- Solvation of Anions in Water-Acetonitrile Mixtures
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The enthalpies of transfer from water to mixtures with acetonitrile (ΔH0t) for various anions reach maxima at a mole fraction of acetonitrile (χAN) ca. 0.3, and decrease linearly and in parallel in the intermediate region.A linear relation is found between ΔH0t at χAN 0.3 and the hydration enthalpies for halide and symmetrical ions.This finding and the parallel χAN dependence of ΔH0t in the intermediate region are interpreted on the basis of the linear relation between the solvation enthalpies and the entropies for the halide ions.The reduction in the hydrogen-bonding interaction extending beyond the primary hydration sphere (ΔHINT) for halide ions in the mixtures is estimated based on a modified Eley and Evans hydration model.At χAN 0 to ca. 0.3, ΔHINT compared with that in water agree well with the observed ΔH0t, indicating that the increase in ΔH0t is due to the reduction in the outer hydration sphere interaction.However, they split gradually at χAN above 0.3.The adequacy of the modifications in the treatment of the solvation enthalpy cycle in the mixtures is re-evaluated from the structural viewpoint.The exothermic change in the intermediate region may be attributable to the reduction in the cavity formation energy.
- Miyaji, Kiyoshi,Morinaga, Kenichi
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- Carba-closo-dodecaborates – Synthesis, Structure, and Energetics
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A full set of analytical data of salts (e.g., Me3NH+, Cs+, Ag+) bearing nido-[B11H14]–, closo-[CHB11H11]–, and chlorinated congener [CHB11Cl11]– is reported. Structures and energetics of [CHB11H11–nXn]– and [B12XmH12–m]2– (n = 5, 11; m = 0, 12; X = halogen, CH3, CF3) and their protonated and silylated forms are studied. A direct correlation between theoretical calculated NICS values, gas-phase acidities, and experimentally determined 13C NMR shifts is discussed.
- Hepp, Alexander,Labbow, René,Rei?, Fabian,Schulz, Axel,Villinger, Alexander
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- Syntheses of tricyanofluoroborates M[BF(CN)3] (M = Na, K): (CH3)3SiCl catalysis, countercation effect, and reaction intermediates
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Potassium tricyanofluoroborate, K[BF(CN)3], which is the starting material for tricyanofluoroborate room-temperature ionic liquids [N. Ignatev et al. J. Fluorine Chem., submitted] was obtained on a molar scale (140 g) from Na[BF4] and (CH3)3SiCN with a purity of up to 99.9%. The initial product of the reaction that was catalyzed by (CH3)3SiCl was Na[BF(CN)3]·(CH3)3SiCN that was characterized by multinuclear NMR and vibrational spectroscopy, elemental analysis, differential scanning calorimetry, and single-crystal X-ray diffraction. Na[BF(CN)3]·(CH3)3SiCN was converted to K[BF(CN)3] via a simple extraction protocol. The catalytic effect of (CH3)3SiCl was evaluated and some intermediates of the reaction, including the isocyanoborate anion [BF(NC)(CN)2]-, were identified using multinuclear NMR and vibrational spectroscopy. K[BF2(CN)2] also reacted with (CH3)3SiCN in the presence of (CH3)3SiCl, to result in K[BF(CN)3]. The interpretation of the experimental observations was supported by data derived from density functional theory (DFT) calculations. In addition, the influence of selected countercations of the tetrafluoroborate anion on the progress of the (CH3)3SiCl-catalyzed reaction was studied. The fastest reaction was observed for Na[BF4], while the conversion of [BF4]- to [BF(CN)3]- was slower with the countercation K+. Li[BF4] and [Et4N][BF4] were converted under the reaction conditions applied to Li[BF2(CN)2] and [Et4N][BF2(CN)2] only.
