TY - JOUR
T1 - Rich Polymorphism of a Metal-Organic Framework in Pressure-Temperature Space
AU - Widmer, Remo N.
AU - Lampronti, Giulio I.
AU - Chibani, Siwar
AU - Wilson, Craig W.
AU - Anzellini, Simone
AU - Farsang, Stefan
AU - Kleppe, Annette K.
AU - Casati, Nicola P.M.
AU - Macleod, Simon G.
AU - Redfern, Simon A.T.
AU - Coudert, François Xavier
AU - Bennett, Thomas D.
N1 - Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/6/12
Y1 - 2019/6/12
N2 - We present an in situ powder X-ray diffraction study on the phase stability and polymorphism of the metal-organic framework ZIF-4, Zn(imidazolate)2, at simultaneous high pressure and high temperature, up to 8 GPa and 600 °C. The resulting pressure-temperature phase diagram reveals four, previously unknown, high-pressure-high-temperature ZIF phases. The crystal structures of two new phases - ZIF-4-cp-II and ZIF-hPT-II - were solved by powder diffraction methods. The total energy of ZIF-4-cp-II was evaluated using density functional theory calculations and was found to lie in between that of ZIF-4 and the most thermodynamically stable polymorph, ZIF-zni. ZIF-hPT-II was found to possess a doubly interpenetrated diamondoid topology and is isostructural with previously reported Cd(Imidazolate)2 and Hg(Imidazolate)2 phases. This phase exhibited extreme resistance to both temperature and pressure. The other two new phases could be assigned with a unit cell and space group, although their structures remain unknown. The pressure-temperature phase diagram of ZIF-4 is strikingly complicated when compared with that of the previously investigated, closely related ZIF-62 and demonstrates the ability to traverse complex energy landscapes of metal-organic systems using the combined application of pressure and temperature.
AB - We present an in situ powder X-ray diffraction study on the phase stability and polymorphism of the metal-organic framework ZIF-4, Zn(imidazolate)2, at simultaneous high pressure and high temperature, up to 8 GPa and 600 °C. The resulting pressure-temperature phase diagram reveals four, previously unknown, high-pressure-high-temperature ZIF phases. The crystal structures of two new phases - ZIF-4-cp-II and ZIF-hPT-II - were solved by powder diffraction methods. The total energy of ZIF-4-cp-II was evaluated using density functional theory calculations and was found to lie in between that of ZIF-4 and the most thermodynamically stable polymorph, ZIF-zni. ZIF-hPT-II was found to possess a doubly interpenetrated diamondoid topology and is isostructural with previously reported Cd(Imidazolate)2 and Hg(Imidazolate)2 phases. This phase exhibited extreme resistance to both temperature and pressure. The other two new phases could be assigned with a unit cell and space group, although their structures remain unknown. The pressure-temperature phase diagram of ZIF-4 is strikingly complicated when compared with that of the previously investigated, closely related ZIF-62 and demonstrates the ability to traverse complex energy landscapes of metal-organic systems using the combined application of pressure and temperature.
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U2 - 10.1021/jacs.9b03234
DO - 10.1021/jacs.9b03234
M3 - Article
C2 - 31117654
AN - SCOPUS:85067050674
SN - 0002-7863
VL - 141
SP - 9330
EP - 9337
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 23
ER -