Natasha N. Zaitseva

A novel methodology for the synthesis of complexes containing long carbon chains linking metal centres: molecular structures of {Ru(dppe)Cp*}2(μ-C14) and {Co3(μ-dppm)(CO)7}2(μ3:μ3-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).

Transition metal alkynyl complexes by transmetallation from Au(CCAr)(PPh3) (Ar = C6H5 or C6H4Me-4)

Facile acetylide transfer reactions take place between gold(I) complexes Au(CCAr)(PPh3) (Ar = C6H5 or C6H4Me-4) and a variety of representative inorganic and organometallic complexes MXLn (M = metal, X = halide, Ln = supporting ligands) featuring metals from groups 8–11, to afford the corresponding metal–alkynyl complexes M(CCR)Ln in modest to good yield. Reaction products have been characterised by spectroscopic methods, and molecular structure determinations are reported for Fe(CCC6H4Me-4)(dppe)Cp, Ru(CCC6H4Me-4)(dppe)Cp*, Ru(CCC6F5)(η2-O2)(PPh3)Cp*, Ir(CCC6H4Me-4)(η2-O2)(CO)(PPh3)2, Ni(CCC6H4Me-4)(PPh3)Cp and trans-Pt(CCAr)2L2 (Ar = C6H5, L = PPh3; Ar = C6H4Me-4, L = PPh3, PMe3).

A new approach to the synthesis of carbon chains capped by metal clusters

Abstract Reactions of Co3(μ3-CBr)(μ-dppm)(CO)7 with {Au[P(tol)3]}2{μ-(CC)n} (n=2–4) have given {Co3(μ-dppm)(CO)7}{μ3:μ3-C(CC)nC} [n=2 (1), 3 (2), 4 (3)] containing carbon chains capped by the cobalt clusters. Tetracyanoethene reacts with 2 to give {Co3(μ-dppm)(CO)7}2{μ3:μ3-C(CC)2C[C(CN)2]C[C(CN)2]C} (4). X-ray structural characterisation of 1, 3 and 4 are reported, that for 3 being the first of a cluster-capped C10 chain.

Reactions between ruthenium cluster carbonyls and 1,4-diphenylbuta-1,3-diyne

Abstract The complexes RuC(CCPh)CPhC(CCPh)CPh(CO)3(NMe3) (3), Ru2μ-C(CCPh)CPhC(CCPh)CPh(CO)6 (1), Ru2μ-[C(CCPh)CPh]2CO(CO)6 (2), Ru3(μ3-PhC2CCPh)(μ-CO)(CO)9 (4) and Ru4(μ4-PhC2CCPh)(CO)12 (5) have been isolated from reactions between PhC2C2Ph and Ru3(CO)12 or RU3(CO)10(NCMe)2. The molecular structures of complexes 1, 2, 3 and 5 have been determined from single-crystal X-ray studies. All complexes have precedents in similar products obtained from reactions involving mono-ynes; in the present cases, each alkyne fragment retains a phenylethynyl (PhCC) group as a non-coordinated substituent.

Preparation and thermolysis of complexes derived from some trinuclear ruthenium clusters and 1,4-diphenylbuta-1,3-diyne

Reactions between Ru 3 ( μ -dppm)(CO) 10 and PhC≡CC≡CPh in thf, in the presence of Me 3 NO, afford the complexes Ru 3 ( μ 3 -PhC 2 C≡CPh)( μ -dppm)( μ -CO)(CO) 7 ( 1 ) and Ru 3 ( μ -dppm) μ -C 4 Ph 2 (C≡CPh) 2 (CO) 6 ( 2 ). Complex 1 was also obtained from Ru 3 ( μ 3 -PhC 2 C≡CPh)( μ -CO)(CO) 9 ( 3 ) and dppm in thf on heating. Two of the complexes formed by thermolysis of 1 in xylene at 130°C were identified crystallographically as Ru 3 μ 3 -CPhCHCC(C 6 H 4 -2)( μ -dppm)(CO) 8 ( 4 ) and Ru 3 μ 3 -C 4 H 2 Ph 2 ( μ CO)(CO) 5 (dppm) ( 5 ). In 4 , fragmentation of the cluster and metallation of one of the diyne phenyl groups took place; the dppm ligand bridges two non-bonded Ru atoms. In 5 , partial hydrogenation of the diyne has occurred to give a 2 η 1 : η 4 : η 4 -butadiendiyl ligand, the dppm ligand adopting a chelating mode on one of the two Ru atoms which is η 4 attached to the hydrocarbon. In comparison, thermolysis of 3 gave Ru 4 ( μ 4 -PhC 2 C≡CPh)(CO) n ( n = 12 ( 6 ) and 14 ( 7 )). The former has a distorted C 2 Ru 4 octahedral core, while in the latter the Ru 3 cluster has fragmented to give a ruthenacyclopentadiene derivative in which the central C-C bond bridges an Ru 2 (CO) 8 group.

