Read more about how to correctly acknowledge RSC content.Everything related to the Xbox One. Permission is not required) please go to the Copyright If you want to reproduce the wholeĪrticle in a third-party commercial publication (excluding your thesis/dissertation for which If you are the author of this article, you do not need to request permission to reproduce figuresĪnd diagrams provided correct acknowledgement is given. Provided correct acknowledgement is given. If you are an author contributing to an RSC publication, you do not need to request permission Please go to the Copyright Clearance Center request page. To request permission to reproduce material from this article in a commercial publication, Provided that the correct acknowledgement is given and it is not used for commercial purposes. This article in other publications, without requesting further permission from the RSC, Bai,Ĭreative Commons Attribution-NonCommercial 3.0 Unported Licence. Isomerization-induced fluorescence enhancement of two new viologen derivatives: mechanism insight and DFT calculations Vio1♲Cl and Vio2♲Br are the first examples of isomerization-induced fluorescence enhancement of viologen derivatives, which shows strong solvatofluorochromism under UV light, making up for the disadvantage that it is easy for a viologen radical to fade in air, and providing a new strategy for designing and synthesizing viologen materials with strong fluorescence. The calculated results are in good agreement with the experimental results. The fluorescence relative oscillator strength of Vio1 2+ and Vio2 2+ enol structures is significantly higher than that of keto structures ( f value changes from 1.53 to 2.63 for Vio1 2+ and from 1.62 to 2.81 for Vio2 2+), indicating stronger fluorescence emission of the enol structure. ![]() The fluorescence emission peaks of the keto and enol structures of Vio1 2+ and Vio2 2+ were at 416–417 nm and 563–582 nm, respectively. DFT calculations show that the enol form is almost coplanar throughout the molecular structure, which is conducive to stabilizing the structure and enhancing fluorescence. The NMR and ESI-MS data at different times further confirmed that the fluorescence enhancement was caused by isomerization, and no other fluorescent impurities were produced in solution. The time-dependent fluorescence spectrum shows obvious keto-to-enol isomerization-induced fluorescence enhancement. The keto group (–CH 2CO–) on the substituents is prone to isomerize into the enol structure (–CH COH–) in organic solvents, especially in DMSO, resulting in a larger conjugated system to stabilize the molecular structure and enhance fluorescence. Here, Vio1♲Cl and Vio2♲Br were synthesized by introducing aromatic acetophenone and naphthophenone substituents into the viologen structure. If a suitable substituent is introduced into the structure, it will have the dual function of chromism and luminescence, which will broaden its application field. The dark-colored viologen radical cations are unstable in air and easily fade, thus greatly limiting their applications.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |