Design molecular hosts

Calixarenes, which are macrocyclic compounds, are one of the best building blocks to design molecular hosts in supramolecular chemistry [158]. Synthesis of calix[4]arenes, which have been adamantylated, has been reported [105, 109]. In calix[4]arenes, adamantane or its ester/carboxylic acid derivatives were introduced as substituents (Fig. 29). The purpose of this synthesis was to learn how to employ the flexible chemistry of adamantane in order to construct different kinds of molecular hosts. The X-ray structure analysis of p-(l-adamantyl)thiacalix[4]arene [109] demonstrated that it contained four CHCI3 molecules, one of which was located inside the host molecule cavity, and the host molecule assumed the cone-like conformational shape (Fig. 30). 

Molecular Design of Hosts for the Formation of Inclusion Compounds with Apolar Guests... 

From this information, general principles for the design of spherical molecular hosts have been developed. [11] These principles rely on the use of convex uniform polyhedra as models for spheroid design. To demonstrate the usefulness of this approach, structural classification of organic, inorganic, and biological hosts - frameworks which can be rationally compared on the basis of symmetry - has revealed an interplay between symmetry, structure, and function. [53]... 

Cram DJ. The design of molecular hosts, guests, and their complexes. Science 1988 240 760-767. 

Cram, D. J. (1988) The design of molecular hosts, guests, and their complexes (Nobel Lecture). Angew. Chem., Int. Ed., U (8), 1009-1020. 

The loading amounts of the dyes, the pore size and surface modification are expected to affect the photoprocesses of the adsorbed dyes. In order to construct molecularly designed functional host-guest systems from nanoporous silica films, further study on the adsorption and the photoprocesses of the dyes is now underway and will be reported subsequently. 

Atwood, J. L., MacGillivray, L. R., Structural classification and general principles for the design of spherical molecular hosts , Angew. Chem. Lit. Ed. 1999, 38, 1018-1033. 

Donald J. Cram Department of Chemistry and Biochemistry University of California Los Angeles, California. U.S.A. The Design of Molecular Hosts, Guests, and Their Complexes... 

CALORIMETRY AN INDISPENSIBLE TOOL IN THE DESIGN OF MOLECULAR HOSTS... 

As the aforementioned results indicate, it is difficult to predict the molecular structure of a suitable host for Cl-MIT, so it is necessary to employ a degree of trial and error. However, it becomes easier to design the host molecule if the crystal structure and stability of the inclusion complex are predictable. 

Since the pioneering work of Pedersen (1), Lehn (2), and Cram (3) on synthetic macrocyclic and macropolycyclic host systems such as the crown ethers, cryptands, and spherands, there has been an enormous development of the field of host-guest or supramolecular chemistry. Molecular hosts designed to bind inorganic and organic, charged and neutral guest species via cumulative, noncovalent interactions have all been reported and extensive reviews on this subject have appeared (4-8). 

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