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Research has been conducted on the [PPN] (sub)3 [Re (sub)7 C(CO) (sub)21]. The reaction of this compound with Hg(NO (sub)3) (sub)2 .H (sub)2 O has been carried out in the dichloromethane producing the complex [PPN] (sub)4 [(Re (sub)7 C(CO) (sub)21 Hg) (sub)2] and the molecular and crystal structures of [PPN] (sub)4 have been determined and reported.

Research has been conducted on the decapping reagent mercury acetate in the methanol presence. Results indicate the isolation of the rhenium carbonyl fragment as a dinuclear complex with bridging acetate ligands.

A study was conducted to investigate the nucleation and growth of a carbon-supported bimetallic nanoclusters that are almost a homogeneous population. Fourier transformed magnitudes were carried out after treating carbon-supported cluster precursor at various temperatures in H2. Results indicated that nanoparticles subjected to a high-temperature treatment support an inverted structure wherein Pt is preferentially at the surface of the nanoparticle.

The facile decapping of a heptanuclear rhenium-iridium carbido carbonyl cluster and the capping reactions of the cluster with (triphenylphosphine)gold(I) derivatives are described. Both monogold and digold derivatives are formed with the addition of [AuP-Ph3]+ caps to the trianion. While the digold complex exhibits only one structure in both the solid and liquid states, several isomers of the monogold complex are seen in the solution.

Addition of Au(PPh3)Cl to (NEt4)3(HRe6C(CO)18) resulted into (NEt4)2(HRe6C(CO)18(AuPPh3)) while utilizing Au(PPh3)NO3 produced (NEt4)(HRe6C(CO)18(AuPPh3)2). The latter compound was deprotonated by NEt3 to produce (NEt4)2(Re6C(CO)18(AuPPh3)2), which can also be produced by treating either (NEt4)3(HRe6C(CO)18) or (NEt4)2(H2Re6C(CO)18) with 2 equiv of Au(PPh3)Cl in the presence of the strong base DBU.

The mixed-metal cluster IrRe2(mu-H)2(CO)9(eta5-C9H7) (1) was produced in 80% yield from the reaction of Ir(CO)(eta2-C8H14)(eta5-C9H7) with Re2(mu-H)2(CO)8. Variable-temperature 1H and 13C NMR spectra show that 1 undergoes migration of one hydride ligand between the two Ir-Re edges. Deprotonation of 1 in the presence of (PPN)(Cl) yields (PPN)(IrRe2(mu-H)(CO)9(eta5-C9H7)). The reaction of 1 with PPh3 produces IrRe2(mu-H)2(CO)8(PPh3)(eta5-C9H7), with phosphine ligand on one of the ruthenium centers, together with cluster fragmentation.

Neutral PtRu2C(CO) complexes were utilized as molecular cluster precursors for the synthesis of carbon-supported Pt-Ru nanoparticles. The formation of the bimetallic particles was dependent on the activation of the cluster precursors on the carbon support via narrow compositional and size distributions. Analysis of the resulting carbon-supported Pt-Ru nanoparticles via X-ray absorption fine structure spectroscopy also indicated the presence of a face-centered cubic packing structure.

A novel method of synthesizing thiolate derivatives was described. The design involved the reaction of cluster-complexed hydroxomercury compound, [Re7C(CO)21HgCl](super)2- with dithioerythritol/dithioreitol mixture as the dispersing material. Data indicated that the reactivity of the starting compound toward sulfhydryl groups was secondary to the high thiophilicity of mercury. The starting compound required interactions with sulfhydryl groups in order to yield derivatives that contain electron-dense markers.

A set of supported bimetallic catalysts, (Re7Ir-N), (Re7Ir-P), (Re5IrRe2-N) and (Re5IrRe2-P) was produced from two structural isomers (1 and 2) of the cluster compound (Z)2(Re7IrC(CO)23) (Z+ = NEt4+, N(PPh3)2+) by deposition into high surface area alumina. A combination of methods applied under temperature-controlled conditions revealed that the evolution of the final catalyst particle nanostructure depends on significant initial fragmentation of the cluster framework followed by preferential nucleation at iridium centers.

The synthesis and characterization of large rhenium and molybdenum carbonyl clusters containing either a group 6 or group 8 transition metal cap are described. The scheme involves the photochemical reaction of ReC(CO)19 (super 2-) with Mo(CO)6 and Ru3(CO)12. The capped-octahedral clusters were characterized by 13C NMR and electronic absorption spectroscopies and by cyclic voltammetry. Analysis showed that the molybdenum cap more readily undergoes cleavage than its ruthenium analogue.

