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Thermally Induced Intra‐Carboxyl Proton Shuttle in a Molecular Rack‐and‐Pinion Cascade Achieving Macroscopic Crystal Deformation
Author(s) -
Huang YouGui,
Shiota Yoshihito,
Su ShengQun,
Wu ShuQi,
Yao ZiShuo,
Li GuoLing,
Kanegawa Shinji,
Kang Soonchul,
Kamachi Takashi,
Yoshizawa Kazunari,
Ariga Katsuhiko,
Sato Osamu
Publication year - 2016
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201607886
Subject(s) - cascade , molecular machine , chemistry , molecule , supramolecular chemistry , molecular motor , proton , chemical physics , molecular dynamics , crystal structure , crystal (programming language) , crystallography , nanotechnology , materials science , computational chemistry , physics , organic chemistry , chromatography , quantum mechanics , computer science , programming language
Abstract Proton transport via dynamic molecules is ubiquitous in chemistry and biology. However, its use as a switching mechanism for properties in functional molecular assemblies is far less common. In this study, we demonstrate how an intra‐carboxyl proton shuttle can be generated in a molecular assembly akin to a rack‐and‐pinion cascade via a thermally induced single‐crystal‐to‐single‐crystal phase transition. In a triply interpenetrated supramolecular organic framework (SOF), a 4,4′‐azopyridine (azpy) molecule connects to two biphenyl‐3,3′,5,5′‐tetracarboxylic acid (H 4 BPTC) molecules to form a functional molecular system with switchable mechanical properties. A temperature change reversibly triggers a molecular movement akin to a rack‐and‐pinion cascade, which mainly involves 1) an intra‐carboxyl proton shuttle coupled with tilting of the azo molecules and azo pedal motion and 2) H 4 BPTC translation. Moreover, both the molecular motions are collective, and being propagated across the entire framework, leading to a macroscopic crystal expansion and contraction.