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A series of N-heterocyclic carbene complexes [AuCl(NHC)] 1 [NHC: IPr, a; SIPr, b; IPrMe, c; IPrCl, d; IMes, e; SIMes, f; ItBu, g; IAd, h; and ICy, i] were reacted with chlorine gas or PhICl2 to afford [AuCl3(IPr)], 2a; [AuCl3(SIPr)], 2b; [AuCl3(IPrMe)], 2c; [AuCl3(IPrCl)], 2d; [AuCl3(IMes)], 2e; [AuCl3(SIMes)], 2f; [AuCl3(ItBu)], 2g; [AuCl3(IAd)], 2h; and [AuCl3(ICy)], 2i, respectively. Complete characterization by 1H and 13C NMR spectroscopies as well as by single-crystal X-ray diffraction was performed in order to discern electronic and structural differences between organogold(I/III) congeners. Calculations of the buried volume of the NHC ligand in complexes [AuCl3(NHC)] 2 were also performed in order to evaluate the steric hindrance of the NHC. These data permit comparisons with the related complexes [AuCl(NHC)] 1 and [AuBr3(NHC)].

Two new dicarbonyl N-heterocyclic carbene nickel(0) complexes of the type (NHC)2Ni(CO)2 (NHC = ICy, [N,N′-bis(cyclohexylimidazol)-2-ylidene (2), IMes [N,N′-bis(2,4,6-trimethylphenyl)imidazol)-2-ylidene] (3)) have been prepared by a substitution reaction of (NHC)Ni(CO)2 (NHC = ItBu [N,N′-bis(tert-butylimidazol)-2-ylidene], IAd [N,N′-bis(1-adamantylimidazol)-2-ylidene]) and 2 equivalents of ICy or IMes. Single-crystal X-ray analyses confirmed the monomeric 18-electron compositions of [(ICy)2Ni(CO)2] (2) and [(IMes)2Ni(CO)2] (3). The greater electron-donating properties of the NHC ligands compared to tertiary phosphines are also demonstrated through calorimetric studies and enabled the determination of average bond dissociation enthalpies for Ni−L (L = NHC and tertiary phosphine).

Complexes of iridium bearing NHC (NHC = N-heterocyclic carbene) ligands were synthesized and fully characterized. The series [(NHC)Ir(cod)Cl] were obtained by simple cleavage of [Ir(cod)Cl]2. The [(NHC)Ir(cod)Cl] complexes were reacted with excess carbon monoxide, leading to [(NHC)Ir(CO)2Cl]. The infrared carbonyl stretching frequencies of these were recorded to quantify the electronic parameter of NHC ligands. X-ray diffraction study results allow for determination of NHC steric parameters within this series. These data allow for comparison with other ligand families.

The reaction of GaCl3 with 1 equiv of NHC ligand (NHC = N-heterocyclic carbene) at room temperature in pentane yielding the corresponding 1:1 adduct [GaCl3(NHC)] is reported. Using IPr (N,N‘-bis(2,...

A series of (NHC)AuICl (1, NHC = N,N‘-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr); 2, NHC = N,N‘-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMes); 3, NHC = N,N‘-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene (SIPr); 4, NHC = N,N‘-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene (SIMes); 5, NHC = N,N‘-dicyclohexylimidazol-2-ylidene (ICy); 6, NHC = N,N‘-diadamantylimidazol-2-ylidene (IAd); 7, NHC = N,N‘-di-tert-butylimidazol-2-ylidene (ItBu)) complexes were reacted with LiBr to generate [(IPr)AuBr] (8), [(IMes)AuBr] (9), [(SIPr)AuBr] (10), [(SIMes)AuBr] (11), [(ICy)AuBr] (12), [(IAd)AuBr] (13), and [(ItBu)AuBr] (14). These (NHC)AuIBr complexes undergo oxidative addition of elemental bromine, leading to the new Au(III) complexes [(IPr)AuBr3] (15), [(IMes)AuBr3] (16), [(SIPr)AuBr3] (17), [(SIMes)AuBr3] (18), [(ICy)AuBr3] (19), [(IAd)AuBr3] (20), and [(ItBu)AuBr3] (21). Complete characterization by NMR spectroscopy and single-crystal X-ray diffraction were performed in order to discern structural diffe...

