Methylene-bridged Complex Research Articles

(μ-Di-tert-butyl-silanediolato)bis-[bis-(η5-cyclo-penta-dien-yl)methyl-zirconium

The reaction of t-Bu2Si(OH)2 with two equivalents of Cp2Zr(CH3)2 produces the title t-Bu2SiO2-siloxide bridged dimer, [Zr2(CH3)2(C5H5)4(C8H18O2Si)] or [Cp2Zr(CH3)]2[μ-t-Bu2SiO2] (1), where one methyl group is retained per zirconium atom. The same product is obtained at room temperature even when equimolar ratios of the silanediol and Cp2Zr(CH3)2 are used. Attempts to thermally eliminate methane and produce a bridging methyl-ene complex resulted in decomposition. The crystal structure of 1 displays typical Zr-CH3 and Zr-O distances but the Si-O distance [1.628 (2) Å] and O-Si-O angle [110.86 (15)°] are among the largest observed in this family of compounds suggesting steric crowding between the t-Bu substituents of the silicon atom and the cyclo-penta-dienyl groups. The silicon atom lies on a crystallographic twofold axis and both Cp rings are disordered over two orientations of equal occupancy.

Intramolecular C–H Bond Activation in Bridged Dicyclopentadienyl Dimethyl Dinuclear Complexes

Photolysis of the doubly bridged dicyclopentadienyl dimethyl dinuclear complexes [(η5-C5H2R)2(SiMe2)2]M2(CO)4Me2 (M = Ru, R = H (2a), tBu (2b); M = Fe, R = H (2c)) in benzene yields the corresponding methylene-bridged complexes [(η5-C5H2R)2(SiMe2)2]M2(CO)2(μ-CO)(μ-CH2) (3a–c) and the M–M-bonded complexes [(η5-C5H2R)2(SiMe2)2]M2(CO)4 (1a–c). Irradiation of the analogous diethyl complex [(η5-C5H2R)2(SiMe2)2]Ru2(CO)4Et2 (4) affords only 1a. Unlike the case for the doubly bridged complexes, photolysis of the singly bridged dicyclopentadienyl dimethyl diruthenium complexes [(η5-C5H4)2(EMe2)]Ru2(CO)4Me2 (E = C (5a); E = Si (5b)) in benzene yields the corresponding “twisted” ruthenium methyl complexes with a cyclopentadienyl–Ru σ bond (η5,η5:η1-C5H4(EMe2)C5H3)[Ru(CO)2][Ru(CO)2Me] (6a,b) and the similar phenyl complexes (η5,η5:η1-C5H4(EMe2)C5H3)[Ru(CO)2][Ru(CO)2Ph] (7a,b), from reaction with the benzene solvent. Plausible mechanisms for the formation of the different types of products are proposed involving intra...

Rare‐Earth‐Metal Alkylaluminates Supported by N‐Donor‐Functionalized Cyclopentadienyl Ligands: CH Bond Activation and Performance in Isoprene Polymerization

