Chemical Structure and Nomenclature of Macromolecules

The Commission of Nomenclature of the Macromolecular Division of lUPAC International Union of Pure and Applied Chemistry) formulated general rules for the nomenclature of polymers (relevant publications see Sect. 1.4.4). Selected recommendations are explained in the following paragraph. 

However, only (a) and (b) are constitutional repeating units, describing the polymer s constitution precisely and completely. The polyamide prepared from hex-amethylenediamine and adipic acid has the following constitutional repeating unit  

In contrast to this, a statistic copolymer (often also called random copolymer, see Table 1.1), schematically described as follows  

The lUPAC names for polymers are often very complicated and lengthy. Therefore, parallel to the systematic names, some semi-systematic or trivial names are allowed. Here, in most cases, the name of the basic monomer is used in combination with the prefix poly . Polystyrene may serve as an example. Brackets are used for the name of the monomer when it contains more than one word such as poly(vinyl chloride)  

The part of a macromolecule corresponding to the smallest molecule or to a molecule from which the macromolecule is or could be built is designated as a monomer unit. In vinyl polymers such as poly(vinyl chloride), the monomer 

A polymer is defined as a substance consisting of molecules that are characterized by multiple repetitions of one or more species of atoms or groups of atoms. These repeating species of atoms or groups of atoms are designated constitutional units. A regular polymer can be described by a certain sequence of 

Binary copolymer (general) Poly(A-co-B) e.g. Poly(styrene-co-butadiene) 

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On the other hand, modern nomenclature is based on the chemical structure of the macromolecules. The name of a polymer of unspecified degree of polymerization consists of the prefix poly and the name of the smallest repeating unit. With unbranched polymers, the smallest repeating unit is a diradical. The name of this diradical is the same as that met with in the nomenclature for low-molecular-weight organic diradicals. Thus, the group —CH2— is called methylene and the corresponding polymer is called poly(methylene) (example 1 in Table 1-4). The diradicals —CH2—CH2— and —CH2—CH(CH3)— do not have simple definitive names the trivial names ethylene and propylene are retained. Examples of names for other diradicals are as follows ... 

The Principle of Structure-Based Nomenclature. Structure-based nomenclature is based on a method of naming the sequence of constitutional or strnctnral nnits that represent the ideal, and sometimes the actual, repeating pattern of the strnctnre of a typical macromolecule in a polymer. The name has no direct relation to the strnctnre of the (co)monomer(s) used to synthesize the polymer. Details are given below in both the lUPAC Nomenclature and Chemical Abstracts Nomenclature sections entitled Structure-Based Nomenclature. ... 

Macromolecules, including biopolymers, represent a challenge in generating meaningful structure representations and corresponding names, because frequently complete structural information is not known. Illustrations are shown from existing recommendations of the International Union of Pure and Applied Chemistry (lUPAC), and the International Union of Biochemistry (lUB). Examples from drafts under consideration by the lUPAC Commission on Macromolecular Nomenclature are also presented. Current handling of macromolecules by Chemical Abstracts Service (CAS) as well as some enhancements under development are illustrated. 

The next three chapters concern chemical nomenclature. One from Hull University deals with integration of structure-based systems and nomenclature. Janusz Wisniewski, in a popularly acclaimed presentation, demonstrated Beilstein s AUTONOM program at the conference and his chapter describes this microcomputer program for generating lUPAC names from structural input. Val Metanomski and Joy Merritt provided a poster on Chemical Abstracts Service conventions for macromolecules. 

As with all macromolecules, protein nomenclature predominantly uses trivial names. Proteins can be classified from a variety of perspectives, which reflect their importance in nutrition, origin, structure, chemical and biochemical properties and other attributes. 

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