Functional Groups Containing Heteroatoms

Sulfur, phosphorus, and silicon compounds Some absorption bands of the heteroatoms S, P, and Si commonly seen in organic compounds are listed in Tables 4.15 through 4.17. There are many classes of compounds containing S, P, and Si atoms detailed discussions of these compounds may be found in the texts already recommended. 

Functional Group Vibrational Mode and Strength Wavenumber (cm- ) 

The halide atom Is substituted directly on a carbon atom In an aromatic ring. 

Mercaptan, RSH Sulfide, RjS Disulfide, RSSR Thiocarbonyl, R2C=S Sulfoxide, R2S=0 Sulfone, R2SO2  

s (note that there are two other single bonds, not shown, from the sulfur atom to the two R groups) 

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Corrosion of steel in acid solution has practical importance hence, efforts to develop more efficient and environmentally compliant methods to prevent corrosion have been ongoing <1996SM(78)103>. Compounds with functional groups containing heteroatoms such as alkylimidazole <1996MI1> and triazole <1996MI2> compounds, which can donate lone pair electrons, are found to be particularly useful as inhibitors for corrosion of metals and have been used as effective inhibitors for steel in acidic media. 

Infrared spectroscopy is most effective for functional groups containing heteroatoms such as oxygen or nitrogen. Infrared spectroscopy cannot effectively determine aromaticity, because CH bands do not respond well, partic-... 

Since the fundamental studies of the Russian schools of Dubinin and Kiselev were carried out in the 1960s, the change in the approach of science toward application and concerns about environmental pollutions, directed the focus of scientific research toward studies of the adsorption of VOCs on carbons from the point of view of the feasibility of the removal process. Of course, this feasibility is related to the strength of the interactions, especially important at low concentrations, and the adsorption capacity (for high concentrations). Since that time also more has been done to understand specific interactions with the carbon surfaces, especially those decorated with functional groups containing heteroatoms [62, 63]. 

B IR Spectra of Some Functional Groups Containing Heteroatoms... 

In Sections 8.2 and 8.3, the main interactions of alkyl substituents and hydrogen atoms were steric interactions because dipole-dipole interactions and hydrogen bonding are not possible. If heteroatoms or functional groups containing heteroatoms are introduced into a carbon chain, however, the polarizing influence of these atoms and groups may have a profound influence on the rotamer populations of individual bonds and the conformation of molecules. 

The presence of functional groups containing oxygen-, nitrogen-, and phosphorus-chelating heteroatoms does frequently have regiochemical consequences in the... 

Systemization of experimental data on the syntheses of heterocyclic compounds with perfluoroalkyl groups from perfluoroolefins is based on reactions with various 1,1-, 1,2-, 1,3-, and 1,4-binucleophilic reagents. While the main features of nucleophilic reactions are preserved, further transformations of the primary products (or adducts, or the products of substitution of the functional groups at the internal multiple bond) occur under the influence of the added functional group containing a heteroatom. Here one can expect dramatic differences in the effect of the nature of the nucleophilic reagent between cyclizations by new nucleophilic centers and centers already available in the molecule. Another important aspect is isomerization of the primary internal olefin into the terminal olefin or internal olefin with a different structure under the action of the nucleophilic agent. This may be critical to the structure of the heterocycle formed. 

All functional groups contain a heteroatom, a n bond, or both, and these features make electron-deficient (or electrophilic) sites and electron-rich (or nucleophilic) sites in a molecule. Molecules react at these sites. To predict reactivity, first locate the functional group and then determine the resulting electron-rich or electron-deficient sites it creates. Keep three guidelines in mind. 

In Chapter 3 we learned that a functional group contains a heteroatom or n bond and constitutes the reactive part of a molecule. Alkanes are the only family of organic molecules that have no functional group, and therefore, alkanes undergo few reactions. In fact, alkanes are inert to reaction unless forcing conditions are used. 

Typical functional groups which are capable of polar interactions include hydroxyls, amines, carbonyls and groups containing heteroatoms such as... 

Ketones with useful heteroatomic functional groups containing nitrogen 199 2121, oxygen[163, 213 2171, phosphorus12181 and sulfur11 4, 18+1 219-2271 have been reduced by biocatalysts. For example, an intermediate in the synthesis of p-lactam antibiotics was obtained by microbial reduction of a P-keto ester as shown in Fig. 5-39(a)(1991, while yeast reduction of a p-keto dithioester afforded an easily separable mixture of p-hydroxy-dithioesters, the major component of which was converted enantiose-lectively into a sex attractant of the pine saw-fly as shown in Fig. 15-39(b)12191. 

Compounds with aromatic rings, C=C double bonds, or with functional groups containing double bonds to some heteroatoms, particularly when these structures are multiply... 

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