TY - JOUR
T1 - Oxazines
T2 - A New Class of Second-Order Nonlinear Optical Switches
AU - Beaujean, Pierre
AU - Bondu, Flavie
AU - Plaquet, Aurélie
AU - Garcia-Amorós, Jaume
AU - Cusido, Janet
AU - Raymo, Françisco M.
AU - Castet, Frédéric
AU - Rodriguez, Vincent
AU - Champagne, Benoît
N1 - Funding Information:
This work was supported by funds from the Belgian Government (IUAP No P7/5 "Functional Supramolecular Systems"), the Francqui Foundation, by grants from the ANR (PHOEBUS) and the National Science Foundation (CHE-1049860). It has also been done in the frame of the Centre of Excellence LAPHIA (Investments for the future: Programme IdEx Bordeaux - LAPHIA (ANR-10-IDEX-03-02)). V.R. is grateful to F. Adamietz for HRS experimental support and technical developments as well as to the CNRS and the R?gion Aquitaine for funding supports. We thank V. Li?geois for the use of DrawMol, employed to make the TOC. The calculations were performed on the computers of the Consortium des ?quipements de Calcul Intensif, including those of the Technological Platform of High-Performance Computing, for which we gratefully acknowledge the financial support of the FNRS-FRFC (Convention Nos. 2.4.617.07.F and 2.5020.11) and of the University of Namur, as well as on zenobe, the Tier-1 facility of the Walloon Region (Convention 1117545).
PY - 2016/5/4
Y1 - 2016/5/4
N2 - A combined experimental-theoretical investigation has revealed that oxazine-based compounds are multiaddressable, multistate, and multifunctional 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 utilizing 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 characterized not only 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 the 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.
AB - A combined experimental-theoretical investigation has revealed that oxazine-based compounds are multiaddressable, multistate, and multifunctional 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 utilizing 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 characterized not only 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 the 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.
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U2 - 10.1021/jacs.5b13243
DO - 10.1021/jacs.5b13243
M3 - Article
AN - SCOPUS:84966453571
VL - 138
SP - 5052
EP - 5062
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 15
ER -