- Free and Assosiated Trimethylsilyl Cation in Solution
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The trimethylsilyl cation (Me3Si+) has been prepared as an ion pair with perclorate in CH2Cl2 or as the nonspecifically solvated ion in dilute sulpholane ny hydride abstraction from triethylsilane.
- Lambert, Joseph B.,McConnell, JoAnn A.,Schilf, Wojciech,Schulz, William J.
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- Alkoxycyanoborates: Metal salts and low-viscosity ionic liquids
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Syntheses of alkoxytricyanoborates and dialkoxydicyanoborates are described using different readily available boron-based starting compounds such as tetrahydrido-, tetrafluoro-, and tetraalkoxyborates, as well as trimethoxyborane and trimethylsilylcyanide as cyano sources. The salts obtained have been characterized by NMR and vibrational spectroscopy, elemental analysis, and DSC and DTA measurements. In addition to alkali metal salts, room temperature ionic liquids [EMIm][ROB(CN)3] (R = CH3, C2H5, CH2CF3) have been prepared. These ionic liquids exhibit very low melting points or glass transition temperatures, low viscosities, and high chemical, thermal, and electrochemical stabilities. The influence of alkyl chain length and the effect of partial fluorination of the alkoxy group on these properties have been elucidated. The advantageous physicochemical properties, in general, and in conjunction with the easy accessibility make alkoxytricyanoborate-ILs interesting compounds for potential applications in materials sciences. Furthermore, the Li salt of the [CH3OB(CN)3]- ions was prepared and found to provide a significantly higher solubility in propylene carbonate compared to lithium tetracyanoborate. Alkali metal salts Li[CH3OB(CN)3]·H2O, Na[CH3OB(CN)3]·H2O, K[CH3OB(CN)3], Na[C2H5OB(CN)3], and Na[CF3CH2OB(CN)3]·0.5H2O have been characterized by single-crystal X-ray diffraction. This journal is
- Finze, Maik,Ignat'Ev, Nikolai V.,Reiss, Guido J.,Schopper, Nils,Sprenger, Jan A. P.,Zapf, Ludwig
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p. 14973 - 14987
(2021/09/04)
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- Perfluoroalkyltricyanoborate and Perfluoroalkylcyanofluoroborate Anions: Building Blocks for Low-Viscosity Ionic Liquids
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The potassium perfluoroalkyltricyanoborates K[CnF2 n+1B(CN)3] [n=1 (1 d), 2 (2 d)] and the potassium mono(perfluoroalkyl)cyanofluoroborates K[CnF2 n+1BF(CN)2] [n=1 (1 c), 2 (2 c)] and [CnF2 n+1BF2(CN)]? [n=1 (1 b), 2 (2 b), 3 (3 b), 4 (4 b)] are accessible with perfect selectivities on multi-gram scales starting from K[CnF2 n+1BF3] and Me3SiCN. The K+ salts are starting materials for the preparation of salts with organic cations, for example, [EMIm]+ (EMIm=1-ethyl-3-methylimidazolium). These [EMIm]+ salts are hydrophobic room-temperature ionic liquids (RTILs) that are thermally, chemically and electrochemically very robust, offering electrochemical windows up to 5.8 V. The RTILs described herein, exhibit very low viscosities with a minimum of 14.0 mPa s at 20 °C for [EMIm]1 c, low melting points down to ?57 °C for [EMIm]2 b and extraordinary high conductivities up to 17.6 mS cm?1 at 20 °C for [EMIm]1 c. The combination of these properties makes these ILs promising materials for electrochemical devices as exemplified by the application of selected RTILs as component of electrolytes in dye-sensitised solar cells (DSSCs, Gr?tzel cells). The efficiency of the DSSCs was found to increase with a decreasing viscosity of the neat ionic liquid. In addition to the spectroscopic characterisation, single crystals of the potassium salts of the anions 1 b–d, 2 d, 3 b and 4 c as well as of [nBu4N]2 c have been studied by X-ray diffraction.