- Sprenger, Jan A. P.,Landmann, Johannes,Drisch, Michael,Ignatev, Nikolai,Finze, Maik
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- Fe4 cluster and a buckled macrocycle complex from the reduction of [(dmgBF2)2Fe(L)2] (L = MeCN, tBuiNC)
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We report the syntheses, X-ray structures, and reductive electrochemistry of the FeII complexes [(dmgBF2)2Fe(MeCN) 2] (1; dmg = dimethylglyoxime, MeCN = acetonitrile) and [(dmgBF 2)Fe(tBuiNC)2] (2; tBuiNC = tert-butylisocyanide). The reaction of 1 with Na/ Hg amalgam led to isolation and the X-ray structure of [(dmgBF2)2Fe(glyIm)] (3; glyIm = glyimine), wherein the (dmgBF2)2 macrocyclic frame is bent to accommodate the binding of a bidentate apical ligand. We also report the Xray structure of a rare mixed-valence Fe4 cluster with supporting dmg-type ligands. In the structure of [(dmg2BF2)3Fe3(1/2dmg) 3Fe(O)6] (4), the (dmgBF2)2 macrocycle has been cleaved, eliminating BF2 groups. Density functional theory calculations and electron paramagnetic resonance data are in accordance with a central FeIII ion surrounded by three formally Fe IIdmg2BF2 units.
- Rose, Michael J.,Winkler, Jay R.,Gray, Harry B.
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- Tris(5-methylpyrazolyl)methane: Synthesis and properties of its iron(II) complex
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The new ligand, tris(5-methylpyrazolyl)methane (1), has been prepared by the reaction of n-butyl lithium with tris(pyrazolyl)methane followed by trimethylation of the tetralithiated species with methyl iodide. The BF 4-, ClO4-, and BPh 3CN- salts of the Fe(II) complex of this ligand were also synthesized. The X-ray crystal structure of the BF4- complex (2) at 100 K had Fe-N bond lengths of 1.976 A, indicative of a low spin Fe(II) complex, while at room temperature, the structure of this complex had a Fe-N bond distance close to 2.07 A, indicative of an admixture of approximately 50% low-spin and 50% high-spin. The solid-state structure of the complex with a ClO4- counterion was determined at 5 different temperatures between 173 and 293 K, which allowed the thermodynamic parameters for the spin-crossover to be estimated. Moessbauer spectra of the BF4- complex further support spin-state crossover in the solid state with a transition temperature near 300 K. UV-visible spectroscopy and 1H NMR studies of 2 show that the transition temperature in solution is closer to 400 K. No spin-crossover was observed for [Fe(1) 2]2+·2BPh3CN-. The results allow the separation of effects of groups in the 3-position from those in the 5-position on tpm ligands, and also point toward a small cooperative effect in the spin-crossover for the Fe(II) complex.
- Goodman, Margaret A.,Nazarenko, Alexander Y.,Casavant, Barbara J.,Li, Zhanjie,Brennessel, William W.,Demarco, Michael J.,Long, Gen,Goodman, M. Scott
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- Metathetical reactions in the system Na(K)PF6 - LiBF4 - Aprotic media
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19F NMR spectroscopy, X-ray powder diffraction, elemental analysis, and ab initio quantum chemical calculations were used to study metathetical reactions between potassium or sodium hexafluorophosphate and lithium tetrafluoroborate in a mixture of propylene carbonate (PC) - dimethyl carbonate (DMC). It was shown that the increase in size of the cations in the second coordination sphere from Na+ to K+ results in an increase of the equilibrium conversion. This is in agreement with the influence of the cation size on the solubility of tetrafluoroborates in the media investigated.
- Plakhotnyk, Andriy V.,Tarasova, Lidiya D.,Ernst, Ludger,Schmutzler, Reinhard
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- Calorimetric study of alkali metal tetrafluoroborates
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Adiabatic calorimetric investigation of the low-temperature heat capacity of sodium tetrafluoroborate as well as a DSC study of the thermal behavior of potassium tetrafluoroborate and of lithium tetrafluoroborate and its hydrates were carried out. Temperatures and enthalpies of phase transitions at temperature above ambient were determined for potassium tetrafluoroborate, lithium tetrafluoroborate, and lithium tetrafluoroborate mono- and trihydrate. It was demonstrated that lithium tetrafluoroborate has only one phase transition in the solid at 300 K.
