Effects of an amphiphilic perfluoro-carboxylate on the J-aggregates of a long-chain merocyanine with chlorine substituent in the mixed monolayers and their mixed Langmuir–Blodgett films

Murata, Michio; Mori, Kazuhiko; Sakamoto, Akira; Villeneuve, Masumi; Nakahara, Hiroyuki

doi:10.1016/j.cplett.2005.01.123

Cited by 11 publications

(8 citation statements)

References 21 publications

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“…The solid and dotted lines denote A ∥ and A ⊥ , respectively. In Figure a, a blue-shifted peak with sharp absorption is observed at 505 nm, which is ascribed to H-aggregation. − The absorption maximum at 505 nm shows the dichroic ratio with R < 1, where R is defined as A ∥ / A ⊥ . This tendency of R originates from the MS 18 side-by-side arrangement in the H-aggregate 13-20 and the flow orientation effect .…”

Section: Resultsmentioning

confidence: 99%

“…We have been engaged in research on the control of dye aggregation states by using mixed Langmuir−Blodgett (LB) films with merocyanine dye having an octadecyl group ( n = 18, MS 18 , 3-carboxymethyl-5-[2-(3-octadecylbenzothiazolin-2-ylidene)ethylidene]rhodanine; see Figure ). In a mixed LB film composed of an MS 18 −arachidic acid (C 20 ) binary system, a sharp, red-shifted J-band with an absorption maximum at 590 nm is formed, which is markedly shifted to a lower-energy side from the MS 18 monomer peak near 530 nm when it is prepared under an aqueous subphase containing a cadmium (Cd 2+ ) ion. − In addition, a blue-shifted band appears at 505 nm by adding a small amount of n -octadecane (AL 18 ) to the above MS 18 −C 20 binary system. − We assigned the 505 nm band to the H-band on the basis of the shift to the higher-energy side, sharpness, and in-plane anisotropy of the band. − …”

Section: Introductionmentioning

confidence: 99%

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Conversion of the Aggregation State of Merocyanine Dye, Modification of the Subcell Packing of Arachidic Acid, and Removal of the Majority of n-Octadecane by Hydrothermal Treatment in the Liquid Phase in a Mixed Langmuir−Blodgett Film of the Ternary System

2008

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We have investigated the influence of heat treatment in an air atmosphere (HT) and hydrothermal treatment in the liquid phase (HTTL) on the H-aggregate in a mixed Langmuir-Blodgett (LB) film of merocyanine dye with an octadecyl group (MS(18))-arachidic acid (C(20))-n-octadecane (AL(18)) ternary system by means of polarized visible and IR absorption spectroscopy. HT causes the variation from the H-aggregate to the monomer, the increment in the number of gauche conformers in the MS(18) hydrocarbon chain, the slight orientation change in the C(20) hydrocarbon chain, and the complete evaporation of AL(18). The dissociation of MS(18) is probably ascribed to the complete evaporation of AL(18) from the mixed LB film and the increase in thermal mobility of the long axis of the MS(18) hydrocarbon chain during HT. However, HTTL can easily and rapidly induce the conversion of the MS(18) aggregation state from H- to J-aggregates, the modification of the C(20) subcell packing from hexagonal to orthorhombic, and the removal of most of the AL(18) molecules. The conversion of the MS(18) aggregation state can be interpreted to consist of two processes from the H-aggregate to the monomer and from the monomer to the J-aggregate. In the initial stage of HTTL, the MS(18) aggregation state changes from the H-aggregate to the monomer, which is caused by the removal of almost all of the AL(18) molecules from the mixed LB film to warm water via the thermal energy of warm water. Then, the large relative permittivity of warm water is expected to relate strongly to the subsequent variation from the monomer to the J-aggregate. This transformation results in the decrease in the total value of the electrostatic energy based on the MS(18) permanent dipole interaction. Moreover, the modification of the C(20) subcell packing is possibly due to the hydrophobic effect, where the C(20) hydrocarbon chains cohere again in the warm water during HTTL. Consequently, it has been found that HTTL is quite effective to reorganize the chromophore alignment of MS(18), to modify the subcell packing of C(20) and to erase the majority of AL(18) molecules in the mixed LB film of the MS(18)-C(20)-AL(18) ternary system in a short time.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Conversion of the Aggregation State of Merocyanine Dye, Modification of the Subcell Packing of Arachidic Acid, and Removal of the Majority of n-Octadecane by Hydrothermal Treatment in the Liquid Phase in a Mixed Langmuir−Blodgett Film of the Ternary System

2008

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“…Cryst n-octadecane (AL 18 ) to the MS 18 -C 20 binary system. 14, [28][29][30][31][32][33][34][35][36][37][38] We assigned the 505 nm band to the H-band on the basis of the shift to a higher-energy side, sharpness, and in-plane anisotropy of the band. [28][29][30][31][32][33][34][35] We characterized the individual structures of the J-and H-aggregates, aiming at the elucidation of the formation mechanism of the H-aggregate.…”

