Clathrate-type complexation of cephalosporins with beta-naphthol

The cephalosporin derivatives cephradine, cephalexin, cefaclor, and cefadro xil form complexes with beta-naphthol, provided water is present. The cryst al structures of these complexes have been determined by single-crystal X-r ay diffraction, The complexes appear to be inclusion compounds of the clath rate type. In all cases, the cephalosporin molecules play the role of host, while beta-naphthol is the guest molecule. Water molecules, which are acco mmodated in the crystal, play an essential role in the interaction between the guest and host molecules. Cephradine, cephalexin, and cefaclor form iso morphous complexes with beta-naphthol, whereas cefadroxil crystallizes in a different morphology. The crystal structures are described in detail and d iscussed in terms of hydrogen-bonding, van der Waals and electrostatic inte ractions. The structure of the cefadroxil complex is basically different fr om that of the other three complexes, although there are notable structural similarities.