Polyhedral designs

Fig. 9. Designation of configuration pattern vector in polyhedral geometry a tetrahedral reference configuration pattern and the corresponding sample configurational pattern b Generation and comparison of the configurational pattern vectors for two enantiomer polyhedral geometric patterns...

Polyhedral niosomes were found to be thermoresponsive Fig. 7 (a). Above 35 °C, there was an increase in the release of CF from these niosomes even though the polyhedral shape was preserved until these vesicles were heated to 50 °C. Solulan C24-free polyhedral niosomes do not exhibit this thermoresponsive behavior [160] due to a decrease in the interaction of the polyoxyethylene compound solulan C24 with water at this temperature (due to decreased hydrogen bonding) as identified by viscometry [161]. This observed thermoresponsive behavior was used to design a reversible thermoresponsive controlled release system Fig. 7 (b). Thermoresponsive liposomal systems which rely on the changing membrane permeability, when the system transfers from the gel state (La) to the liquid crystal state (L 3) [162], are not reversible. This is not unex-... 

Several silver(I) complexes with crown ethers and calixarenes have been synthesized. In the design of discrete molecules and infinite chains in silver acetylide chemistry, crown ethers function as blocking groups or protective cordons around a polyhedral C2 Ag cage so that the isolation of lower-dimensional supramolecular entities can be achieved. " ... 

Another technique which has been used to prepare 3-D polyhedra is Raymond s symmetry-interaction method.19 This strategy derives from the realization that many natural supramo-lecular assemblies are formed in a symmetry-driven process which relies on incommensurate lock-and-key interactions. By closely examining a desired polyhedral structure, one may establish the relevant symmetry interactions and their associated geometric relationships, and then design metal-ligand systems capable of fulfilling them. 

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