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The temperature dependence of the heat capacity of a first-generation siloxane dendrimer with terminal trimethylsilyl groups is determined for the first time via high-precision adiabatic vacuum calorimetry in the temperature range of 6 to 347 K, and by differential scanning calorimetry in the temperature range of 330 to 410 K. An anomalous change in heat capacity is detected in the range of T = 42–76 K. A transition is observed in the range of T = 137–153 K, due to devitrification of the dendrimer. The thermal stability of the compound is studied via thermogravimetric analysis. The obtained experimental data are used to calculate standard thermodynamic functions of the dendrimer in the temperature range T → 0 to T = 400 K, along with the standard entropy of its formation at T = 298.15 K.

(1R,4R,5S-5-{[(tert-Butyldimethylsilyl)oxy]methyl}-4-(trimethylsilyl)cyclopent-2-ene-1-carbaldehyde in a toluene–DBU–O2 medium undergoes a tandem-type isomerization/oxidation transformation to form (3S,4S,5S)-5-{[(tert-butyldimethylsilyl)oxy]methyl}-3-hydroxy-4-(trimethylsilyl)cyclopent-1-ene-1-carbaldehyde in a good yield. Possible way of formation of the product was proposed, involving the C3-oxidation of the starting allylsilane by a carbanion/enolate mechanism.

The surface modification of poly[1-(trimethylsilyl)propyne] (PTMSP) film via a thiol-ene click reaction with sodium 3-mercapto-1-propanesulfonate has yielded membranes having a CO2 permeance as high as 530 GPU with a CO2/N2 selectivity of 21. This level of performance, together with the simplicity of this surface modification, suggests that such materials could become viable alternatives to some of the most promising membrane materials that are currently being explored for the practical capture of CO2 from flue gas.

A cyclic (R2 SnAu)3 anion (3- , R2 Sn=2,2,5,5-tetrakis(trimethylsilyl)-1-stannacyclopentane-1,1-diyl) has been synthesized as a stable blue salt with K+ (THF)6 through the reaction of stable dialkylstannylene 1 with R'3 PAuCl (R'=Et, Ph) followed by the reduction with KC8 . Crystallographic and NMR analysis shows that the six-membered (SnAu)3 ring of 3- is planar and highly symmetric with an equal distance of six Au-Sn bonds. A UV/Vis spectrum of 3- in hexane reveals an intense absorption maximum at 598 nm. While cyclic Au3 - with four valence electrons is known as unstable anti-aromatic anion, 3- with three divalent tin ligands is stable σ aromatic anion with an unprecedented Mobius orbital array as predicted by the perturbation MO and CCSD analysis of 3- .

A green chemical approach for silicon containing 4-iodo-3-trimethylsilylpyrano[4,3-b]quinolines, 8 is established through DIH mediated regioselective electrophilic iodocyclisation of unactivated internal alkynes, 7 with high yields. An excellent 6-endo-dig regioselectivity owing to the behaviour of DIH in different solvents was observed.

The origin of the large difference of room-temperature fluorescence yields (Φf(RT)) among tris(trimethylsilyl)silylated oligothiophene derivatives was investigated. Tris(trimethylsilyl)silylated th...

A closed synthetic cycle for the transformation of carbon dioxide to carbonate with a mid-valent tris(aryloxide)-ligated uranium(IV) terminal oxo complex is presented herein. Starting from the previously reported uranium(III) complex, [UIII(OArAd,Ad,Me)3], the uranium(V) terminal oxo complex, obtained by oxidation with N2O or NO, can be reduced with KC8 to yield CO2 activating anionic uranium(IV) oxo complexes [(Ad,Ad,MeArO)3UIV(O)]−. The cycle proceeds with the formation of [(Ad,Ad,MeArO)2(κ2-Ad,Ad,MeArOCO2)UIV(μ-κ1:κ2-CO3)]− upon reaction of the oxo anion with excess CO2 that adds to the terminal oxido ligand and inserts into the uranium–aryloxide bond. Treating this complex with trimethylsilyl halide eliminates both carbonates and generates, for instance, [K(2.2.2-crypt)][(Ad,Ad,MeArO)3UIV(I)2], which can ultimately be reduced with KC8 to recover the trivalent starting material, thus closing the cycle. In contrast, reaction of the 18-crown-6 stabilized U(IV) oxo analogue with CO2 yields a rare and isol...

A simple derivatization reaction with N,N-dimethylformamide dimethyl acetal (DMF-DMA) was developed for the analysis of perfluorocarboxylic acids (PFCA, C4–C12) in solid samples by gas chromatography–mass spectrometry (GC–MS). After extraction with methyl tert-butyl ether (MTBE), the samples are mixed with derivatizing agent and injected into GC. The derivatization reaction takes place in injection block forming corresponding N,N,N′,N′-tetramethyl diamines. The method provides excellent separation of nine PFCA (C4–C12) in 15 min and is characterized by good precision (max. RSD = 6.21% for 10 ng/mL, n = 6), linearity and detection limits in the range of 0.15–0.38 ng/mL. The main aim of the study was to develop a quick and easy GC–MS screening for PFCA. The method was successfully applied for sewage sludge, textiles and dental flosses. To confirm the laboratory evaluation, two samples were measured by an external laboratory using LC–MS/MS and showed comparable results. The proposed method is very promising, taking into account its simplicity, mild conditions and application of cost-effective GC–MS system. Additionally, a comparison with two other derivatization methods for PFCA: reaction with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and benzyl bromide is presented.

