ABSTRACT
NOTT-401 was found to be a highly stable adsorbent for SO2 and CO with excellent cyclability and a straightforward regeneration at room temperature. Moreover, the preferential CO binding sites within the MOF material have been identified by experimental in situ DRIFT spectroscopy coupled with DFT and QTAIM calculations. Such preferential CO adsorption sites were correlated to identify the most significant SO2 interactions within NOTT-401. This study sheds light on the role of the thiophene and hydroxo functionality, for a MOF material, in the binding of SO2 or CO.
ABSTRACT
The fluorescent properties of MIL-53(Al)-TDC are drastically changed due to the presence of iodine, even in small quantities, as a result of an energy transfer process from the host material (MIL-53(Al)-TDC) to the guest molecule (I2). While MIL-53(Al)-TDC's emission spectrum shows a weak and broad band, after I2 adsorption, it exhibits well-resolved and long-lasting emission lines, which could be exploited for iodine detection. Density Functional Theory periodical calculations demonstrated that in the most stable MIL-53(Al)-TDCI2 configuration, the I2 molecule is bonded mainly by an O-HI hydrogen bond. The QTAIM showed that other non-covalent interactions also provided stability to MIL-53(Al)-TDCI2. The electrostatic potential analysis indicated that the I2 molecule adsorption occurs by a combination of specific interactions with a strong electrostatic contribution and weak interactions. These results postulate fluorescent MIL-53(Al)-TDC as an efficient I2 detector (potentially for radioactive I2), using a simple fluorimetric test.
