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Highly efficient O-silylation of alcohol with vinylsilane was developed using a catalyst system consisting of [(COE)(2)RhCl](2) and HCl. In this reaction, a key intermediate is chlorosilane, generated from vinylsilane and HCl, which can be regenerated in the catalytic cycle. Various alcohols and vinylsilanes were applied to the preparation of silyl ether compounds with this catalyst system.

The reaction of α-chlorine-substituted allylsilanes with primary amines was promoted by CuCl to result in the selective formation of secondary amines bearing the vinylsilane functionality by a probable SN2′-allylation keeping the silyl group intact.

The stereoselective syntheses of pyrrolidine-fused aspartate and glutamate analogs, (S)-α-carboxymethyl-proline 3 and (S)-α-2-carboxyethyl-proline 4, using a chirality-transferring ester-enolate Claisen rearrangement of α-vinyl-α-acyloxysilane having a Boc-Pro as an acyloxy group, are described. The stereochemical outcome of the proline ester-derived ester-enolate Claisen rearrangement is also disclosed.

Sonogashira coupling of ( E)-α-iodovinylsilanes 1 with (trimethylsilyl)acetylene gave ( Z)-1,3-bis(trimethylsilyl)alk-3-en-1-ynes 2, which underwent a desilylation reaction to afford ( Z)-3-(trimethylsilyl)alk-3-en-1-ynes 3 in high yields. (1 E,3 Z)-1-Halo-3-(trimethylsilyl)-substituted 1,3-dienes 5 could be synthesised stereoselectively via hydrozirconation of ( Z)-3-(trimethylsilyl)alk-3-en-1-ynes 3, followed by trapping with iodine or N-bromosuccinimide.

Fluoroalkanoyl peroxide [RF-C(=O)OO(O=)C-RF] decomposes homolytically through concerted three bond radical fission to afford fluoroalkyl radical (RF·) selectively, although the corresponding alkanoyl peroxide [R-C(=O)OO(O=)C-R] decomposes homolytically through stepwise radical fission to afford acyloxy radical [R-C(=O)O·] and alkyl radical [R·]. This decomposition of fluoroalkanoyl peroxide was applied to the direct fluoroalkylation of two end-sites of vinylsilane oligomers and (meth)acrylate oligomers. Fluoroalkyl end-capped trimethoxyvinylsilane oligomers [RF-(CH2CHSi(OMe)3)n-RF] thus obtained were applied to the surface modification on glass and traditional organic polymers such as PMMA and rubbers to exhibit not only strong hydrohobicity but good oleophobicity imparted by fluorine with extremely higher adhesive property on their surface. Fluoroalkyl end-capped actylate and methacrylate oligomers exhibited surface active properties imparted by fluorine, the same as for low-molecular weight fluorinated surfactants, and these fluorinated cooligomers formed the nanometer size-controlled self-assembled molecular aggregates in aqueous and organic media. These fluorinated molecular aggregates interacted with a variety of guest molecules such as low molecular biocides, fullerenes, and carbon nanotubes to afford the corresponding fluorinated oligomers/guest molecules nanocomposites. These fluorinated oligomers were applied to the preparation of fluorinated oligomers/silica gel nanocomposites and cross-linked fluorinated oligomeric nanoparticles.

Pd-catalyzed intra-molecular olefin insertion/carbonylation reaction of optically active α-alkenyl-α-acyloxysilanes is described. The reactions proceeded in a stereoselective manner to give five- and six-membered optically active carbocycles having (E)-vinylsilane in their side chains. Under CO condition, optically active carbocycles containing one-carbon homologated side chain were produced by Pd-catalyzed tandem olefin insertion–carbonylation reaction.

An organosilane-based strategy has been used to accomplish the convergent total synthesis of (−)-exiguolide. The key steps involve: (1) geminal bis(silyl) Prins cyclization to construct the A ring; (2) silicon-protected RCM reaction to construct the 20-membered macrocycle; and (3) Hiyama–Denmark cross-coupling of vinylsilane with vinyliodide to install the triene side chain.

An organosilane-based strategy has been used to accomplish the convergent total synthesis of (−)-exiguolide. The key steps involve: (1) geminal bis(silyl) Prins cyclization to construct the A ring; (2) silicon-protected RCM reaction to construct the 20-membered macrocycle; and (3) Hiyama–Denmark cross-coupling of vinylsilane with vinyliodide to install the triene side chain.