Aliphatic aldehydes readily react with nonstabilized azomethine ylides in one of the three ways to give oxazolidines, pyrrolidines, or Mannich bases, depending on the structure of the starting compound and the reaction conditions. The use of N-(methoxymethyl)-N-[(trimethylsilyl)methyl]benzylamine in DMF provided 5-alkyloxazolidines in 40–97% yields. On the other hand, three-component reactions of aliphatic aldehydes bearing one α-hydrogen with N-methyl(benzyl)glycine and formaldehyde gives Mannich bases in yields of 47–98%. A similar reaction of aldehydes bearing branched alkyl groups and two hydrogen atoms at the α-position proceeds as a domino process that gives 3-alkyl-3-formylpyrrolidines in yields of 34–93%.

Fluoroethylene carbonate (FEC) has been proven an effective electrolyte additive for silicon-based Li-ion cells. However, studies have shown that it will promote the formation of acid during storage and cycling in LiPF6-based electrolyte, thus deteriorating the performance of cell. Herein, tris(trimethylsilyl)phosphite (TMSPi) and fluoroethylene carbonate (FEC) are used as combinative electrolyte additive for LiNi0.6Co0.2Mn0.2O2-SiOx/graphite (NCM622-SiOx/Gr) coin-type full cell. Electrolyte storage experiments show that TMSPi can eliminate the acid present in FEC-containing electrolyte. Theoretical calculations and electrochemical analysis confirm that TMSPi could be oxidized previously on NCM622 to optimize the cathode electrolyte interphase (CEI) and FEC can also be reduced in advance on SiOx/Gr to modify the solid electrolyte interphase (SEI). Such a full cell with 3% TMSPi + 5% FEC as electrolyte additive has the best electrochemical performance; the specific discharge capacity is maintained at 156.1 mAh g−1 after 200 cycles at rate of 1 C between 2.8 and 4.25 V. X-ray photoelectron spectroscopy results of electrode surface show that CEI has a certain amount of Li2CO3 and LixPOyFz and lower LiF, while SEI has a certain amount of Li2CO3 and LiF and less LixPOyFz, which could be beneficial to improve the cyclic stability of NCM622-SiOx/Gr full cell.

This study was designed to develop a fast and convenient methodology for the preparation of 10-nonyl acridine orange (NAO) and its silyl analogues to improve their photo-physical properties for the detection and quantification of cardiolipin (CL). Optimized conditions allow the effective synthesis of NAO analogues with good yield and excellent purity. The introduction of a 3-(trimethylsilyl)propyl moiety improves the dye's solubility and stability in buffer solution and increases its emission intensity by ≈30%. The novel dye can be used for the selective quantification of CL in a liposomal inner mitochondrial membrane model with greater fluorescence intensity and linear slope compared to NAO. The novel silicon-containing NAO analogue has lower cytotoxicity, and is a convenient fluorescent dye for cell staining.

A novel carboxylation radiosynthesis methodology is described starting from cyclotron-produced [11C]CO2 and fluoride-activated silane derivatives. Six carbon-11 labelled carboxylic acids were obtained from their corresponding trimethylsilyl and trialkoxysilyl precursors in a one-pot labelling methodology. The radiochemical yields ranged from 19% to 93% within 12 minutes post [11C]CO2 delivery with a trapping efficiency of 21-89%.

The direct synthesis of methyl acrylate (MA) from methyl acetate and trioxane at 350–380 °C is regarded as a supplementary route for the industrial propylene oxidation process; however, it suffers from rapid catalyst deactivation. Herein, a novel ionic liquid catalyzed mild liquid-phase system was developed for the direct synthesis of MA from methyl acetate and trioxane, where N,O-bis(trimethylsilyl)acetamide (BSA) was used as a probase for α-deprotonation and enol silyl etherification of methyl acetate. The trioxane decomposition to formaldehyde and methyl acetate enolization to 1-methoxy-1-trimethylsilyloxyethene proceeded with the catalysis of [Cation]Cl/MClx (M = Cu+, Fe3+, Zn2+ and Al3+) and [Cation]F, respectively. The cations and anions were observed to have significant effects on the yield and selectivity of MA, owing to the steric hindrance, acid site category and strength confirmed by pyridine probing FT-IR characterization. As a result, up to 60.2% yield with 94.6% selectivity of MA could be achieved when [N3,3,3,3]F and [N3,3,3,3]Cl/AlCl3 with 67 mol% AlCl3 were used in the presence of BSA at 25 °C. Kinetic studies indicated that the trioxane decomposition with the activation barrier of 41.2 ± 0.3 kJ mol−1 was the rate-determining step.