- Landmann, Johannes,Sprenger, Jan A. P.,Hennig, Philipp T.,Bertermann, Rüdiger,Grüne, Matthias,Würthner, Frank,Ignat'ev, Nikolai V.,Finze, Maik
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supporting information
p. 608 - 623
(2017/11/21)
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- Di- and tetrametallic hafnocene oxamidides prepared from CO-induced N 2 bond cleavage and thermal rearrangement to hafnocene cyanide derivatives
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Carbonylation of the hafnocene dinitrogen complex [(η5- C5H2-1,2,4-Me3)2Hf] 2(μ2,η2:η2-N 2) with 4 atm of carbon monoxide yielded the tetrametall
- Semproni, Scott P.,Margulieux, Grant W.,Chirik, Paul J.
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p. 6278 - 6287,10
(2020/08/24)
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- IONIC COMPOUND, PROCESS FOR PRODUCING SAME, AND ION-CONDUCTIVE MATERIAL COMPRISING SAME
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The present invention provides a method of producing a tetracyanoborate-containing ionic compound in a milder condition more efficiently and less expensively than conventional methods, and a tetracyanoborate-containing ionic compound having a reduced content of impure components. An ionic compound of the present invention is represented by the following general formula (I), has a content of fluorine atom-containing impurities of 3 mol% or less per 100 mol% of the ionic compound, and a method for producing an ionic compound represented by the general formula (I) of the present invention comprises a step of reacting starting materials containing a cyanide and a boron compound. (In the formula, Ktm+ denotes an organic cation [Kt b]m+ or an inorganic cation [Kta]m+; and m denotes an integer of 1 to 3.)
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Page/Page column 44
(2011/06/23)
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- Efficient synthesis of trimethylsilyl pseudohalides catalyzed by PEG400/ZnI2 under ultrasound irradiation
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Trimethylsilyl pseudohalides Me3SiX, where X = NCS, NCO, or CN, were readily prepared conveniently in desirable yields by the reaction of Me3SiCl with NaX or KX catalyzed by PEG400 and zinc iodide under ultrasound irradiation. Copyright Taylor & Francis, Inc.
- Sufang, Wang,Shaobing, Wang,Yongshen, Xu
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p. 1271 - 1276
(2007/10/03)
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- Synthesis of some new chiral bifunctional o-hydroxyarylphosphonodiamides and their application as ligands in Ti(IV) complex catalyzed asymmetric silylcyanation of aromatic aldehydes
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Some new chiral bifunctional o-hydroxyarylphosphonodiamides were synthesized starting from (+)-cis-1,2,2-trimethylcyclopentane-1,3-diamine and the absolute configuration of the phosphorus atom was determined by X-ray diffraction analysis. Excellent enantioselectivity (up to 98% ee) was achieved in asymmetric silylcyanation of aromatic aldehydes using a chiral titanium complex formed in situ from Ti(OiPr)4 and o-hydroxyarylphosphonodiamide as the catalyst. Graphical Abstract.
- He, Ke,Zhou, Zhenghong,Wang, Lixin,Li, Kangying,Zhao, Guofeng,Zhou, Qilin,Tang, Chuchi
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p. 10505 - 10513
(2007/10/03)
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- A study on the haterogeneous reaction of trialkylsilyl chlorides with inorganic salts and monocarboxylates catalysed by PEG400
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The important and useful trialkylsilyl pseudohalides R3SiX, where X=NCS, NCO, N3 or CN and R=methyl or ethyl, and trimethylsilyl monocarboxylates, where X=RCOO, were readily prepared in high yields by nucleophilic substitution of R3SiCl with X ions provided by NaX or KX at room temperature catalysed by PEG400 and zinc iodide. The reactions of trimethylsilyl chloride with some metal oxysalts were also studied for the first time.
