J-aggregation of photochromic spiropyran in Langmuir-Blodgett films

J-aggregate Formation and Thermal Decay Kinetics of Photoinduced Merocyanine in Bilayer Membrane as a Function of the Mixing Ratio.

“…The monomeric PMC band and a bathochromic narrow and intense band assigned to that of J-PMC [2,12,13] were observed at around 571 and 613 nm, respectively, regardless of the R value. From the absorbance (A) changes in both bands with R, it was suggested that the J-PMC formation tends to increase with the increase in R up to ca.…”

“…Experimental 2.1. Materials SP 1822 was synthesized according to the method of Ando et al [2]. 2C18N+2C1 was obtain from Tokyo Kasei Kogyo Co. and recrystallized from ethyl acetate.…”

“…Photochromic reactions occurring within the molecular assemblies such as micelles, polymer films, and Langmuir-Blodgett multi-layers have attracted much attention with respect to practical applications as a possible recording medium for information storage and retrieval devices [1][2][3][4][5][6][7][8][9]. Among the many related subjects, extensive studies on the photochromism behavior of spiropyrans (SPs) in bilayer membranes as a simplified model of the initial process of biological vision systems have been reported by Seki and Ichimura [10][11][12][13][14][15] and Tomioka and Inagaki [16,17].…”

Triggered J-aggregation in Mixed Langmuir–Blodgett Films of Amphiphilic Spiropyran Having a Methoxy Group at the 5’ Position and an Azobenzene Derivative

“…Careful investigation of light-induced J-aggregation in mixed LB films of SP1822 and alkanes shows that J-aggregates are formed at temperatures above the melting point of the mixture 22 . At temperatures below the melting point, alkanes pack with the alkyl chains of SP1822 and those of its merocyanine form to hinder J-aggregation, which explains the temperaturedependent photoreactions of mixed LB films of SP1822 and octadecane reported by Ando et al 17 . Langmuir films of SP1822 show thermal hysteresis of light-induced J-aggregation, which is related to the phase transition that occurs in bulk SP1822 23 .…”

“…Ando et al first reported the UV irradiation-induced isomerization of spiropyran to merocyanine followed by the formation of J-aggregates 17 . Room temperature UV irradiation of six-layer LB films of an amphiphilic spiropyran, 1 ,3 -dihydro-3 ,3 -demethyl-6-nitro-1 -octadecyl-8-docosanoyloxymethyl spiro 2H-1-benzopyran-2,2 -2H -indole SP1822 , mixed with octadecane leads to the isomerization of SP1822 to its merocyanine form without the formation of J-aggregates.…”