Catenanes nomenclature

Because of space limitations, only meso- and macrocycles possessing heteroatoms and/or subheterocyclic rings are reviewed in general, lactones, lactams, and cyclic imides have been excluded. In view of the delayed availability of some articles appearing in previous years, several have been incorporated. The introduction of a systematic nomenclature of catenanes, rotaxanes, and derived assemblies has recently appeared <00JPC437> this should have appeared two decades ago, but is still timely in futuristic point of view. 

Like other known (macro)molecules (e.g. molecular knots [41], catenanes, rotax-anes [42]), dendritic molecules can be named in accordance with the IUPAC Rules of Nomenclature. However, these rules are not always sufficiently comprehensive to adequately, unequivocally, and clearly name such complex structures as dendritic molecules [43]. 

Whereas neither I.U.P.A.C. nor nodal nomenclature bother to extend their system to what is, at present, a very small group of topologically restrained compounds, the proposed system allows for a simple extension to the set of catenanes and rotaxanes. Also, one may readily adapt this system to canonically naming endothelial compounds, such as endothelial fullerenes, etc. Moreover, extension to "chemical" knots having multiple interconnections and windings, without having to resort to the tedium employed by Schill to extend I.U.P.A.C. nomenclature to these compounds, is straightforward. 

Another use for the zero integer superscript occurs in the domain of catenanes and rotaxanes. Although the same examples as the ones cited in Schill s monograph [1] for the development of a suitable nomenclature have been selected for discussion, his organizational scheme — which is merely an extension of I.U.P.A.C. s organic chemistry nomenclature — has not been. Instead, the nomenclature developed earlier for more traditional compounds is easily expandable to include these "compounds". Toward this end, note that in the formulation described in Chapter 1, the semi-colon was selected as a co-ordinate separator and the colon as a sub-ordinate separator of strings of nomenclature code. One now needs only to introduce the use of the zero superscript to indicate that the choice of locant numbering is irrelevant. 

The evolving domain of radial, as well as linear, addition of modules to form an expanding moiety, in a manner akin to the development of polymers, referred to as "dendrimers", is examined and nomenclated The direct inclusion of topology in the description of isomers, once a very insignificant part of chemical nomenclature, is now a factor to be reckoned with, not only for the small class traditionally referred to as "topological" (including catenanes, rotaxanes, and knots), but also as new compositions of matter, such as the endothelial fullerenes, are formulated. 

A catenane may bear more than two intertwined macrocycles. In this section, we wish to introduce several more complex topologies. The increasing complexity not only caused synthetic problems but also prompted Vogtle et al. to introduce a systematic nomenclature for mechanically linked molecules." ... 

Safarowsky, O. Windisch. B. Mohry. A. Vogtie, F. Nomenclature for catenanes. rotaxanes, molecular knots. 

Catenanes and Other Interlocked Molecules, p. 206 DNA Nanotechnology, p. 475 Nomenclature in Crystal Engineering, p. 967 Plutonic and Archimedean Solids, p. 1100 Self-Assembling Catenanes. p. 1240 Strict Self-Assembly and Self-Assembly with Covalent Modifications, p. 1372 Supramolecular Isomerism, p. 1420 The Template Effect, p. 1493... 

In this article, a brief and general review of catenanes in terms of their nomenclature, self-assembly, and a few pertinent properties will be presented. Examples of the concepts discussed were limited to representative transition metal-mediated processes. 

The simplest class of catenane involves two interlocked rings, as depicted in Fig. la. Such singly-interlocked species are termed 2-crossing catenanes and are formally given the nomenclature 2-crossing-[njcatenane, where... 

Biological Models and Their Characteristics, p. 701 Catenanes and Other Interlocked Molecules, p. 206 Classification and Nomenclature of Supramolecular Compounds, p. 261... 

Carbohydrates, Recognition of, p. 169 Carcerands and Hemicarcerands, p. 189 Catenanes and Other Interlocked Molecules, p. 206 Cavitands, p. 219 Chiral Guest Recognition, p. 236 Classical Descriptions of Inclusion Compounds, p. 253 Classification and Nomenclature of Supramolecular Compounds, p. 261 Comple.xation of Fullerenes, p. 302 Concepts in Crystal Engineering, p. 319 Crown Ethers, p. 326 Cryptands, p. 334 Cryptophanes, p. 340... 

Figure 1 Catenanes (a) nomenclature [w+2]catenane and (b) general synthetic strategies to obtain a [2]catenane (i) clipping (ii) double clipping , and (iii) magic ring synthesis .

To conclude, the nomenclature of macromolecular topological compounds should be briefly mentioned. In fact, it does not exist. The use of the Schill s nomenclature is difficult, since the name of polymeric catenanes and rotaxanes, where the chain consists of many interlocked rings or rings threaded on a long macromolecule, becomes cumbersome and hard to nronounce. Therefore, trivial names are often used. 

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