It is demonstrated that halogen bonding can be used to construct low-molecular-weight supramolecular complexes with unique light-responsive properties. In particular, halogen bonding drives the formation of a photoresponsive liquid-crystalline complex between a non-mesogenic halogen bond-donor molecule incorporating an azo group, and a non-mesogenic alkoxystilbazole moiety, acting as a halogen bond-acceptor. Upon irradiation with polarized light, the complex exhibits a high degree of photoinduced anisotropy (order parameter of molecular alignment > 0.5). Moreover, efficient photoinduced surface-relief-grating (SRG) formation occurs upon irradiation with a light interference pattern, with a surface-modulation depth 2.4 times the initial film thickness. This is the first report on a halogen-bonded photoresponsive low-molecular-weight complex, which furthermore combines a high degree of photoalignment and extremely efficient SRG formation in a unique way. This study highlights the potential of halogen bonding as a new tool for the rational design of high-performance photoresponsive suprastructures.

Photoalignment and Surface-Relief-Grating Formation are Efficiently Combined in Low-Molecular-Weight Halogen-Bonded Complexes

PRIIMAGI, ARRI;SACCONE, MARCO;CAVALLO, GABRIELLA;PILATI, TULLIO MARIA;METRANGOLO, PIERANGELO;RESNATI, GIUSEPPE
2012

Abstract

It is demonstrated that halogen bonding can be used to construct low-molecular-weight supramolecular complexes with unique light-responsive properties. In particular, halogen bonding drives the formation of a photoresponsive liquid-crystalline complex between a non-mesogenic halogen bond-donor molecule incorporating an azo group, and a non-mesogenic alkoxystilbazole moiety, acting as a halogen bond-acceptor. Upon irradiation with polarized light, the complex exhibits a high degree of photoinduced anisotropy (order parameter of molecular alignment > 0.5). Moreover, efficient photoinduced surface-relief-grating (SRG) formation occurs upon irradiation with a light interference pattern, with a surface-modulation depth 2.4 times the initial film thickness. This is the first report on a halogen-bonded photoresponsive low-molecular-weight complex, which furthermore combines a high degree of photoalignment and extremely efficient SRG formation in a unique way. This study highlights the potential of halogen bonding as a new tool for the rational design of high-performance photoresponsive suprastructures.
azobenzene; halogen bonding; liquid crystals; self-assembly; supramolecular complexes
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11311/697516
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