2-(4′-Pyridyl-N-oxide)-Substituted Hemithioindigos as Photoresponsive Guests for a Super Aryl-Extended Calix[4]pyrrole Receptor

Moncelsi G, Escobar L, Dube H, Ballester P (2018)

Publication Type: Journal article

Publication year: 2018

Journal

Chemistry - An Asian Journal Wiley

Book Volume: 13

Pages Range: 1632-1639

Journal Issue: 12

DOI: 10.1002/asia.201800463

Abstract

We report the synthesis of two 2-(4′-pyridyl-N-oxide)-substituted hemithioindigos (HTIs). We probed their photoisomerization by using UV/Vis and ¹H NMR spectroscopy techniques. Light irradiation at λ=450 nm provoked the isomerization of the HTI Z isomer to the E counterpart to a large extent (≈80 % at the photostationary state). 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 (association constant>10⁴ m⁻¹). Photoirradiation at λ=450 nm of the inclusion complexes induced the isomerization of the bound HTI N-oxide to afford 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 by using isothermal titration calorimetry experiments. The results showed that the stability constants of the (E)-HTI complexes were 2.2–2.8-fold lower than those of the (Z)-HTI counterparts, which explains the lack of light-induced release of the former to the bulk solution.

Authors with CRIS profile

Henry Dube

Involved external institutions

Ludwig-Maximilians-Universität (LMU)

Germany (DE) Autonomous University of Barcelona (UAB) / Universitat Autònoma de Barcelona

Spain (ES)

How to cite

APA:

Moncelsi, G., Escobar, L., Dube, H., & Ballester, P. (2018). 2-(4′-Pyridyl-N-oxide)-Substituted Hemithioindigos as Photoresponsive Guests for a Super Aryl-Extended Calix[4]pyrrole Receptor. Chemistry - An Asian Journal, 13(12), 1632-1639. https://doi.org/10.1002/asia.201800463

MLA:

Moncelsi, Giulia, et al. "2-(4′-Pyridyl-N-oxide)-Substituted Hemithioindigos as Photoresponsive Guests for a Super Aryl-Extended Calix[4]pyrrole Receptor." Chemistry - An Asian Journal 13.12 (2018): 1632-1639.

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