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Solvent mediated reversible solid state photochromism of {Mo72Fe30} Keplerate
Kesar Tandekar1, Neeraj Kumar Mishra1, Sabbani Supriya1
1School of Physical Sciences, Jawaharlal Nehru University, New Delhi-110067, India. ssabbani@mail.jnu.ac.in sabban07@gmail.com.
Abstract:
When the yellow rhombohedral crystals of Keplerate [Mo72Fe30O252(CH3COO)12{Mo2O7(H2O)}2{H2Mo2O8(H2O)}(H2O)91]·150H2O (1), on wetting with N,N-dimethylformamide (DMF), are irradiated with sunlight, a remarkable reversible solid state photochromic behaviour is achieved with the formation of green coloured crystals (1red). The reduction of the {MoVI} centres to {MoV} is responsible for the observed colour change from yellow to dark green. Importantly, compound 1 can be activated towards photochromism only in the presence of the DMF solvent. The photochromic phenomenon displayed by Keplerate compound 1 is a classic example of sunlight activated solvent driven photoactivity.
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