Homoleptic tetramethylaluminate complexes [Ln(AlMe4)3] (Ln=La, Nd, Y) reacted with HCp(NMe2) (Cp(NMe2) =1-[2-(N,N-dimethylamino)-ethyl]-2,3,4,5-tetramethyl-cyclopentadienyl) in pentane at -35 °C to yield half-sandwich rare-earth-metal complexes, [{C5 Me4CH2CH2NMe2 (AlMe3)}Ln(AlMe4)2]. Removal of the N-donor-coordinated trimethylaluminum group through donor displacement by using an equimolar amount of Et2O at ambient temperature only generated the methylene-bridged complexes [{C5Me4CH2CH2NMe(μ-CH2)AlMe3}Ln(AlMe4)] with the larger rare-earth-metal ions lanthanum and neodymium. X-ray diffraction analysis revealed the formation of isostructural complexes and the C-H bond activation of one aminomethyl group. The formation of Ln(μ-CH2)Al moieties was further corroborated by (13)C and (1)H-(13)C HSQC NMR spectroscopy. In the case of the largest metal center, lanthanum, this C-H bond activation could be suppressed at -35 °C, thereby leading to the isolation of [(Cp(NMe2))La(AlMe4)2], which contains an intramolecularly coordinated amino group. The protonolysis reaction of [Ln(AlMe4)3] (Ln=La, Nd) with the anilinyl-substituted cyclopentadiene HCp(AMe2) (Cp(AMe2) =1-[1-(N,N-dimethylanilinyl)]-2,3,4,5-tetramethylcyclopentadienyl) at -35 °C generated the half-sandwich complexes [(Cp(AMe2))Ln(AlMe4)2]. Heating these complexes at 75 °C resulted in the C-H bond activation of one of the anilinium methyl groups and the formation of [{C5Me4C6H4NMe(μ-CH2)AlMe3}Ln(AlMe4)] through the elimination of methane. In contrast, the smaller yttrium metal center already gave the aminomethyl-activated complex at -35 °C, which is isostructural to those of lanthanum and neodymium. The performance of complexes [{C5Me4CH2CH2NMe(μ-CH2 )AlMe3}-Ln(AlMe4)], [(Cp(AMe2))Ln(AlMe4)2], and [{C5Me4C6H4NMe(μ-CH2)AlMe3}Ln(AlMe4)] in the polymerization of isoprene was investigated upon activation with [Ph3C][B(C6F5)4], [PhNMe2 H][B(C6F5)4], and B(C6F5)3. The highest stereoselectivities were observed with the lanthanum-based pre-catalysts, thereby producing polyisoprene with trans-1,4 contents of up to 95.6 %. Narrow molecular-weight distributions (Mw/Mn <1.1) and complete consumption of the monomer suggested a living-polymerization mechanism.

Diverse Coordination Modes and Transformations of Allenes at Adjacent Iridium/Osmium Centers

The methylene-bridged complex, [IrOs(CO)3(μ-CH2)(dppm)2][BF4] (dppm = μ-Ph2PCH2PPh2) (2), reacts with allene, resulting in C–C bond formation, to yield an equilibrium mix of two isomers of [IrOs(CO...

Facile Carbon–Carbon Bond Formation and Multiple Carbon–Hydrogen Bond Activations Promoted by Methylene-Bridged Iridium/Ruthenium Complexes

The methylene-bridged complex [IrRu(CO)4(μ-CH2)(dppm)2][BF4] (1; dppm = μ-Ph2PCH2PPh2) reacts with 1,1-dimethylallene and 1,2-butadiene, resulting in coupling of the cumulene and the bridging methylene group, yielding the complexes [IrRu(CO)4(κ1:κ1-Me2C═CCH2CH2)(dppm)2][BF4] (2) and [IrRu(CO)4(κ1:κ1-MeCH═CCH2CH2)(dppm)2][BF4] (3), respectively, in which the resulting hydrocarbyl fragment is chelating on iridium. Reaction of 1 with 1,1-difluoroallene initially yields the analogous insertion product [IrRu(CO)4(κ1:κ1-F2C═CCH2CH2)(dppm)2][BF4] (6), which slowly converts to [IrRu(CO)3(κ1:κ1-F2C═CCH2CH2CO)(dppm)2][BF4] (7) by carbonyl migratory insertion. Reaction of 1 with propadiene leads to the elimination of 1,3-butadiene and the formation of [IrRu(CO)4(dppm)2][BF4]. In the presence of excess 1,1-dimethylallene, compound 2 reacts further via multiple C–H bond activations to yield [IrRu(CO)3(κ1-C(CH2CH3)═C(CH3)2)(μ-κ1:η2-C≡CC(CH3)═CH2)(dppm)2][BF4] (8) with the elimination of H2, together with [IrRu(CO)3(κ1-...

