Conversion of C[triple bond]C to CO in alkynyl-metal complexes: oxidation of carbon chains capped by carbon-tricobalt clusters.

Treatment of Co(3)(mu(3)-CC[triple bond]CR)(mu-dppm)(CO)(7) with O(2) (air) in the presence of [FcH]PF(6) afforded Co(3){mu(3)-CC(O)R}(mu-dppm)(CO)(7) by the formal conversion -C[triple bond]C- + O-O --> >C-O + C[triple bond]O. In this way, complexes with R = Ph, Fc, and W(CO)(3)Cp, bis-clusters {Co(3)(mu-dppm)(CO)(7)}(2){mu(3):mu(3)-[[triple bond]C(O)(C[triple bond]C)C[triple bond]]}, {Co(3)(mu-dppm)(CO)(7)}(2){mu(3):mu(3)-[[triple bond]C(O)(C[triple bond]C)(x)C(O)C[triple bond, length as m-dash]]} (x = 1, 2), and {Co(3)(mu-dppm)(CO)(7)}(2){mu(3):mu(3)-[[triple bond]CC(O)C[triple bond, length as m-dash]CC(6)H(4)C[triple bond]CC(O)C[triple bond]]}, and heterometallic bis-clusters {Co(3)(mu-dppm)(CO)(7)}{mu(3):mu(3)-[[triple bond]CC(O)C[triple bond]CC[triple bond]]}{M(3)(mu-H)(3)(CO)(9)} (M = Ru, Os) have been prepared. Single-crystal XRD structure determinations of several products are reported together with that of precursor {Co(3)(mu-dppm)(CO)(7)}(2){mu(3):mu(3)-[[triple bond]C(C[triple bond]C)(2)C(6)H(4)(C[triple bond]C)(2)C[triple bond]]}.

Some reactions of an eta3-tetracyanobutadienyl-ruthenium complex.

In the eta(3)-butadienyl complex Ru{eta(3)-C(CN)(2)CPhC=C(CN)(2)}(PPh(3))Cp 1, which is formed from Ru(C[triple bond]CPh)(PPh(3))(2)Cp and tcne, a CN group reacts with MeO(-) to give the methoxy-amide Ru{NH=C(OMe)C(CN)=CCPh=C(CN)(2)}(PPh(3))Cp 2, in which the NH has displaced the C=C from the Ru centre with formation of a RuC(3)N ring. "Click addition" of azide to a CN group in 1 gives the oligomeric tetrazolato complex Ru{N(3)N[Na(OEt(2))]=CC(CN)=CCPh=C(CN)(2)}(PPh(3))Cp 3, also containing a RuC(3)N ring. Salt-elimination reactions of 3 with MeOTf, FeCl(dppe)Cp, RuCl(dppe)Cp* and trans-PtCl(2){P(tol)(3)}(2) result in selective substitution at one nitrogen atom of the RuC(3)N ring. Geometries of 1 and the anion in 3 were computed by DFT methods. Preferences for CN groups attacked in the nucleophilic and cycloaddition reactions of 1 are supported by NBO calculations. Alkylation of 1 in reactions with 1,2-dimethoxyethane gave two isomers of Ru{N(3)[CH(CH(2)OMe)(OMe)]N=CC(CN)=CCPh=C(CN)(2)}(PPh(3))Cp 8 and 9, differing in the sites of attachment of the alkyl group, likely by radical processes. The molecular structures of eight complexes are reported, including a re-determination of 1. Computed NMR chemical shifts are used to reassign the butadienyl carbon resonances in the (13)C NMR spectrum of 1.

Syntheses and molecular structures of some tricobalt carbonyl clusters containing 2,4,6-trimethyl-1,3,5-trithiane.