An ethanolic extract at 50% obtained by maceration process was characterized by GC-MS using a Shimadzu QP2010 spectrometer and the Silylation agent was N,O-bis (trimethylsilyl) trifluoroacetamide (BSTFA). The compounds were analyzed using GC/MS NIST21 and NIST107 libraries and having into account the results obtained after phytochemical screening and comparing the results with NISTDEMO Software. After 78 minutes of running 859 chemical components were identified from the sample, and among them, the presence of five essential oils, six triterpenes and/or steroids, an anthracene derivative, six aminoacids or their derivatives, and one flavonoid were tentatively characterized. The sample also contains a lot of amount of reductants sugars and their derivatives, hydrocarbons, and aromatic and/or aliphatic acids (unsaturated and saturated).

Unsymmetrical C–Si bond bifunctionalization of 2,2′-bis(trimethylsilyl) diphenylmethanol via “on–off–on” sequential [1,4]-Csp2 to O-silyl migration installs Csp3/Csp3, Csp3/Csp2 or Csp2/Csp3 in one pot, giving sterically congested unsymmetrical diarylmethanols in good yields.

A method was developed for the synthesis of 2,2′-bis(trimethylsilyl)- and 2,2′-bis(triethoxysilyl)-azobenzenes based on oxidation of 2-(silyl)anilines with trimethylamine and N-methylmorpholine oxides in the presence of CuX (X = Cl, Br).

A simple and sensitive procedure has been developed for the determination of 1-hydroxypyrene in urine as a biological marker of the effects of polycyclic aromatic hydrocarbons. After enzymatic hydrolysis for conjugate cleavage, the analyte was extracted from the matrix by liquid–liquid extraction with n-hexane, the extract was evaporated to dryness, and the analyte was derivatized with the silylating reagent N,O-bis(trimethylsilyl)trifluoroacetamide into trimethylsilyl ether at room temperature. The trimethylsilyl extract was analyzed by capillary gas chromatography with mass-selective detection. Quantitative high-precision determination was achieved with the use of the isotope-labeled 1-hydroxypyrene-d9 reference standard. No matrix effects were observed. The detection limit was 0.02 ng/mL, and the linearity range was 0.1–100 ng/mL. Relative standard deviations were 0.044 and 0.064 under the conditions of repeatability and intralaboratory precision, respectively. The percentage recovery was 96–102%.

A class of aryne precursors, that is, 2-(trimethylsilyl)aryl 4-chlorobenzenesulfonates, has been developed through well-established synthetic routes, which allow the formation of arynes under relatively mild conditions. All the aryne precursors were obtained from phenols and 4-chlorobenzenesulfonyl chloride, an inexpensive and easy-to-handle reagent with relatively low toxicity, and subjected to nucleophilic addition reactions, providing addition products in yields of 24 to 92%, and to cycloaddition reactions, affording cycloadducts in yields up to 80%. This work provides interesting insights into the mechanisms of aryne generation. In addition, 2-(trimethylsilyl)phenyl 4-chlorobenzenesulfonate was successfully employed in the total synthesis of (±)-aporphine.

Tris(trimethylsilyl)silane (TTMSS) is introduced as a non-toxic and kinetically superior hydrogen source for the photo-driven reduction of trithiocarbonates from poly(methyl methacrylate), polystyrene, and poly(vinyl pyridine)s (PVP)s created through RAFT polymerization. No other reagents were necessary and quantitative reduction is achieved under UV- and blue-light irradiation. PVP reduction and sequestering of chain combination events is investigated for the first time.

A general procedure for the synthesis of 2-substituted tetrahydro-1,3-thiazepines by MW-assisted cyclization of 4-thioamidobutanols is presented. The acyclic precursors were prepared in high overall yields by an expeditious three-step diacylation/thionation/deprotection sequence from 4-aminobutanol. Microwave-assisted ring closure of 4-thioamido alcohols promoted by trimethylsilyl polyphosphate (PPSE) in solvent-free conditions allowed for the synthesis of several hitherto unreported seven-membered iminothioethers bearing 2-aryl, alkenyl, aralkyl and alkyl substituents. The cyclodehydration reaction is likely to involve an SN2-type displacement and affords good to excellent yields of the desired heterocycles in very short reaction times.

The initiator-free electrochemical trifluoromethylsilylation and cyanosilylation of aldehydes were developed in an undivided cell. A DFT study reveals that the direct cathodic activation of trimethylsilyl reagents significantly released the congestion around the 'Si' atom, allowing the Si-O bond affinity to form concerted anion intermediates with aldehydes. Thus, intramolecular -CF3 and -CN migration make the reactions much easier to carry out without initiators.

Efficient gas-separation systems comprising gas-permeable membranes are important for energy conservation in various industrial applications. Herein, high-molecular-weight copolymers (2ab and 2ac) were synthesized in good yields by the copolymerization of 1-(p-trimethylsilyl)phenyl-2-(p-trimethylsilyl)phenylacetylene (1a) with 1-phenyl-2-(p-tert-butyl)phenylacetylene (1b) and 1-phenyl-2-(p-trimethylsilyl)phenylacetylene (1c) in various monomer feed ratios using TaCl5–n-Bu4Sn. Tough membranes were obtained by solution casting. The copolymers exhibited very high gas permeabilities (PO2: 1700–3400 barrers). Desilylation of 2ac membranes decreased the gas permeability, but desilylation of 2ab membranes resulted in a significant increase in the gas permeability. The highest oxygen permeability coefficient obtained was 9300 barrers, which was comparable to that of poly(1-trimethylsilyl-1-propyne), a polymer known to have the highest gas permeability.

