Three-Dimensional Honeycomb-like Pb-MOF with Multiple Sites for Selective Gas Adsorption and Efficient CO ₂ Catalytic Conversion

One novel honeycomb-like Pb 2+ -based metal–organic framework [Pb(dtzip) 0.5 (H 2 O)]·NMP·2H 2 O (H 4 dtzip = 4,6-di(1H-tetrazol-5-yl) isophthalic acid, NMP = N -methyl-2-pyrrolidone) was synthesized through solvothermal reaction of Pb 2+ ions with the azolate–carboxylate linker H 4 dtzip, which displays hexagonal channels with multiple accessible metal centers and N sites. Desolvated framework Pb(dtzip) 0.5 shows high porosity and significant adsorption selectivity, achieving effective separation for C 2 H 2 /CO 2, CO 2 /CH 4, and C 2 H 2 /CH 4 mixtures, respectively. The exposed Pb 2+ Lewis acidic sites in Pb(dtzip) 0.5 lead to efficient heterogeneous catalysis for CO 2 -epoxide cycloaddition, producing cyclic carbonates in high yields. This unusual material demonstrates remarkable substrate versatility, achieving quantitative conversion (99%) for simple substrates such as 1,2-epoxybutane, while maintaining excellent performance (>85% conversion) even with sterically demanding substrates. The role of metal centers and accessible organic sites in selective adsorption and catalytic reactions was deeply investigated through molecular simulations.