Reactions of CCo3 carbonyl clusters Co3(mu3-CR)(CO)9 with 2,4,6-trimethyl-1,3,5-trithiane (SMe3) have given Co3(mu3-CR)(mu3-SMe3)(CO)6 [R = H (1), C[triple bond]CSiMe3 (2)]. A small amount of the coupled-alkyne product Me3SiC2[Co2(CO)6]C2[Co2(mu-SMe3)(CO)4]C[triple bond]CSiMe3 (3) was isolated from the latter reaction. The reaction of Co3(mu3-CC[triple bond]CSiMe3)(mu3-SMe3)(CO)6 (2) with AuCl(PPh3) in the presence of NaOMe gave Co3{mu3-CC[triple bond]CAu(PPh3)}(mu3-SMe3)(CO)6 (4), which in turn reacts with Co3(mu3-CBr)(CO)9 in the presence of catalytic amounts of Pd(PPh3)4 and CuI to give {(OC)9Co3}(mu-C[triple bond]CC[triple bond]C){Co3(mu3-SMe3)(CO)6} (5). Further substitution of 5 with SMe3 gave symmetrical {Co3(mu3-SMe3)(CO)6}2(mu-C[triple bond]CC[triple bond]C) (6), also obtained from a reaction between {Co3(CO)9}2(mu-C[triple bond]CC[triple bond]C) and two equivalents of SMe3. Similar substitution of Co3{mu3-C(C[triple bond]C)2[Ru(dppe)Cp*]}(CO)9 with SMe3 gave Co3{mu3-C(C[triple bond]C)2[Ru(dppe)Cp*]}(mu3-SMe3)(CO)6 (7). In all of these compounds, the SMe3 ligand caps the basal face of the CCo3 cluster on the opposite side to the mu3-CR group. The three S donors occupy axial sites, with all CO groups being in equatorial sites. Reactions of Co3(mu3-CBr)(CO)9 with SMe3 gave only Co3(mu3-CX)(mu3-SMe3)(CO)6 [X = C(O)NMe2 (8), CO2H (9)]. The redox properties and electronic structure of the C4-bridged bis-cluster 6 have been investigated through a combination of cyclic voltammetry, IR spectroelectrochemistry and DFT calculations, with comparisons made with suitable model systems. Single-crystal X-ray diffraction structure determinations of 1, 2, 3, 4 and 8 are reported.

Transition metal alkynyl complexes by transmetallation from Au(C[triple bond]CAr)(PPh3) (Ar = C6H5 or C6H4Me-4).

Facile acetylide transfer reactions take place between gold(I) complexes Au(C[triple bond]CAr)(PPh3) (Ar = C6H5 or C6H4Me-4) and a variety of representative inorganic and organometallic complexes MXL, (M = metal, X = halide, L, = supporting ligands) featuring metals from groups 8-11, to afford the corresponding metal-alkynyl complexes M(C[triple bond]CR)Ln in modest to good yield. Reaction products have been characterised by spectroscopic methods, and molecular structure determinations are reported for Fe(C[triple bond]CC6H4Me-4)(dppe)Cp, Ru(C[triple bond]CC6H4Me-4)(dppe)Cp*, Ru(C=CCsF,)(l2-O2)(PPh3)Cp*, Ir(C-CC6H4Me-4)(eta2-O2)(CO)(PPh3), Ni(C[triple bond]CC6H4Me-4)(PPh3)Cp and trans-Pt(C[triple bond]CAr)2L2 (Ar = C6H5, L = PPh3; Ar = C6H4Me-4, L = PPh3, PMe3).

Tricyanovinylalkynyl-metal complexes: synthesis and some reactions.

Reactions of Group 8 metal ethynyls with tetracyanoethene afford tricyanovinylethynyl-metal derivatives, M{C[triple bond]CC(CN)=C(CN)(2)}(PP)Cp' [2; M = Ru, Os; PP = (PPh(3))(2), dppe; Cp' = Cp, Cp*; not all combinations]; a similar reaction occurs with the vinylidene RuCl(=C=CHPh)(PPh(3))Cp. Further replacement of a CN group in occurs with nucleophiles, while homo- and hetero-metallic derivatives are obtained by coordination of one of the remaining CN groups to other metal-ligand fragments.

