Topological compounds

Here the assignment of odd integer locant numbers to atoms and even integers to bonds is important inasmuch as the individual mercury atoms bond to specific edges of the sandwiched benzene rings above and below it. This is indicated in the superscripts. Without such locant numbering, one does not know whether to assume that there is free rotation between the layers in much the same manner as shall be evident for the topological compounds described in Chapter 7. 

ABSTRACT. A Lennard-Jones potential is used to derive for-mulaefor the potential of interaction between shell macro-molecules and gas atoms. Calculations are carried as far as thespherlcal symmetry approximation. The potential of interaction determines the stability of a shell topological compound. When the distance R between a shell molecule and a gas atom is equal the radius 1 of the outer shell, the potential is the highest and determines a barrier, which must be lower than an energy of the trapped / by the shell molecule / atom to be released. 

The potential can be used in the calculation of the partition function and then in thecUtermlnatlon of the free energy of the system. However, the potential Itself especially that of the outer shell f a shell molecule is Important and determines the stability of a shell topological compound which is a topological isomer of two... 

The statistical method of syntl s of topological compounds can be divided into a truly statistical synthesis and a thesis with elements of directionality. Prq>aring catenanes by the statistical method is described in ddail by Sdiill in his monograph The statistical technique of synthesis of rotaxanes will be presented here in greater detail. The scheme of the technique is as follows bulky end groups are connected to a linear molecule in the presence of a macrocycle. Sudi a re kn, where the macrocycle remains imchanged, results in the formation of some amount of rotaxane and a molecular dumb-beU ... 

Synthesis and nKture of M romo]eciiter Topological Compounds S3... 

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. 

In reahty, the situation with polycatenanes is much more comphcated. The problem is that a catenane-like structure of IPN is hard to identify by any single method. The difficulty is that neither catenanes nor other topological compounds (knots, rotaxanes) differ from the mixture of their individual components [ 11,12]. If IPNs were true polycatenanes, they would exhibit no phase separation. Therefore, catenane-Hke IPNs may be formed only in the case when the network components are miscible for the whole range of composition and temperature values [13], and when the IPNs have a one-phase homogeneous structure. 

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