- Gavrichev,Sharpataya,Gorbunov
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- Improved procedures for the generation of diborane from sodium borohydride and boron trifluoride
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Improved procedures for the generation of diborane by the reaction of NaBH4 in triglyme or tetraglyme with the BF3 adducts of di-n-butyl ether, tert-butyl methyl ether, monoglyme, dioxane, and tetrahydropyran were developed. In these
- Kanth, Josyula V. B.,Brown, Herbert C.
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- Synthesis and properties of diacetatodinitrosylmolybdenum complex as precursor for olefin metathesis catalyst
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Reaction of the [Mo(NO)2]2+ moiety with a suitable ligands is a very convenient method to synthesize different dinitrosylmolybdenum complexes. It was also applied for the synthesis of a new compound of empirical formula Mo(NO)2(O2CMe)2. The reaction of catalyst precursor with EtAlCl2 was spectroscopically examined (IR in the v(NO) region). Reagent concentrations were as in the metathesis reaction. The reaction between Mo(NO)2(O2CMe)2 and EtAlCl2 is accompanied by liberation of ethane. During the stable period of the system (decrease in intensity of the bands v(NO) 1%) one molar equivalent (vs. precursor concentration) of ethane evolved.
- Keller
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- Thermal studies of potassium tetrahydroborate?sodium tetrafluoroborate mixtures
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The KBH4?NaBF4 mixture was studied by thermal analysis (differential scanning calorimetry). Chemical analysis, X-ray powder diffraction analysis, IR spectroscopy, and 11B and 19F MAS NMR spectroscopy showed that the primary stage of the complex pyrolysis process is a metathesis reaction between components to form a new mixture, NaBH4?KBF4, the decomposition of which with the release of gaseous products and the formation of polyhedral borohydride compounds (mainly B12H12 2-) in the solid residue begins at a temperature of about 563 K. At a certain ratio between reactants in the initial mixture KBH4?NaBF4, the B12H12 2- anion can form with the material participation of the BF4 - anion.
- Saldin,Sukhovei,Savchenko,Slobodyuk,Kavun, V. Ya.
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p. 489 - 497
(2017/05/05)
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- Thermal decomposition of 4-fluorobenzenediazonium perfluoroorganyl(fluoro) borates, [4-FC6H4N2]Y (Y = RFBF 3 (RF = C6F5, C6F 13, trans-C4F9CFCF, cis-C6F 13CFCF, CF3CC) and (C6F13) 2BF2)
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Heating of the neat salts [4-FC6H4N 2][RFBF3] (RF = C6F 5, C6F13, trans-C4F9CFCF, cis-C6F13CFCF, CF3CC) or in solid mixtures with NaF gives the principal product 1,4-C6F2H4 besides RFBF2 or Na[RFBF3], respectively. Thermolysis of [4-FC6H4N2] [(C6F13)2BF2] in NaF results in 1,4-C6F2H4, Na[BF4], Na[(C 6F13)2BF2], and a new type of product, the isomer Na[C6F13CF(BF3)C 5F11].
