Robust {Pb 10 }-Cluster-Based Metal-Organic Framework for Capturing and Converting CO 2 into Cyclic Carbonates under Mild Conditions.

Developing a highly active catalyst that can efficiently capture and convert carbon dioxide (CO 2 ) into high-value-added energy materials remains a severe challenge, which inspires us to explore effective metal-organic frameworks (MOFs) with high chemical stability and high-density active sites. Herein, we report a robust 3D lead(II)-organic framework of {(Me 2 NH 2 ) 2 [Pb 5 (PTTPA) 2 (H 2 O) 3 ]·2DMF·3H 2 O} n ( NUC-111 ) with unreported [Pb 10 (COO) 22 (H 2 O) 6 ] clusters (abbreviated as {Pb 10 }) as nodes (H 6 PTTPA = 4,4',4″-(pyridine-2,4,6-triyl)triisophthalic acid). After thermal activation, NUC-111a is functionalized by the multifarious symbiotic acid-base active sites of open Pb 2+ sites and uncoordinated pyridine groups on the inner surface of the void volume. Gas adsorption tests confirm that NUC-111a displays a higher separation performance for mixed gases of f CO 2 and CH 4 with the selectivity of CO 2 /CH 4 at 273 K and 101 kPa being 31 (1:99, v/v), 23 (15:85, v/v), and 8 (50:50, v/v), respectively. When the temperature rises to 298 K, the selectivity of CO 2 /CH 4 at 101 kPa is 26 (1:99, v/v), 22 (15:85, v/v), and 11 (50:50, v/v). Moreover, activated NUC-111a exhibited excellent catalytic performance, stability, and recyclability for the cycloaddition of CO 2 with epoxides under mild conditions. Hence, this work provides valuable insight into designing MOFs with multifunctionality for CO 2 capture, separation, and conversion.