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Published on: October 31, 2019
A Reversible Redox Reaction in a Keggin Polyoxometalate Crystal Driven by Visible Light: A Programmable Solid-State
Kesar Tandekar1, Somenath Garai2, Sabbani Supriya1
1School of Physical Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
Abstract:
The colourless crystals of (PPh4 )3 [PW12 O40 ]⋅3 C3 H7 NO (1) are converted to the dark blue crystals of {(PPh4 )3 [PW12 O40 ]⋅3C3 H7 NO}0.85 {(PPh4 )3 (C3 H7 NO)+. [PWV WVI11 O40 ]- ⋅2C3 H7 NO)}0.15 (2) upon irradiation with visible light in an interesting single crystal to single crystal transformation. This photochromic conversion is accompanied by the reduction of concerned Keggin anion from {PWVI12 } to {PWV WVI11 }. This redox conversion is characterized by various spectroscopic techniques including single crystal X-ray diffraction studies. The photochromic properties of compound 1 can be controlled reversibly through the dimethylformamide (DMF) molecule as a function of temperature and proton exposure in a gas-solid reaction. The present work can be described as a new concept of programmable photochromism with the formation of photochromic pockets in crystalline 1 host (solid state), wherein a solvent can be plugged at a time to show light induced coloration.
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