Isostructural MFM-300(Sc) and MFM-300(In): Adsorption Behavior to Determine Their Differences

MFM-300(Sc) and MFM-300(In) are isostructuralmaterials that experimentally exhibit similar benzene adsorptionproperties with a higher capture value for MFM-300(Sc). Thisdifference is explained in this report with a theoretical study.Intermolecular interactions are analyzed with the electron densityfunctional theory, using Quantum Theory of Atoms in Molecules(QTAIM) and Non-Covalent Interactions index (NCI). Theoreticalresults indicate the establishment of two interactions between thebenzene molecule and two mu 2-OH groups from MFM-300(In).Meanwhile, in MFM-300(Sc), there is only one interaction betweena benzene molecule and the mu 2-OH group. According to the NCIand QTAIM, this additional C-HmiddotmiddotmiddotO contact is with a neighbor mu 2-OH from MFM-300(In). Therefore, MFM-300(In) shows twooccupied mu 2-OH groups. These mu 2-OH groups are also less directed to the center of the pore. In combination with a higher BET(Brunauer, Emmett, and Teller) surface area, this inactivates the adsorption sites, affording a higher benzene uptake for MFM-300(Sc). We present an interesting explanation of adsorption behavior beyond experimentally available parameters such as surfacearea or pore volume, focusing on different molecular interactions. In this investigation, experiments and theory together explain thesimilarities and differences of these isostructural materials.

Automated summary

This study explains the difference in benzene adsorption properties between MFM-300(Sc) and MFM-300(In) through theoretical analysis. The results show that MFM-300(In) exhibits two interactions between benzene molecules and μ2-OH groups, while MFM-300(Sc) only has one interaction. In addition, MFM-300(In) has a higher BET surface area compared to MFM-300(Sc).