Issue 34, 2021

Fluorine as a robust balancer for tuning the reactivity of topo-photoreactions of chalcones and the photomechanical effects of molecular crystals

Abstract

Fluorine-free chalcones and chalcones bearing different numbers of fluorine atoms have been synthesized. It is found that fluorine can tune the reactivity of photo-induced [2 + 2] cycloaddition reactions in crystals. The higher the number of fluorine atoms, the higher the reactivity of the photodimerization. The single crystal structures and Hirshfeld surface analysis illustrated that the introduction of fluorine not only increased the molecular planarity but could also steer the potentially reactive double bonds in appropriate positions of the crystal lattices to meet Schmidt's criteria. Therefore, the stereospecific [2 + 2] cycloaddition reactions took place to afford one diastereoisomer from the reactive chalcones except for (E)-3-(4-fluorophenyl)-1-phenylprop-2-en-1-one (1FChH). Additionally, the chalcone-based molecular crystals exhibited various photomechanical behaviors, such as bending toward or away from the light source, swinging, cracking and jumping, driven by topo-photoreactions. As expected, the more efficient photo-induced [2 + 2] cycloaddition reactions in crystalline states led to more significant motions of the molecular crystals. Powder X-ray diffraction results suggested that the solid state [2 + 2] cycloaddition reactions changed the unit cell of the single crystals. The photo-induced bending toward or away from the light source for the needle-like crystals originated from the contraction or the expansion of the phototropic surface. Hence, the robust balancer fluorine in chalcones might play an important role in the crystalline packing. This provides a facile approach in crystal engineering to fabricate photo-induced mechanically responsive crystalline materials.

Graphical abstract: Fluorine as a robust balancer for tuning the reactivity of topo-photoreactions of chalcones and the photomechanical effects of molecular crystals

Supplementary files

Article information

Article type
Paper
Submitted
19 яну 2021
Accepted
25 мар 2021
First published
26 мар 2021

CrystEngComm, 2021,23, 5856-5868

Fluorine as a robust balancer for tuning the reactivity of topo-photoreactions of chalcones and the photomechanical effects of molecular crystals

Y. Shu, K. Ye, Y. Yue, J. Sun, H. Wang, J. Zhong, X. Yang, H. Gao and R. Lu, CrystEngComm, 2021, 23, 5856 DOI: 10.1039/D1CE00086A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements