Layered cyclophanes

Bohrer, I. M. Evaluation Systems in Quantitative Thin-Layer Chromatography, 126,95-118 (1984). Boekelheide, V. Syntheses and Properties of the [20] Cyclophanes, 113, 87-143 (1983). 

Optical Activity Caused by Restricted Rotation of Other Types. Substituted paracyclophanes may be optically active and 25, for example, has been resolved. In this case, chirality results because the benzene ring cannot rotate in such a way that the carboxyl group goes through the alicyclic ring. Many chiral layered cyclophanes (e.g., 26) have been prepared. ... 

Another type of face-to-face-arrangement is found in the multi-layered annulene systems [ 14] and [15], Here, unlike the para-cyclophanes, in which the phenyl units are connected by external alkanediyl groups, the stacking of annulene layers is achieved by internal linkages, with the bridge located inside the 7t-clouds. The advantage of the latter structure is that one can... 

In contrast to the conformationally mobile dianthrylethanes, the rigid cyclophane [11], with a face-to-face arrangement of the rc-layers, is electrostatically less favourable for reduction and only gives rise to a dianion upon alkali-metal reduction (Huber et al., 1983). 

The sensitivity of the resulting electrochemical sensor was tuned via control over the number of assembled layers on the conductive surface 47 For example, layered assemblies consisting of cyclophane 3 and gold NPs were produced on ITO surfaces. The number of layers was varied from one to five in the presence of an... 

The lattice morphology of the nanocomposite assembly also affects selectivity between analytes (Fig. 11.13). Two nanocomposites consisting of six total layers of cyclophane and gold NPs assembled on an electrode surface. Nanocomposite was assembled with three layers of cyclophane 3 closer to the electrode surface,... 

Figure 11.13 (A) Cyclic voltammograms of five-layered assembly of cyclophane 5 and...

By using a similar method, we can prove that the cell complexes of the molecules [m [n]paracyclophane [22] and triple layered cyclophane [23] are also intrinsically chiral. Figure 30 illustrates these molecules... 

T. Otsubo, S. Mizogami, Y. Sakata, S. Misumi, Layered cyclophanes. J. Chem. Soc. Chem. Commute 1971, 678-678. 

The medium may have a marked effect on the shape of receptor molecules itself. Shape modifications could strongly influence their substrate binding properties, for instance in the case of amphiphilic cyclophane receptors subjected to hydrophobic-hydrophilic factors in aqueous solution. Such medium effects in action are visualized by the solid state structures of two different forms of the water-soluble hexasodium salt of the macrobicyclic cyclophane 66, which could be crystallized in two very different shapes an inflated cage structure 71 building up cylinders disposed in a hexagonal array and a flattened structure 72 stacked in molecular layers separated by aqueous layers in a lamellar arrangement [4.73]. These two... 

Figure 8.4 Cyclic voltammograms of one to five layers of bis-bipyridinum cyclophane (1) cross-linked AuNPs at an ITO electrode showing adsorption (oxidation) and desorption (reduction) of oxygen at the NP surface corresponding to surface area. 1.0 M H2S04, scan rate = 50 mV s 1. Inset Calibration curve is the number of AuNPs cm 2 (n) versus number of layers.4 (Reprinted with permission from A. N. Shipway et al., ChemPhysChem 2000,1, 18-52. Copyright Wiley-VCH Verlag GmbH Co. KGaA.)...

The above materials are useful in highlighting two further aspects of benzene-based chemistry, i.e., (i) transition from 2D to 3D structures and (ii) transition from macromolecular to supramolecular architectures. While already traditional benzene chemistry has proceeded from flat disc-type structures to double and multilayered cyclophanes such as 1831 and 19,32 graphite and its intercalation cannot be understood without considering layer formation. A closely related... 

Cyclophane ruthenium complexes have been prepared by the methods developed to make arene ruthenium complexes (Section II,A). Treatment of the solvated complexes of type 7, obtained from the dimers 1 and silver tetrafluoroborate in acetone, with 1 equiv of cyclophanes a-j in the presence of trifluoroacetic acid gives the double-layered (i76-arene)-(i76-cyclophane)ruthenium(II) complexes 263 in good yield (Scheme 26, p. 222). When 7 is used in excess, the triple-layered complex 264 is formed (159-162). 

Cyclic Voltammetry and Reduction of Double-Layered Cyclophane Complexes... 

An electrochemical study of the reduction of the double-layered (arene)-(cyclophane)ruthenium complexes 263 and of bis(arene)ruthenium complexes 235c has been reported (160,166). The compounds show in... 

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