Silicon-attached Hydrogen Research Articles

Ein Zirconiumamid‐Komplex mit Si‐β‐H–Zr‐Wechselwirkungen

A Zirconium Amide Complex with Si‐β‐H–Zr InteractionsZrCl4 (1) reacts in diethyl ether with Li[N(SiHMe2)2] (2) to form the title compound of formula [ZrCl(μ‐Cl){N(SiHMe2)2}2]2 (3). A single‐crystal X‐ray structure analysis in combination with IR data provides evidence for an unprecedented type of β‐hydrogen interactions between a silicon‐attached hydrogen atom of the bis(dimethylsilyl)amide ligand and the zirconium atom (Zr–N–Si–H).

Reactions of chloro(chlorophenyl)methylsilanes with hydride chlorosilanes

1. By the thermal condensation of hydride chlorosilanes with alkylchloro(chloroaryl)silanes we prepared phenylenebis[trichlorosilane], phenylenebis[chlorodimethylsilane], and the previously undescribed compounds: 1-(dichloromethylsilyl)-4-(trichlorosilyl)benzene, 1-(chlorodimethylsilyl)-4-(trichlorosilyl)benzene, 1-(chlorodimethylsilyl)-4-(dichloromethylsilyl)benzene, 1-(trichlorosilyl)-4-(trimethylsilyl)benzene, and 1-(dichloromethylsilyl)-4-(trimethylsilyl)benzene. 2. The side reaction of the reduction of chloro(chlorophenyl)silanes is accompanied by the replacement of not only silicon-attached hydrogen, but also silicon-attached methyl groups by chlorine (both in the starting compounds and in the reaction products). 3. The best yields of phenylenedisilanes are given by trichloro(chlorophenyl)silane (n=0), and as n (number of CH3 groups) increase the yield of the main product diminishes. In their reactivity in reactions leading to phenylenedisilane derivatives the alkylchloro(chloroaryl)silanes which we have investigated may be arranged in the following series: ClC6H4SiCl3>ClC6H4Si(CH3)Cl2>ClC6H4Si(CH3)2 · Cl2> ClC6H4Si(CH3)2Cl>ClC6H4Si(CH3)3.

Addition of arylfluorosilanes containing silicon-attached hydrogen

1. In additions to unsaturated compounds in presence of a H2PtCl6 catalyst, hydride arylfluorosilanes are considerably more reactive than their chloro analogs. 2. The arylfluorosilyl groups of difluorophenylsilane and difluoro-1-naphthylsilane add at both of the carbon atoms of the vinyl group of styrene (mainly at the α-carbon atom), whereas the dichlorophenylsilyl group of dichlorophenylsilane adds only, to the end carbon atom of the double bond. The fluorodiphenylsilyl group of fluorodiphenylsilane adds to almost equal extents at both carbon atoms of the vinyl group of styrene. 3. In high-temperature condensation with chlorobenzene the replacement of the chlorine atoms of dichlorophenylsilane by fluorine atoms leads to a reduction in the ratio of condensation and reduction products.

Dehydrochlorination of trichloro(2,3-dichloropropyl)silane

1. In the dehydrochlorination of trichloro(2,3-dichloropropyl)silane with quinoline Cl3SiCH2CH=CHCl and Cl3SiCH=CHCH2Cl are formed. 2. The addition of silanes containing silicon-attached hydrogen to 2-propynyl chloride leads to the formation of 3-chloropropenyl- and l-(chloromethyl)vinyl-silanes.

Synthesis of alkylcyclosilazanes containing silicon-attached hydrogen

1. Triethylcyclotrisilazane and tetraethylcyclotetrasilazane were synthesized and characterized. 2. The ammonolysis of dichloromethylsilane gives tetramethylcyclotetrasilazane and an individual product, which consisted of condensed rings and had the empirical formula (CH3SiH)6N2(NH)3. Both products were isolated and characterized.

Gas-phase reaction of bromo- and chloro-silanes containing silicon -attached hydrogen with some organic bromo compounds and with alkylchlorobenzenes

1. The gas-phase reaction of tribromosilane with organic bromides leads to a higher molar ratio of condensation products to reduction products (C/R) than the reaction of organic bromides with trichlorosilane under the same conditions. 2. The high-tempera fare reaction of mixtures of alkylchlorobenzene isomers with chlorosilanes containing siliconattached hydrogen leads to the formation of (alkylphenyl)chlorosilanes containing the same proportion of isomers in yields of 20.50%.

