J-aggregate structure in a chloroform solvate of a 2,3-dicyanopyrazine dye ? Separation of two-dimensional stacking dye layers by solvate formation

Abstract

Here, we report the J-aggregate structure of a chloroform solvate of 5-t-butyl-2,3-dicyano-6-[4-(dimethylamino)styryl]-pyrazine with a strong intramolecular charge transfer system. The dye was found to form a two-dimensional brick-wall structure separated by chloroform molecules in the solvated crystals, which exhibited intense red fluorescence. The absorption maximum of the solvate was also found to show a bathochromic spectral shift. These observed optical characteristics were interpreted in terms of excitonic intermolecular interaction based on two-dimensional brick-wall structure which is one of the proposed structures for J-aggregates.

Exciton Coupling of Merocyanine Dyes from H- to J-type in the Solid State by Crystal Engineering

“…Addressing this issue, control over supramolecular packing and finally crystal engineering are among the most powerful approaches and the prototype examples of potential achievements in terms of intermolecular coupling are the H-/J-aggregates as described by Davydov and Kasha in the molecular exciton theory. − Up to today, the importance of structural coupling control for several nanosystems and applications could be demonstrated, for example, beyond silver halide photo­graphy for many new optoelectronic functions. − For the merocyanines’ ionic counterparts, the cyanine dyes, a variety of aggregates has been reported in solution and the crystalline state since the discovery of J-aggregates in the 1930s; − however, for the merocyanines the situation is different. While the formation of cofacially stacked dimers and larger H-aggregates has extensively been studied, the structural arrangement of merocyanines into slipped-stack structures with J-type coupling is mostly limited to rather special experimental conditions. − Hence, neither J-aggregates in solution nor J-type coupling in the pure solid state with correlation to a crystal structure have been reported so far.…”

The effect of terminal dimethyl and diethyl substituents on the J-aggregate-like molecular arrangement of bisazomethine dye molecules

“…J-aggregates are known as low-dimensional aggregates of molecules. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] They exhibit a characteristic narrow and intense visible absorption band at longer wavelengths, 2 a large optical nonlinearity [3][4][5] and ultrafast photoexcitation decay 6 that is attributed to intermolecular interactions in certain arrangement of molecules. [7][8][9][10][11][12][13][14][15][16][17][18] Because of these optical properties, J-aggregates are attracting increasing attention as candidates to improve the functionality of organic optoelectronic devices.…”

Dynamic Analysis of Adsorption-Desorption Equilibrium of Sublimed Aromatic Molecules Using Polarized Optical Waveguide Spectroscopy

“…17,18 OWG spectroscopy can trace any change of the transition moment of interface molecules depending on time of using polarization for incident light. 19 In general, two types of polarized light have been used, namely, a transverse magnetic mode (TM) and a transverse electric mode (TE) having perpendicular and parallel amplitudes to the waveguide, respectively.…”