- Bardin, Vadim V.,Frohn, Hermann-Josef
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p. 333 - 338
(2014/01/06)
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- Rearrangement Reactions of the Transient Lewis Acids (CF3) 3B and (CF3)3BCF2: An Experimental and Theoretical Study
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Short-lived (CF3)3B and (CF3) 3BCF2 are generated as intermediates by thermal dissociation of (CF3)3BCO and F-abstraction from the weak coordinating anion [B(CF3)4]-, respectively. Both Lewis acids cannot be detected because of their instability with respect to rearrangement reactions at the B-C-F moiety. A cascade of 1,2-fluorine shifts to boron followed by perfluoroalkyl group migrations and also difluorocarbene transfer reactions occur. In the gas phase, (CF 3)3B rearranges to a mixture of linear perfluoroalkyldifluoroboranes CnF2n+1BF2 (n = 2-7), while the respective reactions of (CF3)3BCF 2 result in a mixture of linear (n = 2-4) and branched monoperfluoroalkyldifluoroboranes, e.g., (C2F5)(CF 3)FCBF2. For comparison, the reactions of [CF 3BF3]- and [C2F5BF 3]- with AsF5 are studied, and the products in the case of [CF3BF3]- are BF3 and C2F5BF2 whereas in the case of [C 2F5BF3]-, C2F 5BF2 is the sole product. In contrast to reports in the literature, it is found that CF3BF2 is too unstable at room temperature to be detected. The decomposition of (CF3) 3BCO in anhydrous HF leads to a mixture of the new conjugate Bronsted-Lewis acids [H2F][(CF3)3BF] and [H2F][C2F5BF3]. All reactions are modeled by density functional calculations. The energy barriers of the transition states are low in agreement with the experimental results that (CF3)3B and (CF3)3BCF2 are short-lived intermediates. Since CF2 complexes are key intermediates in the rearrangement reactions of (CF3)3B and (CF3)3BCF2, CF2 affinities of some perfluoroalkylfluoroboranes are presented. CF2 affinities are compared to CO and F- affinities of selected boranes showing a trend in Lewis acidity, and its influence on the stability of the complexes is discussed. Fluoride ion affinities are calculated for a variety of different fluoroboranes, including perfluorocarboranes, and compared to those of the title compounds.
- Finze, Maik,Bernhardt, Eduard,Zaehres, Manfred,Willner, Helge
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p. 490 - 505
(2008/10/09)
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- Reactions of arenediazonium tetrafluoroborates with 1,4-bis(acryloyloxy)butane in the presence of thiocyanate ion
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The first thiocyanatoarylation reaction with an unsaturated compound containing two isolated multiple bonds, 1,4-bis(acryloyloxy)butane, was effected. The reactions of 1,4-bis(acryloyloxy)butane with arenediazonium tetrafluoroborates occur in aqueous acet
- Gorbovoi,Baranovskii,Koval'skii,Grishchuk
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p. 1230 - 1232
(2007/10/03)
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- Palladium(II) terminal phosphido complexes derived from cyclometalated dimesitylphosphine: Synthesis, structure, and low-barrier phosphorus inversion
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The cyclometalated cationic Pd(II) and Pt(II) complexes [M(diphos)(CH2C6H2Me2P(Mes)-(H))] [X] (5-8: M = Pd, Pt; diphos = dppe (Ph2PCH2CH2PPh2), dppen (cis-Ph2PCH=CHPPh2); Mes = 2,4,6-Me3C6H2; X = OTf, BF4) were prepared by thermolysis of the cations [M(diphos)-(Me)(PMes2H)] [X]. Deprotonation of 5-8 gave the neutral phosphido complexes M(diphos)-(CH2C6H2Me2P(Mes)) (9-12); the Pd(II) compounds 9 and 11 are the first examples of stable palladium terminal phosphido alkyl complexes, and their crystal structures were determined. Fluxional processes in complexes 9-12 were studied by variable-temperature NMR spectroscopy; the spectra are consistent with low barriers to phosphorus inversion.
- Zhuravel, Michael A.,Glueck, David S.,Zakharov, Lev N.,Rheingold, Arnold L.