New method for the preparation of of organosilicon monomers by the high-temperature condensation of alkenyl chlorides, aryl chlorides, and olefins with silanes containing silicon-attached hydrogen

1. The high-temperature condensation (600–700°) of alkenyl and aryl chlorides with hydride silanes (i.e., silanes containing silicon-attached hydrogen) in a flow system at atmospheric pressure is a general method for the synthesis of alkenyl- and aryl-chlorosilanes. On the basis of this new method we developed syntheses, differing from those known previously in their simplicity and high yields, for various organosilicon monomers. 2. A reaction scheme is proposed for the high-temperature condensation of hydride silanes with alkenyl and aryl chlorides; the scheme requires the participation of free radicals. 3. A new reaction of hydride silanes with olefins leading to the formation of alkenylchlorosilanes was discovered.

Synthesis of unsaturated organosilicon compounds by the dehydrochlorination of chloro(3-chloroalkyl)silanes

1. A method was developed for the synthesis of unsaturated organosilicon compounds by the dehydrochlorination of various chloro(3-chloroalkyl)silanes with catalytic amounts of piperidine. 2. A method not requiring the use of an autoclave was developed for the synthesis of chloro(3-chloroalkyl)-silanes by the addition of various silanes containing silicon-attached hydrogen to 2-alkenyl chlorides in presence of H2PtCl6.

Reaction of acetylene with siloxanes and silanes containing silicon-attached hydrogen

1. The reaction of acetylene with disiloxanes (tetramethyl-, tetraethyl-, and diethyldimethyl-disiloxanes) was investigated. Polymers were obtained in the form of thick oils. 2. A study was made of the reaction of acetylene with chlorosilanes containing silicon-attached hydrogen (chloromethylphenyl- and dichloromethyl-silanes), and it was shown that at atmospheric pressure in presence of H2PtCl6 reaction proceeds with formation of 1,2-bis(alkyl(or aryl)chlorosilyl)ethanes.

Structures of substances formed in the high-temperature condensation of silanes containing silicon-attached hydrogen with trichloroethylene

As maintained by Murata [4], in the high-temperature condensation of trichlorosilane with trichlorethylene it is trichloro(2,2-dichlorovinyl)silane that is formed, andnottriehlorc(l,2-dichlorovinyl)silane.

Mechanism of the polymerization of alkenylsilanes containing silicon-attached hydrogen

1. An investigation was made of the polymerization of allyldialkylsilanes (containing silicon-attached hydrogen) in presence of platinized charcoal and in presence of tert-butyl peroxide. 2. The mechanism of the polymerization of alkenyldialkylsilanes, and therefore the structure of the polymer formed, differs according to the nature of the initiator used. 3. Polymers formed with the aid of platinum have a poly(trimethylenesilylene) structure: $$\begin{gathered} ---\begin{array}{*{20}c} R \\ | \\ {Si} \\ | \\ \end{array} ---CH_2 ---CH_2 ---CH_2 ---\begin{array}{*{20}c} R \\ | \\ {Si---} \\ | \\ \end{array} \hfill \\ R \hfill \\ \end{gathered} $$

Reaction of ethyl bromide with silicon

1. The reaction of ethyl bromide with silicon in presence of reduced copper was studied in the temperature range 260–380°. 2. The main reaction product was tribromoethylsilane, the yield of which increased considerably with rise in reaction temperature. As a result of the partial pyrolysis of ethyl bromide at the temperature of the formation of bromoethylsilanes, the formation of dibromodiethylsilane, and particularly of bromotriethylsilane, occurred to a much lower extent. The reaction products included also silicon compounds containing silicon-attached hydrogen, namely tribromo- and dibromoethyl-silanes.

Addition of 1-buten-3-yne to silanes containing silicon-attached hydrogen

1,3-Butadienlychlorosilanes were synthesized for the first time by reaction at room temperature between 1-buten-3-yne and silanes containing silicon-attached hydrogen in presence of a homogeneous platinum catalyst.

Chloroplatinic acid as a catalyst for the addition of silanes containing silicon-attached hydrogen to unsaturated compounds

1. Addition reactions of CH3SiHCl2 were carried out in presence of chloroplatinic acid with ethylene, propene, and acetylene at room temperature and with CH2 = CF2 and CF2 = CF2 at 160°. 2. It was shown that, as compared with reaction in presence of platinum on carriers, in the case of CH2 = CF2 the yield of addition products was increased by a factor of 3–4. whereas in the case of CH2=CH2, CH2 = = CH- CH3 and CH ≡ CH almost quantitative yields were obtained.

