Anisotropic Thermal Expansion as the Source of Macroscopic and Molecular Scale Motion in Phosphorescent Amphidynamic Crystals

Abstract

Herein we report ac rystalline molecular rotor with rotationally modulated triplet emission that displays macroscopic dynamics in the form of crystal moving and/or jumping, also knownassalient effects.Molecular rotor 2 with ac entral 1,4-diethynyl-2,3-difluorophenylene rotator linked to two gold(I) nodes,c rystalizes as infinite 1D chains through intermolecular gold(I)-gold(I) interactions.T he rotational motion changes the orientation of the central phenylene, changing the electronic communication between adjacent chromophores,a nd thus the emission intensities.C rystals of 2 showed the large and reversible thermal expansion/compression anisotropy, whicha ccounts for 1) an onlinear Arrhenius behavior in molecular-level rotational dynamics,w hichc orrelates with 2) changes in emission, and determines 3) the macroscopic crystal motion. Am olecular rotor analogue 3 has properties similar to those of 2,s uggesting ag eneralized way to control mechanical properties at molecular and macroscopic scales.

Mechanical Bending and Modulation of Photoactuation Properties in a One-Dimensional Pb(II) Coordination Polymer

“…1,[5][6][7] A new class of macroscopic crystals also known as "soft crystals" exhibit mechanical movements induced by pressure, heat, and light which often results in hopping, splitting, bending, curling, coiling, twisting, swimming of the crystals. 1,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] With the upsurge of dynamic crystals, several examples of mechanically flexible crystals have been reported in the literature showing elastic and plastic deformation upon the application of an external force. [27][28][29][30][31][32][33][34] Apart from actuation by mechanical force, photomechanical actuation is of great advantage due to its remotely controlled process.…”

Mechanically Responsive Organic Crystals by Light

“…[80] Most of the motions of such salient crystals are irreversible, [76][77][78][79][80]84] except for the few reversible thermosalient crystals. [81][82][83] Once the salience occurs, the crystals are broken down. Such the thermosalient crystals were successfully applied to a solid-state fuse, an electrical safety device that actuates to break for overcurrent protection of an electrical circuit.…”

Thermal Energy-Driven Solid-State Molecular Rotation Monitored by Real-Time Emissive Color Switching

“…To construct a molecular rotor that can mediate emissions in crystalline states in response to external stimuli, it is necessary to exquisitely tailor-make the stator and rotor structures, which could well separate the structural rigid elements responsible for the lattice structures from those designed to perform the required rotations. 36,37 Herein, we demonstrate the achievement of a thermal energy-driven solid-state molecular rotor, which is featuring with N-substituted phenyl group as a rotor that directly transduces the surrounding thermal energy into rotational movements in the crystalline states. [38][39][40] Figure 1a depicts the molecular rotor of o-1 possessing a functional rotor connected to the 3,6-carbazole-substituted o-carborane as a stator by essential single bond serving as the rotation axle was successfully constructed.…”