Groups for Substitutive Nomenclature

Listed in order of decreasing priority for citation as principal group or parent name 

Acid halides —CO—halogen Haloformyl -carbonyl halide 

TABLE 1.7 Characteristic Groups for Substitutive Nomenclature (continued) 

In Table 1.8 are listed characteristic groups that are cited only as prefixes (never as suffixes) in substitutive nomenclature. The order of listing has no significance for nomenclature purposes. 

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IR-2.15.3.3 Ordering characteristic groups for substitutive nomenclature IR-2.15.3.4 Ordering ligands in formulae and names IR-2.15.3.5 Ordering components in salt formulae and names IR-2.15.3.6 Isotopic modification IR-2.15.3.7 Stereochemical priorities IR-2.15.3.8 Hierarchical ordering of punctuation marks IR-2.16 Final remarks IR-2.17 References... 

Table 8. Prefixes and suffixes for the most important characteristic groups in substitutive nomenclature... 

Diols are almost always given substitutive lUPAC names As the name of the prod uct m the example indicates the substitutive nomenclature of diols is similar to that of alcohols The suffix dwl replaces ol and two locants one for each hydroxyl group are required Note that the final e of the parent alkane name is retained when the suffix begins with a consonant ( diol) but dropped when the suffix begins with a vowel ( ol)... 

Substitutive Nomenclature. The first step is to determine the kind of characteristic (functional) group for use as the principal group of the parent compound. A characteristic group is a recognized combination of atoms that confers characteristic chemical properties on the molecule in which it occurs. Carbon-to-carbon unsaturation and heteroatoms in rings are considered nonfunctional for nomenclature purposes. 

Systematic names formed by applying the principles of substitutive nomenclature are single words except for compounds named as acids. First one selects the parent compound, and thus the suffix, from the characteristic group listed earliest in Table 1.7. All remaining functional groups are handled as prefixes that precede, in alphabetical order, the parent name. Two examples may be helpful ... 

Compounds containing the neutral (formally zwitterionic) group =N2 attached by one atom to carbon are named by adding the prefix diazo- to the name of the parent compound (Rule 931.4), e.g., diazomethane, ethyl diazoacetate. Diazo is a so-called characteristic group appearing only as a prefix in substitutive nomenclature. Chemical Abstracts and Beilstein indexing of diazo compounds is analogous to that mentioned above for diazonium ions and salts, but Diazo compounds is not... 

Some variants are also allowed for mononuclear cations of Groups 15, 16 and 17. These are based on the usage of substitutive nomenclature, where the formal addition of a hydron to a parent hydride to give a cation is represented by the suffix -onium. 

These names are used in oi anic substitutive nomenclature for situations in which the substituent group is joined to the parent skeleton by a single element-carbon bond. 

An area of current development is the nomenclature of organometallic compounds. Organometallic compounds of Main Group elements can, to a first approximation, be considered to be derivatives of hydrides, and the methods of substitutive nomenclature can be applied. Even then, the accessibility of different oxidation states, as with phosphorus(iii) and phosphorus(v), introduces complications. Transition metal organometallic compounds are even more difficult to treat, and the development of a unified, self-consistent and accepted and applied nomenclature is not easy. Witness the different ways (k, t and italicised symbols) for denoting donor atoms in ligands. 

Substitutive nomenclature is employed for exo-cyclic N-PACs (and the O- and S-PACs). Functional groups such as amino (-NH2), cyano (- C=N), nitro (-NOz), and hydroxyl (-OH) are attached as prefixes to the parent PAH, e.g., 1-nitropyrene, VI. 

An understanding of the concept of the principal characteristic group is vital for the correct application of substitutive nomenclature this will therefore be dealt with in some detail. 

In the common nomenclature for ethers, each of the R groups in R—O—R is named as a separate word, except when the groups are identical, in which case the prefix di or bis may be used (di is used for simple groups, bis for substituted groups) ... 

Polyketones in which two or more contiguous carbonyl groups have rings attached at each end may be named (1) by the radicofunctional method or (2) by substitutive nomenclature. For example,... 

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