Silicones overview

Although these methods were applied for the synthesis of a number of various phthalocyanines with different central atoms (e.g., H2, Cu, Zn, Ni, Pt, Pd, Lu, etc.) not all metal phthalocyanines can be prepared by one of these methods. For example, the synthesis of silicon phthalocyanine, rhenium phthalocyanine and boron subphthalocyanine need more drastic conditions. In the following, an overview of the synthesis of phthalocyanines containing all central metals which have hitherto been inserted into the ring is given. 

The hydrogen content Ch greatly influences structure and consequently electronic and optoelectronic properties. An accurate measurement of Ch can be made with several ion-beam-based methods see e.g. Arnold Bik et al. [54]. A much easier accessible method is Fourier-transform infrared transmittance (FTIR) spectroscopy. The absorption of IR radiation is different for different silicon-hydrogen bonding configurations. The observed absorption peaks have been indentified [55-57] (for an overview, see Luft and Tsuo [6]). The hydrogen content can be determined from the absorption peak at 630 cm , which includes... 

Organometallic polymer precursors offer the potential to manufacture shaped forms of advanced ceramic materials using low temperature processing. Polysilazanes, compounds containing Si-N bonds in the polymer backbone, can be used as precursors to silicon nitride containing ceramic materials. This chapter provides an overview of the general synthetic approaches to polysilazanes with particular emphasis on the synthesis of preceramic polysilazanes. 

Boron-containing nonoxide amorphous or crystalline advanced ceramics, including boron nitride (BN), boron carbide (B4C), boron carbonitride (B/C/N), and boron silicon carbonitride Si/B/C/N, can be prepared via the preceramic polymers route called the polymer-derived ceramics (PDCs) route, using convenient thermal and chemical processes. Because the preparation of BN has been the most in demand and widespread boron-based material during the past two decades, this chapter provides an overview of the conversion of boron- and nitrogen-containing polymers into advanced BN materials. 

Rauter and her coauthors Xavier, Lucas, and Santos (Lisbon) present here a detailed overview of the potential for heterogeneous catalysts in useful synthetic transformations of carbohydrates. Such silicon-based catalysts as zeolites are easy to handle and recover, are nontoxic, and can offer interesting possibilities for exercising stereo- and regio-control in many established carbohydrate transformations. 

We will now proceed to provide an overview of chemical shift effects of 29Si when framework elements other than silicon and oxygen are present in zeolites. 

Lewis, L. N. From Sand to Silicones An Overview of the Chemistry of Silicones. In Silicones and Silicone-Modified Materials Clarson, S. J., Fitzgerald, J. J., Owen, M. J., Smith, S. D., Eds. ACS Symposium Series 729 American Chemical Society Washington, DC, 2000 pp 11-19. 

Pujol, J.-M. Frances, J.-M. Letoffe, M. Condensation Vulcanizing Silicone Elastomers An Overview of Research and Development. In Progress in Organosilicon Chemistry-, Marciniec, B., Ghojnowski, J., Eds. Gordon Breach Basel, 1995 pp 503—521. 

To treat all the different wet processes for silicon wafers developed in the last five decades exhaustively would make up a book of its own. However, a few basic aspects are important, because chemical etching of silicon is closely related to the electrochemical behavior of Si electrodes, especially to the OCP condition. A brief overview of the most common etching and cleaning solutions will be given, with emphasis on the electrochemical aspects. 

Table 2.2 gives an overview of the most common materials in silicon device manufacturing and their etch rates in different etching solutions. 

There are fewer studies devoted to the electrochemistry of silicon in alkaline electrolytes than is the case for HF. This can partly be ascribed to the fact that pore formation is not observed in alkaline electrolytes, which limits the field of applications. This section gives a brief overview of the characteristic features of I-V curves of silicon electrodes in alkaline electrolytes. 

This section gives a brief overview of theoretical investigations dealing with the properties of quantum-confined silicon structures. 

Silicon microstructures can be categorized according to the dimensionality of the confinement. Most PL studies deal with silicon structures confined in three dimensions such dot-like structures are designated zero-dimensional (OD). An overview of size-dependent properties of silicon spheres is given in Table 6.1. Standard methods of generating such microstructures are gas-phase synthesis [Di3, Li7, Scl2], plasma CVD [Ru2, Col, Ta8] or conventional chemical synthesis [Mal5]. 

Fig. 7.8 TEM images of the Si SiOx/C nanocomposite nanoparticles produced by hydrothermal carbonization of glucose and Si and further carbonization at 750 °C under N2. (a) Overview of the Si SiOx/C nanocomposites and a TEM image at higher magnification (in the inset) showing uniform spherical particles (b) HRTEM image clearly showing the core/shell structure (c), (d) HRTEM image displaying details of the silicon nanoparticles coated with SiOxand carbon.

The use of free-radical reactions in organic synthesis started with the reduction of functional groups. The purpose of this chapter is to give an overview of the relevance of silanes as efficient and effective sources for facile hydrogen atom transfer by radical chain processes. A number of reviews [1-7] have described some specific areas in detail. Reaction (4.1) represents the reduction of a functional group by silicon hydride which, in order to be a radical chain process, has to be associated with initiation, propagation and termination steps of the radical species. Scheme 4.1 illustrates the insertion of Reaction (4.1) in a radical chain process. 

An example of C—Si bond formation concludes this overview of carbon heteroatom bond formation. Reflux of bromide 62 in benzene and in the presence of small amounts of (TMS)3SiH and AIBN afforded the silabicycle 63 in 88 % yield (Reaction 7.64) [76]. The key step for this transformation is the intramolecular homolytic substitution at the central silicon atom, which occurred with a rate constant of 2.4 x 10 s at 80 °C (see also Section 6.4). The reaction has also been extended to the analogous vinyl bromide (Reaction 7.65) [49]. 

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