Davydov Split Aggregates of Cyanine Dyes on Self-Assembled Nanotubes

Abstract

The Davydov splitting of dye aggregates represents unique molecular excitons. In this paper, we report the formation of Davydov split aggregates of 3,3′-diethylthiacarbocyanine iodide (DiSC2 (3)) and 3,3′-diethylthiadicarbocyanine iodide (DiSC2 (5)) templated by the helical nanotubes of lithocholic acid (LCA). The templated Davydiv split aggregates show a strong J-band and a weak H-band in the adsorption spectra. As the LCA helical nanotubes transform into a straight shape, the relative intensities of the J-band and the H-band of the templated Davydov split aggregates become roughly equal. The twisted angle change of the transition moment of DiSC2 (3) and DiSC2 (5) molecules in the templated Davydov split aggregates in response to the helical-to-straight shape transformation of LCA nanotubes is estimated. The templated Dvaydov split aggregates with well-defined shapes and molecular excitons are of interest for artificial light-harvesting and optoelectronic devices.

Nanotube Template-Directed Formation of Strongly Coupled Dye Aggregates with Tunable Exciton Fluorescence Controlled by Switching between J- and H-Type Electronic Coupling

“…41 Fang and co-workers have reported the formation of dye aggregates (J-and H-aggregates) from the co-assembly of LCA with 3,3′-diethylthiadicarbocyanine iodide dyes (DiSC 2 (3) and DiSC 2 (5)) in aqueous ammonia solution. 42,46 However, so far, no detailed investigation on the exciton fluorescence properties of the LCA-templated dye aggregates has been reported.…”

“…The LCA has been chosen in this work because of its unique ability to self-assemble into highly monodisperse nanotubes through helical ribbon formation in ammonia solution. , In the past, LCA nanotubes have been utilized for the formation of supramolecular assemblies with dyes, − proteins, and heavy metal ions . Fang and co-workers have reported the formation of dye aggregates (J- and H-aggregates) from the co-assembly of LCA with 3,3′-diethylthiadicarbocyanine iodide dyes (DiSC 2 (3) and DiSC 2 (5)) in aqueous ammonia solution. , However, so far, no detailed investigation on the exciton fluorescence properties of the LCA-templated dye aggregates has been reported.…”

Crystalline H-aggregate nanoparticles for detecting dopamine release from M17 human neuroblastoma cells

“…27 In a previous study, we showed that DiSC 2 (5) in 15% ammonia solution formed both H- and J-aggregates. 28 Interestingly, 1 mM DiSC 2 (5) in 30% ammonia solution only formed H-aggregates with the H-band at 450 nm (Fig. 2b).…”

Fluorescent H-Aggregate Vesicles and Tubes of a Cyanine Dye and Their Potential as Light-Harvesting Antennae

“…Furthermore, the H-aggregate tubes showed the predominance of the H 1 -band over the H 2 -band, while the H-aggregate vesicles showed the predominance of the H 2 -band over the H 1band. The inclination angle (θ) of DiSC 2 (3) molecules in Haggregate vesicles and tubes could be calculated from the oscillation strength of the two Davydov components (H 1 -and H 2 -bands) with the equation 32,33 tan…”

“…Furthermore, the H-aggregate tubes showed the predominance of the H 1 -band over the H 2 -band, while the H-aggregate vesicles showed the predominance of the H 2 -band over the H 1 -band. The inclination angle (θ) of DiSC 2 (3) molecules in H-aggregate vesicles and tubes could be calculated from the oscillation strength of the two Davydov components (H 1 - and H 2 -bands) with the equation , , where A H1 ‑ band and A H2 ‑ band are the oscillation strengths of the H 1 -band and the H 2 -band, respectively. The ratio of A H1 ‑ band / A H2 ‑ band is proportional to the ratio of the areas under the H 1 -band and the H 2 -band in adsorption spectra.…”