Carbon common functional groups

Electron spin resonance (esr) (6,44) has had more limited use in coal studies. A rough estimate of the free-radical concentration or unsatisfied chemical bonds in the coal stmcture has been obtained as a function of coal rank and heat treatment. For example, the concentration increases from 2 X 10 radicals/g at 80 wt % carbon to a sharp peak of about 50 x 10 radicals/g at 95 wt % carbon content and drops almost to zero at 97 wt % carbon. The concentration of these radicals is less than that of the common functional groups such as hydroxyl. However, radical existence seems to be intrinsic to the coal molecule and may affect the reactivity of the coal as well as its absorption of ultraviolet radiation. Measurements from room... 

The polarity patterns of some common functional groups are shown in Table 5.1. Carbon is always positively polarized except when bonded to a metal. 

Figure 3. Schematic representation of the common functional groups that are present on carbon (a) quinone (b) phenol (c) carboxyl (d) carbonyl (e) lactone (f) hydrogen.

Functional groups are either attached to the carbon backbone of a molecule or form part of that chain. Examples are the chlorine atom in chloroethane, CH3CH2CI, and the OFF group in ethanol, CFF CI OFi. Carbon-carbon multiple bonds, such as the double bond in 2-butene, are also often considered functional groups. Table 19.1 lists the most common functional groups. Double and triple carbon-carbon bonds were considered in Chapter 18. In the following eight... 

In Organic I you probably started with the hydroccirbons, compounds of carbon and hydrogen, including the alkenes and alkynes that contained double and single bonds, respectively. Then you probably touched on some of the more common functional groups, such as alcohols and maybe even some aromatic compounds. 

FIGURE 1-15 Some common functional groups of biomolecules. In this figure and throughout the book, we use R to represent "any substituent." It may be as simple as a hydrogen atom, but typically it is a carbon-containing moiety. When two or more substituents are shown in a molecule, we designate them R1, R2, and so forth. 

While the carbon-carbon double bond is a common functional group in complex natural products, it is far rarer in simple natural compounds. 

The addition of sp3 or sp2 carbon-centred radicals to unsaturated carbon carbon bonds is yet another class of synthetically useful reactions promoted by the low-valent lanthanide reagent Sml2. Halides and sulfones are the most common functional groups used as precursors to radicals, although other groups have also been successfully employed. Although the intermolecular variant of this reaction has found only limited application, intramolecular variants can be highly successful. In most of these cyclisation events, the... 

There is a host of less common functional groups that involve unsaturated (i.e., multiply bonded) carbon and appear in the same downfield region of the 13C spectrum as carbonyls, for example, the central (sp hybridized) carbon of an allene linkage (C=C=C). Such carbons give very weak signals... 

The vast majority of organic molecules contain elements in addition to carbon and hydrogen. However, most of these substances can be viewed as hydrocarbon derivatives, molecules that are fundamentally hydrocarbons but that have additional atoms or groups of atoms called functional groups. The common functional groups are listed in Table 22.4. Because each functional group exhibits characteristic chemistry, we will consider the groups separately. 

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