The reactivity of aminosilane and vinylsilane with a dihydroxy (Bisphenol AF) crosslinkable fluoroelastomer containing only vinylidene fluoride (VF2) and hexafluoropropylene (HFP) was monitored using Differential Scanning Calorimetry (DSC) and X-ray Photoelectron Spectroscopy (XPS). The DSC results showed that the introduction of an aminosilane, or a combination of aminosilane and vinylsilane solutions, to the cure system of the fluoroelastomer resulted in a peak shift. This shift indicates that crosslinking in fluoroelastomer-silane system occurs at a lower temperature when aminosilane is present. Results also confirm that the organofunctional group on the silane reacts with the elastomer. XPS analysis of the silane-coated fluoroelastomer heated at 120 °C, 160 °C and 200 °C reveals that dehydrofluorination of the polymer is one of the steps in the reaction. It is our hypothesis that the amine group on the aminosilane is a contributor to the dehydrofluorination of the fluoroelastomer.

Tertiary amines with three different substituents, in one of which a vinylsilane functionality was included, were straightforwardly formed by the copper(I) chloride-catalyzed tandem reaction of primary amines, a-halogen-substituted allylsilanes, and electrophiles such as electron-deficient olefins, alkyl halides, alkyl tosylates, or epoxides. In the case using electron-deficient olefins as the electrophile, the addition of chloroacetone to the reaction system afforded the three-component coupling reaction more effectively. The addition of trimethyl borate as a co-catalyst improved the yields of the three-component coupling products in the reaction using alkyl halides, alkyl tosylates, or epoxides as the electrophiles, although the reaction times were lengthened.

Fluoroalkanoyl peroxide was reacted with 1,3-divinyltetramethyldisiloxane under very mild conditions to afford the fluoroalkyl end-capped vinylsilane oligomer containing vinyldimethylsiloxane segments. This fluoroalkyl end-capped vinylsilane oligomer was applied to the preparation of novel fluorinated block copolymers by the copolymerizations with traditional radical polymerizable monomers. It was demonstrated that these fluorinated block copolymers thus obtained can form the dendritic-type unimolecular micelles in aqueous solutions, and these fluorinated block copolymers were able to provide suitable host moieties to interact with fullerenes as guest molecules. Copyright © 2006 John Wiley & Sons, Ltd.

Silyl ethers can be produced from alcohols and vinyl-silanes under a rhodium(I) catalyst. The reaction is believed to proceed through an O-H bond cleavage of alcohol by rhodium(I) complex and a subsequent hydride insertion into vinylsilane followed by β-silyl elimination of the resulting β-silylethyl rhodium(III) complex.

The synthesis and characterization of octavinylsilsesquioxane (OVS)-based nanocomposite dendrimers with luminescent and charge transport properties are reported. The nanocomposite dendrimers were prepared in high yield using mild Heck chemistry of mono-haloaromatic compounds with the peripheral vinylsilane groups of OVS. Attachment of 2-naphthalene, 2-(9,9-dimethyl)fluorene, and 2-(4-phenyl)-5-(1-naphthyl)-1,3,4-oxadiazole resulted in materials with blue-violet emission (360–380 nm) and photo-luminescent quantum efficiencies (PLQEs) from 1 to 26%. Blue-green emission was observed for attachment of 1-pyrene, 9-anthracene, and N1-(4-phenyl)-N1,N4,N4-triphenylbenzene-1,4-diamine with PLQEs ranging from 23 to 50%. Despite the planar characteristics of the organic dendrons, the nanocomposite dendrimers are completely amorphous and have high glass transition temperatures (Tg) ranging from 115 to 186°C with decomposition temperatures (Td) exceeding 450°C. Matrix-assisted laser desorption ionization–time of flight shows that unlike traditional Heck chemistry, haloaromatic compounds are adding twice across the vinylsilane groups. Finally, organic light emitting diodes using the aromatic amine-based dendrimer as hole injection layers show 55% improvement in device efficiency over traditional materials (5.16 vs. 3.24 cd A−1) with brightness levels exceeding 40,000 cd m−2. © 2006 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 6: 157–168; 2006: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20080

Allylbenzene derivatives are ubiquitous frameworks in organic chemistry. Herein is described an efficient copper-catalyzed cross-coupling reaction using vinylsilanes and benzyl bromides, leading to the synthesis of allylbenzenes. This methodology allows the use of cis, trans and 1,1′-disubstituted vinylsilanes as well as a large number of sensitive moieties. © the Partner Organisations 2014.

