8-HaloBODIPYs and Their 8-(C, N, O, S) Substituted Analogues: Solvent Dependent UV鈥揤is Spectroscopy, Variable Temperature NMR, Crystal Structure Determination, and Quantum Chemical Calculations

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• 作者：No毛l Boens ; Lina Wang ; Volker Leen ; Peijia Yuan ; Bram Verbelen ; Wim Dehaen ; Mark Van der Auweraer ; Wim D. De Borggraeve ; Luc Van Meervelt ; Jeroen Jacobs ; David Beljonne ; Claire Tonnel茅 ; Roberto Lazzaroni ; Maria J. Ruedas-Rama ; Angel Orte ; Luis Crovetto ; Eva M. Talavera ; Jose M. Alvarez-Pez
• 刊名：Journal of Physical Chemistry A
• 出版年：2014
• 出版时间：March 6, 2014
• 年：2014
• 卷：118
• 期：9
• 页码：1576-1594
• 全文大小：867K
• 年卷期：v.118,no.9(March 6, 2014)
• ISSN：1520-5215

文摘

The UV鈥搗is electronic absorption and fluorescence emission properties of 8-halogenated (Cl, Br, I) difluoroboron dipyrrin (or 8-haloBODIPY) dyes and their 8-(C, N, O, S) substituted analogues are reported. The nature of the meso-substituent has a significant influence on the spectral band positions, the fluorescence quantum yields, and lifetimes. As a function of the solvent, the spectral maxima of all the investigated dyes are located within a limited wavelength range. The spectra of 8-haloBODIPYs display the narrow absorption and fluorescence emission bands and the generally quite small Stokes shifts characteristic of classic difluoroboron dipyrrins. Conversely, fluorophores with 8-phenylamino (7), 8-benzylamino (8), 8-methoxy (9), and 8-phenoxy (10) groups emit in the blue range of the visible spectrum and generally have larger Stokes shifts than common BODIPYs, whereas 8-(2-phenylethynyl)BODIPY (6) has red-shifted spectra compared to ordinary BODIPY dyes. Fluorescence lifetimes for 6, 8, and 10 have been measured for a large set of solvents and the solvent effect on their absorption and emission maxima has been analyzed using the generalized Catal谩n solvent scales. Restricted rotation about the C8鈥揘 bond in 7 and 8 has been observed via temperature dependent ¹H NMR spectroscopy, whereas for 10 the rotation about the C8鈥揙 bond is not hindered. The crystal structure of 8 demonstrates that the short C8鈥揘 bond has a significant double character and that this N atom exhibits a trigonal planar geometry. The crystal structure of 10 shows a short C8鈥揙 bond and an intramolecular C鈥揌路路路蟺 interaction. Quantum-chemical calculations have been performed to assess the effect of the meso-substituent on the spectroscopic properties.