TY - JOUR
T1 - Interrogating Kinetic versus Thermodynamic Topologies of Metal-Organic Frameworks via Combined Transmission Electron Microscopy and X-ray Diffraction Analysis
AU - Gong, Xinyi
AU - Noh, Hyunho
AU - Gianneschi, Nathan C.
AU - Farha, Omar K.
N1 - Publisher Copyright:
© 2019 American Chemical Society.
Copyright:
Copyright 2019 Elsevier B.V., All rights reserved.
PY - 2019/4/17
Y1 - 2019/4/17
N2 - Synthetic protocols that preferentially result in metal-organic framework (MOF) crystallization of one topology over another remain an elusive, empirical process. This is primarily because of a lack of fundamental insights into MOF crystal growth and the effect of various experimental parameters on the resulting topologies. In this Communication, we demonstrate the temperature-topology relationship of MOFs constructed from hexanuclear oxozirconium cluster nodes and tetrakis(4-carboxylphenyl)porphyrin linkers via a combined transmission electron microscopy and powder X-ray diffraction study. Synthesis at room temperature led to a mixed phase consisting of 12-connected (assuming no defects) MOF-525 and 6-connected PCN-224, possessing ftw and she topologies, respectively. When the temperature was raised to 145 °C, 8-connected PCN-222 (csq topology) was found, with a possible concurrence of another 8-connected NU-902 (scu topology) and 12-connected PCN-223 (shp topology), in addition to MOF-525 and PCN-224. With an increase in reaction time at 145 °C, a change in product distribution was observed where PCN-222 remained the major crystal phase after 7 days, while the contribution from MOF-525 and PCN-224 decreased. These data suggest that MOF-525 and PCN-224 are the kinetic products while PCN-222 is the thermodynamic product.
AB - Synthetic protocols that preferentially result in metal-organic framework (MOF) crystallization of one topology over another remain an elusive, empirical process. This is primarily because of a lack of fundamental insights into MOF crystal growth and the effect of various experimental parameters on the resulting topologies. In this Communication, we demonstrate the temperature-topology relationship of MOFs constructed from hexanuclear oxozirconium cluster nodes and tetrakis(4-carboxylphenyl)porphyrin linkers via a combined transmission electron microscopy and powder X-ray diffraction study. Synthesis at room temperature led to a mixed phase consisting of 12-connected (assuming no defects) MOF-525 and 6-connected PCN-224, possessing ftw and she topologies, respectively. When the temperature was raised to 145 °C, 8-connected PCN-222 (csq topology) was found, with a possible concurrence of another 8-connected NU-902 (scu topology) and 12-connected PCN-223 (shp topology), in addition to MOF-525 and PCN-224. With an increase in reaction time at 145 °C, a change in product distribution was observed where PCN-222 remained the major crystal phase after 7 days, while the contribution from MOF-525 and PCN-224 decreased. These data suggest that MOF-525 and PCN-224 are the kinetic products while PCN-222 is the thermodynamic product.
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U2 - 10.1021/jacs.9b01789
DO - 10.1021/jacs.9b01789
M3 - Article
C2 - 30929446
AN - SCOPUS:85064550161
VL - 141
SP - 6146
EP - 6151
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 15
ER -