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Competitive processes associated to the interaction of a cavitand derivative with caffeic acid |
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| Authors: | Zsuzsanna Czibulya Éva Horváth Zoltán Nagymihály László Kollár |
| Affiliation: | 1. Department of General and Physical Chemistry, University of Pécs, Pécs, Hungary;2. Research Group for Green Chemistry, Szentágothai Research Center, Pécs, Hungary;3. Department of Inorganic Chemistry and MTA-PTE Research Group for Selective Chemical Syntheses, University of Pécs, Pécs, Hungary;4. Research Group for Green Chemistry, Szentágothai Research Center, Pécs, Hungary;5. Department of Inorganic Chemistry and MTA-PTE Research Group for Selective Chemical Syntheses, University of Pécs, Pécs, Hungary |
| Abstract: | AbstractThe interaction of caffeic acid and a newly synthesised cavitand derivative was investigated by UV–vis and fluorescence spectroscopy in tetrahydrofuran–water matrix. The temperature dependence of the equilibrium constants was determined first, then the thermodynamic parameters were calculated using the van’t Hoff equation. Absorption measurements highlighted entropy-controlled formation of cavitand–caffeic acid complexes with 1:2 stoichiometry. It was proved by fluorescence measurements that caffeic acid dimerisation is followed by the formation of cavitand–caffeic acid complexes with 1:2 stoichiometry. It was also shown that both the caffeic acid dimerisation and the formation of 1:2 complexes are controlled by the entropy gain. PL signal is preferred to use for analytical application in this particular case. |
| Keywords: | Cavitand caffeic acid host–guest chemistry thermodynamics |