Photochromic molecules have been widely used as sensors in hybrid materials to provide dynamic information about the microenvironment.  Photoisomerization can also be used to change the assembly of nanoparticles.  We have studied the influence of a covalently tethered silica nanoparticle on the photoisomerization rate of two ubiquitous chromophore systems � nitrospiropyran and azobenzene.  Formation of the chromophore-nanoparticle hybrid was performed using click chemistry.  We have studied two tether-lengths for the chromophore-nanoparticle linkage.  Fluorinated derivatives of the azobenzene system have been studied where the photoinduced isomerization of both isomers is possible in the visible region.  Mechanistic insight into spiropyran photoisomerization was obtained by the synthesis and photoactivity of tetrahydrochromeno[2,3-b]indole.  This new chromophore reacts readily with cyanide with a colormetric change.  A more extensive description of this chromophore's reactivity will be presented.

Photoisomerization of chromophore-functionalized nanoparticles

246th National Meeting (2013)

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