Photosalience and Thermal Phase Transitions of Azobenzene- and Crown Ether-Based Complexes in Polymorphic Crystals

Chi Hsien Wang; Yi Chia Lin; Surojit Bhunia; Yuanning Feng; Pramita Kundu; Charlotte L. Stern; Pei Lin Chen; J. Fraser Stoddart; Masaki Horie

doi:10.1021/jacs.3c06371

Photosalience and Thermal Phase Transitions of Azobenzene- and Crown Ether-Based Complexes in Polymorphic Crystals

Chi Hsien Wang, Yi Chia Lin, Surojit Bhunia, Yuanning Feng, Pramita Kundu, Charlotte L. Stern, Pei Lin Chen, J. Fraser Stoddart, Masaki Horie^*

^*Corresponding author for this work

Chemistry

Research output: Contribution to journal › Article › peer-review

11 Scopus citations

Abstract

Stimuli-responsive molecular crystals have attracted considerable attention as promising smart materials with applications in various fields such as sensing, actuation, and optoelectronics. Understanding the structure-mechanical property relationships, however, remains largely unexplored when it comes to functionalizing these organic crystals. Here, we report three polymorphic crystals (Forms A, B, and C) formed by the non-threaded complexation of a dibenzo[18]crown-6 (DB18C6) ether ring and an azobenzene-based ammonium cation, each exhibiting distinct thermal phase transitions, photoinduced deformations, and mechanical behavior. Structural changes on going from Form A to Form B and from Form C to Form B during heating and cooling, respectively, are observed by single-crystal X-ray crystallography. Form A shows photoinduced reversible bending, whereas Form B exhibits isotropic expansion. Form C displays uniaxial negative expansion with a remarkable increase of 44% in thickness under photoirradiation. Force measurements and nanoindentation reveal that the soft crystals of Form A with a low elastic modulus demonstrate a significant photoresponse, attributed to the non-threaded molecular structure, which permits flexibility of the azobenzene unit. This work represents a significant advance in the understanding of the correlation between structure-thermomechanical and structure-photomechanical properties necessary for the development of multi-stimulus-responsive materials with tailored properties.

Original language	English (US)
Pages (from-to)	21378-21386
Number of pages	9
Journal	Journal of the American Chemical Society
Volume	145
Issue number	39
DOIs	https://doi.org/10.1021/jacs.3c06371
State	Published - Oct 4 2023

Funding

We are grateful to Dr. Margaret Schott of Northwestern University for editing the manuscript and enlightening discussion. We extend our thanks to Prof. Hsin-Lung Chen and Ms. Weici Huang of National Tsing Hua University for their support with DSC and UV-Vis measurements, respectively. This work was financially supported by the National Science and Technology Council, Taiwan (110-2221-E-007-006-MY3, 110-2113-M-007-013-MY3, and 111-2917-I-007-002 for C.-H.W.). This work (VT-SCXRD) made use of the IMSERC Crystallography Facility at Northwestern University, which receives support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-2025633) and Northwestern University. We are grateful to Dr. Margaret Schott of Northwestern University for editing the manuscript and enlightening discussion. We extend our thanks to Prof. Hsin-Lung Chen and Ms. Weici Huang of National Tsing Hua University for their support with DSC and UV–Vis measurements, respectively. This work was financially supported by the National Science and Technology Council, Taiwan (110-2221-E-007-006-MY3, 110-2113-M-007-013-MY3, and 111-2917-I-007-002 for C.-H.W.). This work (VT-SCXRD) made use of the IMSERC Crystallography Facility at Northwestern University, which receives support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-2025633) and Northwestern University.

ASJC Scopus subject areas

Catalysis
General Chemistry
Biochemistry
Colloid and Surface Chemistry

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10.1021/jacs.3c06371

Cite this

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title = "Photosalience and Thermal Phase Transitions of Azobenzene- and Crown Ether-Based Complexes in Polymorphic Crystals",

abstract = "Stimuli-responsive molecular crystals have attracted considerable attention as promising smart materials with applications in various fields such as sensing, actuation, and optoelectronics. Understanding the structure-mechanical property relationships, however, remains largely unexplored when it comes to functionalizing these organic crystals. Here, we report three polymorphic crystals (Forms A, B, and C) formed by the non-threaded complexation of a dibenzo[18]crown-6 (DB18C6) ether ring and an azobenzene-based ammonium cation, each exhibiting distinct thermal phase transitions, photoinduced deformations, and mechanical behavior. Structural changes on going from Form A to Form B and from Form C to Form B during heating and cooling, respectively, are observed by single-crystal X-ray crystallography. Form A shows photoinduced reversible bending, whereas Form B exhibits isotropic expansion. Form C displays uniaxial negative expansion with a remarkable increase of 44% in thickness under photoirradiation. Force measurements and nanoindentation reveal that the soft crystals of Form A with a low elastic modulus demonstrate a significant photoresponse, attributed to the non-threaded molecular structure, which permits flexibility of the azobenzene unit. This work represents a significant advance in the understanding of the correlation between structure-thermomechanical and structure-photomechanical properties necessary for the development of multi-stimulus-responsive materials with tailored properties.",

author = "Wang, {Chi Hsien} and Lin, {Yi Chia} and Surojit Bhunia and Yuanning Feng and Pramita Kundu and Stern, {Charlotte L.} and Chen, {Pei Lin} and Stoddart, {J. Fraser} and Masaki Horie",

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AU - Wang, Chi Hsien

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AU - Feng, Yuanning

AU - Kundu, Pramita

AU - Stern, Charlotte L.

AU - Chen, Pei Lin

AU - Stoddart, J. Fraser

AU - Horie, Masaki

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AB - Stimuli-responsive molecular crystals have attracted considerable attention as promising smart materials with applications in various fields such as sensing, actuation, and optoelectronics. Understanding the structure-mechanical property relationships, however, remains largely unexplored when it comes to functionalizing these organic crystals. Here, we report three polymorphic crystals (Forms A, B, and C) formed by the non-threaded complexation of a dibenzo[18]crown-6 (DB18C6) ether ring and an azobenzene-based ammonium cation, each exhibiting distinct thermal phase transitions, photoinduced deformations, and mechanical behavior. Structural changes on going from Form A to Form B and from Form C to Form B during heating and cooling, respectively, are observed by single-crystal X-ray crystallography. Form A shows photoinduced reversible bending, whereas Form B exhibits isotropic expansion. Form C displays uniaxial negative expansion with a remarkable increase of 44% in thickness under photoirradiation. Force measurements and nanoindentation reveal that the soft crystals of Form A with a low elastic modulus demonstrate a significant photoresponse, attributed to the non-threaded molecular structure, which permits flexibility of the azobenzene unit. This work represents a significant advance in the understanding of the correlation between structure-thermomechanical and structure-photomechanical properties necessary for the development of multi-stimulus-responsive materials with tailored properties.

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Photosalience and Thermal Phase Transitions of Azobenzene- and Crown Ether-Based Complexes in Polymorphic Crystals

Abstract

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ASJC Scopus subject areas

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CCDC 2269385: Experimental Crystal Structure Determination

CCDC 2269391: Experimental Crystal Structure Determination

CCDC 2269399: Experimental Crystal Structure Determination

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Photosalience and Thermal Phase Transitions of Azobenzene- and Crown Ether-Based Complexes in Polymorphic Crystals

Abstract

Funding

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Datasets

CCDC 2269385: Experimental Crystal Structure Determination

CCDC 2269391: Experimental Crystal Structure Determination

CCDC 2269399: Experimental Crystal Structure Determination

Cite this