Alkyne/Methylene Coupling at Adjacent Iridium/Osmium Centers: Facile Carbon−Carbon and Carbon−Oxygen Bond Formation

The methylene-bridged complex [IrOs(CO)4(μ-CH2)(dppm)2][CF3SO3] (dppm = μ-Ph2PCH2PPh2) (3) can be synthesized by the addition of diazomethane to [IrOs(CO)5(dppm)2][CF3SO3] (1) or [IrOs(CO)4(dppm)2][CF3SO3] (2). Reaction of 3 with dimethyl acetylenedicarboxylate (DMAD) leads to the insertion of the alkyne into the iridium−carbon bond, yielding both [IrOs(CO)4(μ-κ1:κ1-C(CO2CH3)═C(CO2CH3)CH2)(dppm)2][CF3SO3] (5) and [IrOs(CO)3(μ-κ1:κ1-C(CO2CH3)═C(CO2CH3)CH2)(dppm)2][CF3SO3] (6), each of which can be obtained as the exclusive product under either CO or an Ar purge, respectively. Hexafluorobutyne (HFB) fails to react with 3, but reacts with [IrOs(CO)3(μ-CH2)(dppm)2][CF3SO3] (4) yielding [IrOs(CO)3(μ-κ1:κ1-C(CF3)═C(CF3)CH2)(dppm)2][CF3SO3] (7). Reaction of 7 with diazomethane results in the insertion of a second methylene unit into the iridium−carbon bond, yielding [IrOs(CO)3(μ-κ1:κ1-CH2(CF3)C═C(CF3)CH2)(dppm)2][CF3SO3] (9), which can be characterized by NMR spectroscopy only at low temperatures owing to deinse...

Comparative Analysis of Electron‐Density and Electron‐Localization Function for Dinuclear Manganese Complexes with Bridging Boron‐ and Carbon‐Centered Ligands

Bonding in borylene-, carbene-, and vinylidene-bridged dinuclear manganese complexes [MnCp(CO)(2)](2)X (X = B-tBu, B = NMe(2), CH(2), C=CH(2)) has been compared by analyses based on quantum theory of atoms in molecules (QTAIM), on the electron-localization function (ELF), and by natural-population analyses. All of the density functional theory based analyses agree on the absence of a significant direct Mn-Mn bond in these complexes and confirm a dominance of delocalized bonding via the bridging ligand. Interestingly, however, the topology of both charge density and ELF related to the Mn-bridge-Mn bonding depend qualitatively on the chosen density functional (except for the methylene-bridged complex, which exhibits only one three-center-bonding attractor both in -nabla(2)rho and in ELF). While gradient-corrected functionals provide a picture with localized two-center X-Mn bonding, increasing exact-exchange admixture in hybrid functionals concentrates charge below the bridging atom and suggests a three-center bonding situation. For example, the bridging boron ligands may be described either as substituted boranes (e.g., at BLYP or BP86 levels) or as true bridging borylenes (e.g., at BHLYP level). This dependence on the theoretical level appears to derive from a bifurcation between two different bonding situations and is discussed in terms of charge transfer between X and Mn, and in the context of self-interaction errors exhibited by popular functionals.

Alkyne/Methylene Coupling Reactions at Adjacent Rh/Os Centers: Stepwise Transformations from C1- through C4-Bridged Species

Reaction of the methylene-bridged complex [RhOs(CO)3(μ-CH2)(dppm)2][CF3SO3] (dppm = μ-Ph2PCH2PPh2) with dimethyl acetylenedicarboxylate or hexafluorobutyne results in alkyne insertion into the Rh−CH2 bond, yielding [RhOs(CO)3(μ-η1:η1-RCC(R)CH2)(dppm)2][CF3SO3] (R = CO2Me (5), CF3 (6)). Carbonyl removal from each of these species results in a Rh-bound carbonyl being replaced by a triflate ion. Reaction of 5 with diazomethane results in CH2 insertion into the Rh−C(R) bond with accompanying C−H activation of the original osmium-bound CH2 group, yielding [RhOs(CO)3(μ-η1:η1-CH2C(R)C(R)CH)(μ-H)(dppm)2][CF3SO3] (R = CO2Me). Reaction of the alkyne-bridged species [RhOs(CO)3(μ-η1:η1-RCCR)(dppm)2][CF3SO3] (R = CO2Me) with diazomethane at −78 °C yields [RhOs(CO)3(μ-η1:η1-CH2C(R)CR)(dppm)2][CF3SO3] (12), which upon warming to ambient temperature, in the absence of diazomethane, undergoes alkyne deinsertion to yield [RhOs(CO)3(η2-RC⋮CR)(μ-CH2)(dppm)2][CF3SO3] (13). This species and the inserted product (12) appear to ...