Two new gold(I) complexes bearing the bulky N-heterocyclic carbene IPr (IPr = bis(2,6-diisopropylphenyl)imidazol-2-ylidene) and respectively 2,3,4,6-tetra-O-acetyl-1-thio-β-d-pyranosatothiolato [(IPr)AuTgt (1)] and a saccharin ligand [(IPr)AuSac (2)] have been synthesized in good yield and are fully characterized by NMR spectroscopy and by inert-atmosphere MALDI-TOF. These complexes are well-behaved compounds analogous to gold drugs such as Auranofin and Solganol.

A novel homogeneous catalytic system has been developed for the regioselective hydrothiolation of alkynes based on CpNi(NHC)Cl complexes (NHC = N-heterocyclic carbene). The designed catalyst was efficient for the selective addition of a single ArS group to an alkyne and was suitable for the synthesis of vinylsulfides, without side reactions leading to bis(arylthio)alkenes. Furthermore, this catalytic system allowed for the S−H bond addition to alkynes to be performed with high regioselectivity (up to 31:1) and in good yields (61−87%). A mechanistic study showed that this reaction involved three steps: (1) a nickel-based substitution of chloride for the ArS group, (2) alkyne insertion into the Ni−S bond, and (3) protonolysis of the Ni−C bond. The intermediate CpNi(NHC)(SAr) complexes were unambiguously characterized by X-ray analysis.

A series of N-heterocyclic carbene (NHC)AgCl complexes [NHC = SIMes (1), IPr (2), SIPr (3), IPrMe (4), IMe (5), ICy (6), IAd (7), IsB (8), IDD (9), and TPh (10)] have been synthesized through reaction of the imidazolium chloride salts with Ag2O or by direct metalation of the corresponding imidazol-2-ylidene carbene in the presence of AgCl. All silver(I) complexes [(SIMes)AgCl] (11), [(IPr)AgCl] (12), [(SIPr)AgCl] (13), [(IPrMe)AgCl] (14), [(IMe)AgCl] (15), [(ICy)AgCl] (16), [(IAd)AgCl] (17), [(IsB)AgCl] (18), [(IDD)AgCl] (19), and [(TPh)AgCl] (20) have been spectroscopically and structurally characterized. The structure of these silver complexes is dependent on the halide and the solvent used for the synthesis. Adjusting these parameters has led to the previously reported complex, [(IMes)2Ag]+[AgCl2]- (21), and to a new silver complex, [(IMes)2Ag]+2[Ag4I6]2- (22).

The reaction of saturated and unsaturated imidazolium salts with nickelocene in refluxing THF results in the formation of NHC complexes of general formula CpNi(NHC)Cl (NHC = SIMes (2), IPr (3), SIPr (4)). This protonation of Cp2Ni was also tested using phosphonium salts, and the reaction of nickelocene with triethylphosphonium chloride leads to CpNi(PEt3)Cl (5). All compounds were characterized by NMR and X-ray crystallography. The catalytic activity of the NHC compounds was tested in aryl amination (Buchwald−Hartwig reaction) and in aryl halide dehalogenation reactions.

The synthesis and reactivity of palladium acetate/trifluoroacetate complexes stabilized by the presence of N-heterocyclic carbene (NHC) ligands are described. The structures and coordination characteristics of both (IPr)Pd(OAc)2 (1) and (IPr)Pd(OOCCF3)2(H2O) (2) were elucidated by spectroscopic and X-ray diffraction studies. The structure of 1 shows a novel coordination of the anions in a monomeric complex, with one acetate anion acting as a monodentate ligand while the second one coordinates through both oxygens. The NHC ligands in 1 and 2 are stable under acidic conditions. The complexes were used as precatalysts in the hydroarylation of alkynes. Using this simple protocol, a number of arenes react with various alkynes to produce stilbenes.

The synthesis and structural characterization of a series of palladium complexes bearing N-heterocyclic carbenes (NHC) as supporting ligands are described. The reaction of commercially available [Pd(allyl)Cl]2 and isolated or in situ generated NHC leads to monomeric palladium complexes where one NHC is bound to the metal center, as indicated by spectroscopic and single-crystal X-ray diffraction studies. The relative reactivity trend for these complexes as catalysts in aryl amination is discussed in terms of ligand steric properties, which vary as a function of imidazole-nitrogen substituents and perturbation resulting in modulation of ring planarity. The concept of buried volume is used to quantify the steric demand of each NHC in the corresponding complexes.

