Metal-organic frameworks(MOFs)are an emerging dass of porous materials with many unique properties that make them promising candidates for carbon dioxide(CO_(2))capture and storage.A better understanding of the behavi...Metal-organic frameworks(MOFs)are an emerging dass of porous materials with many unique properties that make them promising candidates for carbon dioxide(CO_(2))capture and storage.A better understanding of the behavior of CO_(2) adsorbed inside MOF will enable researchers to develop the ability of designing new MOF based materials with high CO_(2) adsorption capabilities.It is well known that presence of open metal sites(OMSs)can greatly enhance the gas adsorption capability of MOFs.MOF UTSA-74,a framework isomer of well-known MOF-74 has a unique feature that upon activation,a single metal ion has two OMSs.Therefore,it presents a unique opportunity to probe the dynamics of CO_(2) molecules adsorbed on these OMSs.In this work,the CO_(2) adsorptive properties of MOF UTSA-74 are examined with particular attention being paid to the dynamics of the CO_(2) adsorbed on these OMSs.Specifically,variable temperature 13C static solid-state nuclear magnetic resonance(SSNMR)experiments were conducted to directly monitor the behavior of BCO_(2) in UTSA-74 at different loadings.All CO_(2) molecules undergo localized wobbling.At low loadings,some CO_(2) molecules jump among three OMSs from three different Zn atoms in the cOsS section of the channel.Others hop back and forth between the two neighboring OMSs.At high loading,the three site jump has ceased,but two-site hopping persists.The dynamical behavior of CO_(2) in UTSA-74 results from the unique Zn coord ination environment It was discovered that CO_(2) is less mobile in UTSA-74 than in its.framework isomer,MOF-74-Zn.展开更多
基金Y.H.thanks the Natural Sciences and Engineering Research Council(NSERC)of Canada for a Discovery Grant.
文摘Metal-organic frameworks(MOFs)are an emerging dass of porous materials with many unique properties that make them promising candidates for carbon dioxide(CO_(2))capture and storage.A better understanding of the behavior of CO_(2) adsorbed inside MOF will enable researchers to develop the ability of designing new MOF based materials with high CO_(2) adsorption capabilities.It is well known that presence of open metal sites(OMSs)can greatly enhance the gas adsorption capability of MOFs.MOF UTSA-74,a framework isomer of well-known MOF-74 has a unique feature that upon activation,a single metal ion has two OMSs.Therefore,it presents a unique opportunity to probe the dynamics of CO_(2) molecules adsorbed on these OMSs.In this work,the CO_(2) adsorptive properties of MOF UTSA-74 are examined with particular attention being paid to the dynamics of the CO_(2) adsorbed on these OMSs.Specifically,variable temperature 13C static solid-state nuclear magnetic resonance(SSNMR)experiments were conducted to directly monitor the behavior of BCO_(2) in UTSA-74 at different loadings.All CO_(2) molecules undergo localized wobbling.At low loadings,some CO_(2) molecules jump among three OMSs from three different Zn atoms in the cOsS section of the channel.Others hop back and forth between the two neighboring OMSs.At high loading,the three site jump has ceased,but two-site hopping persists.The dynamical behavior of CO_(2) in UTSA-74 results from the unique Zn coord ination environment It was discovered that CO_(2) is less mobile in UTSA-74 than in its.framework isomer,MOF-74-Zn.
