Direct visualization of a guest-triggered crystal deformation based on a flexible ultramicroporous framework.
Host-guest composites may exhibit abnormal and/or controllable physical properties that are unavailable for traditional solids. However, it is still very difficult to control or visualize the occupancy and motion of the guest. Here we report a flexible ultramicroporous coordination polymer showing exceptional guest-responsive thermal-expansion properties. The vacant crystal exhibits constant and huge thermal expansion over a wide temperature range not only in vacuum but also in air, as its ultramicroporous channel excludes air adsorption even at 77 K. More interestingly, as demonstrated by single-crystal X-ray crystallography, molecular dynamic simulations and solid-state nuclear magnetic resonance, it selectively responds to the molecular rearrangement of N,N-dimethylformamide, leading to conformation reversion of the flexible ligand, which transfers these actions to deform the whole crystal lattice. These results illustrate that combination of ultramicroporous channel and flexible pore surface could be an effective strategy for the utilization of external physical and chemical stimuli.
MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, China.
Hao-Long
HL
Zhou
Rui-Biao
RB
Lin
Chun-Ting
CT
He
Yue-Biao
YB
Zhang
Ningdong
N
Feng
Qiang
Q
Wang
Feng
F
Deng
Jie-Peng
JP
Zhang
Xiao-Ming
XM
Chen