The hydrosilylation of various ketones is mediated by an imidazolium salt/Cu(I) salt system or by a well-defined (NHC)CuCl (NHC = N-heterocyclic carbene) catalyst precursor system. Reactions are conducted at room temperature. The synthesis and characterization of well-defined (NHC)CuCl complexes are described.

The synthesis and characterization by X-ray crystallography of the complexes [Ir(cod)(py)(L)]PF6 (L = IMes, 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (2); L = IPr, 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (3); L = ICy, 1,3-bis(cyclohexyl)imidazol-2-ylidene (4)) are reported. Complexes 2−4 have been employed as catalysts for transfer hydrogenation reactions from 2-propanol to a number of unsaturated substrates and their activity compared with that of the related cationic iridium(I) species [Ir(cod)(py)(SIMes)]PF6 (1), [Ir(cod)(py)(PCy3)]PF6 (5), and complexes formed in situ from [Ir(cod)(py)2]PF6 and diazabutadienes (RNCHCHNR, DAB-R; R = cyclohexyl, DAB-Cy; R = 2,4,6-trimethylphenyl, DAB-Mes; R = adamantyl, DAB-Ad; R = 2,4,6-trimethoxyphenyl, DAB-trimethoxyphenyl). All complexes tested were found to be active catalysts for transfer hydrogenation of ketones, with complex 4 displaying the highest activity. Complex 4 also exhibits moderate activity toward simple olefins and an aromatic nitro co...

The reaction of [Cp*RuCl]4 (1) with chiral nucleophilic carbene ligands L = 1,3-R2-imidazol-2-ylidene (R = (R)-1-cyclohexylethyl ((−)ICMe), (1S,2S,3S,5R)-isopinocamphenyl ((+)IiPCamp), (R)-α-methyl...

The new cationic iridium carbene complex [Ir(cod)(py)(SIMes)]PF6 (2) has been synthesized by reaction of [Ir(cod)(py)2]PF6 with SIMes. Complex 2 is an active hydrogenation catalyst capable of hydrogenating simple olefins at room temperature and atmospheric pressure of hydrogen.

Using an exchange reaction involving one PCy3 ligand in HRu(CO)Cl(PCy3)2 (1) for one IMes, a ruthenium−hydride complex HRu(CO)Cl(PCy3)(IMes) (2) has been prepared. Complex 2 is an active catalyst in the hydrogenation of alkenes. A TON of 24 000 h-1 has been obtained at 100 °C under 4 atm of hydrogen. Addition of HBF4·OEt2 as cocatalyst enhanced the catalytic activity.

Reaction enthalpies of the complex (COD)PtMe2 (1; COD = eta(4)-1,5-cyclooctadiene) with an extensive series of bidentate phosphines (dpype, dppf, diop, dppe, dppb, dppp, dpmcb, depe, dmpe, dcpce) have been measured by solution calorimetry. The relative stabilities of the resulting complexes PtMe2(PP) are determined by a combination of the donor and bite angle/ steric properties of the bidentate phosphine ligand. In general, good sigma donor ligands with small bite angles result in more thermodynamically stable complexes. Additionally, the molecular structures of 1, Pt(Me)(2)(pype) (2), Pt(Me)(2)(dppf) (8), Pt(Me)(2)(diop) (4), Pt(Me)(2)(dppe) (6), Pt(Me)(2)(dpmcb) (9), and Pt(Me)(2)(Et(2)dppp) (13) have been determined by single-crystal X-ray diffraction. No correlation between the thermochemical results and the structural parameters, e.g, M-P distance (as observed in other systems), is apparent in this class of complexes.

An orthometalated rhodium−carbene complex Rh(IMes)(H)(IMes‘)Cl (2) was obtained in high yield by reacting 2 equiv of a nucleophilic carbene, 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMes) with [Rh(COE)2Cl]2 (1). The X-ray structure of 2 shows an intramolecular C−H activation of one aryl ortho methyl group. Complex 2 reacts rapidly with H2 and CO at room temperature, leading to the formation of Rh(IMes)2(H)2Cl (3) and Rh(IMes)2(CO)Cl (4), respectively.