The complex [Cp*Ru(MeCN)3]PF6 is shown to catalyze the hydrosilylation of a wide range of alkynes. Terminal alkynes afford access to alpha-vinylsilane products with good regioselectivity. Deuterium labeling studies indicate a clean trans addition process is at work. The same complex is active in internal alkyne hydrosilylation, where absolute selectivity for the trans addition process is maintained. Several internal alkyne substrate classes, including propargylic alcohols and alpha,beta-alkynyl carbonyl compounds, allow regioselective vinylsilane formation. The tolerance of a wide range of silanes is noteworthy, including alkyl-, aryl-, alkoxy-, and halosilanes. This advantage is demonstrated in the direct synthesis of triene substrates for silicon-tethered intramolecular Diels-Alder cycloadditions.

A series of new vinylsilane complexes of the type [W(CO) 5 (η 2 -H 2 C CHSiR 3 )] ( 1a – e ) and trans -[W(CO) 4 (η 2 -H 2 C CHSiR 3 ) 2 ] ( 2a – e ) (R = Me, OMe, OCH 2 CH 2 OMe, and Cl) have been synthesized photochemically and characterized by IR and 1 H, 13 C and 29 Si NMR spectroscopy. The values of the coordination shifts of the vinylic protons and carbons, Δ δ = δ (free vinylsilane) − δ (coordinated vinylsilane), strongly suggest that trimethylvinylsilane ( a ) is coordinated more loosely to the tungsten atom in compounds of type 1 and 2 than other vinylsilanes ( b – e ). The strongest dπ–π* interaction takes place between the carbonyltungsten moiety and trichlorovinylsilane. Analysis of 13 C NMR data of vinylsilane compounds revealed that the electron-donating methyl substituents and the electron-withdrawing chlorine substituents at the silicon atom cause opposite deviations from the ideal symmetrical η 2 -coordination of vinylsilane to the tungsten atom. The bis(vinylsilane) complexes 2a – e are shown to exist in several isomeric forms, whose solution dynamics were investigated by variable-temperature 1 H NMR studies.

Many efficient stereo- and regio-selective methodologies for synthesis of substituted vinylsilanes have been reported, involving mostly classical stoichiometric routes as well as, more recently, transition metal catalyzed transformations, in particular, hydrosilylation of alkynes and hydrogenation of silylalkynes. In the last two decades, two new reactions based on transformations of silicon derivatives catalyzed by transition metal complexes have been developed to provide universal routes for synthesis of well-defined molecular and macromolecular compounds with vinyl-silicon functionality commonly used in organic and polymer synthesis. These are the reactions of silylation of alkenes by hydrosilanes and by vinylsilanes. Since the synthetic aspects of these reactions have been recently discussed, this review is focused on the mechanism of homogeneous catalysis, i.e., the way of activation of Cvinyl H bond of alkenes as well as Si H and/or Si Cvinyl of silicon derivatives by late transition metal complexes both leading to vinyl-silicon containing compounds. The two reactions occur via the same active intermediates, i.e., late TM complexes involving M H and M Si bonds (where M is representative at iron- and cobalt-triades: for silylation by hydrosilane also nickel-triad). On the basis of experimental and theoretical studies of the reactivity, structure and catalytic activity of late transition metal complexes in the above mentioned reactions, particularly those reported in the last decade, generalized schemes for catalysis of both reactions have been proposed. The common crucial step of the two reactions catalyzed by complexes containing initially M H and/or M Si bond is an insertion of alkene into M Si bonds followed by β-H transfer to metal with elimination of substituted vinylsilane. In this case, a formation of M Si bond proceeds either via oxidative addition of hydrosilane (silylation by hydrosilane) or via insertion of vinylsilane into M H bond followed by β-Si transfer with evolution of ethylene (silylation by vinylsilane). Yet, if the catalysts contain initially no M H and M Si bond, their formation occurs via oxidative addition of hydrosilane (silylation by hydrosilane) or via preliminary oxidative addition of Cvinyl H of alkene to get M H bond, followed by insertion of vinylsilane to this bond and next β-Si transfer to metal with elimination of ethylene (silylation by vinylsilane).