The reactions between terminal ethynylpyridines, (trimethylsilyl)ethynylpyridines and cyclopentadienyliron dicarbonyl iodide were studied under Pd/Cu-catalyzed conditions to develop a synthetic approach to the σ-alkynyl iron complexes Cp(CO)2Fe–CC–R (R = ortho-, meta-, para-pyridyl). Depending on the catalyst and reagents used, the yields of the desired σ-pyridylethynyl complexes varied from 40 to 95%. In some cases the reactions with ortho-ethynylpyridine gave as byproduct the unexpected binuclear FePd μ-pyridylvinylidene complex [Cp(CO)Fe{μ2-η1(Cα):η1(Cα)-κ1(N)-CαCβ(H)(o-C5H4N)}(μ-CO)PdI]. The conditions, catalysts, and reagents that provide the highest yields of the desired σ-pyridylethynyl iron compounds were determined. The methods developed allowed the synthesis of the corresponding σ-4-benzothiadiazolylethynyl complex Cp(CO)2Fe–CC–(4-C6H3N2S) as well. Eventually, synthetic approaches to σ-alkynyl iron complexes of the type Cp(CO)2Fe–CC–R (R = ortho-, meta-, para-pyridyl, 4-benzothiadiazol-2,1,3-yl) based on the Pd/Cu-catalyzed cross-coupling reactions were elaborated.

The reaction of acetophenone hydrazones with TeCl4 in the presence of DBU gave a mixture of divinyl ditellurides and divinyl tellurides, which easily reacted with Cu powder in refluxing toluene to afford divinyl tellurides in good yields. The reaction of divinyl tellurides with bromine (1.2 eq.) gave the corresponding tellurium dibromide rather than the addition of the double bond whereas 3 molar amount of bromine gave excess brominated and oxidized products. The reaction of divinyl tellurides with 2-(trimethylsilyl)phenyl triflate in the presence of CsF gave (E)-2-alkenyldiaryl tellurides in good yields.

The synthesis of the novel room temperature stable titanacyclopropane derivative Cp*Ti(η2-C2H4)(η5-C5H4AdH) (2) in a one-step-two-transformation protocol and first insights into its reactivity are presented, including the synthesis of the corresponding bis(trimethylsilyl)acetylene complex Cp*Ti(η2-Me3SiC2SiMe3)(η5-C5H4AdH) (4). Given these results, a novel one-pot procedure toward Cp2Ti(η2-Me3SiC2SiMe3) was subsequently developed.

Herein, novel photoinduced catalyst-free deborylation–deuteration of arylboronic acids with D2O is reported. The protocol was compatible with a variety of functionalities, including halogen, alkoxy, cyano, sulfonyl, trimethylsilyl, trifluoromethoxy, alkyl, hydroxyl, free acid, amide, and heteroaromatic rings. A wide range of deuterated products were obtained in good yields with a high level of deuteration. This method provides a green and practical pathway to synthesize deuterium labelled compounds under mild conditions.

Attempts have been made to prepare salts with the labile tris(trimethylsilyl)chalconium ions, [(Me3Si)3E]+ (E=O, S), by reacting [Me3Si‐H‐SiMe3][B(C6F5)4] and Me3Si[CB] (CB−=carborate=[CHB11H5Cl6]−, [CHB11Cl11]−) with Me3Si‐E‐SiMe3. In the reaction of Me3Si‐O‐SiMe3 with [Me3Si‐H‐SiMe3][B(C6F5)4], a ligand exchange was observed in the [Me3Si‐H‐SiMe3]+ cation leading to the surprising formation of the persilylated [(Me3Si)2(Me2(H)Si)O]+ oxonium ion in a formal [Me2(H)Si]+ instead of the desired [Me3Si]+ transfer reaction. In contrast, the expected homoleptic persilylated [(Me3Si)3S]+ ion was formed and isolated as [B(C6F5)4]− and [CB]− salt, when Me3Si‐S‐SiMe3 was treated with either [Me3Si‐H‐SiMe3][B(C6F5)4] or Me3Si[CB]. However, the addition of Me3Si[CB] to Me3Si‐O‐SiMe3 unexpectedly led to the release of Me4Si with simultaneous formation of a cyclic dioxonium dication of the type [Me3Si‐μO‐SiMe2]2[CB]2 in an anion‐mediated reaction. DFT studies on structure, bonding and thermodynamics of the [(Me3Si)3E]+ and [(Me3Si)2(Me2(H)Si)E]+ ion formation are presented as well as mechanistic investigations on the template‐driven transformation of the [(Me3Si)3E]+ ion into a cyclic dichalconium dication [Me3Si‐μE‐SiMe2]2 2+., Labile chalconium ions of the type [(Me3Si)3E]+ (E=O, S) were generated by reacting [Me3Si‐H‐SiMe3][B(C6F5)4] and Me3Si[CB] (CB−=carborate=[CHB11H5Cl6]−, [CHB11Cl11]−) with Me3Si‐E‐SiMe3. A ligand exchange in case of the oxonium species, leading to the surprising formation of the persilylated [(Me3Si)2(Me2(H)Si)O]+ oxonium ion, was observed. With Me3Si[CB] as silylating reagent, a cyclic dioxonium dication of the type [Me3Si‐μO‐SiMe2]2[CB]2 was isolated in an anion‐mediated reaction.