Bridging Methylene to Bridging Acyl Conversion in Heterobinuclear Rh/Ru Complexes: Models for Adjacent-Metal Involvement in Bimetallic Catalysts

Protonation of the methylene-bridged complex [RhRu(CO)4(μ-CH2)(dppm)2][CF3SO3] (1) at −80 °C yields an asymmetrically bridged methyl complex in which the methyl ligand is σ-bound to Ru while being involved in an agostic interaction with Rh. Warming to −40 °C results in migration of the methyl group to a terminal site on Rh, and further warming to 0 °C results in migratory insertion to give the acetyl-bridged complex [RhRu(OSO2CF3)(CO)2(μ-C(CH3)O)(μ-CO)(dppm)2][CF3SO3] (4), in which the acetyl carbon is bound to Rh and its oxygen is bound to Ru. At ambient temperature one carbonyl is lost from 4 to give [RhRu(OSO2CF3)(CO)2(μ-C(CH3)O)(dppm)2][CF3SO3] (5). Carbon-13 NMR spectroscopy and the X-ray structures of both acetyl-bridged products suggest significant carbene character in the acyl carbon. Attempts to obtain methyl and subsequently acetyl species by methylene insertion into metal−hydride bonds of the appropriate precursors [RhRu(X)(CO)4(μ-H)(dppm)2][X] (X- = CF3SO3-, BF4-) failed, with these hydride sp...

Methylene-to-Acetyl Conversion in Heterobinuclear Rh/Os Complexes: Models for Oxygenate Formation by Bimetallic Fischer−Tropsch Catalysts

Protonation of the methylene-bridged complex [RhOs(CO)3(μ-CH2)(μ-CO)(dppm)2][CF3SO3] with triflic acid at −80 °C yields the methyl complex [RhOs(CO)4(μ-CH3)(dppm)2][CF3SO3]2 (1) in which the methyl group is primarily bound to Os while involved in an agostic interaction with Rh. Warming this species to −20 °C results in methyl migration to a terminal site on Rh, yielding [RhOs(CH3)(CO)2(μ-CO)2(dppm)2][CF3SO3]2 (2), and subsequent warming to ambient temperature results in migratory insertion to yield the acetyl-bridged [RhOs(CF3SO3)(CO)2(μ-C(CH3)O)(μ-CO)(dppm)2][CF3SO3] (3). Replacement of the coordinated triflate anion in 3 by CO and PMe3 occurs at low temperature to give [RhOs(L)(CO)2(μ-C(CH3)O)(μ-CO)(dppm)2][CF3SO3]2 (L = CO (4), PMe3 (5a)). Warming the PMe3 adduct results in transformation of the acetyl group, which is C-bound to Rh in 5a, to a group that is C-bound to Os in 5b. One carbonyl in 3 is labile and is readily lost, yielding [RhOs(CF3SO3)(CO)2(μ-C(CH3)O)(dppm)2][CF3SO3] (6). Attempts to obtain the above methyl or acetyl species by reaction of the hydride-bridged species [RhOs(X)(CO)3(μ-H)(μ-CO)(dppm)2][X] (X = CF3SO3 (7a), BF4 (7b)) with diazomethane were unsuccessful.

Methylene-Bridged Complexes of Rhodium/Ruthenium as Models for Bimetallic Fischer−Tropsch Catalysts: Comparisons with the Rh/Os and Ir/Ru Analogues

The cationic heterobinuclear complex [RhRu(CO)3(μ-H)2(dppm)2][X] (1) is prepared by protonation of the monohydride species [RhRu(CO)3(μ-H)(dppm)2] (dppm = μ-Ph2PCH2PPh2; X- = BF4-, CF3SO3-). Treatment of 1 with carbon monoxide affords the tetracarbonyl complex ion [RhRu(CO)4(dppm)2][X] (2), which yields the methylene-bridged product [RhRu(CO)4(μ-CH)2(dppm)2][X] (3), upon treatment with excess diazomethane at −78 °C. Reaction of 3 with trimethylamine-N-oxide results in CO removal, affording the methylene-bridged tricarbonyl species [RhRu(CO)3(μ-CH)2(dppm)2][X] (4). Although compound 3 is unreactive toward further treatment with CH2N2, compound 4 reacts readily with diazomethane, yielding a mixture of uncharacterized products. Compounds 3 and 4 react with PMe3 to yield [RhRu(PMe3)(CO)3(μ-CH)2(dppm)2][X] (5), in which coordination of PMe3 at the unsaturated Rh center occurs. The structures of compounds 2, 3, and 5 have been determined by X-ray methods. Comparisons of the reactivity of compound 3 with that of the analogous Ir/Ru and Rh/Os complexes toward diazomethane are presented.

