Optical devices system, photochemical

As just mentioned, phosphorus porphyrins have unique photochemical properties. Their photophysics is also interesting. Emitter-quencher assemblies based on porphyrin building blocks have attracted attention due to their potential to serve as models in photosynthetic research (see [90] for an example) or for the development of photoswitches that could be used for the fabrication of molecular electronic/optical devices. In this context, Maiya and coworkers constructed a P(VI) porphyrin system 59b with two switchable azobenzene groups positioned in the apical positions of the pseudo-octahedral phosphorus atom [92]. Photoswitch ability (luminescence on/off) was demonstrated as... 

Azobenzene systems represent very attractive phototriggers in Ch LCs, thanks to their resistance to photofatigue, the simplicity of the molecules, and the ease of modification of their molecular structures. This chapter first describes helical twisting ability of chiral azobenzene compounds by focusing the structural effects on HTP as well as photochemical change in HTP, and then phototuning of helical structures of Ch LCs through the trans-cis photoisomerization of the chiral azobenzene compounds for applications to optical devices. 

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