Zeise-type complexes with vinylsilanes as π-ligands [K(18C6)][PtCl3(η2-CH2=CHX)] (X = SiMe3, 4; SiPh3, 5; Si(OMe)3, 6; 18C6 = 18-crown-6) and [K(18C6)]2[(PtCl3)2{η2,η2-(CH2=CHSiMe2)2O}] (7) have been prepared by the reaction of [K(18C6)]2[Pt2Cl6] (3) with the appropriate vinylsilanes. The identities of the complexes have been confirmed by NMR spectroscopy as well as for 4, 5 and (PPh4)[PtCl3{η2-CH2=CHSi(OMe)3}] (6′) also by single-crystal X-ray diffraction measurements. DFT calculations exhibited, that the coordination induced C=C bond lengthenings and the pyramidalization angles of the olefins in the vinylsilane complexes [PtCl3(η2-CH2=CHX)]− (X = SiMe3, 4c; SiPh3, 5c; Si(OMe)3, 6c) are the same as in Zeise's anion [PtCl3(η2-CH2=CH2)]− (8c) while the amount of the π back-donation in the vinylsilane complexes 4c–6c is higher than that in the ethylene complex 8c.

The electrochemical synthesis and characterisation of poly(methyl vinylsilane) and a series of poly(methyl vinylsilane-co-metallocenes) network polymers are described in detail. This class of polymers are not accessible through Wurtz coupling reaction and are however prepared by electro-reduction of dichloro methyl vinylsilane in a non-aqueous system using aluminum electrodes in a single compartment cell. These polymers have been characterised using UV, FTIR, XRD, SEM and NMR spectral techniques. Cyclic voltammetric studies of the above polymers reveal their conducting behavior. These polymers show optical properties as explained from the results. Polymers of this type are proposed as potential soluble precursors for SiC and metal doped SiC materials.

The silylcupration of allenes and the subsequent capture of the intermediate cuprate with alpha,beta-unsaturated nitriles is reported. The influence of the substitution of the nitrile, the nature of the silylcopper species, and the temperature on the selectivity of the reaction is studied. An interesting diaddition process was observed (1,2-addition and 1,4-addition), leading to oxo compounds which simultaneously have an allylsilane and a vinylsilane group. The different reactivity of these two units has been employed in the intramolecular allylsilane-terminated cyclization of these adducts, where the vinylsilane moiety remains unchanged. To shed some light on the reaction pathway, the behavior of alpha,beta-unsaturatedd imines was also checked and a new and convenient way for cycloheptane annulation presented. In light of the former results a feasible mechanism is proposed.

A catalytic acylation of vinylsilane with acid anhydride is accomplished by the use of [RhCl(CO)2]2, in which the transmetalation between vinylsilane and rhodium(I) carbonyl complex plays a key rol...

The regioselective hydrosilylation of the acetylenedicobalt complex on the terminal acetylene with special reference to the ligands to produce a vinylsilane is described. It was found that the use of the ligands exchanged dicobalttetracarbonyl bis(diphenylphosphino)methane complex dramatically changed the regioselectivity compared to the corresponding dicobalthexacarbonyl complex.

Two novel silicon-containing acetylenic synthons, 1-[dimethyl(ethynyl)silyl]-2-[ethynyl(methyl)-(vinyl)silyl]ethyne and bis[(ethynyldimethylsilyl)ethynyl](methyl)vinylsilane, were obtained by the reaction of diethynyl(methyl)vinylsilane with ethylmagnesium bromide and ethynylfluorodimethylsilane. The reaction of magnesium derivatives of the products and diethynyl(methyl)vinylsilane with organylhalosilanes gave macrocyclic polyunsaturated silahydrocarbons containing numerous endo- and exocyclic miltiple bonds.

Some circumstantial evidence for the directing effect of the 2-pyridylsilyl group in the Ru-catalyzed intermolecular Pauson-Khand-type reaction (PKR) of alkenyl(2-pyridyl)silane, alkyne, and carbon monoxide has been provided. Most importantly, we have succeeded in isolating several monometallic Ru complexes relevant to the catalytic reaction: Ru(vinylsilane)(CO)(3) complexes and ruthenacyclopentene. While the stoichimetric reaction of the Ru(vinylsilane)(CO)(3) complex with an alkyne led to the formation of the corresponding cyclopentenone (PKR product) at 100 degrees C, the ruthenacyclopentene intermediate was quantitatively produced at 50 degrees C. This complex was also converted to a cyclopentenone upon heating at 100 degrees C. Moreover, it was also found that the Ru(vinylsilane)(CO)(3) complex and ruthenacyclopentene serve as catalysts in intermolecular PKR.

[reaction: see text] A two-step approach that involves the synthesis of vinylsilane from allyl(isopropoxy)dimethylsilane (6) and the subsequent Pd-catalyzed cross-coupling of the resulting vinylsilane is applied in developing a novel diversity-oriented, three-component synthesis to homoallylic alcohols of common structure 1. Upon treatment of 6 with s-BuLi, the silylallylmetal 5 is generated and reacted with carbonyl compounds to produce functionalized vinylsilanes, which can couple with aryl/vinyl halides in the presence of palladium catalyst to afford 1.