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p. 3208 - 3214
(2008/10/08)
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- Synthesis of Novel Organometallic Compounds Containing η1-Carbon Polycyclic Ligands: Condensation of Propargyl Alcohol with the Allenylidene Ligand of [Ru(η5-C5H5)(C=C=CPh 2)(CO)(PPri3)]BF4
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The allenylidene complex [Ru(η5-C5H5){C=C=CPh 2}(CO)(PPri3)]BF4 (1) reacts with propargyl alcohol to give the α,β-unsaturated alkoxycarbene derivative [Ru(η5-C5H5){C(OCH2C≡ CH)CH=CPh2}(CO)(PPri3)]BF4 (2). The structure of 2 was determined by an X-ray investigation, revealing a Ru-C distance of 1.965(4) A?. Treatment of 2 with 1 equiv of Na2-CO3 affords [Ru(η5-C5H 5){9-phenyl-1,3-dihydronaphtho[2,3-c]-1-furanylidene}(CO)(PPr i3)]BF4 (3), which reacts with NaBH4 to give Ru(η5-C5H5){CH 2(1-phenyl-3-hydroxymethyl-2-naphthyl)}-(CO)(PPri 3) (4). The structure of 3 was determined by an X-ray diffraction analysis, revealing a Ru-C bond length of 2.004(2) A?. Treatment of 2 with 3 equiv of NaOCH3 leads to a mixture of compounds containing the racemic form (RuR,CR;RuS,CS)-Ru(η 5-C5H 5){9-phenyl-1,3-dihydronaphtho[2,3-c]-1-furanyl}(CO)(PPr i3) (5) as the main component. This racemic form was obtained as a pure solid by passing the crude products through an Al2O3 column using diethyl ether as eluent. The structure of 5 was also determined by an X-ray diffraction analysis. In this case, the investigation reveals a Ru-C distance of 2.203(3) A?. When the crude products were passed through an Al2O3 column using a pentane/diethyl ether (5:1) mixture, the epimerization of 5 into (RuR,CS;RuS,CR)-Ru(η 5-C5H 5){9-phenyl-1,3-dihydronaphtho[2,3-c]-1-furanyl}(CO)(PPr i3) (6) was observed. When the above-mentioned chromatography is carried out using an increasing polarity mixture of toluene/diethyl ether (from 10:1 to 1:10) as eluent, the transformation of 5 into its isomer Ru(η5-C5H5){CH 2(1-phenyl-3-carboxa-2-naphthyl)}(CO)(PPri3) (7) occurs. The complex Ru(η5-C5H 5){9-phenyl-3,3a-dihydronaphtho[2,3-c]-1-furanyl}(CO)(PPr i3) (8) was also synthesized, by passing 2 through an Al2O3 column using a tetrahydrofuran/dichloromethane (5:1) mixture as eluent.
- Esteruelas, Miguel A.,Gómez, Angel V.,López, Ana M.,Oliván, Montserrat,O?ate, Enrique,Ruiz, Natividad
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- Addition of Secondary and Primary Amines to the Allenylidene Ligand of [Ru(η5-C5H5)(C=C=CPh 2)(CO)(PiPr3)]BF4: Synthesis of Azoniabutadienyl, Aminoallenyl, and Azabutadienyl Derivatives of Ruthenium(II)
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The allenylidene complex [Ru(η5-C5H5)(C=C=CPh 2)(CO)(PiPr3)]BF4 (1) reacts with diethylamine and piperidine to give the azoniabutadienyl derivatives [Ru(η5-C5H5){C(CH= CPh2)=NEt2}(CO)(PiPr3)]BF 4 (2) and [Ru(η5-C5H5){C(CH=CPh2)=NCH 2(CH2)3CH2}(CO)(PiPr 3)]BF4 (3), respectively. The molecular structure of 2 has been determined by X-ray crystallography. The geometry around the ruthenium center is close to octahedral with the cyclopentadienyl ligand occupying three sites of a face. The Ru-Cα bond length is 2.063(6) A?, whereas the Cα-N distance is 1.306(7) A?. Treatment of 2 and 3 with sodium methoxide produces the deprotonation of the CH=CPh2 fragment to afford the aminoallenyl derivatives Ru(η5-C5H5){C(NEt2)=C=CPh 2}(CO)(PiPr3) (4) and Ru(η5-C5H5){C(NCH2(CH 2)3CH2)=C= CPh2}(CO)(PiPr)3 (5). Complex 1 also