The Ti(O-iPr)4 and EtMgBr-catalyzed regio and stereoselective carbocyclization of N-allyl-substituted 2-alkynylamines with Et2Zn, followed by deuterolysis or hydrolysis, affords the corresponding methylenepyrrolidine derivatives in high yields. It was found that Ti–Mg-catalyzed carbocyclization of N-allyl-substituted 2-alkynylamines with Et2Zn is equally selective in dichloromethane, hexane, toluene, and diethyl ether. The reaction was tolerant to the presence of aryl, alkyl, trimethylsilyl, methoxymethyl and aminomethyl substituents on the alkyne. A selective method was proposed for the preparation of bis-pyrrolidine derivatives using Ti–Mg-catalyzed carbocyclization of bis-allylpropargyl amines with Et2Zn.

Kinetic modeling is effective in the development of efficient and manageable polymerization systems. Herein, a kinetic model of the group-transfer polymerization (GTP) of an alkyl crotonate using a silicon Lewis acid catalyst having a trialkylsilyl (trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, or triisopropylsilyl) moiety and various silyl ketene acetals with a corresponding trialkylsilyl moiety as an initiator is developed to understand the polymerization mechanism. The kinetic model quantitatively verifies proposed elementary reactions. When using a trimethylsilyl moiety, the activation energy of the cyclization reaction (a well-known termination reaction in GTP; Ec = 37.8 kJ mol−1) exceeds that of the propagation reaction (Ep = 28.6 kJ mol−1). This reveals that termination reactions are accelerated more than propagation reactions at high temperatures. In addition, comparison of various trialkylsilyl moieties confirmed that the greater bulkiness of the alkyl substituent on the silyl group increases the ratio of the activation energies of the cyclization and propagation reactions.

In this account, examples of the influence of equilibrium and mesomerism/valence tautomerism on reactions of selected group 4 metallocene complexes will be discussed. Complexes of bis(trimethylsilyl)acetylene Me3SiC2SiMe3 (mono-functional alkynes: C[triple bond, length as m-dash]C) in Cp'2M(η2-Me3SiC2SiMe3) (Cp' = substituted η5-cyclopentadienyl), of α-di-Ph2P- (hetero-tri-functional: P, C[triple bond, length as m-dash]C, P) in Cp'2M(η2-Ph2C2PPh2), and of α-mono-SiH- (hetero-bi-functional: C[triple bond, length as m-dash]C, SiH) and α-di-SiH-substituted alkynes (hetero-tri-functional: SiH, C[triple bond, length as m-dash]C, SiH) in Cp'2M(η2-Me3SiC2SiMe2H) and Cp'2M(η2-HMe2SiC2SiMe2H), respectively, were considered. Additionally, unusual all-C-metallacycles like metallacyclopentynes Cp'2M[η2-C(R2)-C2-C(R2)-] (formed by coordination of tri-functional trienes: C[double bond, length as m-dash]C, C[double bond, length as m-dash]C, C[double bond, length as m-dash]C), five-membered metallacycloallenes Cp'2M[η2-C(R)[double bond, length as m-dash]C[double bond, length as m-dash]C(R)-C(R2)-] (formed by coordination of bi-functional enynes: C[double bond, length as m-dash]C, C[triple bond, length as m-dash]C), metallacyclocumulenes Cp'2M[η2-C(R)[double bond, length as m-dash]C[double bond, length as m-dash]C[double bond, length as m-dash]C(R)-] (formed by coordination of bi-functional diynes: C[triple bond, length as m-dash]C, C[triple bond, length as m-dash]C), and seven-membered metallacyclocumulenes Cp'2M[η2-C(R)[double bond, length as m-dash]C(C2R)-C(R)[double bond, length as m-dash]C[double bond, length as m-dash]C[double bond, length as m-dash]C(R)-] (formed by coordination of two bi-functional diynes: C[triple bond, length as m-dash]C, C[triple bond, length as m-dash]C), with M = Ti, Zr, and Hf were selected as examples for considerations of equilibrium and mesomerism/valence tautomerism. On the basis of spectroscopic investigations, their molecular structures and selected calculations, it is discussed how the different interpretations of the equilibrium and mesomerism/valence tautomerism are in line with observed reactivity patterns.

