Related Experiment Video
Updated: Jan 6, 2026

Preparation of Liquid Crystal Networks for Macroscopic Oscillatory Motion Induced by Light
Published on: September 20, 2017
Anisotropic Thermal Expansion as the Source of Macroscopic and Molecular Scale Motion in Phosphorescent Amphidynamic
Mingoo Jin1,2, Sho Yamamoto3, Tomohiro Seki3
1University of California Los Angeles, Department of Chemistry & Biochemistry, Los Angeles, California, 90095-1569, USA.
Abstract:
Herein we report a crystalline molecular rotor with rotationally modulated triplet emission that displays macroscopic dynamics in the form of crystal moving and/or jumping, also known as salient effects. Molecular rotor 2 with a central 1,4-diethynyl-2,3-difluorophenylene rotator linked to two gold(I) nodes, crystalizes as infinite 1D chains through intermolecular gold(I)-gold(I) interactions. The rotational motion changes the orientation of the central phenylene, changing the electronic communication between adjacent chromophores, and thus the emission intensities. Crystals of 2 showed the large and reversible thermal expansion/compression anisotropy, which accounts for 1) a nonlinear Arrhenius behavior in molecular-level rotational dynamics, which correlates with 2) changes in emission, and determines 3) the macroscopic crystal motion. A molecular rotor analogue 3 has properties similar to those of 2, suggesting a generalized way to control mechanical properties at molecular and macroscopic scales.
Related Concept Videos
X-ray Crystallography
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
Thermal Strain
Thermal Expansion
Polymer Classification: Crystallinity
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
Variables Affecting Phosphorescence and Fluorescence
Photoluminescence: Applications

