Stable cyclopropenylvinyl ligands insertion into a transient cyclopropenyl metal bond.

Treatment of the rhodium pincer complexes [RhCl(RPm)] (RPm = ,'-bis(di-R-phosphinomethyl)perimidinylidene, R = Ph, Cy) with triphenylcyclopropenium hexafluorophosphate affords rhodacyclobutadiene complexes. These in turn react with activated alkynes (RCCCOMe, R = H, COMe) to afford unusually stable cyclopropenylvinyls, implicating the intermediacy of σ-cyclopropenyl isomers. In contrast, treatment of [RhCl{py(NHPBu)-2,6}] with the same reagent instead results in double functionalisation (Ar) at the pincer backbone.

Poly(imidazolyliden-yl)borato Complexes of Tungsten: Mapping Steric vs. Electronic Features of Coordinating Ligands.

A convenient synthesis of [HB(HImMe)](PF) (ImMe = -methylimidazolyl) is decribed. This salt serves in situ as a precursor to the tris(imidazolylidenyl)borate Li[HB(ImMe)] pro-ligand upon deprotonation with BuLi. Reaction with [W(≡CCHMe-4)(CO)(pic)(Br)] (pic = 4-picoline) affords the carbyne complex [W(≡CCHMe-4)(CO){HB(ImMe)}].

A Metallabicycle From Thiocarbonyl-Cyclopropenium Coupling.

Addition of triphenylcyclopropenium bromide to the thiocarbonyl complex [RhCl(CS)(PPh ) ] affords novel bicyclic metalla-3-mercapto-thiapyrylliums [Rh(κ -C,S-C S Ph )(PPh ) X ] (X=Cl, Br) - heterocycles with no metal-free isolobal precedent. Halide abstraction with silver triflate (AgOTf) in acetonitrile affords the salt [Rh(κ -C,S-C S Ph )(NCMe) (PPh ) {Ag(OH ) }{Ag(OTf) }]-OTf which in turn reacts with sodium chloride to return [Rh(κ -C,S-C S Ph )(PPh ) Cl ].

C-H activation in bimetallic rhodium complexes to afford N-heterocyclic carbene pincer complexes.

The pro-ligands 1,8-bis(di-R-phosphinomethyl)-2,3-dihydroperimidine (RHPm, R = phenyl, cyclohexyl) react with [RhCl(CE)(PPh)] (E = O, S) to afford the bimetallic complexes [RhCl(CE)(μ-RHPm)] (E = O, S). Upon heating, these species undergo double C-H activation to afford the N-heterocyclic carbene (NHC) pincer complexes [RhCl(RPm)]. Reduction of [RhCl(CO)(μ-PhHPm)] with KC results in the bimetallic rhodium(0) complex, [Rh(μ-CO)(PhHPm)], with a formal Rh-Rh bond and a hydrogen-bonding interaction between rhodium and the central methylene group (C-H⋯Rh = 2.

Organometallic flow chemistry: complexes.

Photolysis under optimised flow conditions of metal carbonyls [{L}M(CO)] [{L}M(CO) = Cr(CO), Mo(CO), W(CO), Mn(CO)(η-CHMe), Re(CO)(η-CH)] in tetrahydrofuran (THF) conveniently affords the synthetically versatile and labile complexes [{L}M(CO)(THF)], thereby obviating many of the caveats associated with photochemical syntheses using either 'batch' or falling film techniques. Conversions were optimised and yields assayed by a combination of infrared spectroscopy and derivatisation as the corresponding triphenylphosphine complexes [{L}M(CO)(PPh)].

Advances in Transition Metal Seleno- and Tellurocarbonyl Chemistry.

In contrast to the ubiquity of transition-metal carbonyl, and (to a lesser extent) thiocarbonyl complexes, transition-metal complexes of carbon monoselenide L MCSe and monotelluride L MCTe remain scarce. The last few years, however, have seen notable steps towards expanding this chemistry, specifically with regards to new systematic studies on homologous sets of chalcocarbonyl complexes L MCE (E=O, S, Se, Te), the first reports of new bi- and polynuclear CSe and CTe bridging complexes and a confluence with metal carbido chemistry. Herein the properties, syntheses and reactions of these rare but fundamentally intriguing compounds are discussed.

A heterobimetallic cumulenic μ-carbido complex.

The reaction [W(CSe)(CO)2(Tp*)]NEt4 (Tp* = hydrotris(dimethylpyrazolyl)borate) with N-methyl-N-nitroso-4-toluenesulfonamide affords the nitrosyl complex [W(CSe)(CO)(NO)(Tp*)] which on treatment with excess [Re(THF)(CO)2(η-C5H5)] affords the cumuenic μ-carbido complex [WRe(μ-C)(CO)3(NO)(Tp*)(η-C5H5)] in addition to the μ-selenido complex [Re2(μ-Se)(CO)4(η-C5H5)2].

Bridging selenocarbonyl ligands: an open and shut case.

Novel bis(isoselenocarbonyl) complexes [W2Pt(μ-CSe)2(CO)4(L2)(Tp*)2] (L2 = cyclooctadiene, norbornadiene) eliminate the diene upon heating to provide [W2Pt(μ-CSe)2(CO)4(Tp*)2], in which the CSe ligands close to bridge W-Pt bonds in a σ-π mode that may be re-opened by addition of new ligands (CNR: R = tBu, C6H2Me3) to re-establish the isoselenocarbonyl coordination in [W2Pt(μ-CSe)2(CO)4(CNR)2(Tp*)2].

Bi- and Polynuclear Transition-Metal Carbon Tellurides.

The first examples of bi- and polynuclear tellurocarbonyl complexes were obtained from the reactions of [W(≡CTe)(CO) (Tp*)]NEt (Tp*=hydrotris(dimethylpyrazolyl)borate) with [MCl(PCy )]/TlPF (M=Cu, Au) or [Au Cl (μ-dppm)], which afford [WM(μ-CTe)(PCy )(CO) (Tp*)] (M=Cu, Au) and [WAu (μ-CTe)(μ-dppm)(CO) (Tp*)] (PF ) . In all cases it is specifically the tellurocarbonyl that assumes a bridging, but in each case distinct, role including examples of isotellurocarbonyl, semi-bridging and σ-π coordination and combinations thereof. Tetrametallic complexes bridged by C Te and C Te ligands are also described.

New binding modes for CSe: coinage metal coordination to a tungsten selenocarbonyl complex.

The new tungsten selenocarbonylate [NEt][W([triple bond, length as m-dash]CSe)(CO)(Tp*)] (Tp* = hydrotris(dimethylpyrazolyl)borate) reacts with group 11 reagents to provide σ-π or isoselenocarbonyl complexes of the form [WM(μ-CSe)(CO)(PR)(Tp*)] (M = Cu, Ag, Au; R = Ph, Cy; n = 1,3) depending on the phosphine stoichiometry or steric bulk. With [Cu(NCMe)]PF and 1,4,7-trithiacyclononane ([9]aneS) however, the tetrametallic species [WCu(μ-CSe)(CO)([9]aneS)(Tp*)](PF) is obtained in which one Cu coordinates to the W[triple bond, length as m-dash]C triple bond and two coordinate to the Se atom.