reacts with n-propylamine and aniline. In this case, the reaction products are [Ru(η5-C5H5){C(CH=CPh2)=NH nPr}(CO)(PiPr3)]BF4 (6) and [Ru(η5-C5H5){C(CH=CPh 2)=NHPh}(CO)(PiPr3)]BF4 (7). Treatment of 6 and 7 with sodium methoxide produces the deprotonation of the nitrogen atom of the unsaturated η1-carbon ligand, to give the azabutadienyl compounds Ru(η5-C5H5){C(CH=CPh2)=N nPr}(CO)(PiPr3) (8) and Ru(η5-C5H5){C(CH=CPh 2)=NPh}(CO)(PiPr3) (9), respectively. The ellipticities of the Ru-Cα and Cα-N bonds of the model compounds [Ru(η5-C5H5){C(CH=CH2)=NH 2}(CO)(PH3)]+ (10), Ru(η5-C5H5){C(NH2)=C=CH 2}(CO)(PH3) (11), and Ru(η5-C5H5){C(CH=CH2)= NH}(CO)(PH3) (12) have been studied using the AIMPAC series of programs. The obtained values are 0.07 and 0.12 (10), 0.05 and 0.07 (11), and 0.07 and 0.10 (12), respectively.
- Bernad, D. Javier,Esteruelas, Miguel A.,López, Ana M.,Modrego, Javier,Carmen Puerta,Valerga, Pedro
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p. 4995 - 5003
(2008/10/08)
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- Electrochemical Reduction of Arylxenon Tetrafluoroborates
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Reduction potentials of arylxenon(II) tetrafluoroborates have been measured by cyclic voltammetery method on platinum disc and ultramicro electrodes. The electrochemical properties of the arylxenon(II) tetrafluoroborates are quite different to those of corresponding arylperfluoroalkyliodine(III) salts.
- Naumann, Dieter,Gnann, Robert,Ignatev, Nikolai,Datsenko, Sergei
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- Hydrocarbon-Bridged Metal Complexes, XX. - Nucleophilic Addition of Carbonyl Metallates to Cationic Hexadienyl, Cyclohexadienyl, Cycloheptadienyl, and Cyclooctadienyl Complexes of Iron and Ruthenium: Heterobimetallic Complexes with η1:η4-C6, -C7, and -C8 Hydrcarbon Bridges
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The addition of Re(CO)5-, Mn(CO)5-, and 5-C5H5)W(CO)3>- to the cationic dienyl complexes 5-dienyl)M(CO)3>+ (M = Fe, Ru; dienyl = hexadienyl, cyclohexadienyl, cycloheptadienyl, cyclooctadienyl, bicyclooctadienyl) gives the heterobimetallic η1:η4-hydrocarbon-bridged complexes 1-4, 6, 7.In solution the initial nucleophilic adduct 2e of 5-cycclohexadienyl)Ru(CO)3>+ and - rearranges to the complex 3, in which the Re(CO)5 group is bound to a sp2 carbon atom.By using Mn(CO)5- also the products of electron transfer between cation and anion have been observed.The crystal structures of (OC)3Fe(μ-η4:η1-hexadiene)Re(CO)5 (1), (OC)3Ru(μ-η4:η1-cyclohexadiene)Re(CO)5 (3), (OC)3Fe(η4:η4-C7H9-C7H9)Fe(CO)3 (5), (OC)3Ru(μ-η4:η1-cyclooctadiene)Re-(CO)5 (6b), and of (OC)3Fe(η4:η1-bicyclooctadiene)-Re(CO)5 (7) have been determined by X-ray diffraction.Key Words: Heterobimetalic complexes / Tungsten complexes / Iron complexes / Ruthenium complexes / Manganese complexes / Rhenium complexes / Diene bridges, ?,?-C6, -C7, and -C8
- Niemer, Burkhard,Breimair, Josef,Wagner, Barbara,Polborn, Kurt,Beck, Wolgang
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p. 2227 - 2236
(2007/10/02)
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- Hydrocarbon-bridged Metal Complexes, XXI. - Addition of Tetracarbonylosmate and -ruthenate to Coordinated Unsaturated Hydrocarbons: Trinuclear Complexes with two ?,?-Allyl, Methylallyl, Cyclohexadiene, Cycloheptadiene, Cyclohexadienyl, Cycloheptatrien, and Thiophene Bridges
