Cavities, layers, and channels in the hosting framework of molecular complexes derived from cephradine

The cephalosporin-type antibiotics Cephradine, Cephalexin, and Cefaclor for m clathrate-type complexes with a variety of naphthalene derivatives. The c rystal structures of these complexes are isomorphous. Interestingly, the ho sting framework formed by these cephalosporins can adapt to the guest molec ule. This phenomenon of induced-fit appears to have a much larger potential , with the consequence that a series of smaller compounds (such as benzene derivatives) as well as bulkier compounds can also be hosted by Cephradine. When benzene derivatives were used as guests, pronounced deviations in the antibiotic framework were observed, and it is possible to induce deviation s strikingly different from those found for the complexes with the naphthal ene derivatives. Evidently, the hosting structure formed by Cephradine is h ighly flexible. Hosting frameworks containing layers, channels, and various other types of cavities can be obtained by selection of an appropriate gue st molecule. Remarkably, a number of structural features and interactions r emain unaffected in all these antibiotic frameworks. These persistent featu res seem to delineate the boundaries of framework formation for these antib iotics, thus defining the scope of complex formation.