Issue 1, 2020

Crystal structure and thermoresponsive luminescence of a 9,10-bis(phenylethynyl)anthracene-based cyclophane

Abstract

Introducing a cyclic structure to luminophores is a promising approach for achieving external stimuli-responsive luminescence. This is because luminescent cyclophanes containing flexible linkers tend to form several molecular assembled states. However, previously reported cyclophanes exhibiting thermoresponsive and/or mechanoresponsive luminescence have not given crystals suitable for single crystal X-ray structure analysis because of the flexible cyclic molecular structures. Such analysis is important because solved crystal structures can show unambiguous correlation between the arrangement of luminophores and photophysical properties. Here, we report the crystal structure of a cyclophane featuring a 9,10-bis(phenylethynyl)anthracene group and the thermoresponsive luminescence. The cyclophane was designed with shorter flexible oligo(ethyleneglycol) chains used as linkers bridging the luminophore and another aromatic group. The two different π-conjugated groups were orthogonally arranged in the individual molecule, and the luminophores partially overlapped between adjacent molecules. The cyclophane showed a supercooled nematic phase at room temperature upon cooling. Thermal treatment for the kinetically trapped state led to a transition to another crystalline state and, consequently, a change in photoluminescence colour. Emission spectroscopic studies and emission lifetime measurements revealed that the luminophores formed excimers in the supercooled nematic phase, whereas no excimer formation was observed for the crystalline phases.

Graphical abstract: Crystal structure and thermoresponsive luminescence of a 9,10-bis(phenylethynyl)anthracene-based cyclophane

Supplementary files

Article information

Article type
Paper
Submitted
13 авг 2019
Accepted
02 сеп 2019
First published
02 сеп 2019

Mol. Syst. Des. Eng., 2020,5, 205-211

Author version available

Crystal structure and thermoresponsive luminescence of a 9,10-bis(phenylethynyl)anthracene-based cyclophane

Y. Sagara, K. Takahashi, T. Nakamura and N. Tamaoki, Mol. Syst. Des. Eng., 2020, 5, 205 DOI: 10.1039/C9ME00105K

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