Nomenclature polynuclear compounds

Polynuclear compounds may be either of such large extended structures as to make rational structure-based nomenclature impractical, or the structures may be undefined or partially elucidated. In these instances compositional nomenclature is most suited. 

Structural nomenclature for more complex polynuclear compounds is based on the description of the fundamental structural unit, and a logical procedure for numbering the atoms of the fundamental or central structural unit. For nonlinear clusters, descriptors such as tetrahedro, dodecahedro, etc. have traditionally been used to describe a central structural unit (CSU). However, synthetic chemistry has now advanced far beyond the utility of the limited CSU set associated... 

The designation of central atom and ligands, generally straightforward in mononuclear complexes, is more difficult in polynuclear compounds where there are several central atoms in the compound to be named, e.g. in polynuclear coordination compounds, and chain and ring compounds. In each case, a priority order or hierarchy has to be established. A hierarchy of functional groups is an established feature of substitutive nomenclature Table VI shows an element sequence used in compositional and additive nomenclature. 

Second, boron chemistry, particularly that of polynuclear compounds, has also seen extensive development. Again, therefore, only the basics of the nomenclature of boron-containing compounds are covered here (cf. the separate, more comprehensive but dated, chapter on boron nomenclature, 1-11, in Red Book I), within Chapter IR-6 (Parent Hydride Names and Substitutive Nomenclature), while more advanced aspects are left for elaboration in a future project. 

The names of unsaturated compounds are derived by using appropriate substitutive nomenclature rules. Note that trivial names are also allowed for particular polynuclear species, for example, N2H4, diazane, commonly known as hydrazine. For a discussion of names of hydrides in which elements exhibit non-standard bonding numbers, see the Nomenclature of Inorganic Chemistry, p. 85. Note that for the hydrides of Table 5.1 and their derivatives, substitutive names are generally preferred. 

Later, D. W., C. W. Wright, K. L. Loening, and J. E. Merritt, Systematic Nomenclature of the Nitrogen, Oxygen, and Sulfur Functional Polycyclic Aromatic Compounds, in Polynuclear Aromatic Hydrocarbons Nomenclature Guide (K. Loening, J. Merritt, D. Later, and W. Wright, Eds.), pp. 27-47, Battelle Press, Columbus, OH, 1990. 

Polynuclear inorganic compounds exist in a bewildering array of structural types, such as ionic solids, molecular polymers, extended assemblies of oxounions both of metals and nonmeinis, nonmetal chains and rings, bridged melui complexes, and homo- and hetero-nuclcar clusters. This section treats primarily the nomenclature of bridged metal complexes and homo- and hetero-nuclear dusters. 

The present discussion of isomerism in coordination compounds is not, nor was it intended to be, comprehensive and exhaustive. The examples considered are an eclectic selection, and many important systems may have been neglected through ignorance. An obvious omission is any detailed consideration of polynuclear complexes139,256"259 and it is, of course, a quite arbitrary decision not to include any consideration of organometallic species. Other neglected issues, such as the development of a truly comprehensive system of stereochemical nomenclature, are perhaps not yet capable of solution. Nevertheless, it is to be hoped that the principal factors to be considered... 

Polynuclear Aromatic Hydrocarbons 735 16-11 Aromatic Allotropes of Carbon 737 16-12 Fused Heterocyclic Compounds 739 16-13 Nomenclature of Benzene Derivatives 740... 

IR-1.5.3.2 Compositional nomenclature IR-1.5.3.3 Substitutive nomenclature IR-1.5.3.4 Additive nomenclature IR-1.5.3.5 General naming procedures IR-1.6 Changes to previous IUPAC recommendations IR-1.6.1 Names of cations IR-1.6.2 Names of anions IR-1.6.3 The element sequence of Table VI IR-1.6.4 Names of anionic ligands in (formal) coordination entities IR-1.6.5 Formulae for (formal) coordination entities IR-1.6.6 Additive names of polynuclear entities IR-1.6.7 Names of inorganic acids IR-1.6.8 Addition compounds IR-1.6.9 Miscellaneous... 

Aromatic derivatives are known, including benzene sulfonic acid (81 see Chapter 21). Sulfonic acid 82 is a generic sulfonic acid derived from an aromatic compound (Ar = aryl), where an aryl group is any benzene derivative. The aryl group may also be a polynuclear aromatic compound (see Chapter 21, Section 21.8). The nomenclature for 78 and aryl derivatives is presented in Chapter 21. 

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