New graft copolymer was prepared by incorporating tris(2-methoxyethoxy)vinylsilane (TMEVS) on ethylene-propylene-diene terpolymer (EPDM) by using dicumyl peroxide (DCP) as initiator, in Haake Rheocord 90 torque rheometer. The effect of EPDM concentration, TMEVS concentration, reaction time, reaction temperature and initiator concentration on the graft co polymerization was studied. The grafting efficiency of TMEVS on EPDM was confirmed by Fourier Transform infrared (FT-IR) spectroscopy. The grafting efficiency increased with increase in the silane concentration upto 6% by weight. The grafting efficiency decreased beyond 6% by weight due to homopolymerization of TMEVS and non-availability of carbon–carbon double bond in the EPDM terpolymer. The thermal properties of peroxide cured EPDM and hot water cured EPDM-g-TMEVS were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis. The results show thermal properties like degradation tempertature and glass transition temperature of the EPDM-g-TMEVS were increased due to introduction of TMEVS on to EPDM terpolymer as well as the formation of thermally stable three-dimensional network. Copyright © 2004 John Wiley & Sons, Ltd.

To produce high performance optical adhesives, adhesives were prepared by mixing triethoxy vinylsilane (TVSi) as a silane coupling agent into basic compositions consisting of 15 wt% 2-hydroxyethyl methacrylate (HEMA), oligo-siloxanyl dimethacrylate (SiMA) and acrylicacid tricyclo [5,2,1,02,6] decane (TCDA). When the composition includes TCDA from 43 to 69 wt%, copolymers polymerized from the composition exhibit high adhesion strength to glass, good optical transparency and excellent water-resistance. The high quality of the adhesives comes from microscopically homogeneous structures of the copolymers in which all components are mixed randomly.

In the presence of a catalytic amount of RuHCl(CO)(PR 3 ) n (R= i Pr, n =2; R=Ph, n =3), 1,1,2,2-tetramethyl-1,2-divinyldisilane ( 1 ) undergoes unexpected and clean isomerization via the Si–Si bond cleavage to yield a mixture of 6- and 5-membered cyclic compounds, 1,1,4,4-tetramethyl-1,4-disilacyclohex-2-ene and 1,1,2,3,3,-pentamethyl-1,3-disilacyclopent-4-ene, the former being the major product.

Treatment of trichlorovinylsilane with 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanol (3 equiv.) in the presence of excess triethylamine produces the fluorous vinylsilane, 1, which can be isolated in 74% yield as an analytically pure oil. The addition of bis(pentafluorophenyl)borane to 1 produces the fluorous boranes, 2a–2b, as an analytically pure, isomeric mixture of anti-Markovnikov and Markovnikov hydroboration products in 38% isolated yield. Compounds 2a–2b are soluble in both arene solvents and perfluoro(methylcyclohexane). Treatment of 2a–2b with excess trimethylphosphine generates a mixture of products, including the Lewis adduct, 3, which can be isolated as an analytically pure oil in 15% yield. When exposed to either dimethylaminopyridine or piperidine at room temperature, the trimethylphosphine donor in 3 is cleanly displaced, based on in situ 31P NMR studies; under similar conditions, triethylamine does not react with 3. Addition of either dimethylaminopyridine or piperidine to 2a–2b, followed by purification and subsequent treatment with an excess of either hydrogen chloride or p-toluenesulfonic acid, results in cleavage of the Si–O linkages and the regeneration of 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanol.Key words: fluorous, borane, silane, Lewis acid.

γ-Trimethylsilyl-substituted allylzirconcenes, prepared by hydrozirconation of trimethylsilyl-substituted terminal allenes, react with aldehydes at the γ-position to give 1,3-butadienes in one step with good stereoselectivity and undergo conjugate addition to α,β-unsaturated aromatic ketones at the α-position to selectively afford functionalized vinylsilanes in the presence of catalytic CuBr·SMe 2 .

Bismetallative cyclization of enynes with Bu3SnSiMe3 catalyzed by Pd(0) complex was realized for the first time, which gives cyclized products containing a vinylsilane moiety and a homoallyltin moiety in good yield. In this cyclization, Pd2(dba)3·CHCl3 or Pd(OH)2 on charcoal is effective as a Pd(0) catalyst and the addition of a phosphine ligand increased the formation of alkyne bismetallation by-product. On the other hand, it was found that a nucleophilic N-heterocyclic carbene could be utilized as a ligand for this cyclization. The utility of the cyclized products obtained from this cyclization in synthetic organic chemistry have been proven by transformation into cyclopropanol derivatives.