Section: Introductionmentioning

confidence: 99%

Thermal Behavior of J-Aggregates in Mixed Langmuir−Blodgett Films Composed of Merocyanine Dye and Deuterated Arachidic Acid Investigated by UV−visible and Infrared Absorption Spectroscopy

2007

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We have investigated the thermal behavior of J-aggregates in the mixed Langmuir-Blodgett (LB) films composed of the merocyanine dye (MS18)-deuterated arachidic acid (C20-d) binary system in the temperature range from 25 to 250 degrees C by means of UV-visible and IR transmission absorption spectroscopy. The temperature-dependent variations in both UV-visible and IR absorption spectra indicate that the MS18 aggregation states are linked with the MS18 intramolecular charge transfer and the behavior of the packing, orientation, conformation, and thermal mobility of the MS18 hydrocarbon chain. The J-aggregate formed at 25 degrees C in the mixed LB films dissociates in the temperature range from 25 to 110 degrees C, which is mainly ascribed to the increase in the thermal mobility of MS18 hydrocarbon chain and the dissociation of the chelation by a cadmium ion to the MS18 keto group. A thermally induced blue-shifted band appears at around 515 nm from 110 to 160 degrees C. This band is attributed to oligomeric aggregation with side-by-side alignment of the MS18 transition dipole moments on the basis of the shift to a higher-energy side, broadening, and temporary increment of the MS18 intramolecular charge transfer of the band. Consequently, the appearance of the thermally induced blue-shifted band indicates the possibility that the MS18 aggregation states can be controlled from the red shift to the blue shift by the annealing method adopted in the present study.

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“…1) are among the most extensively studied LB films of amphiphilic dyes. 4,[10][11][12][13][14][15] Two main approaches, both aiming to promote J aggregation in the precursory Langmuir floating monolayers of MC2, can be singled out in the literature. One of them fabricates monolayers of the pure merocyanine dye using an aqueous subphase containing metal or ammonium cations.…”

Section: And Ref 4)mentioning

confidence: 99%

A comparative study of two amphiphilic merocyanines: from monomers to aggregates in Langmuir and Langmuir–Blodgett mixed films

et al. 2013

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The Langmuir-Blodgett (LB) films with J aggregates of the amphiphilic MC2 merocyanine have been deeply investigated for more than two decades, mainly because of their interest for applications in photonic devices. To extend the excitation/emission wavelength range, we have studied an homologous dye, MC1, based on a shorter merocyanine chromophore, aiming at checking the ability of this compound to arrange into J aggregates within stable LB films. In this comparative MC1/MC2 investigation, we have addressed the structural and spectroscopic properties of the monomers in solution, the thermodynamic and morphological properties of the Langmuir monolayers at the air-water interface and the spectroscopic and photophysical properties, and the structural features thence obtainable, of the aggregates in the LB films. 1 H NMR experiments have shown that, in chloroform solutions, both dyes adopt planar conformations with the hydrophilic and hydrophobic groups pointing to opposite directions. Strongly attractive interactions are exhibited by both dyes towards arachidic acid in monolayers at the airsubphase interface, with a maximum stability for the 1 : 2 MC(1/2) : AA mixture. Relatively homogeneous LB multilayers have been obtained from 1 : 4 and 1 : 2 MC : AA mixtures with good transfer ratios. Absorption and emission of the LB films of MC1 are dominated by J aggregates, while those of MC2 show some H aggregate contributions too. The J aggregates of both compounds exhibit a tendency to align with the transition dipoles along the film dipping direction, only slightly tilted relative to the substrate surface; however, this tendency is more pronounced for the MC1 J aggregates. Overall, MC1 yields slightly more stable monolayers and more solid multilayers compared to MC2.

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Effects of an amphiphilic perfluoro-carboxylate on the J-aggregates of a long-chain merocyanine with chlorine substituent in the mixed monolayers and their mixed Langmuir–Blodgett films

Cited by 11 publications

References 21 publications

Conversion of the Aggregation State of Merocyanine Dye, Modification of the Subcell Packing of Arachidic Acid, and Removal of the Majority of n-Octadecane by Hydrothermal Treatment in the Liquid Phase in a Mixed Langmuir−Blodgett Film of the Ternary System

Conversion of the Aggregation State of Merocyanine Dye, Modification of the Subcell Packing of Arachidic Acid, and Removal of the Majority of n-Octadecane by Hydrothermal Treatment in the Liquid Phase in a Mixed Langmuir−Blodgett Film of the Ternary System

Thermal Behavior of J-Aggregates in Mixed Langmuir−Blodgett Films Composed of Merocyanine Dye and Deuterated Arachidic Acid Investigated by UV−visible and Infrared Absorption Spectroscopy

A comparative study of two amphiphilic merocyanines: from monomers to aggregates in Langmuir and Langmuir–Blodgett mixed films

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