Silicon and derivs

Silicon Carbide. See in Vol 1, A79-L R. Also the following Addnl Refs (the numbers indicate the appropriate refs listed at the end of this article on Silicon and Derivatives ) ... 

Extra mild surfactants (nonionic) polyethoxylated sorbitan ester Combination with amphoteric or zwitterionic surfactants cocamidopropyl betaine Surfactants/glycol soap agents Cationic surfactants Cationic polymers Silicones and derivatives... 

We have considered all the known types of organic derivatives of silicon and we see how few is their number in comparison with the purely organic compounds. Since the few which are known are very limited in their reactions, the prospect of any immediate and important advance in this section of chemistry does not seem very hopeful. ... 

A bis(chelate) structure was found for the closely related germylene [MeC(NPr )2]2Ge, which was also made from GeCl2(dioxane) and 2 equivalents of the lithium amidinate (colorless crystals, 81%). The same synthetic approach was used to make bis(amidinato) metal dichlorides of silicon and germanium in high yields (83-95%). Rapid oxidative addition of chalcogen atom sources (styrene sulfide and elemental Se) to the germylene derivatives resulted in a series... 

In the alkylation of benzene with (dichloroalkyl)chlorosilanes in the presence of aluminum chloride catalyst, the reactivity of (dichloroalkyl)silanes increases as the spacer length between the C—Cl and silicon and as the number of chloro-groups on the silicon of (dichloroalkyl)chlorosilanes decreases as similarly observed in the alkylation with (cD-chloroalkyl)silanes. The alkylation of benzene derivatives with other (dichloroalkyl)chlorosilanes in the presence of aluminum chloride gave the corresponding diphenylated products in moderate yields.Those synthetic data are summarized in Table XI. 

The preference for formation of dihalocarbenes (but not the trihalomethyl radicals) upon thermolysis of trihalomethyl mercury, silicon and germanium derivatives seems to be a result of intermolecular coordination, of type [1], and of a thermodynamic preference for the carbene-forming pathway. The... 

The oxazasilolidine derived from pseudoephedrine incorporates chirality around the silicon and leads to enantioselective addition. 

Interaction of the lithium derivative with a range of chloro- and fluoro-derivatives of arsenic, boron, phosphorus, silicon and sulfur during warming to 25°C tended to be violently exothermic in absence of solvent. Thionyl chloride reacted with explosion. See Hexafluoroisopropylideneamine Butyllithium See other jv-metal derivatives... 

Isomerically pure 1 is obtained when HMes2SiSiPh2SiPh2SiMes2H (Mes = mesityl) 5 is used as a starting material, because bonds between silicon and methyl substituted aryl groups like p-tolyl or mesityl are cleaved much faster by hydrogen halides than Si-Ph bonds [3], Further reaction of I with HCl or HBr leads to the formation of the corresponding halo-derivatives 2 and 3 ... 

All these properties but the first and the last are also typical for cyclopentadienyl ligands, which are used extensively in organometallic chemistry. In organosilicon chemistry, the first stable monomeric silicon(II) derivative could be isolated with the aid of these ligands [3], It therefore seemed challenging to investigate the interaction of phosphinomethanides I with silicon centers. 

As mentioned above the 1,1-organoboration reaction is reversible, and exchange is slow on the NMR timescale. This statement is in agreement with the chemical behavior of equilibrated mixtures of products. Thus, treatment of silicon borahomoadamantane derivative 92 with bis(trimethylstannyl)ethyne leads to the tin-containing compound 93 and liberation of bis(trimethylsilyl)ethyne (Scheme 44). With pyridine, the equilibrium is moved toward 1-boraadamantane completely due to the complexation <2001JOM(620)51>. 

Compounds of this type, listed in Table 9, are available by interaction of triallylboranes with certain polyyne derivatives of silicon and tin. Their formation involves 1,1- and 1,2-allylboration of triple and double carbon-carbon bonds. 

Silicon enolates derived from ketones, thioesters, and esters reacted smoothly with different types of aldehyde in the presence of 5mol.% Sc(OTf)3 to afford the aldol adducts in high yields. 

The silicon(IV) phthalocyanine (12) is also effective in the photoinactivation of the parasite Plasmodium falciparum384 and various enveloped viruses in red blood cell concentrates.385-387 Other silicon (and aluminum) phthalocyanines have been evaluated for the photoinactivation of viruses cationic derivatives appear to be most effective.388... 

Bi- and poly-thioethers with aliphatic backbones are produced by attack of RS on the appropriate haloalkane. This is the method of choice for RS(CH2)raSR (R = Me or Ph),26 MeC(CH2SR)3,27,28 MeS(CH2)raS(CH2)raSMe (n = 2 or 3) and MeS(CH2)raS(CH2) S(CH2) SMe.28,29 [Caution Some of these syntheses involve sulfur mustard derivatives as intermediates - these are very powerful vesicants and should be handled only with extreme care.] The other tridentates RS(CH2)3S(CH2)3SR (R = Et, Pr or Ph) may be obtained from nucleophilic attack by RS on the ditosylate TsO(CH2)3S(CH2)3OTs.30 Tetra-dentate thioethers involving o-phenylene interdonor linkages are also known.31 More recently the preparation and coordination chemistry of the silicon-apex derivative MeSi(CH2SMe)3 has been described.32... 

Modelli and coworkers126 studied by PES and ETS (electron transmission spectroscopy) some silicon and tin derivatives of thiophene and furan, with the aim of following the energy gap between the HOMO and the LUMO as a function of the substituents. In particular they investigated the following tin derivatives ... 

Constrained-geometry heterocarbaboranes with silicon and germanium have been synthesized in moderate yield starting with the o-carborane derivative r,/6u,o-l-(CH2OH)-2-(Me)-l,2-C2B1oH10.47... 

---