Source: School of Chemistry
Written by: School of Chemistry
Edited by: Wang Dongmei

Recently, Prof. Wei-Xiong Zhang’ group at School of Chemistry, Sun Yat-sen University revealed a unique phase transition behavior with supercooling phenomenon and dipole-glass-like dielectric relaxation as well as the related mechanism for a novel kind of ice-like hydrate, i.e., the three-dimensional (3D) water framework with 1D organic templates. The result was published in the top chemical journal J. Am. Chem. Soc. recently with Prof. Wei-Xiong Zhang and Dr. Dong-Dong Zhou as the corresponding author, PhD student Rui-Kang Huang as the first author.
 
Revealing the dynamic behavior of solid water is one interesting fundamental problem in science because of its importance in chemical and biological processes. However, for many kinds of ices, i.e., the solid state of pure water, it is difficult to reveal their structural details and relevant dynamics, owing to their structural complexity, uncertain positions of hydrogen atoms and susceptive preparation. As important supplements, various novel ice-like systems are of great interest for understanding the unique water dynamics in solid-state, but most known 3D ice-like frameworks were found in gas hydrates such as methane hydrates and are templated by cage units. In contrast, the 3D ice-like frameworks with 1D templates are very scarce.
 
According to the early studies on a hydrate obtained by Dr. Dong-Dong Zhou from Prof. Jie-Peng Zhang’s group (Chem. Commun. 2016, 52, 4991), Prof. Wei-Xiong Zhang and coworkers believed that this hydrate containing 3D water framework with 1D organic templates may serve as a novel ice-like model to host unique dynamics of water molecule. Then, they comprehensively studied the dynamics for this hydrate by combined technologies of in-situ synchrotron X-ray single-crystal analyses, in-situ neutron powder diffraction, DSC with different cooling rate, variable-temperature infrared spectra and dielectric measurements. They found that this hydrate exhibits a unique phase transition behavior with supercooling phenomenon and dipole-glass-like dielectric relaxation, and suggested that such unique dynamics is resulted from the short-range-correlated water cluster induced by the block effect between two typical mechanisms, i.e., proton hopping and water reorientation, in this novel 3D water framework. In consideration of the diversity of amphiphilic organic guests, their study provides a new clue to assemble more 3D ice-like frameworks with 1D templates for promoting the understandings on the dynamic behavior in diverse solid water.
This work had got the generous help from Prof. Xiao-Ming Chen and Prof. Jie-Peng Zhang at School of chemistry, Sun Yat-sen University, as well as the Institute of Nuclear Physics and Chemistry (INPC), China Academy of Engineering Physics and the National Center for Protein Sciences Shanghai (NCPSS) and Shanghai Synchrotron Radiation Facility (SSRF). This work was supported by the NSFC (21722107, 21671202, and 21701191).
 
Link to the paper: https://pubs.acs.org.ccindex.cn/doi/10.1021/jacs.9b01866