Various vinylsilanes, SiX(CHCH2)(CH3)[2-(CH3)2NCH2C6H4], and ethylsilanes, SiX(CH2CH3)(CH3)[2-(CH3)2NCH2C6H4] [X=Cl (1); OMe (2); H (3); F (4); OSiMe3 (5); NMe2 (6); Me (7)], were synthesized in order to investigate the electronic effect of vinyl group on silicon atom having an intramolecular coordination arm. The magnitude of Δδ (ethyl→vinyl for 29Si-NMR) of chlorosilane, 1, was the biggest one among 1–7. The differences of 29Si chemical shifts between vinylsilanes and ethylsilanes increased in the following order: X=Me, NMe2

Reaction of the Cramer's complex [{Rh(C 2 H 4 ) 2 (μ-Cl)} 2 ] with the appropriate vinylsilane molecules yields, by displacement of the ethylene ligands, the complexes [{Rh(η 2 -CH 2 CHSiR 3 ) 2 (μ-Cl)} 2 ] (where R 3 =Me 3 ( 1 ), Me 2 Ph ( 2 ), MePh 2 ( 3 ), Ph 3 ( 4 ), Me 2 (OSiMe 3 ) ( 5 )). The structures of 1 , 2 and 3 complexes have been determined crystalographically. There are the first crystal structures of dinuclear rhodium(I) complexes with monovinylsilanes. All complexes have been characterised by multinuclear NMR spectroscopy.

The substitution of a carbon atom by silicon provides an attractive, novel approach to modification of the thermal stability and volatility of metal-organic chemical vapor deposition precursors supported by β-diketonate ancillary ligands. The low temperature reaction of the lithium enolates of acetyltrialkylsilanes with acyl chlorides affords the sila-β-diketones, R′C(O)CH2C(O)SiR3 (R′=Me, Et, n-Pr, i-Pr, n-Bu, i-Bu, s-Bu, t-Bu; SiR3=SiMe3, SiEt3, SiMe2(t-Bu), SiMe2(t-hexyl), Si(i-Pr)3), in good yields. Multinuclear NMR studies suggest that the sila-β-diketones exist as the enolic tautomer with a vinylsilane isomeric structure. Homoleptic Cu(II) sila-β-diketonate complexes were prepared in a first pass study to evaluate how precursor performance is affected by modulation of the peripheral substituents in the ligands. Thermal analyses, (TGA, DSC) show that the silylated Cu(II) precursors (SiR3=SiMe3; R′=t-Bu or i-Bu) have greater volatility than the corresponding carbon analogues. Some of the new Cu(II) complexes exist as liquids or low melting solids, which are preferred states for industrial deposition processes. X-ray diffraction studies of selected copper complexes showed them to have typical, square planar geometry; calculations of molecular volumes suggest that packing in the solid-state is less efficient for the silicon-containing complexes than for the non-silylated analogues.

Vinylsilane monomers (vinyltrimethoxysilane (VTMOS) and vinyltriethoxysilane (VTEOS)), methyl methacrylate (MMA), tert-butyl acrylate (tBA) and N-vinyl-2-pyrrolidone (VP) were used in the synthesis of functionalized vinyl copolymers. By using these monomers, VTMOS-co-MMA, tBA-co-VP and VTEOS-co-VP, with various compositions, were synthesized. The copolymers were characterized by viscometry, 1H-NMR, FTIR and elemental analysis. The monomer reactivity ratios were estimated by the Fineman–Ross and Kelen–Tudos linear procedures. These parameters were also estimated by using a computer program based on a non-linear minimization procedure known as Reactivity Ratios Error in Variables Model. Random copolymers and others containing blocks of one of the monomer units were obtained, depending on the chemical nature of the comonomers. The estimated comonomer sequence and distribution are discussed in terms of structural properties of the monomers such as molecular volume of the side groups, electronegativity of the substituents and steric hindrance. Analysis by comparison with other copolymers with analogous structures was also performed. Copyright © 2003 Society of Chemical Industry