The exchange reaction of one phosphine ligand in Cl2(PCy3)2RuCHPh (1; Cy = cyclohexyl, C6H11) with the sterically demanding carbene ligands 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMes), 1,3-bis(4-methylphenyl)imidazol-2-ylidene (ITol), and 1,3-bis(4-chlorophenyl)imidazol-2-ylidene (IpCl) leads to the isolation of the new complexes (PCy3)(IMes)Cl2RuCHPh (2), (PCy3)(ITol)Cl2RuCHPh (3), and (PCy3)(IpCl)Cl2RuCHPh (4). Similarly, one IMes ligand can be substituted for one PCyp3 ligand in Cl2(PCyp3)2RuCHCHC(CH3)2 (5; Cyp = cyclopentyl, C5H9) to produce (PCyp3)(IMes)Cl2RuCHPh (6) in high yield. X-ray structure analysis of 6 confirmed a near-square-pyramidal coordination sphere around the metal center. Improved catalytic properties and thermal stability are observed for 2 and 6 in comparison to the parent 1 and 5.

The indenylidene−imidazolylidene complexes of ruthenium (IMes)(PR3)Cl2Ru(3-phenylindenylid-1-ene) and (IPr)(PR3)Cl2Ru(3-phenylindenylid-1-ene) (IMes = 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene, IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene, and R= Ph, Cy) were prepared and found to be efficient catalyst precursors for ring-closing metathesis.

The reaction of [Cp*RuCl]4 (1) with carbene ligands affords unsaturated Cp*Ru(L)Cl [Cp* = η5-C5Me5; L = 1,3-R2-imidazol-2-ylidene [R = cyclohexyl (ICy, 2); 4-methylphenyl (ITol, 3); 4-chlorophenyl (IpCl, 4); adamantyl (IAd, 5)] and 4,5-dichloro-1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMesCl, 6)] complexes 2−6 in high yield. Solution calorimetric investigations of this series provides a measure of the electron donor properties of all ligands, and comparisons are made with IMes [1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene] and the widely used PCy3. Structural information from single X-ray studies for complexes 2, 3, 5, 6, Cp*Ru(IMes)Cl (7), Cp*Ru(PCy3)Cl (8), and Cp*Ru(PiPr3)Cl (9) permits a quantitative treatment of steric parameters associated with these ligands.

The reaction of air-stable [RuCl2(COD)]x with Ph2PNMeNMePPh2 and NaOMe in sec-butyl alcohol under argon at 85 °C affords the ruthenium dihydride Ru(Ph2PNMeNMePPh2)2H2 (1) in high yield. 1 reacts with CO, O2, S8, and CH2Cl2, affording the complexes Ru(Ph2PNMeNMePPh2)2(CO) (2), Ru(Ph2PNMeNMePPh2)2(O2) (3), Ru(Ph2PNMeNMePPh2)2(S2) (4), and Ru(Ph2PNMeNMePPh2)2(H)(Cl) (5), respectively. 1 also reacts with PhC⋮CH, EtO2CC⋮CH, and C6H6 by C−H activation, yielding the complexes Ru(Ph2PNMeNMePPh2)2(H)(C⋮CPh) (6), Ru(Ph2PNMeNMePPh2)2(H)(C⋮CCO2Et) (7), and Ru(Ph2PNMeNMePPh2)2(H)(Ph) (8), respectively. The crystal structures of 3, 4 and 5 have been determined.

The enthalpies of reaction of Cp‘Ru(COD)Cl (Cp‘ = C5H5, C5Me5; COD = 1,5- cyclooctadiene) with a series of π-acceptor bidentate phosphines, leading to the formation of Cp‘Ru(PP)Cl complexes, have been measured by anaerobic calorimetry in THF at 30 °C. These reactions are rapid and quantitative. Structural studies have been carried out on two complexes in this series. The overall relative order of stability established for these complexes in both Cp and Cp* systems is (PhO)2PNMeNMeP(OPh)2 > Ph2PNMeNMeP Ph2 ≈ (C4H4N)2PCH2CH2P(NC4H4)2 > ((EtO2C)2C4H2N)2PCH2CH2P(NC4H2(CO2 Et)2)2. Present thermochemical data are discussed in terms of the nature of the bonding involved in the present complexes.

The enthalpies of reaction of Cp‘Ru(COD)Cl (Cp‘ = η5-C5H5 (Cp), η5-C5Me5 (Cp*); COD = cyclooctadiene) with a series of monodentate phosphite ligands, leading to the formation of Cp‘Ru(P(OR)3)2Cl, h...

