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Metal complexes of new photochromic chelator: Structure, stability and photodissociation

Paper ID Volume ID Publish Year Pages File Format Full-Text
26963 43990 2013 9 PDF Available
Title
Metal complexes of new photochromic chelator: Structure, stability and photodissociation
Abstract

•A new spironaphthopyran-based photochromic chelator was synthesised.•Merocyanine isomer was formed 1:1 and 1:2 complexes with metal ions simultaneously.•The structure of merocyanine–ZnCl2 complex was characterised by X-ray diffraction.•A technique of quantum yields estimation of complex photodissociation was proposed.

A new spironaphthopyran-based photochromic chelator was synthesised, and its photochromic, thermochromic and metallochromic properties were investigated. In the presence of Cd2+, Mn2+, Ni2+, Co2+, Zn2+ and Cu2+ ions in acetone solutions 1:1 and 1:2 metal:merocyanine complexes were formed simultaneously. Electron absorption spectroscopy (isomolar solution technique) and electrospray ionisation mass-spectrometry techniques were employed in order to define stoichiometry of the complexes. Additionally, single-crystal X-ray diffraction was used to determine molecular structure of merocyanine–zinc chloride 1:1 complex in the solid state. By means of multiwavelength spectrophotometric analysis the thermodynamic and spectral parameters of the 1:1 and 1:2 metal:merocyanine complexes were calculated. The obtained results demonstrate that stability of the complexes increases in the range of metal ions Cd2+, Mn2+, Ni2+, Co2+, Zn2+, Cu2+. The stability constants of 1:1 complexes are higher than those of the complexes formed at the second complexation step. Complexation with Cd2+ and Zn2+ can be reversed by irradiation of the coloured merocyanine complex with visible light which leads to dissociation towards the initial spironaphthopyran and the metal ion. A new approach to estimate the metal–merocyanine complex photodissociation quantum yields was proposed and employed for Cd2+ and Zn2+ containing complexes.

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Keywords
Spiropyrans; Transition metals; Complexation; Photochromism; Quantum yield of photodissociation
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Metal complexes of new photochromic chelator: Structure, stability and photodissociation
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 265, 1 August 2013, Pages 1–9
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us