Silicon organometallic compounds

Although inhibitors are deliberately added to the silicone formulation to control cure rate, unwanted cure inhibition can be caused by other species that react to form strong complexes with the platinum catalyst. Most notable of these undesired inhibitors include organotin and other organometallic compounds, sulfur, polysulfides, polysulfones or other sulfur-containing materials, amines, urethanes or amine-containing materials, unsaturated hydrocarbons in plasticizers, and some solder flux residues. 

The Peterson olefination can be viewed as a silicon variant of the Wittig reaction, the well-known method for the formation of carbon-carbon double bonds. A ketone or aldehyde 1 can react with an a-silyl organometallic compound 2—e.g. with M = Li or Mg—to yield an alkene 3. 

Van Dyke, C. H. Synthesis and Properties of the Silicon-Halogen and Silicon-Halogenoid Bond in Organometallic Compounds of the Group IV Elements, MacDiarmid, A. G. (Ed.), Vol. 2, Part 1, Marcel Dekker, New York, 1972, p. 184... 

Balog, M., Schieber, M., Patai, S., andMichman, M., Thin Films of Metal Oxides on Silicon by Chemical Vapor Deposition with Organometallic Compounds, J. of Crystal Growth, 17 298-301 (1972)... 

Aylett, B. J., and Tannahill, A. A., Chemical Vapour Deposition of Metal Silicides from Organometallic Compounds with Silicon-Metal Bonds, SIRA Int. Seminar on Thin Film Preparation and Processing Technolgy, Brighton, UK (March 1985)... 

Marciniec, B. Hydrosilylation and Related Reaction of Silicon Compounds. In Applied Homogeneous Catalysis with Organometallic Compounds Cornils, B., Herrmann, W. A., Eds. VCH Weinheim, Germany, 1996 pp 487-506. 

Experimental and estimated thermodynamic data of homoleptic dialkylzinc compounds are listed in Table 3. Like many organometallic compounds, the lower dialkylzincs have a positive enthalpy of formation, and only the incorporation of silicon atoms in the /3-position imparts significant thermodynamic stability. The mean Zn-C bond rupture enthalpies, all of which are quite low, follow a similar trend as the bond lengths in these compounds. Thus, the presence of methyl substituents in the a-position weakens the zinc-carbon bonds, while silyl substituents strengthen them. 

It is somewhat disappointing to realize that the thermochemistry of germanium, tin and lead organometallic compounds is still at the level achieved ten years ago, in contrast to the considerable recent efforts to probe the energetics of the silicon analogues. The data analysis in the previous sections shows that many key values are either missing or require experimental confirmation. To a certain extent, an overall discussion of the thermochemical data for Ge, Sn and Pb is therefore hindered by the probable inaccuracies and the uncertainties that affect those values. 

C.R. Johnson, Sulfoximides, in D. Barton u. W.D. Ollis, Comprehensive Organic Chemistry, Bd. 3, D.N. Jones, Sulphur, Selenium, Silicon, Boron, Organometallic Compounds, S. 223, Pergamon Press, Oxford New York Toronto Sydney Paris - Frankfurt 1979. 

Jones, Sulphur, Selenium, Silicon, Boron, Organometallic Compounds, S. 237, Pergamon Press, Oxford New York Toronto. Sydney Paris Frankfurt 1979. 

---