Методом газовой хроматографии с масс-спектрометрическим детектированием исследован качественный и количественный состав корней заманихи (Oplopanax) двух видов. Извлечение компонентов из исследуемых объектов осуществляли путем экстрагирования сухого измельченного сырья 70% этанолом. Для анализа полярных соединений экстракты дополнительно дериватизировали, получая соответствующие триметилсилильные производные. Идентификацию компонентов проводили с использованием коммерческих (NIST17, Wiley14) и собственной пользовательской библиотек масс-спектров. Процентное содержание найденных компонентов вычисляли, используя площади соответствующих хроматографических пиков. В результате исследований обнаружено 130 соединений различных классов: терпены и их производные, спирты, альдегиды, полиины, полиены, различные кислоты и их производные, фенолы, стеролы, лигнаны, витамины, нуклеозиды, гликозиды и сахара. Установлено, что качественный и количественный состав экстрактов корней варьируется даже в пределах одного вида. Выявлено наличие 26 общих для двух видов Oplopanax соединений, включающих 12 кислот, 3полиина, 6 терпенов и по одному представителю из класса полиенов, альдегидов, лигнанов, гликозидов и стеролов. Врезультате проведенного сравнительного анализа установлено, что 4 соединения из класса полиинов (ацетат фалькариндиола, ацетат оплопандиола, оплопантриол А и оплопантриол В) встречаются только в корнях O. horridus., The qualitative and quantitative composition of two species of Oplopanax root was studied by gas chromatography with mass spectrometric detection. Extraction of components from the investigated objects was carried out by extraction of dry ground raw material with 70% ethanol. For the analysis of polar compounds, the extracts were further derivatized to give the corresponding trimethylsilyl derivatives. Identification of components was carried out using commercial (NIST17, Wiley14) and own custom mass-spectrometer libraries. The percentage of components found was calculated using the areas of the corresponding chromatographic peaks. Found in these samples were 130 compounds of various classes: terpenes and their derivatives, alcohols, aldehydes, polyyns, polyenes, various acids and their derivatives, phenols, sterols, lignans, vitamins, nucleosides, glycosides and sugars. It has been established that the qualitative and quantitative composition of root extracts varies even within the same species. The presence of 26 compounds common to the two species of Oplopanax, including 12 acids, 3 polyyns, 6 terpenes and one representative each from the class polyenes, aldehydes, lignans, glycosides and sterols, was revealed. As a result of the comparative analysis, it was established that 4 compounds from the class of polyyns (falcarindiol acetate, oplopanediol acetate, oplopantriol A and oplopantriol B) are found only in the roots of O. horridus.

The 9-phenyl-9-fluorenyl (PhF) group has been used as an Nα protecting group of amino acids and their derivatives mainly as a result of its ability to prevent racemization. However, installing this group using the standard protocol, which employs 9-bromo-9-phenylfluorene/K3PO4/Pb(NO3)2, often takes days and yields can be variable. Here, we demonstrate that the PhF group can be introduced into the amino group of Weinreb's amides and methyl esters of amino acids, as well as into alcohols and carboxylic acids, rapidly and in excellent yields, using 9-chloro-9-phenylfluorene (PhFCl)/N-methylmorpholine (NMM)/AgNO3. Nα-PhF-protected amino acids can be prepared from unprotected α-amino acids, rapidly and often in near quantitative yields, by treatment with N,O-bis(trimethylsilyl)acetamide (BSA) and then PhFCl/NMM/AgNO3. Primary alcohols can be protected with the PhF group in the presence of secondary alcohols in moderate yield. Using PhFCl/AgNO3, a primary alcohol can be protected in good yield in the presence of a primary ammonium salt or a carboxylic acid. Primary sulfonamides and amides can be protected in moderate to good yields using phenylfluorenyl alcohol (PhFOH)/BF3·OEt2/K3PO4, while thiols can be protected in good to excellent yield using PhFOH/BF3·OEt2 even in the presence of a carboxylic acid or primary ammonium group.

A one-pot method for the synthesis of 3-(pyridin-2-yl)-2,3-dihydroazetes was developed on the basis of Rh2(esp)2-catalyzed reaction of diazoesters with 3-aryl-2-(pyridin-2-yl)-2H-azirines. To prevent deactivation of the catalyst with the pyridine-containing azirine reactant, the trimethylsilyl protection of pyridine nitrogen was used. The insertion and removal of the protecting group were carried out as a onepot synthesis. Reactions involving ethyl 2-diazo-3,3,3-trifluoropropanoate proceed stereoselectively with the formation of only the (2RS,3SR)-isomer of the dihydroazete, which is due to the thermodynamic control of the process.

The electrolyte additives tris(trimethylsilyl)phosphite (TMPSi) and tris(trimethylsilyl)phosphate (TMSPa) have shown their potential to improve lifetime and decrease impedance build-up in lithium i...

A tantalum-catalyzed solvent-free approach for the construction of amide bonds with 1-(trimethylsilyl)imidazole is developed, and the mild reaction conditions are applicable to a wide variety of electrophilic amino acid homologues. This approach delivers a new class of peptides in high yields without any epimerization.

C24H66Li6Si6, triclinic, P1̄ (no. 2), a = 12.2492(9) Å, b = 12.4617(9) Å, c = 14.3841(11) Å, α = 74.189(6), β = 74.543(7), γ = 85.970(6), V = 2036.2(3) Å3, Z = 2, R gt(F) = 0.0465, wR ref(F 2) = 0.0802, T = 173(2) K.