Methylene-Bridged Heterobinuclear Complexes of Iridium and Ruthenium: Models for Bimetallic Fischer−Tropsch Catalysts

The heterobinuclear complexes [IrRu(CO)3(μ-H)(dppm)2] (1) and [IrRuH(CO)3(μ-CO)(dppm)2] (2) are prepared from the reactions of [PPN][HRu(CO)4] with [IrCl(dppm)2] and [Ir(CO)(dppm)2][Cl], respectively (PPN = (Ph3P)2N; dppm = Ph2PCH2PPh2). Protonation of both monohydride species yields the dihydride [IrRu(CO)3(μ-H)2(dppm)2][BF4] (3), which under an atmosphere of carbon monoxide gives [IrRu(CO)4(dppm)2][BF4] (4). The methylene-bridged complex [IrRu(CO)3(μ-CH2)(μ-CO)(dppm)2][BF4] (5) is obtained by the reaction of compound 4 with diazomethane at ambient temperature. Although 5 does not react further with diazomethane under these conditions, carbonyl abstraction using trimethylamine oxide in the presence of CH2N2 yields the methylene-bridged ethylene adduct [IrRu(C2H4)(CO)3(μ-CH2)(dppm)2][BF4] (6). Labeling studies indicate that the majority of the 13C-labeled methylene group of 5 remains in the bridging site, with approximately 10% of the label incorporated into the ethylene formed. Compound 6 can also be pre...

Titanium Complexes Having Chelating Diaryloxo Ligands Bridged by Tellurium and Their Catalytic Behavior in the Polymerization of Ethylene

A series of titanium complexes having tellurium-bridged chelating bis(aryloxo) ligands, [TiX2{2,2‘-Te(4-R-6-R‘-C6H2O)2}]2 (5b, X = Cl, R = Me, R‘ = tBu; 6a, X = OiPr, R = R‘ = H; 6b, X = OiPr, R = Me, R‘ = tBu), were prepared. 5b and 6b were determined by X-ray crystallography to have chloro- and isopropoxo-bridged dimeric structures. The structural data for these complexes indicated that the Ti−Te coordination bonds were stronger than the similar Ti−S coordination bonds in the corresponding sulfur-bridged complexes. The reaction of (C5R5)TiCl3 (R = H, Me) with 2,2‘-Te(4-R-6-R‘-C6H2OLi)2 gave monocyclopentadienyl derivatives, (C5R5)TiCl{2,2‘-Te(4-Me-6-tBu-C6H2O)2} (7, R = H; 8, R = Me). The monomeric four-legged piano-stool geometry of 8 was revealed by X-ray analysis. Upon addition of methylaluminoxane (MAO), these complexes catalyzed the polymerization of ethylene. The activities of the tellurium-bridged complexes were found to be significantly higher than those of the corresponding methylene-bridged complex.

Me2Si(η5-C5H4)2-Bridged Dinuclear Ruthenium Complexes: X-ray Crystal Structures of [Ru2{μ-(η5-C5H4)2SiMe2}(Cl)2(CO)4] and [Ru2{μ-(η5-C5H4)2SiMe2}(μ-Br)(CO)4][BF4