Some transition metal complexes derived from mono- and di-ethynyl perfluorobenzenes.

Transition metal alkynyl complexes containing perfluoroaryl groups have been prepared directly from trimethylsilyl-protected mono- and di-ethynyl perfluoroarenes by simple desilylation/metallation reaction sequences. Reactions between Me(3)SiC[triple bond, length as m-dash]CC(6)F(5) and RuCl(dppe)Cp' [Cp' = Cp, Cp*] in the presence of KF in MeOH give the monoruthenium complexes Ru(C[triple bond, length as m-dash]CC(6)F(5))(dppe)Cp' [Cp' = Cp (); Cp* ()], which are related to the known compound Ru(C[triple bond, length as m-dash]CC(6)F(5))(PPh(3))(2)Cp (). Treatment of Me(3)SiC[triple bond, length as m-dash]CC(6)F(5) with Pt(2)(mu-dppm)(2)Cl(2) in the presence of NaOMe in MeOH gave the bis(alkynyl) complex Pt(2)(mu-dppm)(2)(C[triple bond, length as m-dash]CC(6)F(5))(2) (). The Pd(0)/Cu(i)-catalysed reactions between Au(C[triple bond, length as m-dash]CC(6)F(5))(PPh(3)) and Mo( identical withCBr)(CO)(2)Tp* [Tp* = hydridotris(3.5-dimethylpyrazoyl)borate], Co(3)(mu(3)-CBr)(mu-dppm)(CO)(7) or IC[triple bond, length as m-dash]CFc [Fc = (eta(5)-C(5)H(4))FeCp] afford Mo( identical withCC[triple bond, length as m-dash]CC(6)F(5))(CO)(2)Tp* (), Co(3)(mu(3)-CC[triple bond, length as m-dash]CC(6)F(5))(mu-dppm)(CO)(7) () and FcC[triple bond, length as m-dash]CC[triple bond, length as m-dash]CC(6)F(5) (), respectively. The diruthenium complexes 1,4-{Cp'(PP)RuC[triple bond, length as m-dash]C}(2)C(6)F(4) [(PP)Cp' = (PPh(3))(2)Cp (); (dppe)Cp (); (dppe)Cp* ()] are prepared from 1,4-(Me(3)SiC[triple bond, length as m-dash]C)(2)C(6)F(4) in a manner similar to that described for the monoruthenium complexes -. The non-fluorinated complexes 1,4-{Cp'(PP)RuC[triple bond, length as m-dash]C}(2)C(6)H(4) [(PP)Cp' = (PPh(3))(2)Cp (); (dppe)Cp (); (dppe)Cp* ()], prepared for comparison, are obtained from 1,4-(Me(3)SiC[triple bond, length as m-dash]C)(2)C(6)H(4). Spectro-electrochemical studies of the ruthenium aryl and arylene alkynyl complexes - and -, together with DFT-based computational studies on suitable model systems, indicate that perfluorination of the aromatic ring has little effect on the electronic structures of these compounds, and that the frontier orbitals have appreciable diethynylphenylene character. Molecular structure determinations are reported for the fluoroaromatic complexes , , , and .

A novel methodology for the synthesis of complexes containing long carbon chains linking metal centres: molecular structures of [Ru(dppe)Cp*]2(mu-C14) and [Co3(mu-dppm)(CO)7]2(mu3:mu3-C16).

Elimination of AuX(PR3)(X = halogen, R = Ph, tol) occurs readily in reactions between compounds containing C(sp)- or C(sp2)-X bonds and alkynyl or polyynyl gold(I) complexes; this reaction has been applied to the syntheses of complexes containing a variety of metal centres linked by C(n) chains (n up to 16).