Reactions of dichlorodimethylsilane with 2,3,4,5-tetrafluorophthalic acid bis(trimethylsilyl) ether (1:1, 20°C, 24 h) without a solvent and dichloro(chloromethyl)methylsilane and dichloro(methyl)phenylsilane with bis(trimethylsilyl) ester of ortho-phthalic acid (1:1, 20°C, 168–264 h) in hexane lead to the formation of previously unknown 14-membered cyclic organosilicon esters of ortho-phthalic acids (silacyclophanones) in 36–85% yields. Molecular structures of 14-membered cyclic ethers 4,10-dimethyl-4,10-diphenyl-3,5,9,11-tetraoxo-4,10-disyla-1,7(1,2)-dibenzacyclododecaphane-2,6,8,12-tetraone, 4,4,10,10-tetramethyl-3,5,9,11-tetraoxo-4,10-disila-1,7(1,2)-di-(tetrafluorobenza)cyclododecaphane-2,6,8,12-tetraone, along with bis(trimethylsilyl) esters of 2,3,4,5-tetrafluorophthalic and orthophthalic acids, were studied by X-ray structural analysis.

Herein, the deprotonative functionalization of pyridine derivatives with aldehydes under ambient conditions has been demonstrated using an amide base generated in situ from a catalytic amount of CsF and a stoichiometric amount of tris(trimethylsilyl)amine (N(TMS)3). Pyridine substrates bearing two electron-withdrawing substituents (i.e., fluoro, chloro, bromo, and trifluoromethyl moieties) at the 3- and 5-positions efficiently react at the 4-position with various aldehydes including arylaldehydes, pivalaldehyde, and cyclohexanecarboxaldehyde.

The electroreductive coupling of 1-alkoxycarbonyl-4-quinolones with benzophenones in the presence of trimethylsilyl chloride gave adducts reacted at the 2-position of 4-quinolones as trimethylsilyl ethers. The adducts were transformed to 2-(diarylhydroxymethyl)-4-quinolones. The electroreduction of 1,3-diethoxycarbonyl-4-quinolones and polyhalogenated 3-alkoxycarbonyl-1-alkyl-4-quinolones with benzophenones also gave adducts reacted at the 2-position of 4-quinolones. On the contrary, the electroreductive coupling of 1,3-diethooxycarbonyl-8-methoxy-4-quinolones occurred at the 4-position of 4-quinolones to give 4-substituted quinolines.

A novel method for the N−N bond cleavage of trimethylsilyl diazomethane is reported for the synthesis of terminal nitride complexes. The lithium salt of trimethylsilyl diazomethane was used to generate a rare terminal nitrilimine transition metal complex with partially occupied d‐orbitals. This iron complex 2 was characterized by CHN combustion analysis, 1H and 13C NMR spectroscopic analysis, single‐crystal X‐ray crystallography, SQUID magnetometry, 57Fe Mössbauer spectroscopy, and computational analysis. The combined results suggest a high‐spin d 6 (S=2) electronic configuration and an allenic structure of the nitrilimine ligand. Reduction of 2 results in release of the nitrilimine ligand and formation of the iron(I) complex 3, which was characterized by CHN combustion analysis, 1H NMR spectroscopic analysis, and single‐crystal X‐ray crystallography. Treatment of 2 with fluoride salts quantitatively yields the diamagnetic FeIV nitride complex 4, with concomitant formation of cyanide and trimethylsilyl fluoride through N−N bond cleavage., Chain reaction: A fluoride salt cleaves the N–N bond of an iron trimethylsilyl nitrilimine complex and generates the terminal nitride, fluorotrimethylsilane, and cyanide. The complementary reactivity of nitrilimine and azido ligands provides a new approach for the synthesis of metal terminal nitrido complexes.

A novel synthetically important reaction has been developed for the quick, convenient, and high-yield preparation of trimethylsilyl esters of phosphorus(III) acids, synthetically valuable Michaelis–Arbuzov reaction precursors. Commercially and synthetically available initial compounds used are derivatives of propan-2-ol phosphorylated in the second position capable of long-term storage and available silylating reagents: hexamethyldisilazane, bis(trimethylsilyl)acetamide, and diethyl(trimethylsilyl)amine. Also, a stepwise reaction scheme of the starting compounds with silylating reagents has been proposed.

Extending the chemistry of disilene fluoride adducts studied earlier by us, we investigated the formation of 1,1-bis(trimethylsilyl)fluorodiphenylsilylsilanide, which was prepared by reaction of (Me3Si)3SiSiPh2F with KOtBu. The formed FPh2SiSi(Me3Si)2K displays distinctively different structural and spectroscopic features compared to the earlier reported F(Me3Si)2SiSi(SiMe3)2K. While the latter eliminates metal fluoride upon reaction with MgBr2, the respective magnesium silanide is formed from FPh2SiSi(Me3Si)2K. Reaction of (Me3Si)3SiSiPh2Cl with KOtBu proceeded similarly, but the formed ClPh2SiSi(Me3Si)2K easily undergoes potassium chloride elimination to the disilene Ph2Si═Si(SiMe3)2. Compared to F(Me3Si)2SiSi(SiMe3)2K, which can be regarded as a disilene fluoride adduct, structural, spectroscopic, and reactivity properties of FPh2SiSi(Me3Si)2K distinguish it as a β-fluorodisilanide.

