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      https://www.ias.ac.in/article/fulltext/jcsc/130/10/0140

    • Keywords

       

      Photochromism; naphthopyrans; chromenes; photochemistry; spectrokinetics

    • Abstract

       

      Diarylbenzopyrans and their annulated derivatives are a class of photochromic compounds, which have been extensively investigated for photochromism. In fact, some naphthopyrans are employed industrially in ophthalmic lens applications. Photoirradiation of 2,2-diphenylbenzopyran leads to the formation of coloredo-quinonoid intermediates. The latter revert too rapidly to allow their observation only at low temperatures (173–263 K). Annulation and other strategies are exploited to observe the colored o-quinonoid intermediates that persist for a few minutes at room temperature. We have examined photochromism of a set of silyloxysubstituted 2,2-diphenylbenzo- and naphthopyrans to explore how the mesomeric effects transmitted by the strongly e-donating silyloxy group substituted in the ring and at phenyl groups manifest in the spectrokineticproperties of their photogenerated colored o-quinonoid intermediates. We show that silyloxy substitution in the benzopyran ring leads to remarkable stabilization of the colored intermediates to enable their persistence at 283 K for a few minutes. In contrast, similar substitution in the C2-phenyl rings destabilizes the colored intermediates.

    • Author Affiliations

       

      ARINDAM MUKHOPADHYAY VIJAY KUMAR MAKA JARUGU NARASIMHA MOORTHY1

      1. Department of Chemistry, Indian Institute of Technology, Kanpur, Uttar Pradesh 208 016, India
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  • Journal of Chemical Sciences | News

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