Title:
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2-(4’-pyridyl-N-oxide)-Substituted Hemithioindigos as Photoresponsive Guests for a Super Aryl-Extended Calix[4]pyrrole Receptor
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Author:
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Moncelsi, Giulia; Escobar, Luis; Dube, Henry; Ballester, Pablo
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Abstract:
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We report the synthesis of two 2-(4’-pyridyl-N-oxide)-substituted hemithioindigos. We probed their photoisomerization using UV-Vis and 1H NMR spectroscopic techniques. Light irradiation at 450 nm provoked the isomerization of the HTI Z isomer to the E counterpart in a large extent (~80 % at the PSS). 1H NMR titration experiments revealed the formation of thermodynamically and kinetically stable 1:1 inclusion complexes of the Z-HTI isomers with a super aryl-extended host (Ka > 104 M-1). Photoirradiation at 450 nm of the inclusion complexes induced the isomerization of the bound HTI N-oxide affording the E-HTI⊂calix[4]pyrrole complex. We determined accurate association constant values for the 1:1 inclusion complexes of the Z and E-HTI isomers using isothermal titration calorimetry experiments (ITC). The results showed a 2.2-2.8-fold decrease in the stability constants of the E-HTI complexes in comparison to the Z-HTI counterparts explaining the lack of light-induced release of the former to the bulk solution. |
Publication date:
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2018-06-18 |
Subject(s):
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54 |
Rights:
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L'accés als continguts d'aquest document queda condicionat a l'acceptació de les condicions d'ús establertes per la següent llicència Creative Commons:http://creativecommons.org/licenses/by-nc-nd/4.0/ |
Pages:
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1632 p. |
Document type:
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Article Article - Accepted version |
DOI:
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10.1002/asia.201800463
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