Investigation of the origin of selectivity in cavitand-based supramolecular sensors.
The sensing properties of functionalized cavitands have been studied by thin-film coating TMSR chemical sensors and by measuring their responses towards model analytes. We studied the relationship between the sensor performance, in terms of sensitivity and selectivity, and the molecular recognition properties of the cavitands. The Langmuir-like shape of the adsorption isotherm, obtained in the case of short-chain alcohols, demonstrated that selective binding can be achieved by the synergistic interactions of the cavity and the bridging PO(in) groups. In the absence of these substituents, the peripheral alkyl chains necessary for the formation of highly permeable thin films attenuate the cavity effect because of nonspecific dispersion interactions. This completely overrides the response originating from molecular recognition. The same effect is observed when the PO groups are oriented outward from the cavity. The use of multivariate chemometrics and the study of the correlations between sensors sensitivity and analyte properties provided further evidence of molecular recognition phenomena, whose intensity is enhanced by the permanent free volume created by the rigid cavity surrounding the PO(in) group.
Paolesse
Roberto
R
Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Via della Ricerca Scientifica, 00133 Roma, Italy. roberto.paolesse@uniroma2.it
Di Natale
Corrado
C
Nardis
Sara
S
Macagnano
Antonella
A
D'Amico
Arnaldo
A
Pinalli
Roberta
R
Dalcanale
Enrico
E
D019840:2-Propanol / Q000737:chemistry; D004784:Environmental Monitoring; D000431:Ethanol / Q000737:chemistry; D004988:Ethers, Cyclic / Q000737:chemistry*; D005021:Ethylamines / Q000737:chemistry; D006860:Hydrogen Bonding; D015336:Molecular Probe Techniques; D009943:Organophosphorus Compounds / Q000737:chemistry*; D010420:Pentanes / Q000737:chemistry; D011791:Quartz
D004988:Ethers, Cyclic; D005021:Ethylamines; D009943:Organophosphorus Compounds; D010420:Pentanes; D011791:Quartz; D000431:Ethanol; C033353:pentane; D019840:2-Propanol; C016162:triethylamine