Xenon lamp flash photolysis or continuous sunlamp irradiation of Re2(CO)10 with C60 in benzone creates a new species with IR(v-CO) bands at 2134, 2130, 2036 and 1993 cm (super-1). This product is termed C60(Re(CO)5)2 mainly due to a quantitative IR analysis of its formation stoichiometry. Parallel results are derived from the thermal reaction of C60 with a familiar source of rhenium pentacarbonyl radicals, namely (eta3-Ph3C) Re(CO)4 in the presence of CO. The compound C60(Re(CO)5)2 is not stable and decomposes to Re2(CO)10 and C60 with a first-order rate constant at room temperature. When the decomposition proceeds in the presence of carbon tetrachloride, Re(10)5Cl and C60 are the sole products obtained.

The addition of (Cp2Fe)(PF6) to a dichloromethane solution of (PPN)3(Re7C CO 21) yielded the compound (PPN)(Re7C CO21 P OPh 3). The structure of the compound is a monocapped octahedron, where Re7, the capping rhenium center of (Re7C CO 21 P OPh 3)1-, is coordinated to the phosphite and the three carbonyl ligands. The variable-temperature 13C NMR spectra of the anion at room temperature exhibited only one broad signal at delta 192.7 which is assigned to the single carbonyl ligand trans to the phosphite ligand.

Research has been conducted on the compound involving a rhenium-zinc bond. The structural characterization of this compound has been carried out and the results are described.

(Re(CO)(sub.3))(sub.4-n)(PtMe(sub.3))(sub.n)(OH)4, (n = 1-3), heterobimetallic hydroxy cubane complexes, are discussed based on synthesis and characterization. Studying the use of Re(sub.)3 as a starting material for synthesis of mixed metal hydroxy cubanes by adding the appropriate (ML(sub.n))(super.+) fragments was the focus of the project. The addition of a (PtMe(sub.3))(super.+) fragment is reported. This was extended to synthesis of analogous Re(sub.2)Pt(sub.2) and RePt(sub.3) compounds. One homometallic parent complex gives rise to a set of heterobimetallic hydroxy cubane derivatives.

The reaction of TlPF6 with the carbidoheptarhenate cluster (Re7C(CO)21)3- in dichloromethane was found to produce (Re7C(CO)21(mu3-Tl))2-, isolated in high yield as PPN+ or PPh4+ salts. The complex is strongly dissociated in acetone. The carbidoheptarhenate cluster (Re7C(CO)21Tl)2- reacted easily and cleanly with (triphenylphosphine)gold(I) chloride in dichloromethane to produce (Re7C(CO)21(AuPPh3))2- and TlCl.

The ethylidyne cluster (mu-H)3Os3(CO)9(mu3-CCH3) was synthesized by the addition of excess BH3.THF in CH2Cl2 to (mu-H)2Os3(CO)9(mu3-CCO) which involved the reduction of the unique carbonyl to a methyl group. The presence of ethylidine was also confirmed by X-ray crystal structure determination. The molecular structure of the cluster was described to be of triosmium symmetry made up of an Os3 triangle with three bounded carbonyls per Os atom. The observation was parallel with the result from an X-ray powder diffraction analysis.

Two methods to prepare new bimetallic heterogeneous catalysts for the reduction of perchlorate in water with dihydrogen are reported. The first method by by impregnating 5 wt % Pd on activated carbon powder with one of the complexes trans-[[Re[O.sub.2][(py-X).sub.4]].sup.+] (py-X = 4-substituted pyridine; X = H, Me, OMe, N[Me.sub.2]) showed evidence of facile formation of perrhenate from handling under ambient conditions while second method with 2 equiv of of dimethylaminopyridine per Re is especially active and stable up to pH 4.5.

A hexahapto C60 complex, Ru3-(CO)9(C60), was prepared by heating a mixture of C60 and Ru3(CO)12 in n-hexane under reflux. The compound was then characterized via single-crystal x-ray diffraction at 195 K. Consequently, it was found that the C60 exhibits arene-like coordination to the open face of a ruthenium cluster with the Ru3 triangle located centrally over a six-carbon ring in the fullerene system.

An analysis of the octanuclear, mixed-metal cluster compound (Re7IrC(CO)23)(super 2-) confirms the presence of an intramolecular nondegenerate rearrangement. This is significant owing to its symmetry which brings into question contemporary conceptual ideas on transition metal cluster rearrangements. The energetics can be compared to that of Re/Ir heterometallic surfaces' metal atom mobilities.