- Du, Yun-Fei,Cao, Yu-Qing,Dai, Zhi,Chen, Bao-Hua
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p. 223 - 225
(2007/10/03)
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- A practical and improved method for the preparation of trimethylsilyl cyanide catalysed by PEG400 and zinc iodidet
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The useful synthetic reagent trimethylsilyl cyanide was readily prepared in high yield by the cyanation of trimethylchlorosilane with potassium cyanide in the presence of PEG400 and zinc iodide under stirring at room temperature or ultrasonic radiation.
- Cao, Yu-Qing,Du, Yun-Fei,Li, Ji-Tai
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p. 500 - 501
(2007/10/03)
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- Preparation of trifluoromethyl sulfides or selenides from trifluoromethyl trimethylsilane and thiocyanates or selenocyanates
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Trifluoromethyl sulfides (or selenides) are easily obtained in one pot at 0°C from thiocyanates (or selenocyanates), commercial trifluoromethyl trimethylsilane and catalytic amounts of tetrabutylammonium fluoride (TBAF).
- Billard, Thierry,Large, Sylvie,Langlois, Bernard R.
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- Low-temperature photooxygenation of coelenterate luciferin analog synthesis and proof of 1,2-dioxetanone as luminescence intermediate
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Coelenterate luciferin analog having bulky tert-butyl group at the 2-position was suitable for studies on chemiluminescence under various conditions. Photooxygenation of the analog(s) at low temperature (-78°C) afforded luminous intermediates which were proved as peroxides by reduction with PPh3 with resultant loss of luminescence ability. In order to clarify these structures of accumulated luminous intermediates by means of 13C NMR, three 13C enriched analogs were synthesized at the 2, 3 and 5 positions of 3,7-dihydroimidazo[1,2-a]pyrazin-3-one skeleton in 99% enrichment with site-specificity. These 13C-enriched coelenterate luciferin analogs were photooxygenated at -78°C to form two peroxidic products as luminescent intermediates. Structures of these unstable intermediates were deduced by means of 13C NMR spectra at low temperature using substrates enriched at three sites by 13C. Photooxygenation in a mixture of CF3CD2OD and CD3OD as highly protic solvents afforded the dioxetanone and 2-hydroperoxide. These two peroxides emitted light independently at different temperatures either at 400 nm (neutral species) and/or 475 nm (anionic species) after diluting to 10-5 M in diglyme (DGM) containing acid or base.
- Usami, Ken,Isobe, Minoru
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p. 12061 - 12090
(2007/10/03)
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- Small Rings, 78. - Tri-tert-butyl(trimethylsilyl)cyclobutadiene and Tri-tert-butyl(trimethylsilyl)tetrahedrane
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The chemistry of diazo(1,2,3-tri-tert-butylcyclopropenyl)(trimethylsilyl)methane (6) is unexpectedly diverse.Upon irradiation it fragments exclusively into the acetylenes 7 and 8.Flash thermolysis, on the other hand, gives - aside from the two acetylenes - tri-tert-butylazete (10) and trimethylsilyl cyanide (11).Upon heating 6 presumbaly isomerizes via betaine 17 to Dewar-diazabenzene 13 - which is split into 10 and 11 - and diazabenzvalene 18.This reaction course is supported by the isolation of the carbonyliron complexes 15 and 16. - The CuCl-catalyzed thermal decomposition again follows a different route.Under these conditions tri-tert-butyl(trimethylsilyl)cyclobutadiene (5) is formed, probably as a weak CuCl complex.Only after addition of ethylenebis(diphenylphosphane) free cyclobutadiene 5 can be isolated.Upon irradiation of 5 a quantitative isomerization to tri-tert-butyl(trimethylsilyl)tetrahedrane (29) occurs.This second, spectroscopically unequivocally confirmed tetrahedrane melts at 179 deg C.In solution the isomerization to cyclobutadiene 5 starts at about 160 deg C.That means, it is thermally even more stable than tetra-tert-butyltetrahedrane. - Key Words: Diazo compounds / Transition-metal complexes / Photoisomerization / Homocyclopropenylium ions
- Maier, Guenther,Born, Dieter,Bauer, Ines,Wolf, Reinhard,Boese, Roland,Cremer, Dieter
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p. 173 - 190
(2007/10/02)
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- Photochemical Reaction of Arenecarbonitriles in the Presence of Alkylsilanes, Silyl Ethers and Silyl Amines
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The irradiation of benzene-1,2,4,5-tetracarbonitrile, and benzene-1,2,4- as well as benzene-1,3,5-tricarbonitrile in the presence of various tetraalkylsilanes, alkoxytrialkylsilanes, hexamethyldisiloxane or heptamethyldisilazane leads to alkylation of the aromatics.The more substituted alkyl group is selectively fragmented, and the attack takes place at the position(s) of highest spin density in the nitrile radical anion.The reaction involves electron transfer to the nitrile's singlet excited state, and the radical cation appears to cleave mainly in the initial radical ion pair.
