Highlights of Silicon Chemistry

To a great extent, the chemistry of silicon is the chemistry of the silicon-oxygen bond. Just as carbon forms unending —C—C— chains, the —Si—O— grouping repeats itself endlessly in silicates, the most important minerals on the planet, and in silicones, extremely long synthetic molecules that have many applications  

Silicone. These compounds have two organic groups bonded to each Si atom in a very long Si—O chain, as in poly(dimethyl siloxane)  

The organic groups, with their weak intermolecular forces, give silicones flexibility, while the mineral-like —Si—O— backbone gives them thermal stability and inflammability. 

Silicone chemists create structures similar to those of the silicates by adding various reactants to create silicone chains, sheets, and frameworks. Chains are oily liquids used as lubricants and as components of car polish and makeup. Sheets are components of gaskets, space suits, and contact lenses. Frameworks find uses as laminates on circuit boards, in nonstick cookware, and in artificial skin and bone. 

The first two elements of Group 5A(15), gaseous nonmetallic nitrogen (N) and solid nonmetallic phosphorus (P) have great industrial, environmental, and biological significance. Below these nonmetals are two metalloids, arsenic (As) and antimony (Sb), followed by the sole metal, bismuth (Bi), the last nonradioactive element in the periodic table [Group 5A(15) Family Portrait]. 

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How Ending Changes in the Carbon Family s Compounds Highlights of Carbon Chemistry Highlights of Silicon Chemistry... 

PDMS use in the IPN field is very attractive since it allows production of materials with good mechanical properties. Although, as will be described, depending on the targeted applications, some drawbacks of the silicones have to be overcome, such as either their hydrophobicity or their permeability. The silicone-containing IPNs are presented by preparation methods to highlight the PDMS chemistry and any issues of the processes. Many reports are dedicated to the point of view of application thanks to the useful properties of PDMS, however, the ins and outs such as kinetics, morphology or struc-ture/property relationships are also pointed in this discussion. 

Although silane adhesion promoters are probably the most known, used, and versatile, there are many others. Some are based on titanium, chromium, or zirconium, while others, still based on silicon chemistry totally differ in their structure from regular organosilanes. This section will highlight briefly a few examples with their chemistry, mechanisms, and fields of applications. 

Far less compounds have been reported which comprise heavier elements in the coordination sphere of their penta- or hexacoordinated silicon atom. During the past decade significant contributions emerged on the field of silicon coordinatirai chemistry with heavier lone pair donor atoms, and therefore this section will be dedicated to highlight these compounds. 

This volume of Topics in Current Chemistry aims to highlight major developments in the field and it shows the efforts of chemists from various subdisciplines of chemistry to design new dendritic molecules focusing on novel properties, functions, and potential applications. Hyperbranched/dendritic molecules containing silicon, phosphorus, and other elements are reported apart from hydrocarbon, carbohydrate and nucleic acid cascade molecules. 

A general review by Cundy et al. (76) on silicon-transition metal complexes has appeared, and again, we select only a few molecules to highlight different properties and chemistry within an isoelectronic group. In the four examples (Cp)Mn(CO)2(/u-H)Si(F)(Ph)2 (30), (Cp)Fe(CO)2Si-(F)(Ph)2 (31), (Cp)Mn(CO)2(M-H)Si(Cl)3 (32), and (Cp)Fe(CO)2Si(Cl)3 (33), compounds 30-31 and 32-33 are isoelectronic pairs based on the total number of valence electrons. Compounds 30 and 32 also form a related pair with respect to the three-center, two-electron Si—H—Mn interactions. 

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