The reactions of propargylamines 1,4 -bis(3-phenylprop-2-yn-1-yl)piperazine ( 1 ) and 1,4 -bis(3-(trimethylsilyl)prop-2-yn-1-yl)piperazine ( 2 ) with PdCl 2 and CuI is described. 1,4 -Bis(3-phenylprop-2-yn-1-yl)piperazine reacts with one equivalent of PdCl 2 to afford κ 2 - N,N -coordinated complexes [PdCl 2 {Me 3 SiC ≡CCH 2 NC 4 H 8 NCH 2 C≡CSiMe 3 -κ 2 - N,N ] ( 3 ) and [PdCl 2 {Me 3 SiC ≡CCH 2 NC 4 H 8 NCH 2 C≡CSiMe 3 }-κ 2 - N,N ] ( 4 ). The reactions of 1 and 2 with two equivalents of PdCl 2 yielded rare chloropalladated tetranuclear complexes [Pd 4 ( μ -Cl 4 )Cl 4 (PhC≡CCH 2 NC 4 H 8 NCH 2 C≡CPh) 2 ] ( 5 ) and [Pd 4 ( μ -Cl 4 )Cl 4 (Me 3 SiC ≡NC 4 H 8 NCH 2 C ≡C SiMe 3 ) 2 ] ( 6 ), respectively, resulting from the trans nucleophilic addition of chloride ion onto the electrophilic C ≡C bond. The reactions of 1 and 2 with two equivalents of CuI produced 2-D coordination polymers [{Cu 2 ( μ -I)} 2 (PhC≡C–CH 2 NC 4 H 8 NCH 2 C≡CPh)] n ( 7 ) and [{Cu 2 ( μ -I)} 2 (Me 3 SiC ≡CCH 2 NC 4 H 8 NCH 2 C≡CSiMe 3 )] n ( 8 ), respectively. Similar reactions in 1:1 M ratios produced dimeric complexes [Cu 2 ( μ -I) 2 (PhC≡CCH 2 NC 4 H 8 NCH 2 C≡CPh) 2 ] ( 9 ) and [Cu 2 ( μ -I) 2 (Me 3 SiC ≡CCH 2 NC 4 H 8 NCH 2 C≡CSiMe 3 ) 2 ] ( 10 ), respectively. The structures of compounds 3 , 5 and 7 have been established by single crystal X-ray analysis.

Two alternative synthetic approaches to new silicon-containing oligo(arylenevinylenes), 1,4-bis-{(E)-2-[4-(trimethylsilyl)phenyl]ethenyl}benzene and 9,10-bis{(E)-2-[4-(trimethylsilyl)phenyl]ethenyl}anthracene via Heck reactions of trimethyl(4-vinylphenyl)silane with the corresponding dibromoarenes and of (4-bromophenyl)trimethylsilane with the corresponding divinylarenes were studied. The reaction of 9,10-divinylanthracene with (4-bromophenyl)trimethylsilane was found to be accompanied by elimination of one trimethylsilyl group.

A novel and easily accessible MN(SiMe3)2 (M = Li or Na)/Cs2CO3 co-catalyzed benzylation of in situ generated N-(trimethylsilyl) aldimines with toluene derivatives has been successfully developed. T...

Twofold unsymmetrical C-Si bond bifunctionalization of 2,6-di(trimethylsilyl) benzyl alcohols has been achieved in one pot via sequential [1,4]-Csp2 to O-silyl migration. The hydroxyl group functions as an "on-off-on" switch to control two successive silyl migrations, and 4,7-dimethyl-o-phenanthroline ligand favors cleavage of the endocyclic C-Si bond. Diverse Csp3/Csp3 or Csp2/Csp3 electrophiles can be installed at the 2- and 6-positions. This approach was used to chemoselectively functionalize the three C-Si bonds of 2,4,6-tri(trimethylsilyl) benzyl alcohol, transforming it into isochroman derivatives. The approach even works as a five-component reaction to construct complex symmetric structures.

A contrapositionally substituted derivative of cyclohexa-meta-phenylene ([6]CMP) was synthesized by an intramolecular Yamamoto coupling reaction of an appropriate terphenyl unit containing a trimethylsilyl substituent. Iododesilylation of the trimethylsilyl groups of the product with iodine monochloride was used to incorporate iodo groups, an important functionality for metal-catalyzed coupling reactions. The iodo groups were also converted into a (pinacolato)boryl groups, another important functionality for coupling reactions. The diborylated [6]CMP is expected to be a versatile potential comonomer and a precursor for the synthesis of CMP-based materials. The synthetic route to the disubstituted [6]CMP included lithiation, Pd-catalyzed borylation, Suzuki coupling, and Yamamoto coupling. The structure of the product was established by NMR spectroscopy and mass spectrometry.