SupraBank - Photochromism of a Merocyanine Dye Bound to Sulfonatocalixarenes: Effect of pH and the Size of Macrocycle on the Kinetics

DOI:: https://doi.org/10.34804/supra.20210928262
Title:: Photochromism of a Merocyanine Dye Bound to Sulfonatocalixarenes: Effect of pH and the Size of Macrocycle on the Kinetics

Description:: The effect of 1:1 complex formation on the photochromic behavior of the merocyanine isomer of a nitro-substituted spirobenzopyran dye was studied in aqueous solution using 4-sulfonatocalixarene (SCXn) cavitands possessing four or eight phenol units. The binding constants were independent of the size of the macrocycle, and about 7-fold more stable associates were produced at pH 2.3 than in slightly alkaline solution. The complexation with SCXn diminished the acidity of protonated merocyanine (trans-MCH+) and precluded its photoinitiated transition to spirobenzopyran form, but did not affect the reactions in basic media. Upon exposure to light, the complexed trans-MCH+ was converted to cis isomer. The association with 4-sulfonatocalix[4]arene slowed down the thermal back reaction in the dark to a larger extent than the confinement to 4-sulfonatocalix[8]arene. Both the activation energy and the Arrhenius A factor were significantly larger when the smaller, more rigid macrocycle served as a host.

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Citation:	Z. Miskolczy, L. Biczók, SupraBank 2024, Photochromism of a Merocyanine Dye Bound to Sulfonatocalixarenes: Effect of pH and the Size of Macrocycle on the Kinetics (dataset). https://doi.org/10.34804/supra.20210928262
Link:	https://doi.org/10.34804/supra.20210928262
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Citation:	Z. Miskolczy, L. Biczók, J. Phys. Chem. B 2013, 117, 648–653.
Link:	https://doi.org/10.1021/jp310167j
Export:	BibTex \| RIS \| EndNote \|