Cage effect synthesis

The synthesis of nanoparticles inside MOFs is another, still more special example of reactions inside the framework. Nanoparticles trapped inside MOF cavities, with a high number of reactive surface atoms, are indeed reactive species as well. Their synthesis inside the porous hosts, starting from molecular precursors, anticipates the caging effect of the framework. To prevent the clusters from growing to larger, bulk agglomerates, the space confinement of the framework pores is utilized naturally. 

The most widely exploited photochemical 2+2 cycloadditions of alkenes are intramolecular reactions that have been used to effect synthesis of a variety of complex cage skeletons. Cyclization is facilitated in these molecules by the proximity of the two carbon-carbon double bonds. Several examples are given in Scheme 6.8. 

This example demonstrates that free-radical polymerization could be the preferred mechanism for many vinyl monomers since, unlike ionic polymerization, it is tolerant of trace impurities and monomer functionality. However, one of its major drawbacks is the lack of control over the molecular weight distribution due to intrinsic termination reactions. Moreover, the efficiency factor of the initiator decreases by the so-called cage effect, for example by recombination of the primary fi-ee radicals, with increasing molecular weight of the macroinitiator [28]. This normally prevents the synthesis of block copolymers with controlled architectures, narrow molecular weight distributions and well-defined molecular weights. 

The position of the maximum on the curve corresponding to the Schulz-Flory distribution depends on the surface area of the carrier [77] with increasing S, the maximum is shifted to the products with a lower molecular weight. The reasons behind this pattern are the high dispersion of the active catalyst [78] and internal diffusion control of the chain growth by the carrier (the so-called cage-effect typical for zeolites) [79]. The shape-selectivity effects are also observed in the FT synthesis on zeolite-based catalysts, with certain advantages characteristic for zeolites [80] ... 

Adamantane can be used to construct peptidic scaffolding and synthesis of artificial proteins. It has been introduced into different types of synthetic peptidic macrocycles, which are useful tools in peptide chemistry and stereochemistry studies and have many other applications as well. Introduction of amino acid-functionalized adamantane to the DNA nanostmctures might lead to construction of DNA-adamantane-amino acid nanostmctures with desirable stiffness and integrity. Diamondoids can be employed to constmct molecular rods, cages, and containers and also for utilization in different methods of self-assembly. In fact, through the development of self-assembly approaches and utilization of diamondoids in these processes, it would be possible to design and constmct novel nanostmctures for effective and specific carriers for each dmg. 

The l,2-diacyl-l-/-butylhydrazines have been found to be effective as insect-growth regulators. Caged bicyclic phosphates have also shown promise as insecticides. Wang and Huang have combined these effects in the synthesis of compounds 266 and 267 <2000PS(161)173>. Compounds 268 and 269 have been synthesized for their potential... 

RNA synthesis inhibition. Smoke of the leaf, administered to rats at variable doses, was active. The effect of a combination of cigarette and hashish smoke on stress response were measured in rats held in a wire cage inside of a larger cage with a cat. Brains were dissected and measured for protein and catecholamine levels . 

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