Jumping Crystal of a Hydrogen‐Bonded Organic Framework Induced by the Collective Molecular Motion of a Twisted π System

Abstract

There is alimited number of reports on mechanically responsive molecular crystals,i ncluding thermo-responsive and light-responsive crystals.Rigid ordered molecular crystals with aclose-packing structure are less able to accept distortion, which hampers the development of such molecular crystals. The thermosalient effect, or "crystal jumping", refers to athermo-responsive system that converts heat into mechanical force by thermally induced phase transition. While they have recently attracted attention as potential highly efficient molecular actuators,less than two dozens of thermosalient molecular crystals have been reported to date,a nd the design of such molecules as well as how they assemble to express at hermosalient effect are unknown. Herein, we demonstrate how the cooperative molecular motion of twisted p units could serve to develop at hermo-responsive jumping molecular crystal with ah ydrogen-bonded organic framework (HOF) of tetra-[2,3]thienylene tetracarboxylic acid (1). The cooperative change in the molecular structure triggered by the desolvation of THF in the channel of the HOF structure induced not only ac hangei nt he structure of HOF but also mechanical force. Hydrogen bonding interactions contributed significant thermal stability to maintain the HOF assembly even with ad ynamic structural change.

Optical Waveguiding Organic Single Crystals Exhibiting Physical and Chemical Bending Features

“…These works have revealed the diversity of stimuli. Hence, it is significant to realize the assembly of different stimuli‐response mechanical properties, which is also instructive to the exploitation of new versatile organic solid materials . Although different bending modes of organic crystals have been developed, few of these masterpieces about organic crystals have accomplished a combination of different mechanical stimuli‐responses .…”

Metal-Organic Framework-Based Stimuli-Responsive Polymers

“…These materials have been widely used in emerging applications such as wearable electronics [31], tissue engineering [32] and self-healing coatings [33]. Materials with such behavior have been reported in Au nanoribbons [34], perovskite [35], silicon [36], and MOFs [37,38]. Specially, MOF-based MFR materials normally involve crystalline structure re-arrangement or geometry adaption by the introduction of pressure [39].…”

Achieving Bright Mechanoluminescence in a Hydrogen-Bonded Organic Framework by Polar Molecular Rotor Incorporation

“…Generally, ML takes places at the crack surfaces of crystals due to electron bombardment 18 , and therefore, the facile acquisition and regeneration of crystals is important for achieving the ML property. Fortunately, HOFs are highly crystalline, even single-crystalline, which can also be easily prepared and regenerated by simple recrystallization 11,[24][25][26] . HOFs are generally constructed containing carboxyl groups or amine groups that can induce strong hydrogen bonds.…”