- Mella, Mariella,d'Alessandro, Nicola,Freccero, Mauro,Albini, Angelo
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p. 515 - 519
(2007/10/02)
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- Preparation of trialkylsilyl nitrile
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Trialkylsilyl nitrile is prepared by anhydrously reacting stoichiometric amounts of trialkylsilyl halide, hexaalkyldisilazane or trialkylsilyl amine, and hydrogen cyanide, in the absence or presence of a solvent or inert gas atmosphere. No catalyst is necessary, and the reaction preferably is performed at a temperature of from 5° C. to 25° C.
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- Stereoselective and Rapid Synthesis of D-Mannose
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During the course of our studies on labeling reactions with tracer elements, a new rapid and stereoselective synthesis of D-mannose was found.Reaction of 2,3:4,5-di-O-isopropylidene-D-arabinose with trimethylsilylcyanide and zinc iodide in dichloromethane followed by reduction gave D-mannose in good yield.
- Nishimura, Shintaro,Hayashi, Nobuyoshi
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p. 1815 - 1818
(2007/10/02)
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- Photoinduced Electron Transfer by Charge-transfer and Singlet-sensitized Activation. Facile Retro-pinakol via Fragmentation of Cation Radicals
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Direct comparison of the efficiency of photoinduced electron transfer by charge-transfer activation of electron donor-acceptor (EDA) complexes and diffusional quenching of excited singlet acceptors is allowed by a series of silylated pinakols derived from the p-methoxytoluene donor.
- Sankararaman, S.,Kochi, J. K.
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p. 1800 - 1802
(2007/10/02)
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- Nucleophilic Substitution Reactions of Alkyl Halides By Using New Polymer-Supported Reagents Containing Hemin
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A new polymer reagent consisting of hemin, divinylbenzene, and 2-methyl-5-vinylpyridine was synthesized by suspension copolymerization.Substitution reactions of primary, secondary, and tertiary alkyl halides with the hemin copolymer combined with cyanide, azide, and thiocyanate ions were given satisfactory yields.This reaction mechanism was revealed to be a SNi type on the basis of stereochemical study.The hemin copolymer was not only a polymer-supported reagent with functional capabilities, but also served to separate the product from the reaction mixture.
- Saito, Kiyoshi,Harada, Kaoru
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p. 2562 - 2566
(2007/10/02)
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- A Convenient Method for the Synthesis of Alkylsilyl Cyanides Using Potassium or Sodium Cyanide Impregnated on Amberlite XAD Resin
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Potassium and sodium cyanide impregnated on Amberlite XAD resin were found to be effective for converting alkylsilyl chloride to the corresponding alkylsilyl cyanide under mild conditions.