The enthalpies of reaction of Cp'Ru(COD)Cl (1; Cp' = eta(5)-C5H5, eta(5)-C(5)Me(5); COD cyclooctadiene) with a series of para-substituted monodentate tertiary phosphine ligands, leading to the formation of Cp'Ru(PR(3))(2)Cl, have been measured by anaerobic solution calorimetry in THF at 30.0 degrees C. These reactions are rapid and quantitative. Structural studies have been carried out on three complexes in this series. The relative importance of phosphine steric vs electronic ligand parameters is more closely examined in terms of the presented quantitative thermochemical and structural information. Comparisons with enthalpy data in this and related organometallic systems are also presented.

The enthalpies of reaction of (BDA)Fe(CO)(3) (BDA = (C6H5)CH=CHO(CH3), benzylideneacetone) with a series of sterically demanding phosphine ligands, leading to the formation of(L)(2)Fe(CO)(3) complexes (L = phosphine) have been measured by solution calorimetry in THF at 50 degrees C. The range of reaction enthalpies spans some 7 kcal/mol. The overall relative order of stability established is as follows (PR(3); -Delta H, kcal/mol): PPh(3) < PCy(2)Ph < PCyPh(2) < PCy(3) < (PPr3)-Pr-i < PPh(2)Et < PBz(3). A quantitative analysis of ligand effect of the present and previously obtained data for L(2)Fe(CO)(3) complexes helps clarify the exact steric versus electronic ligand contributions to the enthalpy ofreaction in this system. Results of a single-crystal diffraction study for the complex diaxial-(PPh(2)Cy)(2)Fe(CO)(3) (2) show the molecule to be monoclinic, P2(1)/n, with a = 12.393(5) Angstrom, b = 15.811(6) Angstrom, c 18.029(7) Angstrom, alpha = gamma = 90 degrees, beta = 108.00(2)degrees, V = 43360(5) Angstrom(3), Z = 4, d(calcd) = 1.337 g cm(-1), n(obsd) = 3130, and R = 0.052. Electronic effects are overwhelmingly important in this system, yet a steric threshold of 135 degrees can be extracted from the QALE treatment which shows at which point steric factors begin to influence and contribute to the measured enthalpy of ligand substitution.

The synthesis and characterization of novel [(NHC)Pd(allyl)]X complexes (where NHC = N-heterocyclic carbene and X is a counteranion) are reported. The complexes with a general formula [(IPr)Pd(allyl)(S)]X (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene, X = BF4 (1) or PF6 (2)) have been structurally characterized by single-crystal diffraction studies and adopt a distorted square-planar geometry and include a coordinated solvent molecule (S). These cationic complexes promote the rapid and selective combination of 1,3-butadiene and amine into telomers. The active complexes are conveniently prepared in situ and display activity even at very low catalyst loadings. Operating temperatures are mild and can be as low as room temperature. Both secondary and primary amines are cleanly converted to the corresponding telomers.

The enthalpies of reaction of CpRu(COD)Cl (Cp = eta(5)-C5H5; COD = eta(4)-cyclooctadiene) with a series of bidentate ligands, leading to the formation of CpRu(PP)Cl complexes, have been measured by anaerobic solution calorimetry in THF at 30.0 degrees C. The overall relative order of stability established for these complexes is as follows: dppm < dmpm < dppb < dppe < dppp < dppv < depe < dmpe. Comparison between enthalpies of these reactions and those of monodentate phosphine ligands affords a quantitative treatment of ring strain enthalpies in these organoruthenium metallacyclic compounds. Significant ring strain energy is displayed in the four-membered metallacycle and is on the order of 13 kcal/mol. A single crystal X-ray diffraction study has been performed on one of the new complexes, CpRu(dppv)Cl [dppv = bis(diphenylphosphino)ethylene] (C31H27ClP2Ru.CH2Cl2, P1, a 10.344(2) Angstrom, b = 11.907(2) Angstrom, c 13.183(1) Angstrom, alpha 67.89(1)degrees, beta 76.52(1)degrees, gamma = 85.96(2)degrees, V = 1462.5(5) Angstrom(3), and Z = 2). Comparisons of the thermochemical data with the C(5)Me(5)-based system and related metallacyclic complexes are also presented.

