Supramolecular reaction

It is a useful notion to consider that the reaction of a molecular solid, whether formed of organic, organometallic molecules or coordination compounds, with a vapour is conceptually related to the supramolecular reaction of a crystalline material with a volatile solvent to form a new crystalline solid (Fig. 18). Indeed, the two processes, solid-gas reaction and solid-gas solvation, differ only in the... 

The gas-solid reaction can thus be more appropriately described as a special kind of solvation rather than as a heterogeneous acid-base reaction. In the reversible supramolecular reaction the zwitterion reacts with gaseous HCOOH,... 

The examples provided in the previous sections show that one of the means to obtain new pseudo-polymorphs is via solvent uptake. Since the co-crystallizing solvent may be present in the vapour phase (say water), one may regard the process that leads from an unsolvated to a solvated species (and reverse) as a supramolecular reaction whereby a given set of noncovalent bonds (those between molecules in the nonsolvated form, for example) are broken and a new set of noncovalent bonds (those between host and guest molecules) are formed as shown at the beginning of this chapter in Scheme 2. 

Clearly, molecular recognition processes are the prototypical supramolecular reactions on which the other aspects are based. Without molecular recognition, there are no template effects, no self-assembly, and certainly no self-replication. In contrast to opinions sometimes encountered among chemists from other areas, supramolecular chemistry did not come to a halt with the examination of hosts and guests and their interactions. Sophisticated molecular devices are available which not only are based on, but go far beyond mere molecular recognition. 

Scheme 2.5.9 A modular one-pot supramolecular reaction driven by three different selective intermolecular interactions resulting in quaternary supermolecules.

The overriding conclusion from the extensive data available in the CSD is clear. In order to convince two different discrete chemical species to coexist in a molecular co-crystal there needs to be some specific molecular-recognition based reason for their solid-state union [93]. Although individual structures that defy rationalization will appear from time to time, there is no doubt that the important big picture reveals structural trends, patterns of behavior, and reproducible motifs that, when combined, can be developed into a library of high-yielding supramolecular reactions. 

Finally, the assembly of more complex systems requires that the exact supramolecular reaction site be known. For this purpose, micelles and liposomes are very attractive due to the sequestering of reagents, the possibility of conducting various reactions in a confined space, and the similarity with living cells. These particular organized media are examined in detail in chapter 15, which describes the catalytic effect of micelles and supramolecular systems based on cyclophanes. In addition, the encapsulation process of vesicles and their catalytic effect on organic reactions is outlined in chapter 16. And, finally, chapter 17 previews efforts to assemble a semi-synthetic cell. 

Further, supramolecular reactions occur with native blood in blood bags. The change of their rough surface materials, which initially lacked an SNOM contrast, developed typical dark and bright SNOM contrast after various blood filling times. This is of enormous economic importance and should be used for optimizing the allowable storage times by suppression of the deposition reaction. 

The success and efficiency for any set of supramolecular reactions can be judged by the frequency of occurrence of desired intermolecular interactions and connectivities in the resulting solid. The probability that a certain motif will appear in a crystal structure is, in many ways, a... 

Turovskij,N.A. Pastemak,E.N. Raksha,E. Golubitskaya,N.A. Opeida, .A. Zaikov, G. E. Supramolecular Reaction of Lauroyl Peroxide with Tetraalkylammonium Bromides. Oxidation Communications, 2010, 33, 485. 

In the case of complex formation peroxide geometry and electron structure changes bring it to the configm-ation close to that of transition state. Complex decomposition proceeds through oxyradical formation and ammonium salt regeneration. Assumed mechanism of cyclohexanone peroxides decomposition in the presence of tetraethylammonium bromide can be regarded as one of the supramolecular reactions [21]. 

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