1,3,6,8‐Tetraphenylpyrene Derivatives: Towards Fluorescent Liquid‐Crystalline Columns?

Abstract

Tetraphenylpyrene has been selected as a discotic core to promote liquid‐crystalline fluorescent columns in view of its high fluorescence quantum yield in solution and ease of substitution by flexible lateral side chains. The synthesis and characterization of ten new derivatives of pyrene have been carried out; the pyrene core has been substituted at the 1,3,6,8‐positions by phenylene rings bearing alkoxy, ester, thioether, or tris(alkoxy)benzoate groups on the para position; the compounds have been characterized by mass spectrometry and 1H NMR and UV‐vis spectroscopies. In order to generate liquid‐crystalline phases, the nature, number, and size of the side chains as well as the degree of polarity around the tetraphenylpyrene core have been varied. However, the desired liquid‐crystalline behavior has not been observed. The supramolecular order together with the absorption and emission properties in solution and the solid state are discussed and compared to theoretical predictions. Quantum‐chemical calculations rationalize the high solid‐state fluorescence of a tetraphenylpyrene derivative for which the crystal structure has been determined.

Structural−Property Relationship in Pyrazino[2,3-g]quinoxaline Derivatives: Morphology, Photophysical, and Waveguide Properties

“…Despite the reduced reabsorption, there are other two important factors that may contribute to the excellent optical waveguide behaviors of 1 and 2 : (1) both the fibers of 1 and 2 have smooth surface and distinctly flat end facets which have minimized the optical losses caused by scattering; (2) the steric hindrance between nonplanar π planes minimizes effective π−π interaction (4.5 Å), thus the optical features in single molecular level remains in the solid state . Similar conclusion has been drawn by Geerts et al in the study of the high fluorescent solids of tetraphenylpyrene derivatives …”

Low‐Threshold Distributed‐Feedback Lasers Based on Pyrene‐Cored Starburst Molecules with 1,3,6,8‐Attached Oligo(9,9‐Dialkylfluorene) Arms

“…We assign the $405 nm peak to a pÀp à absorption centered on the pyrene core with the stronger, shorter wavelength peak then characteristic of 9,9-dihexylfluorene arm absorption and shifting as a consequence of the increased fluorene conjugation length for P3 relative to P2 (and both relative to P1 [21] ). These assignments are consistent with previous studies on 1,3,6,8-tetraphenylpyrene derivatives [18,20] and pyrene-cored dendrimers [15][16][17] and support the literature-based expectation that the pyrene core can be electronically isolated within dendrimer/starburst structures, thereby avoiding pyrenepyrene p-stacking.…”

Quenching Performance of Surfactant-Containing and Surfactant-Free Fluorophore-Doped Mesoporous Silica Films for Nitroaromatic Compound Detection

“…The emission peak of the fluorophore in the solid material was blue-shifted by 7 nm compared to the peak in solution (the peak occurs at 432 nm in DCM solution), which can be attributed to the reduction of the rotational degree of freedom of the external rings as a result of steric interactions, leading to the requirement for more energy to rotate to the state at which the fluorophore can be excited. 39 The wormlike film showed excellent quenching properties toward DNT vapor, 39% during the first 45 s and 94% after 405 s (Figure 6A and Table 2), comparable to the performance of many CP-based sensors reported in the literature (Table 3; a more extensive table is provided in the Supporting Information, Table S1). The fast reaction can be ascribed to the interconnected pore system, which facilitates the diffusion of DNT through the mesochannel system, and also to the role of the silica and surfactant phases in preventing selfquenching of the encapsulated fluorophore molecules.…”