Four zinc porphyrin molecules have been linked covalently to a central amphiphilic calix[4]arene molecule to form a zinc "calixporph", ZnCP , which displays enhanced sensitivity to dibutylamine compared to both the discrete zinc porphyrin and two-component mixtures of zinc porphyrin with calixarene. Langmuir-Blodgett films (20 monolayers) of ZnCP display UV-visible spectra which are modified upon exposure to dibutylamine in the concentration range 0.09–0.45 ppt (in N2 ) with a t50 response time of 8.8 s. The dense packing of the monomeric porphyrin moieties leads to a high absorbance per layer and thus a large sensing signal compared to other LB films capable of amine-detection. This, coupled to the very fast t50 value, leads to a high figure of merit. This verifies the adopted strategy of using a covalently linked calixporph in order to avoid the potential problems of phase separation associated with two-component mixtures. Furthermore, the ZnCP is selectively responsive to the secondary amine, dibutylamine, compared to the primary and tertiary compounds.
