Cyclophane name

In the following examples the polycyclic name reflecting conventional naming procedures is generally given first and then the new lUPAC cyclophane name derived from the associated supergraph. For a better understanding, the basic skeletons are drawn in bold print where appropriate. Current trivial or traditional names of some prototypical compounds are also shown. 

Chem. Abstr. (P)-12-Methyl-14-nitrobi-cyclo[9.2.2]pentadeca-l(13),ll,14-triene New lUPAC-cyclophane name ... 

By a reaction sequence similar to the one outlined above for the [8][8]cyclophane 32 also the levorotating [8][10]paracyclophane 33 was obtained starting from (—)-methyl[10]paracyclophanecarboxylic acid IS6. Opposite Cotton effects of (+)-32 and (—)-33 indicated that they had opposite chiralities, and hence it followed that both (+)-32 and (+)-33 had the same chirality, namely (S). It should be noted that for (-)-14 the chirality (S) had been established 40) (cf. also Ref.62) and sections 2.9.2. and 2.9.3.) it would be somewhat surprising that its levorotatory methyl derivative 15 had (/ ) chirality as deduced from the above sequence (—)-15 - (-)(/ )-33 44). Moreover, for levorotatory [m][n]paracyclophanes (S)chirality had been proposed by application of a sector rule 63) (see also 2.9.4.). 

In addition to macrocyclic hosts discussed above, many other molecules capable of selective complexation have been synthesized. They belong to so-called macrocyclic chemistry [30] encompassing crown ethers discussed in this Chapter, cryptands 61-63 [21], spherands 70 [31], cyclic polyamines 71 [32], calixarenes 18 [5], and other cyclophane cages such as 72 [33] to name but a few. Hemicarcerand 5 [2b] discussed in Chapter 1 and Section 7.3 also belongs to this domain. Typical macrocyclic host molecules are presented in Chapter 7. 

There is no uniformly accepted definition of cyclophanes. Usually one understands under this name a macrocyclic or macrobicyclic compound having built-in aromatic rings. However, IUPAC rules define (cyclo)phanes much more broadly they include linear molecules containing rings that are not necessarily... 

The first example of electrochemically driven molecular shuttles is rotaxane 284+ (Fig. 13.25) constituted by the electron-deficient cyclophane 124+ and a dumbbellshaped component containing two different electron donors, namely, a benzidine and a biphenol moieties, that represent two possible stations for the cyclophane.10 Because benzidine is a better recognition site for 124+ than biphenol, the prevalent isomer is that having the former unit inside the cyclophane. The rotaxane... 

After this first report, a remarkable number of electrochemically controllable molecular shuttles have been designed, constructed, and studied. Rotaxane 294+ (Fig. 13.26), for instance, incorporates the electron-deficient cyclophane 124+ and a dumbbell containing two kinds of electron-rich units, namely, one 2,6-dioxyanthra-cene and two 1,4-dioxybenzene moieties.34 In solution, the rotaxane is present as the isomer with the 2,6-dioxyanthracene unit inside the cyclophane, owing to the fact that this unit is a better station in comparison to the 1,4-dioxybenzene recognition sites. 

A specialized system of nomenclature has been developed, principally by Smith,16 for naming skeletons consisting of aromatic residues linked in various ways by saturated bridges. Those skeletons containing benzene residues only are termed cyclophanes, and names for heteroaromatic analogues are based on the name of the heterocycle with the termination -ophane. The numbers of atoms in the bridges are indicated in square brackets, and the orientation of substitution on the aromatic residue(s) is shown in parentheses. A few simple examples are given (149-151), with alternative names. 

The spherically shaped cryptophanes are of much interest in particular for their ability to bind derivatives of methane, achieving for instance chiral discrimination of CHFClBr they allow the study of recognition between neutral receptors and substrates, namely the effect of molecular shape and volume complementarity on selectivity [4.39]. The efficient protection of included molecules by the carcerands [4.40] makes possible the generation of highly reactive species such as cyclobutadiene [4.41a] or orthoquinones [4.41b] inside the cavity. Numerous container molecules [A.38] capable of including a variety of guests have been described. A few representative examples of these various types of compounds are shown in structures 59 (cyclophane) 60 (cubic azacyclophane [4.34]), 61a, 61b ([4]- and [6]-calixa-renes), 62 (cavitand), 63 (cryptophane), 64 (carcerand). 

Name the following cyclophanes, along with compounds 6.58 and 6.67 ... 

One of the main reasons why nodal nomenclature [42] was created was that the IUPAC organic nomenclature did not allow for assigning unique canonical names to members of the class of molecules referred to as "cyclophanes" a problem that would not have arisen had beta bonds been available. This is not to devalue the many virtues of nodal nomenclature, rather merely to show how the proposed system nomenclates these compounds without difficulty. 

One of the main motivations for the development of nodal nomenclature was to be able to compensate for inadequacies that prevented the assignment of a consistent set of canonical names to selected, then recently formulated, molecules — especially the cyclophanes. 

The relation to the larger group of substituted cyclophanes (see Figure 15 in Chapter 2) is noted namely, calix[2]arene is an abbreviated name for 2,2 -dihydroxy-[l,l]-meta, metacyclophane. 

This name, used throughout this article, is justified mainly by its similarity to calixarenes which indicates the cup-like shape (calix) and the aromatic units (arenes) of the macrocycle. In the line with newly created names such as calixpyrroles, calixfuranes, calixindoles, etc. it would be reasonable to distinguish between calixphenols (I) and calixresorcinols (II) or calixpyrogallols etc. and to use calixarenes as the general name for the whole class of [l ]-metacyclophanes (or -cyclophanes). 

As already pointed out in the case of rotaxanes, mechanical movements can also be induced in catenanes by chemical, electrochemical, and photochemical stimulation. Catenanes 164+ and 174+ (Fig. 19) are examples of systems in which the conformational motion can be controlled electrochemically [82, 83], They are made of a symmetric electron acceptor, tetracationic cyclophane, and a desymmetrized ring comprising two different electron donor units, namely a tetrathiafulvalene (TTF) and a dimethoxybenzene (DOB) (I64 1) or a dimethoxynaphthalene (DON) (174+) unit. Because the TTF moiety is a better electron donor than the dioxyarene units, as witnessed by the potentials values for their oxidation, the thermodynamically stable conformation of these catenanes is that in which the symmetric cyclophane encircles the TTF unit of the desymmetrized macrocycle (Fig. 19a, state 0). 

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