The treatment of the binuclear tetracarbonyl complex [Ru2{μ-(η5-C5H4)2SiMe2}(μ-CO)2(CO)2] (1) with HBF4 in dichloromethane leads to the electrophilic addition of one proton to yield the bridging hydride complex [Ru2{μ-(η5-C5H4)2SiMe2}(μ-H)(CO)4][BF4] (2). Complex 1 also reacts with Li[BHEt3] to afford the bridging methylene complex [Ru2{μ-(η5-C5H4)2SiMe2}(μ-CH2)(μ-CO)(CO)2] (3). Binuclear complexes [Ru2{μ-(η5-C5H4)2SiMe2}(X)2(CO)4] (X = Cl (4a), Br (4b), and I (4c)) have been synthesized in good yields from the reaction of complex 1 with N-chlorosuccinimide (X = Cl) and X2 (X = Br, I) in CH2Cl2. The structure of complex 4a which has been determined by X-ray crystallography shows a three-legged piano-stool geometry around each ruthenium atom linked by the bridging Me2Si(η5-C5H4)2 group. The cyclopentadienyl rings which are coordinated in a η5 fashion are rotated in opposite directions around the Si−C(bridgehead) bond, leading to the trans arrrangement of the metal fragments and giving rise to a long ruthenium−ruthenium distance (6.120(6) Å). Complex 4c has been used as a precursor in a series of halide and carbonyl substitution reactions. The reaction of 4c with the cuprate derivative Li[CuMe2] in THF leads to the exchange of both iodide anions to give the dimethyl complex [Ru2(μ-(η5-C5H4)2SiMe2}(CH3)2(CO)4] (5). The treatment of complex 4c with AgBF4 in refluxing acetonitrile leads to halide abstraction to afford the cationic complex [Ru2{μ-(η5-C5H4)2SiMe2}(CO)4(NCMe)2][BF4]2 (9). The analogous reaction of complexes 4a−c with AgBF4 in CH2Cl2 or acetone at room temperature gives the cationic double-bridged derivatives [Ru2{μ-(η5-C5H4)2SiMe2)}(μ-X)(CO)4][BF4] (10a−c). The X-ray crystal structure of 10b shows the two ruthenium moieties bridged by a halogen atom, forcing a cisoid arrangement in the molecule. Irradiation of a solution of 4c and PCy3 in THF leads to carbonyl substitutions to yield the monocarbonyl complex [Ru2{μ-(η5-C5H4)2SiMe2}(I)2(CO)2(PCy3)2] (6c). Analogous isocyanide carbonyl substituted complexes [Ru2{μ-(η5-C5H4)2SiMe2}(I)2(CNR)x(CO)4-x] (R = CH2Ph, x = 1 (7a), x = 2 (7b), x = 3 (7c), x = 4 (7d); R = Cy, x = 1 (8a), x = 2 (8b), x = 3 (8c), x = 4 (8d)) have been obtained by UV irradiation of 4c and the corresponding isocyanide in THF, depending on the ligand:complex ratio.

Reactions of Alkylidene-Bridged Cobaltadithiolene Complexes with Lewis Bases. Formation of M−S Sulfur Ylide Structure

The reactions of a malonate (C(COOMe)2)-bridged complex with Lewis bases give novel sulfur ylide (M−S sulfur ylide) complex due to the cleavage of Co−C bond as determined by X-ray sturucture analysis. Acetate (CHCOOEt)- and methylene-bridged complexes, on the other hand, reacted with Lewis bases via an SN2 type reaction to give unstable M−S sulfur ylide complexes and stable six-membered-ring complexes.

Photochemical C–H bond activation of the diruthenium bridging methylene complex, Cp2Ru2(μ-CH2)2(CO)2: insertion of norbornadienes into the methylene C–H bond and unprecedented intramolecular H–D exchange between the two methylene units

Two photochemical reactions of the diruthenium bis-µ-methylene complex (η5-C5H5)2Ru2(µ-CH2)2(CO)2 are described: (i) insertion reaction of norbornadiene into the methylene C–H bonds leading to (η5-C5H5)2Ru2(µ-CHR′)2(CO)2 (R′ = 5-exo-norbornenyl) and (ii) H exchange between the two methylene units, involve µ-methylidyne intermediates generated via C–H bond activation of the µ-methylene ligand.

