Functional groups defined

The names of organic compounds have some system. Each functional group defines a family (for example, alcohols, amines) and a specific modifier is added to identify a particular example (for example, ethyl alcohol, ethyl amine). As an alternate naming system, the family may be named by a general identifying ending (for example, alcohol names end in -ol) and a particular example is indicated by an appropriate stem (ethyl alcohol would be ethanol). These naming systems are illustrated in Tables 18-1 and 18-11. 

Functional Groups Defining Alkenes, Alkynes, and Aromatic Hydrocarbons... 

The [Rw] functional groups defined on the scaffolds and the attachment points [A] groups defined on the building blocks should not be linked to more than one atom. Examples such as UC[R1]C , C1CC[R1]1 , C[A]C , and UC1CC[A]1 are invalid. 

Substituent descriptors of the hydrogen-bonding ability of functional groups, defined by a set of rules [Yang et al, 1986]. 

There are many regularities and similar features in the chemical properties of the more common functional groups in chemistry. In earlier studies [18] a general framework has been developed for the analysis of the interrelations and transformations of flexible functional groups within the configuration space M of all possible chemical species of fixed overall stoichiometry S. This general approach is applicable for functional groups defined in terms of density domains. 

Spectroscopic studies are useful in structural investigations because they provide information which is complementary to that derived from diffractometric data. The information derived from spectra is not directly related to the coordinates of molecules in the unit cell. The spectra are, however, sensitive to the values of internal coordinates which define molecular structure. Thus they provide a basis for testing the degrees of equivalence of structures. Very often also, specific spectral features can be identified with particular functional groups defined by distinctive sets of internal coordinates. 

You learned that functional groups define the families to which organic compounds belong. At this point you should be able to name functional groups when you see them in structural formulas, and, when given the name of a functional group, draw a general example of its stmcture. 

A functional group defines the chemistry of a particular homologous series, but its reactivity can be influenced by its position in the carbon chain. We have seen that position isomers can exist within a series. It is important to realise that the characteristic properties of the group can be moderated by those shifts in position. Consequently it is useful to be able to describe different positions in a structure exactly. This is done by applying the terms primary, secondary and tertiary to identify the location of the carbon atom to which the functional group (e g. -OH, -X or —NH2) is attached in a molecule. 

GC columns with polysiloxane stationary phases are most commonly used (Figures 2.86 to 2.100). The polysiloxane backbone is either 100% methyl substituted, or in large variety modified with other functional groups defining the phase polarity and interaction. Modifications of the backbone as polysilarylene or siloxancarborane improves the thermal stability, a criterion of special importance for GC-MS trace analysis applications. The polar polyethylene glycol stationary... 

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