- Sukata, Kazuaki
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p. 2257 - 2258
(2007/10/02)
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- Process for preparing dimethylsilyl dicyanide
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A process for preparing dimethylsilyl dicyanide comprising reacting trimethylsilyl cyanide with dimethylsilyl dichloride. Advantageously the trimethylsilyl chloride formed as a by-product in the course of the reaction is continuously removed from the reaction, the trimethylsilyl cyanide starting material is produced by reacting trimethylsilyl chloride with an alkali metal cyanide, and the by-product trimethylsilyl chloride of the principal reaction is recycled to the preparation of trimethylsilyl cyanide.
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- A Novel, Facile Access to Noradamantane Derivatives
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A novel cyclisation reaction allows the insertion of a carbonyl bridge between C-3 and C-7 of the bicyclooctane skeleton in high yield and thus provides facile, efficient access to variably substituted noradamantanes.
- Hofmann, Peter,Beck, Erich,Hoffmann, Michael D.,Sieber, Alexander
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p. 1779 - 1786
(2007/10/02)
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- A NOVEL PHOTOSUBSTITUTION OF DICYANOBENZENES BY ALLYLIC AND BENZYLIC SILANES
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The photosubstitution of o- and p-dicyanobenzenes by allylic and benzylic silanes in acetonitrile occurred efficiently, giving the corresponding mono-allylated and benzylated cyanobenzenes.
- Mizuno, Kazuhiko,Ikeda, Munehiro,Otsuji, Yoshio
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p. 461 - 464
(2007/10/02)
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- CATALYTIC AND STOICHIOMETRIC TRANSFORMATIONS WITH TRIPHENYL(P,P,P-TRIPHENYLPHOSPHINE IMIDATO-N) PHOSPHORUS CYANIDE,
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Reactions involving anhydrous +CN-, 1, are described for a series of nucleophilic displacements.The reagent may be used stoichiometrically with moisture sensitive substrates, and also acts as an efficient phase transfer catalyst.
- Dillon, Keith B.,Hodgson, Martin,Parker, David
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p. 849 - 854
(2007/10/02)
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- Preparation of trimethylsilyl cyanide
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Trimethylsilyl cyanide, (CH3)3 Si-CN, is obtained by reacting trimethylsilyl chloride with an approximately equimolar amount of an alkali metal cyanide in the absence of water and in the presence of catalytic, sub-stoichiometric amounts of both an alkali metal iodide and N-methylpyrrolidone, at a temperature of from 15°-25° C.
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- Preparation of trimethylsilyl cyanide
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A process for the preparation of trimethylsilyl cyanide comprising reacting trimethylsilyl chloride with an approximately equimolar amount of an alkali metal cyanide in the presence of a catalytic amount of a heavy metal cyanide and in the presence of an aprotic solvent with a boiling point above about 150° C., at a temperature between about 130° and 250° C. Advantageously the reaction temperature is between about 160° and 220° C., the alkali metal cyanide is sodium cyanide or potassium cyanide, the heavy metal cyanide is copper(I) cyanide, copper(II) cyanide, zinc cyanide or a complex compound of one of them with an alkali metal cyanide and is employed in about 1 to 8 mol % relative to the alkali metal cyanide, and the mixture of aprotic solvent, heavy metal cyanide and alkali metal chloride remaining in the reaction vessel when the reaction has ended is used directly as the reaction medium for a further batch.
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- Trimethylsilyl Cyanide - A Reagent for Umpolung, VIII. Derivatives of 2-(Trimethylsilyloxy)-2-propenenitrile. Syntheses and General Properties
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Rather different derivatives of the new title compuond 7 were synthesized by routes A - H (Table 2 and 3).The effects of substituents and reaction routes on the E/Z ratios (NMR) is discussed.Replacement of SiMe3 in 7 by RCO- and MeSO2- yields other alkenes with donor (O - X) and acceptor groups (CN) at the same C-atom.Their opposite effects on the β-C-atom is estimated from the corresponding 1H- and 13C-NMR signals.
- Hertenstein, Ulrich,Huenig, Siegfried,Reichelt, Helmut,Schaller, Rainer
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p. 261 - 287
(2007/10/02)
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