Chemistry of Bridging Ketene from Facile Carbonylation of a Ditungsten Methylene Complex with No Metal−Metal Bond

The reaction of Cp(CO)3W- (Cp = η5-C5H5) with CH2I2 in CH3CN at −20 °C gives the dinuclear acetylide complex Cp2(CO)6W2(μ-C⋮C) (2). When the same reaction is carried out in methanol at −20 °C, a dinuclear ketene complex, Cp2(CO)5W2(μ,η1,η2-CH2CO) (5), is isolated. The oxygen atom of the ketene unit in 5 is weakly coordinated to one of the tungsten metal centers. Upon dissolution in CH3CN at room temperature, complex 5 transforms to 2. A bridging methylene complex, Cp2(CO)4[P(OMe)3]2W2(μ-CH2) (4a), has been isolated, and its facile carbonylation gives a different ketene complex, Cp2(CO)2[P(OMe)3]2W2(μ,η1,η1-CH2CO)(μ-CO) (6a), in CH3CN. Treatment of 5 with CO affords Cp2(CO)6W2(μ-CH2CO) (8), which, upon reacting with H2O, ROH (R = Me, Et, PhCH2), and i-PrNH2, generates mononuclear complexes Cp(CO)3WCH2COOH (9), Cp(CO)3WCH2COOR (12a−c), and Cp(CO)3WCH2CONH(i-Pr) (14), respectively. The more stable Cp‘ (Cp‘ = C5H4Me) analogues 2‘, 5‘, and 8‘ are also prepared. An experiment using a mixture of 5 and 5‘ to affo...

Specific alkylidene coupling of the labile diruthenium bridging methylene complex [(η-C5H5)2Ru2(μ-CH 2)(CO)2(MeCN)] with diazoalkanes (N2CR2) giving alkenic products

Reaction of the labile diruthenium bridging methylene complex [(η-C 5 H 5 ) 2 Ru 2 (µ-CH 2 )(µ-CO)(CO)(MeCN)] with diazoalkanes (N 2 CR 1 R 2 ) results in specific C–C coupling to give alkenic products, i.e. the bridging alkenyl complex [(η-C 5 H 5 ) 2 Ru 2 (µ-CH CHR 1 )(µ-H)(CO) 2 ] (R 2 = H) or alkene CH 2 CR 1 R 2 (R 1 , R 2 ≠ H).

The reactions of [Pd2Cl2(μ-PP)2] (PP = dppm, dmpm) with Et2NC≡CNEt2in methylene chloride solution: X-ray crystal structures of [Pd2Cl2(μ-CH2)(μ-dppm)2] and hexakis(diethylamino)benzene, C6(NEt2)6

The binuciear palladium(I) complex, [Pd2Cl2(μ-dppm)2] (dppm = bis(diphenylphosphino)methane), has been shown to react with bis(diethylamino)acetylene, Et2NC≡CNEt2, in methylene chloride solution to yield two isolable products, the known methylene-bridged complex, [Pd2Cl2(μ-CH2)(μ-dppm)2], and hexakis(diethylamino)benzene, C6(NEt2)6, both of which have been characterized crystallographically. The source of the bridging methylene group in [Pd2Cl2(μ-CH2)(μ-dppm)2] has been shown to be the methylene chloride solvent. A mechanism that accounts for the formation of the two isolable products is proposed. The complex, [Pd2Cl2(μdmpm)2] (dmpm = bis(dimethylphosphino)methane), was similarly found to react with Et2NC≡NEt2in methylene chloride solution to yield [Pd2Cl2(μ-CH2)(μ-dmpm)2], which was identified spectroscopically. Key words: acetylene, palladium, cyclooligomerization, aminoacetylene, hexakis(diethylamino)benzene.

The redox chemistry of dimethyl(octaethylporphyrinato)ruthenium. Isolation of the bridging methylene complex Ru(OEP-N-.mu.-CH2-)(CH3)+

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe redox chemistry of dimethyl(octaethylporphyrinato)ruthenium. Isolation of the bridging methylene complex Ru(OEP-N-.mu.-CH2-)(CH3)+Jeffery W. Seyler, Lance K. Safford, Phillip E. Fanwick, and Charles R. LeidnerCite this: Inorg. Chem. 1992, 31, 9, 1545–1547Publication Date (Print):April 1, 1992Publication History Published online1 May 2002Published inissue 1 April 1992https://doi.org/10.1021/ic00035a001RIGHTS & PERMISSIONSArticle Views75Altmetric-Citations16LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (385 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts