Oxazines
| Autor: | Janet Cusido, Vincent Rodriguez, Françisco M. Raymo, Frédéric Castet, Flavie Bondu, Jaume Garcia-Amorós, Aurélie Plaquet, Benoît Champagne, Pierre Beaujean |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Substituent
Oxazines 02 engineering and technology 010402 general chemistry 01 natural sciences Biochemistry Catalysis quantum chemistry oxazines chemistry.chemical_compound Colloid and Surface Chemistry Ab initio quantum chemistry methods Computational chemistry Indole test Molecular switch chemistry.chemical_classification nonlinear optical switches Charge (physics) General Chemistry 021001 nanoscience & nanotechnology Acceptor 0104 chemical sciences Crystallography chemistry 0210 nano-technology Excitation |
| Zdroj: | Journal of the American Chemical Society. 138:5052-5062 |
| ISSN: | 1520-5126 0002-7863 |
| DOI: | 10.1021/jacs.5b13243 |
| Popis: | A combined experimental-theoretical investigation has revealed that oxazine-based compounds are multi-addressable, multi-state, and multi-functional molecular switches exhibiting contrasts of both linear and second-order nonlinear optical properties. The switching properties are particularly large when the substituent is a donor group. In this study, the cleavage of the C-O bond at the junction of the indole and oxazine cycles (of the closed a forms) is acido-triggered, leading to an open form (b+) characterized by larger first hyperpolarizabilities (βHRS) and smaller excitation energies than in the closed form. These results are confirmed and interpreted at the light of ab initio calculations that have been carried out on a broad set of compounds to unravel the role of the substituent. With respect to acceptor groups, oxazines bearing donor groups are not only characterized by larger βHRS and βHRS contrast ratios but also by smaller excitation energies, larger opening-induced charge transfer and reduction of the bond length alternation, as well as smaller Gibbs energies of opening reaction. Compared to protonated open forms (b+), calculations on the zwitterionic open forms (b) have pointed out similarities in the long-wavelength UV/vis absorption spectra, whereas their βHRS values might differ strongly as a function of the substituent. Indeed, the open forms present two NLOphores, the indoleninium-substituent entity and the nitrophenol (present in the protonated open form, b+) or nitrophenolate (present in the zwitterionic open form, b) moiety. Then, nitrophenolate displays a larger first hyperpolarizability than nitrophenol and the β tensor of the two entities might reinforce or cancel each other. |
| Databáze: | OpenAIRE |
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