The cephalosporin antibiotics cephradine, cephalexin, cefaclor and cefadrox
il form complexes with beta -naphthol and several other naphthalene derivat
ives. In these clathrate-type complexes, the cephalosporins form the host l
attice for the naphthalene derivatives, Complexation with beta -naphthol an
alogues can be employed to withdraw cephalosporins selectively from an aque
ous solution. In this process, the most important parameter is the complexa
tion efficiency, which expresses the extent to which the cephalosporins can
be withdrawn from a solution. The complexation efficiencies for a series o
f guest molecules are explained in terms of both the thermodynamics of the
complexation reaction and the structural features of the cephalosporin comp
lexes. In this manner, insight is gained into the subtle relationship betwe
en the molecular structure of naphthalene derivatives and the stability of
their complexes with the antibiotics. It is shown which molecular propertie
s of the guest molecules are the most important ones for an optimal complex
ation efficiency of cephalosporins.