Abstract:
The rapid increase in the concentration of atmospheric carbon
dioxide (CO2) has resulted in undesirable environmental issues. Hence, selective
CO2 capture and utilization as C1 feedstock for the preparation of high-value
chemicals and fuels has been considered as a promising step toward mitigating the
growing concentration of atmospheric CO2. In this direction, herein we report
rational construction of a Ag(I)-anchored sulfonate-functionalized UiO-66 MOF
named as MOF-SO3Ag composed of CO2-philic sulfonate functionality and
catalytically active alkynophilic Ag(I) sites for chemical fixation of carbon dioxide.
The MOF-SO3Ag exhibits selective as well as recyclable adsorption of CO2 with a
high heat of adsorption energy (Qst) of 37.8 kJ/mol. On the other hand, the
analogous MOF, UiO-66 doped with Ag(I), showed a lower Qst value of 30 kJ/mol,
highlighting the importance of the sulfonate group for stronger interaction with
CO2. Furthermore, the MOF-SO3Ag acts as an efficient heterogeneous catalyst for
cyclic carboxylation of propargylic alcohols to generate α-alkylidene cyclic carbonates in >99% yield at mild conditions of RT and 1
bar CO2. More importantly, one-pot synthesis of oxazolidinones by a three-component reaction between CO2, propargylic alcohol,
and primary amine has also been achieved using MOF-SO3Ag catalyst under the mild conditions. The MOF is highly recyclable and
retains its superior catalytic activity even after several cycles. To the best of our knowledge, MOF-SO3Ag is the first example of MOF
reported for RT chemical fixation of CO2 to oxazolidinones by aminolysis of α-alkylidene cyclic carbonates under the environmentfriendly
mild conditions.
