Ring assemblies

A retrosynthetic analysis of (50) and (52) involving disconnection at both carbon-heteroatom bonds reveals hexane-2,5-dione as the four-carbon fragment needed for ring assembly ring construction is thus of type (45). The most convenient reagents for the appropriate heteroatom synthons are ammonium carbonate and phosphorus pentasulphide (Expts 8.11 and 8.13). 

In the experimental paper Ref. [105], a weak anomaly in the luminescence spectrum of a neutral exciton in a self-assembled ring was interpreted as a possible manifestation of the Aharonov-Bohm effect. 

To make the search for analogies efficient, AIMB abstracts from the crystal library classes of substructural components. The classes of substructural pieces are then organised hierarchically. The broadest classification scheme places components into one of three classes ring assemblies, rings, and chains. The components of each class are then differentiated on the basis of size. The components are further differentiated on the basis of such things as atom and bond type. 

An important feature of this program is its ability to provide conformation search capability and to generate next best models. Because the program finds and evaluates more than one analogy for each subcomponent, the user can ask to see what the model would look like if a specified ring assembly, ring or chain is replaced with the closest substructure analogy. 

Saalfrank and co-workers have described many multinuclear self-assembled rings and cages,... 

Upset resistance welding electrical resistance between two abutting surfaces and additional pressure used to create butt welds on small pipe assemblies, rings and strips. 

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