 5 C(CO) 15 and Os 5 C(CO) 15 have been prepared and characterised.

[HRu6(CO)18]–: a ruthenium anion having an interstitial H-ligand. X-Ray crystal structures of two modifications

Reaction of [Ru3(CO)12] with [Mn(CO)5]– gives [Ru6(CO)18]2– which on acidification is converted into [HRu6(CO)18]–; this monoanion has spectroscopic properties and an X-ray structure consistent with the H ligand lying at the centre of an octahedron (approximating to Oh symmetry) of ruthenium atoms.

Products from the reaction of M3(CO)12 (M = Ru or Os) with water

Reaction of the carbonyl Ru3(CO)12 with water leads to the formation of polynuclear hydrides α-H4Ru4(CO)12, α-H2Ru4(CO)13; the corresponding reaction with Os3(CO)12 yields the complexes (H)(OH)Os3(CO)10, H2Os4(CO)13, H4Os4(CO)12, H2Os5(CO)16, H2Os5(CO)15, H2Os6(CO)18 and H2Os7(CO)19C.

Chemical syntheses with metal atoms

Abstract Metal evaporation syntheses of [Cr(C7H7)(C7H10)], [Cr(C7H8)(PF3)3], metal carbonyls, and anhydrous metal acetylacetonates are described.

The chemistry of polynuclear compounds. Part 31. Synthesis of undecacarbonylhydridotriosmate(1–) and its reaction with octadeca-carbonylhexaosmium to give a carboxylate-bridged anionic enneaosmium species

Treatment of [Os3(CO)12] with KOH in MeOH gives the anion [Os3H(CO)11]–; low-temperature 13C n.m.r. spectroscopy reveals that the structure of this hydrido-cluster is the same as that established for [Fe3H(CO)11]– in the solid state; at higher temperatures, fluxional behaviour similar to that previously observed for [Fe3H(CO)11]– occurs. The [Os3H(CO)11]– anion reacts with [Os6(CO)18] to produce the Os9, anion [(OC)10HOS3(µ-CO2)Os6(CO)17]– which contains an Os3, and Os6 unit linked by a CO2, group. Carbon- 13 n.m.r. spectroscopic studies reveal that the C atom of the CO2 linkage arises from the [OS6(CO)18].

Isocyanide substitution in octadecacarbonyl hexaosmium

Abstract The crystal structures of the two isocyanide substituted hexaosmium clusters, Os6 (CO)18 (CNC6 H4 Me)2 and Os6 (CO)16 (CNCMe3)2 are reported. The former involves both a triple bridging and a terminal isonitrile group whilst the latter is related to the parent carbonyl Os6 (CO)18. The molecular structures are discussed in terms of electronic inequivalences within the metal cluster framework.

Chemical synthesis with metal atoms: the reaction of iron with some conjugated dienes

Abstract Complexes have been obtained by the reaction of iron atoms with butadiene or styrene at - 196°C followed by treatment with ligands such as CO or (MeO) 3 P.

Chemical synthesis with metal atoms: preparation and X-ray structure of (η5-cycloheptadienyl)-(η5-cycloheptatrienyl) iron. A bifluxional molecule

[Fe(η5-C7H7)(η5-C7H9)] has been prepared by cocondensation of iron vapour with cycloheptatriene; an X-ray analysis shows a sandwich structure with open faces of the two η5-systems skew to each other, and in solution two types of fluxional behaviour are exhibited.

Chemical synthesis with metal atoms. The preparation and structure of cyclo-octadiene trifluorophosphine complexes of chromium. The crystal structure of (η5-cyclo-octa-1,3-dienyl)hydridotris(trifluorophosphine) chromium

The reaction of cyclo-octa-1,5-diene (1,5-cod), PF3, and chromium atoms produces [Cr(1,5-cod)(PF3)4](1) and [Cr(C8H11)(PF3)3H](2). The use of 1,3- rather than 1,5-cod produces only (2) under the same conditions. Complex (1) is readily converted into (2) by heating (90 °C, in toluene). The preparation of [Cr(1,5-cod)(CO)4](3) from 1,3- or 1,5-cod is also described. The structure of (2) was determined by X-ray crystallography. The compound crystallizes in the orthorhombic space group Pbca with a= 13.452(3), b= 14.419(4), c= 15.268(3)A, and Z= 8. The final R value was 0.065 9 for 1 699 observed reflections. The structure is retained in solution below –80 °C, but is shown by 13C and 1H n.m.r. spectroscopy to become fluxional upon warming. There are two distinct exchange processes; one results in pairwise coalescence of the 13C and 1H resonances; the other finally leads to a set of only two 1H signals with an intensity ratio of 8 : 4, thus indicating equivalence of the eight ring positions.