Download Catenanes, Rotaxanes, and Knots by Gottfried Schill, Alfred T. Blomquist PDF

By Gottfried Schill, Alfred T. Blomquist

Natural Chemistry, quantity 22: Catenanes, Rotaxanes, and Knots offers details pertinent to the synthesis of catenanes and rotaxanes. This e-book discusses the way of interplay among the molecular subunits in catenanes within the strong, liquid, and gaseous states.

Organized into 19 chapters, this quantity starts with an outline of the assumption of synthesizing molecules composed of separate entities which are robotically attached to each other. this article then examines the stereochemistry and the opposite actual and chemical homes regarding the mechanical connections in those compounds. different chapters think of the decision of absolutely the configuration of catenanes by way of extension of the Cahn–Ingold–Prelog ideas. This e-book discusses in addition the bond that routinely connects the catenated earrings. the ultimate bankruptcy bargains with the version reports of the synthesis of knots, double wound rotaxanes, and better linear catenanes.

This publication is a invaluable source for chemists, scholars, and learn employees.

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Extra resources for Catenanes, Rotaxanes, and Knots

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The results from trisecting a Möbius strip of n half twists is shown in Fig. 5. For n = 1, a catenane is obtained having one link the same diameter as the original strip and one link with twice this diameter. If n = 2 three FIG. 5. Configurations resulting from cyclization of n half-twisted 3-strips after crosslink scission (taken from van Gulick72). 3. MÖBIUS STRIPS 33 interlocking rings are formed, for n = 3 a trefoil is formed which has an additional ring intertwined. One can recognize that when n is even three variously interlocked rings are formed and when n is odd, except for n = 1, an «-foiled knot is obtained which has an additional ring wound through it.

21 The cleavage of the 7V-phenyl bond according to Schill 15 ' 16 showed that compound 153 was a precatenane and 152 was the extraännular product, respectively. After removal of the methoxyl groups in 152 with hydrobromic acid in propionic acid, and dehydrogenation to the corresponding oquinone, the hydroxybenzoquinone 142 and the macrocycle 154 were obtained by acid hydrolysis. Reductive acetylation of hydroxyquinone 142 led to the triacetate 145, and acetylation of 154 to the compound 155. An 58 160 157: R = H 158: R = N02 159: R = NH2 8 .

3. MÖBIUS STRIPS 31 If both substrates R in 62 are bulky groups, a rotaxane 58 is obtained when the bonds between A and B and between the planar ring and D are cleaved. 3. Möbius Strips Another general method for the synthesis of catenanes and knots depends on the principle of the Möbius strip. 3 ' 7 1 - 7 3 The "endless, edgeless and onesided" Möbius strip is formed by twisting for example a strip of paper by half a turn and joining the ends. Possibilities for the synthesis of catenanes and knots can be seen when circular strips with n half twists are cut lengthwise into halves, thirds, quarters, etc.

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