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The addition of organometallic nucleophiles 2- (M = Os, Ru) to +, +, +, +, +, +, + leads to heterotrimetallic η1:η2-, η1:η3-, η1:η4-, η1:Η5-, η1:η6-hydrocarbon-bridged complexes 1-7.The structures of cis-(OC)4Os1:η4-C4H7)Fe(CO)3>2 (4), cis-(OC)4Os1:η5-C6H6-Mn(CO)3>2 (6), and cis-(OC)4Os-1:η6-C7H7-Mo(CO)3>2 (7b) have been determined by X-ray analysis.The fluxional behaviour of 6 in solution has been studied in a temperature range from -70 to +60 deg C.The comparison of observed and calculated 1H-NMR data indicates a 1,2-shift mechanism (ΔG= 49 kJ/mol).Key Words: Trinuclear carbonyl complexes / Molybdenum complexes / Manganese complexes / Iron complexes / Ruthenium complexes / Osmium complexes / ?,?-Hydrocarbon bridges
- Niemer, Burkhard,Breimair, Josef,Voelkel, Thomas,Wagner, Barbara,Polborn, Kurt,Beck, Wolfgang
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p. 2237 - 2244
(2007/10/02)
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- Regiospecific condensation of methyl propiolate with 2,3-dimethyl-2-butene mediated by the electrophilic η5-cyclopentadienyl dinitrosyl tetrafluoroborate salts of the group 6 metals
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This paper first describes some reaction of the Cp′M(NO)2+ cations as their BF4- salts that further delineate their electrophilic character. It then describes in detail the utilization of these cations for the synthesis of the complete series of six cationic lactone complexes. By their regiospecific mediation of the reaction between methyl propiolate and 2,3-dimethyl-2-butene, which involves concomitant metal-carbon, carbon-oxygen, and carbon-carbon bond formation. Furthermore, the paper presents details of the O-demethylation of these six cationic species to their neutral Cp′M(NO)2(η1-lactone) derivatives, from which the lactone ligands may be liberated by treatment with iodine. It also describes how exposure of both neutral lactone complexes of tungsten to air leads to their being cleanly converted to the corresponding dioxo derivatives. Finally, it presents complete characterization data for all the new organometallic complexes isolated during this work.
- Legzdins,Richter-Addo,Einstein,Jones
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p. 431 - 439
(2008/10/08)
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- Novel cationic monobut-2-yne complexes of tungsten(II) containing dithiocarbamates and related ligands
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Equimolar quantities of 2-MeC2Me)> (dppm = Ph2P(CH2)PPh2) and MS2CX (M = Na, X = NMe2; M = Na, X = NEt2; M = , X = NC4H8; M = Na, X = N(CH2Ph)2; or M = K, X = OEt) react in CH2Cl2 at room temperature to eventually give the cationic monobut-2-yne complexes 2-MeC2Me)>I.The complex 2-MeC2Me)>I can also be prepared by reacting equimolar quantities of 2-MeC2Me)> with (S2CNC4H8> in refluxing chloroform.Both these types of reaction involve the formation of the monodentate dithiocarbamate intermediates 1-S2CX)(CO)(dppm)(η2-MeC2Me)>.Reaction of 2-MeC2Me)> and MS2CX in a 2:1 molar ratio afforded a mixture of the cationic monobut-2-yne complexes 2-MeC2Me)> and 2-MeC2Me)>.Variable temperature 1H NMR studies carried out on 2MeC2Me)>I showed the complex to be fluxional.The barrier to but-2-yne rotation was calculated to be 49.7+/- 1 kJ mol-1. 13C NMR studies show the but-2-yne ligand in 2-MeC2Me)>I is donating four electrons to the tungsten in these compounds.
