Supramolecular Crystals

Scudder, M., Dance, I., A diamondoid supramolecular crystal lattice maintained entirely by sixfold phenyl embraces. Crystengcomm 2001, 3, 46-49. 

Supramolecular Crystals Using molecular recognition via specific interactions such as hydrogen bonding and metal coordination, it is possible to form well-designed crystal structures. Specific recognitions and reactions can be achieved in these supramolecular crystals. 

Various supramolecular crystals have been reported. Several examples of unit molecules used to build supramolecular crystals are summarized in Fig. 4.10. Perhydrotriphenylene (a), 9,9 -bianthryl (b), cyclophosphazene (c)... 

Figure 4.10. Unit molecules that form supramolecular crystals...

Figure 4.14. Diels-Alder reaction performed in a supramolecular crystal...

Aniline, (V.iV-dimethylaniline and toluene form molecular complexes with (4a, b,13b)-13-methyl-16-oxo-17-norkaurane-18-carboxylic acid (isosteviol) (93) investigated by X-ray diffraction159. 93 forms individual 2 1 molecular complexes with aniline or N,N-dimethylaniline and toluene. The supramolecular crystal structure of these complexes is formed by chiral double helices involving isosteviol molecules. The helices are linked together by intermolecular hydrogen bonds between the carboxy and the carbonyl groups160. 

Therefore in inorganic supramolecular chemistry there is a new meaning for the term crystal field (originally developed for metal ions doped in crystal lattices). The supramolecular crystal field is the total influence of the crystal surroundings on a target molecule the magnitude, symmetry and anisotropy of the crystal field are important. We must continually ask to what extent the structures of molecular inorganic compounds are different in solution phases and crystal lattices, and seek quantification of this crystal field and its influences. 

A unique structural phenomenon was found in the supramolecular crystal structure of sodium r-butoxide, 186. The unit cell of this compound contains both hexa-meric and nonameric aggregates (Figure 6.18) [151]. 

In our disgraceful times, if you must write a research proposal, you should not call it A study of fundamentals of intermolecular forces , but Methods in supramolecular crystal engineering for the development of nanomolecular materials, devices and biotechnological anticancer drugs . I have refereed many such abstruse documents, in which some colleagues well known to me for being fine quantum chemistry specialists boast their ability to fabricate nanotubes or to cure AIDS. 

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