Polypropylene (PP)/polyamide blends were compatibilized with PP modified with vinylsilane or maleic anhydride and ethylene–propylene random (EPR) copolymer modified with maleic anhydride. The thermal behavior, mechanical properties, and morphology of the blends were investigated. Thermal analysis showed that the polyamide crystallization temperatures shifted downward with all compatibilizers, whereas its melting behavior did not change. On the other hand, polypropylene crystallization temperatures shifted upward in all cases, except for blends containing EPR modified with maleic anhydride. Tensile strength and elongation at break increased for blends compatibilized with modified PP. Blends containing up to 7% of EPR modified with maleic anhydride did not show good yield stresses. The morphology of the blends showed a finer dispersion of the polyamide minor phase in the PP matrix. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2492–2498, 2003

A vinylsilane-ketiminium ion cyclization involving iminium species derived from amines 6 and 7 was investigated experimentally as a possible approach to some biologically interesting 1-azaspirocycles. However, even under conditions of microwave irradiation at high temperatures no such cyclization was observed whereas (in line with previous results) the corresponding vinylsilane-aldiminium ion cyclizations were more successful. Aldiminium species substituted α to nitrogen displayed no diastereoselectivity in the cyclization of precursors derived from 6 while high trans diastereoselectivity could be obtained for iminium species derived from 7. Quantum-mechanical investigations of the general reaction mechanism underlined the lack of reactivity of ketiminium species and also convincingly explained the observed diastereoselectivities of aldiminium species. The calculations further revealed that (Z)-vinylsilanes cyclize via a silicon-stabilized β-carbocation, and that any formal aza-Cope rearrangement of the starting material to an allylsilane-iminium species does not take place in a concerted fashion. However, the calculations show that the aza-Cope rearrangement precedes cyclization for the corresponding (E)-vinylsilanes, the overall reaction being energetically slightly less favoured than cyclization of the (Z)-isomers.

Free-radical mediated cyclizative carbonylations of azaenynes were carried out using TTMSS as a radical mediator to compare the efficiency and the stereochemistry with those using tributyltin hydride. Using a substrate concentration of 0.1 M, the reactions gave good yields of alpha-silylmethylene lactams having four to seven-membered rings. The observed E-diastereoselectivity of the resulting vinylsilane moiety is in sharp contrast to the Z-selectivity observed during the analogous carbonylation using tributyltin hydride. When hexanethiol was used as the radical mediator, alpha-thiomethylene lactams were formed with E-favoring stereoselectivity again. Ab initio and DFT molecular orbital calculations on the stability of E and Z products were carried out for a set of five-membered methylene lactams bearing SnH3, SiH3, and SMe groups. The distinct thermodynamic preference for the Z-isomer was only predicted for the Sn-bearing lactam. A steric effect due to the bulky (TMS)3Si group is proposed for the E-selectivity observed in the TTMSS-mediated reaction.

Modified silicas were obtained by precipitation from aqueous solutions of sodium metasilicate and sulphuric acid. For the modification, silane coupling agents with various functional groups were applied, including aminosilane (AEAPTS), glycidoxysilane (GPTS), mercaptosilane (McPTS), and vinylsilane (VTMES). Extensive physicochemical evaluation of the obtained modified silicas was conducted, using FTIR, 29 Si CP MAS NMR and XPS techniques. The silica surface modification was proven to depend upon chemical reactions and to show intensity increasing with a rising concentration of a given modifier. A surface charge of the formed silica dispersions was also examined, by determining their zeta potential. Moreover, surface morphology, dispersion and particle size of the obtained silicas were evaluated, employing TEM electron microscopy and the technique of a dynamic light scattering (DLS). The studies demonstrated that application of hydrophobic type silanes for surface modification of the hydrated silicas restricted the intense tendency for agglomeration in the formed precipitated silicas.

Vinylsilanes serve as convenient vinyl anion equivalents which have gained popularity over decades. A variety of non-enolizable aromatic ketones are converted to the corresponding vinylsilanes in a one-pot procedure involving the addition of (trimethylsilylmethyl)lithium to aromatic ketones followed by addition of diethylaluminum chloride and then small amounts of water. Halide and alkoxide substituents are tolerated, and this trans-stereoselective (broad generalization; the most sterically bulky group on the double bond is trans to the trimethylsilyl group) reaction affords vinylsilanes in good yield.

A review, mainly of last 5 years, on the subject of fundamentals as well as technology of polyolefins' crosslinking with vinylalkoxysilanes (Fig. 1) on the background of other methods of such polymers' crosslinking. Threebase steps of this technology have been detaily presented, as follows: preparing of the polymer being able to crosslink (either by grafting of vinylsilane onto polyolefin or by copolymerization of olefin with vinylsilane), hydrolysis of alkoxysilane groups to silanol groups and condensation of the last ones with creation of -C-Si-O-Si-C- bonds connecting individual macromolecules. Thermal and mechanical properties of the products obtained this way (mainly all of PE-HD, PE-LD, PE-LLD and PP products) as well as their practical importance have been also described.