- Baker, Paul K.,Flower, Kevin R.
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- Metallorganische Lewissaeuren. XL. Ein ?,?-vinylverbrueckter Dirheniumkomplex 1:η2-CH=CH2)Re(CO)5>+BF4-
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1:η2-CH=CH2)Re(CO)5>+BF4- (1) is formed by reaction of (OC)5ReFBF3 with Me3SiCH=CH2. 1 reacts with Re(CO)5- or iodide to give (OC)5ReCH2CH2Re(CO)5 and +, respecti
- Steil, Peter,Beck, Wolfgang,Stone, F. Gordon A.
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- Hydrodesulfurization model complexes: Nucleophilic addition to π-coordinated benzo[b]thiophenes and thiophene
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The π-bound thiophene (T) and benzo[b]thiophene (BT) complexes [CpRu(BT)]+, [Cp*Ir(BT)]2+, and [Cp*Ir(T)]2+, models for the adsorption of thiophenic compounds to hydrodesulfurization (HDS) catalyst surfaces, react with a variety of nucleophiles (H-, MeO-, (MeO2C)2CH-, EtS-, and phosphines). The BT complexes yield the first isolable transition-metal cyclohexadienyl complexes derived from fused ring aromatic ligands; four isomers of each cyclohexadienyl complex are produced. The isomers result from addition at the four carbons on the benzene ring; for the nucleophiles studied, addition occurs preferentially at the carbon closest to the sulfur atom, C7. This isomer of CpRu(BT·H) has been characterized by an X-ray structure determination. The T complex reacts with phosphines to produce [Cp*Ir(η4-T·PR3)]2+. Double nucleophilic addition reactions (H- and MeO-) of [Cp*Ir(BT)]2+ and [Cp*Ir(3-MeBT)]2+ are also discussed. Reaction of either NaBEt3H or Cp2Co with [Cp*Ir(T)]2+ results in a 2e reduction of the Ir complex. On the basis of 1H NMR data and by analogy to related complexes, this product is formulated as Cp*Ir(η4-T).
- Huckett, Sara C.,Angelici, Robert J.
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p. 1491 - 1500
(2008/10/08)
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- ZUR KENNTNIS DER CYCLOPENTADIENYL-NITROSYL-CARBONYL-ISONITRIL-KOMPLEXE DER VI. UND DER CYCLOPENTADIENYL-DICARBONYL-ISONITRIL-KOMPLEXE DER VII. NEBENGRUPPE
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The nitrosylcarbonylisonitrile complexes η5-C5H5M(NO)(CO)CNR (R = Me for Cr, Mo, W; R = Et, SiMe3, GeMe3, SnMe3 for Mo) are formed by treatment of the nitrosylcarbonylcyanometalates Na5-C5H5M(NO)(CO)CN> with BF4 (R = Me, Et),
- Behrens, Helmut,Landgraf, Guenter,Merbach, Peter,Moll, Matthias,Trummer, Karl-Heinz
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p. 217 - 230
(2007/10/02)
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- Simplified synthesis of B10H14 from NaBH4 via B11H14- ion
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The synthesis of B11H14- ion from BH4- ion and acids, including BF3·O(C2H5)2, BCl3, SiCl4, or alkyl halides, and the subsequent oxidation of the B11H14- ion to produce B10H14 using Na2Cr2O7, KMnO4, H2O2, or H2O2/FeSO4 is described. An optimum procedure is suggested which can be scaled-up.
- Dunks, Gary B.,Barker, Kathryn,Hedaya, Eddie,Hefner, Catherine,Palmer-Ordonez, Kathy,Remec, Peter
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p. 1692 - 1697
(2008/10/08)
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