Christopher S. Griffith

Reactions of metalloalkynes 3. Facile synthesis of pentanuclear ruthenium clusters. X-ray structures of [Ru5(μ5-CC)(η-C5H4R)2(dppm)(μ2-CO)2(CO)7] (R=H, CH3)

Abstract The reaction of the activated cluster compound, Ru3(CO)10(dppm), 1, with two ethyne-1,2-diyl compounds, [{Ru(CO)2(η-C5H4R)}2(μ-CC)], (2a, R=H; 2b, R=CH3) has resulted in a facile and high yielding synthesis of medium nuclearity cluster compounds, [Ru5(μ5-CC)(η-C5H4R)2(dppm)(μ2-CO)2(CO)7], (3a, R=H; 3b, R=CH3). The core of these compounds incorporate an open and accessible carbide ligand bound to a relatively rare example of a spiked butterfly metal framework. Both of these clusters, 3, have been characterised by X-ray crystallography.

Structural characterization of [Ru3Mo(μ3-η1-CC}(μ-CO)3(CO)2(η-C5H5)5]: a revisitation

Abstract A re-examination, crystallographically, of the structure of [MoRu 3 C 2 (CO) 5 (η-C 5 H 5 ) 4 ] by low temperature single crystal X-ray studies of two forms, one the previously recorded tetragonal P 4/ m dichloromethane solvate, and the other an un-solvated monoclinic P 2 1 / c phase, is recorded, being undertaken in an attempt to establish with greater certainty by such means the disposition of the molybdenum atom among the [M 3 (triangle)+M(pendant)] metal atom complement. The revised interpretation converges on [μ 3 -η 1 -{(η-C 5 H 5 )(CO) 2 MoC–C}Ru 3 (CO) 5 (η-C 5 H 5 ) 3 ] which ensures that the cluster is electron precise.

Reactions of metalloalkynes VII. Protonation of ruthenium ethyne-1,2-diyl complexes

The acid–base chemistry of some ruthenium ethyne-1,2-diyl complexes, [{Ru(CO)2(η-C5H4R)}2(μ2-CC)] (R=H, Me) has been investigated. Initial protonation of [{Ru(CO)2{η-C5H4R}}2(μ2-CC)] gave the unexpected complex cation, crystallised as the BF4 salt, [{Ru(CO)2(η-C5H4R}}3(μ3-CC)][BF4] (R=Me structurally characterised). This synthesis proved to be unreliable but subsequent, careful protonation experiments gave excellent yields of the protonated ethyne-1,2-diyl complexes, [{Ru(CO)2{η-C5H4R)}2(μ2-η1:η2-CCH)](BF4) (R=Me structurally characterised) which could be deprotonated in high yield to return the starting ethyne-1,2-diyl complexes.

Supramolecular interactions between hexabromoethane and cyclopentadienyl ruthenium bromides: Halogen bonding or electrostatic organisation?

The interaction between hexabromoethane and [CpRu(CO)2Br] (Cp = (η-C5H5), results in the deposition of two different isostoichiometric co-crystals, 2[CpRu(CO)2Br]·C2Br6, one crystallising in space group P (Z = 1) and the other in P21/n (Z = 4). These were produced in the reaction of HCBr3 and [(CpRu(CO)2)2] under indoor illumination, following a slight modification of the literature procedure. The origin of the hexabromoethane is as yet unknown but it appears to have been formed in the reaction rather than being an impurity in the bromoform. We have analysed the structures using the Hirshfeld surface approach and electrostatic potentials, supported by DFT theoretical calculations to better define the nature of intermolecular interactions in the solid state. The results indicate that the most significant interactions within both crystal forms arise not from the closest van der Waals contacts but, rather, from more distant interactions between the unsymmetrical electron distributions about the bromine atoms in the solvate and substrate molecules.

A re-investigation of the reaction of [RuCl2(CO)3]2 with C5H5(Me3Si) X-ray structure determination of [Ru(CO)3(η-C5H5)][fac-RuCl3(CO)3]

Abstract The reaction of [RuCl 2 (CO) 3 ] 2 with C 5 H 5 (SiMe 3 ) has been re-investigated. In our hands, in refluxing tetrahydrofuran, the reaction gives consistently [Ru(CO) 3 (η-C 5 H 5 )][ fac -RuCl 3 (CO) 3 ], 1 , and [RuCl(CO) 2 (η-C 5 H 5 )], 2 , in 68% and 12% yield respectively. The reaction of CO with commercially available hydrated OsCl 3 gives [OsCl 2 (CO) 3 ] 2 in 44% yield. The crystal structure of [Ru(CO) 3 (η-C 5 H 5 )][ fac -RuCl 3 (CO) 3 ] is reported; superlattice symmetry is observed.

The Chemistry of Transition Metal Ethyne-1,2-diyl Complexes

The chemistry and reactivity of ethyne-1,2-diyl compounds, LnM–CC–MLn, is reviewed. These complexes are simple analogues of organic alkynes, or dimetalloalkynes, and there appears to be no general route to the preparation of these complexes, except perhaps using acid/base methodology. Reactivity patterns, in general, mimic those of simple organic alkynes but have the added dimension of reactive M–C(sp) bonds that sometimes participate in the formation of multimetallic compounds with metal electrophiles.

Seemingly simple group 8 cyclopentadienyl dicarbonyl metal halides: From little things, interesting things grow

Single crystal X-ray studies are presented for the ‘piano-stool’ structures [CpRu,Os(CO)2Cl], [Cp′Ru(CO)2X] (X = Cl, Br, I (redetermination)), [Cp*Ru(CO)2Cl] (two phases), enabling the assembly of comparative geometric data for the [CpM(CO)2Cl] (M = Fe, Ru, Os), [Cp,Cp′Ru(CO)2X] (X = Cl, Br, I) and [CpxRu(CO)2Cl] (Cpx = Cp (η–C5H5), Cp′ (η–C5H4CH3), Cp* (η–C5CH3)5,CpPh (η–C5(C6H5)5)). In the [Cp′Ru(CO)2X] arrays, the methyl groups are found to consistently lie ‘eclipsed’ vis-a-vis the halogen substituents, with a concomitant tilt of the Cp ring; the reasons for this are explored theoretically.

Reactions of metalloalkynes.‡ The reaction of the ethyne-1,2-diyl complex, [{Ru(CO)2(η-C5H5)}2(µ-C≡C)], with [Mo2(CO)4(η-C5H5)2]. An example of µ3,η1-C≡C coordination of a carbide ligand

Reaction of [{Ru(CO)2(η-C5H5)}2(µ-C≡C)] with [Mo2(CO)4(η-C5H5)2] gave [MoRu2(µ2-CO)3[µ3-C≡C{Ru(CO)2(η-C5H5)}](η-C5H5)3] as the major product after chromatography and not the expected dimolybdenum ‘alkynyl’ adduct; this new complex contains a carbide (C2) ligand bound, in triply bridging mode to the MoRu2 triangle, through one carbon and the other in a monohapto fashion to the other ruthenium atom.