Syntheses and Crystal Structures of Some CCo3 Clusters Containing PPh3 or dppm Ligands

Molecular structural determinations are reported for six Co3C carbonyl cluster complexes containing tertiary phosphines, which have been isolated as by-products from a variety of reactions. Structural features are similar to those of related complexes already reported. Some discussion of apparent orientational preferences of the CH2 group of dppm ligands, which appear to enter into H-bonding interactions with amido or carboxylate substituents, is given. Appropriate comparisons are made with unsubstituted analogues.

A new bow-tie: Synthesis and X-ray structure of Co2Ru3(μ5-η2η2-PhC2C2Ph)(CO)14, which shows a remarkable and unusual asymmetry in the solid state

Abstract The reaction between Ru 3 ( μ 3 - η 2 -PhC 2 C 2 Ph)( μ -CO)(CO) 9 and Co 2 (CO) 8 affords the pentametal cluster Co 2 Ru 3 ( μ 5 - η 2 , η 2 -PhC 2 C 2 Ph)(CO) 14 in quantitative yield. The X-ray determined molecular structure consists of a Co 2 Ru 3 bow-tie cluster which is straddled by the PhC 2 C 2 Ph ligand, interacting with all five metal atoms via the two CC triple bonds, each of which is attached in the 2σ(2Ru), π(Co) bonding mode. Of the 14 CO groups, one bridges one Co-central Ru bond in one half of the molecule, while two are found semibridging the central RuCo and —Ru vectors in the other half of the molecule. In the solid state, there is thus a curious and remarkable asymmetry between the two halves of the molecule, although in solution at room temperature the molecule appears to be symmetrical.

Reactions of Ru(CCPh)(L2)Cp* (L2=dppm, dppe) with tetracyanoethene: cycloaddition, formation of monodentate dppm and dppmO complexes and migration of CN to ruthenium

Abstract The reaction of C2(CN)4 with Ru(CCPh)(dppm)Cp* in THF has given the anticipated tetracyanobuta-1,3-dien-2-yl complex Ru{C[C(CN)2]CPhC(CN)2}(dppm)Cp* (3). In benzene, η3-cyano-enyl complexes Ru{η3-C[C(CN)2]CPhCC(CN)2}(L)Cp* (L=dppm-P (4) or dppmO (5)) are formed, the latter by adventitious oxidation. On warming, complex 3 rearranges to the cyanoruthenium–ylid complex Ru(CN){C(CN)C[CPhC(CN)2]PPh2CH2PPh2}Cp* (6). A possible reaction sequence, involving a zwitterionic intermediate such as Ru(δ-)(CN){C(CN)C(δ+)CPhC(CN)2}(dppm-P)Cp* D, is discussed. Only the η1-dienyl complex 7 is obtained from Ru(CCPh)(dppe)Cp* and TCNE.

Ruthenium cluster carbonyls containing ligands derived from ferrocenylalkynes

Abstract Reactions of FcCCH (a), HCCCCFc (b) and FcCCCCFc (c) with Ru3(CO)10(NCMe)2 (all) and Ru3(μ-dppm)(CO)10 (b and c only) are described. Among the products, the complexes Ru3(μ3-RC2R′)(μ-CO)(CO)9 (R=H, R′=Fc 1, CCFc 2; R=R′=Fc 5), Ru3(μ-H)(μ3-C2CCFc)(μ-dppm)(CO)7 3, Ru3(μ3-FcC2CCFc)(μ-dppm)(μ-CO)(CO)7 6 and Ru3{μ3-C4Fc2(CCFc)2}(μ-dppm)(μ-CO)(CO)5 7 were characterised, including single-crystal structure determinations for 1, 3, 5 and 7; that of 7 did not differ significantly from an earlier study of a mixed CH2Cl2–C6H6 solvate.

Coupling of 1,3-diynes on a triruthenium cluster: reactions of Ru3(μ3-PhC2CCPh)(μ-dppm)(CO)8 with SiMe3CCCCSiMe3

Abstract Reactions between Ru3(μ3-PhC2CCPh)(μ-dppm)(CO)8 (1) and SiMe3CCCCSiMe3 have given the complexes Ru2(μ-dppm){μ-C(CCPh)CPhC(SiMe3)C(CCSiMe3)}(CO)4 (3), containing the two diynes coupled in head-to-head fashion, Ru3{μ3C(SiMe3)C(CCSiMe3)C(CPh)C(CPh)C(O)}(μ-dppm)(CO)7 (4), containing a metalla–indenone ligand formed by coupling of the two diynes with CO, and Ru4(μ4-PhC2CCPh)(μ4-SiMe3C2CCSiMe3)(μ-dppm)(μ-CO)(CO)8 (6), in which the two diynes are on opposite sides of a puckered Ru4 rhomboid. Also formed were thermolysis products of 1, Ru3{μ3-CPhCHCC(C6H4)}(μ-dppm)(CO)8 (5) (previously described) and Ru4(μ4-PhC2CCPh)(μ-dppm)(CO)10 (7), the dppm-substitution product of Ru4(μ4-PhC2CCPh)(CO)12. The X-ray determined structures of 3, 6 and 7 are reported.