Novel siloxane tethered para divinylarene cyclophanes, containing phenyl, biphenyl and naphthalene rings as the aromatic nuclei, were prepared by the hydrolytic condensation of the corresponding bis{[dimethyl(i-propoxy)silyl]vinyl}arenes under basic conditions.The photophysics of the cyclophanes were investigated using UV and fluorescence spectroscopy.

Reaction of 1-lithio-8-dimethylaminonaphthalene with chlorodimethylvinylsilane gives the expected vinylsilane 4 in very poor yield in addition to a large quantity of polymeric material. In addition, the polycyclic silane 6 was obtained in 9% yield; complex 6 arises via an intramolecular cycloaddition of the silene intermediate 7.

New β-amino alcohols possessing a vinylsilane moiety were reacted with glyoxal to produce lactones that were transformed in three steps in enantiopure pipecolic acid derivatives. The key step was a...

In this work, the surface of inorganic fillers were modified with some functional groups such as stearic acid, aliphatic long chain, vinylsilane and aminosilane to control the interaction between inorganic fillers and polymer matrix. Ethylene-vinyl acetate copolymers (EVA) with various amount of vinyl-acetate and copolyether-ester elastomer were used as polymer matrix. The addition of inorganic fillers increases flame retardancy, but results in steep drop of electrical and mechanical properties, which may be caused by the defects in the interface between organic/inorganic hybrid composites. The hybrid composites are found to show better mechanical properties and higher volume resistivities as inorganic fillers are well dispersed and have good adhesion with polymer matrix. Also, the most effective type of functional group coated on fillers depends on the chemical structure of polymer.

Synthesis of the tricyclic BCD-ring segment with high stereoselectivity has been achieved starting from a sugar derivative directed toward the synthesis of the left part of ciguatoxin 1B. The central reactions in the synthesis are (i) ether ring formation mediated by an acetylene cobalt complex, (ii) decomplexation of the endo-acetylene cobalt complex to the vinylsilane, and (iii) ring-opening reaction of the epoxysilane into the allylic alcohol.

We have examined the formation of SiC thin films by chemical vapor deposition (CVD) using vinylsilane and investigated the chemical bonding state and crystallinity of the prepared SiC thin films. We achieved the formation of a Si–H–less SiC film at growth temperatures as low as 600 °C. Also, we investigated the in situ doping effect of N by the incorporation of NH3 gas in the SiC growth and demonstrated that the chemical composition of N in SiC thin films was controlled by adjusting the NH3 flow rate. In addition, we examined the growth of SiC thin films on a Cu substrate and achieved the formation of a SiC thin film while avoiding any significant reaction between SiC and Cu at a growth temperature of 700 °C.

Hydrosilylation of terminal and internal alkynes with chlorosilanes, alkylsilanes, and alkoxysilanes catalyzed by platinum on carbon are discussed. The yields of the isolated vinylsilanes are high and the selectivity of the product depends on the silane used. Hydrosilylation of alkynes with chlorosilanes produced the β-trans vinylsilanes, while alkyl and alkoxysilanes produced two or three vinylsilane isomers. The selectivity of the catalyst platinum on carbon is similar to Karstedt's catalyst in the reaction of phenylacetylene with triethylsilane or triethoxysilane. High resolution electron microscopy showed colloidal platinum to be present in these reactions.

A technique has been examined for reducing the extent of crosslinking resulting from 1,1-di(t-butylperoxy)-3,3,5-trimethylcyclohexane (L-231) initiating melt grafting of vinyltriethoxysilane (VTEOS) onto poly(ethylene-co-vinyl acetate) (EVA). Using measurements of crosslink density and VTEOS conversion, a standard of selectivity for the EVA/VTEOS/L-231 system at 145 °C was defined and used to assess the influence of a range of additives (0.25 mol per mole VTEOS). The data indicated that compounds such as 4-nonene, N,N-dimethylaniline, and cumene improve reaction selectivity, whereas dodecane and cyclohexyl acetate have no effect. A strong correlation between the minimum CH bond dissociation energy and the influence of a given compound is evident, suggesting that a labile CH bond is the key element of an effective additive. A mechanism of additive function on the basis of hydrogen atom donation is proposed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2397–2402, 2002