Mononuclear palladium-allyl complexes bearing one N-heterocyclic carbene (NHC) ligand have been synthesized. These complexes offer a straightforward entryway into a number of catalytic cycles by simple action of a base.

The enthalpies of reaction of Cp*Ru(CH3CN)3OTf (Cp* = eta5-C5(CH3)5, OTf = O3SCF3) with a series of arenes have been measured by solution calorimetry. The results of this study are used to establish the following relative stability scale leading to the formation of Cp*Ru(arene)OTf complexes in THF (in kcal/mol): naphthalene, -1.7 +/- 0.1; benzene, -3.4 +/- 0.1; biphenyl, -3.6 +/- 0.1; toluene, -4.3 +/- 0.2; p-xylene, -4.6 +/- 0.2; (trimethylsilyl)benzene, -5.0 +/- 0.2; anisole, -5.4 +/- 0.2; mesitylene, -5.5 +/- 0.1; indole, -7.3 +/-0.2; NN-dimethylaniline, -7.5 +/- 0.1; p-bis(dimethylamino)benzene, -8.3 +/- 0.2. The solid-state structure of one of these arene complexes, Cp*Ru[C6H5(Si(CH3)3)]OTf, was determined by a low-temperature data collection X-ray crystallographic study. This investigation illustrates the presence of steric interactions between the phenyl TMS methyl groups and the Cp* methyl group and explains the small measured enthalpy of reaction. The enthalpies of arene substitution from Cp*Ru(CH3CN)3OTf span some 6.6 kcal/mol and vary as a function of the electron-donating ability of the arene. Factors affecting the Ru-arene bond energy are discussed, and thermodynamic comparisons with other organometallic systems are presented.

The reaction of anhydrous YCl{sub 3} with 2 equiv of the sodium salt of the anionic tripod complex [({eta}{sup 5}-C{sub 5}H{sub 5})Co((CH{sub 3}CH{sub 2}O){sub 2}P=O){sub 3}]{sup -} (L{sub OEt}) in tetrahydrofuran, under anaerobic conditions, leads to the high-yield formation of [L{sub OEt}Y((C{sub 5}H{sub 5})Co(P(=O)(OEt){sub 2}){sub 2}(P(=O)(OEt)- (O))){sub 2}YL{sub OEt}] (1). The complex has been characterized by standard analytical techniques. Nuclear magnetic resonance spectroscopic studies show a reduction of local symmetry of one of the ligands. To clearly illustrate the structural features of the isolated complex in the solid state, a low-temperature data collection X-ray cryatallographic investigation was performed. This study reveals 1 to be a dimer with bridging phosphonate oxygens (monoclinic system, space group P2{sub 1}/n, with a = 12.261 (4) A b = 21.110 (5) A, c = 19.529 (5) A, {Beta} = 94.77 (2){degrees}, V = 5037 (6) A{sup 3}, Z = 2, T = 102 (2) K, and D{sub calcd} = 1.477 g/cm{sup 3}). The structure also shows that one of the phosphonate ethyl groups has been cleaved in the course of the reaction. Analysis of the volatiles generated during the reaction clearly shows the formation of ethyl chloride, indicating that 1 is produced in conjunction withmore » the elimination of a phosphonate ethyl group in an Arbuzov-type dealkylation. 19 refs., 1 fig., 3 tabs.« less

Reaction of Cp*2Sm (Cp* = eta(5)-C5Me5) with excess hydrazine leads to the formation of a yellow crystalline material in high yield. The product was structurally characterized by a single-crystal diffraction study which shows the molecule to consist of a distorted-tetrahedron arrangement of samarium atoms with bridging hydrazido anions on each edge of the tetrahedron.

Complexes of (η6-arene)ruthenium bearing the carbene ligand 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMes) and 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) Ru(IMes)(Cl)2(η6-arene), Ru(IPr)(Cl)2(η6-arene), and [RuCCCPh2(IMes)(Cl)(η6-arene)]PF6 were prepared and found to be efficient catalyst precursors for ring closing olefin metathesis.

Synthese de [Ir 2 (CO) 3 Cl(μ-CO)(DPM) 2 ]A qui par reaction avec acetylenedicarboxylate de methyle et propiolate de methyle donnent le complexe du titre. Reactivite. Etude RX des structures