Addition of silanes containing silicon- attached hydrogen to unsaturated compounds in presence of platinized charcoal

1. It was shown that in the addition reaction between silanes containing silicon-attached hydrogen and unsaturated compounds in presence of platinized charcoal the structures of the reactants greatly affect the course of reaction: the highest yield of addition products is given by silanes of the types RSiHCl2 and R2SiHCl and by unsaturated compounds having “active” double bonds. 2. It was found that the addition of CH3SiHCl2 and of C2H5SiHCl2 to F2C=CF2 is accompanied by a telomerization reaction. 3. It was shown that it is possible to prepare silanes of the type RR'SiHBr by reaction of RSiHCl2 with R'MgBr and to prepare also compounds having a four-membered ring including a silicon atom by the cyclization, with the aid of magnesium, of γ-chloro compounds containing at least one silicon-attached chlorine atom.

Synthesis and polymerization of compounds in which hydrogen and an unsaturated radical are attached to silicon

Allyl-, 2-methylallyl-, and allyloxy-silanes containing silicon-attached hydrogen were synthesized for the first time and polymerized with formation of polymers having silicon atoms in the main chain.

Synthesis and properties of some vinyl-,phenyl-,and alkyl-silanes containing silicon-attached hydrogen. Stabilizing effect of chlorosilyl groups

1. Reduction of vinyl-, phenyl-, and alkyl-chlorosilanes with the aid of lithium hydride gave various vinyl-, phenyl-, and Alkyl-silanes. 2. The Raman spectra of compounds of formula HSiR3, H2SiR2, and H3SiR ( R is an aliphatic radical ) show that the quasielastic constant of the Si — H bond diminishes as the number of silicon-attached hydrogen atoms diminishes. 3. The dehydrochlorination of some alkyl (2-chloroethyl)silanes and an analogous disilabutane derivative was studied, and it was shown that there is a relationship between the dehydrochlorination reaction and the accompanying β -decomposition reaction. 4. It was shown that chlorosilyl groups have a stabilizing action in the dehydrochlorination reaction and, as chlorine atoms accumulate on silicon, the yield of β -decomposition products falls and the yield of dehydro-chlorination products rises; there is also a reduction in the reactivity of α-chloro compounds.

Synthesis and reactions of oxygen-containing organosilicon compounds

1. It was shown that reaction between alkydichlorosilanes containing silicon-attached hydrogen and alcohols in a ratio of 1 : 1 gives mainly alkoxyalkylhalosilanes RSiH (Cl) (OR???), for a ratio of 1 : 2 it gives mainly dialkoxyalhylsilanes RSiH(OR???)2, and for a ratio of 1 : 3 and for an excess of the alcohol it gives mainly trialkoxyalkylsilanes RSi (OR???)3. 2. The silicon-attached hydrogen atom of such alkylhalosilanes is readily converted into an alkoxy group. 3. A stepwise esterification scheme is proposed which is valid for alkyl-and aryl-halosilanes containing silicon-attached hydrogen.

Synthesis and reactions of vinyl compounds of silicon communication 2. Catalytic vinylation of halo- and alkyldihalo-silanes containing silicon-attached hydrogen

1. It was shown that halo- and alkyldihalo-silanes containing silicon- attached hydrogen (trichlorosilanes, dichloromethylsilane, and dichloroethylsilane) can be vinylated by passing them together with acetylene through a catalysis tube at 260°–300°. 2. This method dces not require the application of pressure and is technically simple.

Synthesis and reactions of oxygen-containing organosilicon compounds communication 6. Preparation of secondary dialkyl(or aryl)chlorosilanes and dialkyl(or aryl)silanols and some of their reactions

1. Dialkyl(or aryl)silanols containing silicon-attached hydrogen R2Si(H)OH and tetraalkyl(or aryl) disiloxanes of general formula were synthesized and characterized for the first time, Diethylethylisobutyl-, and ethylphenyl-silanols and symmetrical tetraethyl-, diethyldiisobutyl-, and diethyldiphenyldisiloxanes were prepared. 2. Chlorodiethyl-, chloroethylisobutyl-, and chloroethylphenyl-silanes were prepared for the first time. 3. It was shown dialkyl(or aryl)chlorosilanes (the example taken was chlorodiethylsilane) react with ammonia with formation of disilazanes . When hydrolyzed, 1,1,3,3-tetra ethyldisilazane gives diethylsilanol and 1,1,3,3-tetraethyldisiloxane. 4. When dialkylsilanols react with vinyl ethers, organosilicon acetals of the following structure are formed: (R1 and R2 are alkyl or aryl groups).