Shape-persistent azobenzene tetramers functionalized at the periphery with alkyloxy substituents of different lengths have been synthesized and their photochemical behaviour has been investigated. Efficient E → Z photoisomerization of the azobenzene units takes place both in solution and in the solid state, a highly desirable yet uncommon property for azobenzene-type photochromic compounds. The solid state E → Z photoisomerization is accompanied by an isothermal crystal-amorphous phase transformation; successively, anisotropic crystals can be grown upon promoting the Z → E isomerization by thermal annealing of the irradiated samples. These results validate the strategy of engineering multiphotochromic architectures with a rigid star-shaped geometry to preserve the solution-based photoreactivity also in the solid state. The observed unexpected photoinduced alignment makes these materials potentially attractive for the development of photo-patternable and photo-responsive surfaces.

Vialetto, J., Groppi, J., La Rosa, M., Silvi, S., Credi, A., Baroncini, M. (2019). Solution and solid state photochromism in a family of shape persistent azobenzene tetramers functionalized with alkyloxy substituents. PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES, 18, 2281-2286 [10.1039/c9pp00022d].

Solution and solid state photochromism in a family of shape persistent azobenzene tetramers functionalized with alkyloxy substituents

Groppi, Jessica;La Rosa, Marcello;Silvi, Serena;Credi, Alberto
;
Baroncini, Massimo
2019

Abstract

Shape-persistent azobenzene tetramers functionalized at the periphery with alkyloxy substituents of different lengths have been synthesized and their photochemical behaviour has been investigated. Efficient E → Z photoisomerization of the azobenzene units takes place both in solution and in the solid state, a highly desirable yet uncommon property for azobenzene-type photochromic compounds. The solid state E → Z photoisomerization is accompanied by an isothermal crystal-amorphous phase transformation; successively, anisotropic crystals can be grown upon promoting the Z → E isomerization by thermal annealing of the irradiated samples. These results validate the strategy of engineering multiphotochromic architectures with a rigid star-shaped geometry to preserve the solution-based photoreactivity also in the solid state. The observed unexpected photoinduced alignment makes these materials potentially attractive for the development of photo-patternable and photo-responsive surfaces.
2019
Vialetto, J., Groppi, J., La Rosa, M., Silvi, S., Credi, A., Baroncini, M. (2019). Solution and solid state photochromism in a family of shape persistent azobenzene tetramers functionalized with alkyloxy substituents. PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES, 18, 2281-2286 [10.1039/c9pp00022d].
Vialetto, Jacopo; Groppi, Jessica; La Rosa, Marcello; Silvi, Serena; Credi, Alberto; Baroncini, Massimo
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/685394
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