Abstract
We report the synthesis of two 2-(4-pyridyl-N-oxide)-substituted hemithioindigos (HTIs). We probed their photoisomerization by using UV/Vis and (HNMR)-H-1 spectroscopy techniques. Light irradiation at =450nm provoked the isomerization of the HTI Z isomer to the E counterpart to a large extent (approximate to 80% at the photostationary state). (HNMR)-H-1 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>10(4)m(-1)). Photoirradiation at =450nm of the inclusion complexes induced the isomerization of the bound HTI N-oxide to afford the (E)-HTI< subset of>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.
Item Type: | Journal article |
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Research Centers: | Center for Integrated Protein Science Munich (CIPSM) |
Subjects: | 500 Science > 540 Chemistry |
ISSN: | 1861-4728 |
Language: | English |
Item ID: | 68186 |
Date Deposited: | 19. Jul 2019, 12:24 |
Last Modified: | 04. Nov 2020, 13:50 |