Strategic Design of a Functionalized Al(III) Metal–Organic Framework for Chemical Fixation of CO₂ inside Alkynes under Ambient Conditions and Synthesis of Biologically Important Heterocycles

The increasing impact of elevated atmospheric CO₂ levels on climate and biological systems underscores the urgent need for effective materials to mitigate these concentrations. Simultaneously, the demand for quinoline derivatives has risen sharply due to their critical role in synthesizing life-saving drugs. Here, we present the synthesis, characterization, and catalytic activity of an aqua-stable Al(III) metal-organic framework (MOF <b>1'</b>) and its postmodified variant doped with Ag(0) nanoparticles (<b>1'</b>-Ag NPs). The native MOF (<b>1'</b>) and its nanoparticle-anchored derivative exhibited remarkable efficacy in two key areas: the quantitative synthesis of quinoline heterocycles and irreversible chemical fixation of CO₂ into various alkynes. Under ambient temperature and atmospheric CO₂ pressure, <b>1'</b>-Ag NPs demonstrated exceptional catalytic performance for the cyclization of propargylic alcohols. Moreover, the catalysts exhibited excellent recyclability across multiple reusability cycles. Detailed control experiments revealed that the outstanding performance of <b>1'</b> and <b>1'</b>-Ag NPs stems from the anchored functional groups within <b>1'</b> and the highly exposed alkalophilic Ag(0) catalytic sites distributed along the surface of <b>1'</b>-Ag NPs. This study highlights the dual utility of <b>1'</b> and <b>1'</b>-Ag NPs, demonstrating their potential in both the selective synthesis of quinoline heterocycles and the environmentally sustainable capture and irreversible chemical conversion of CO₂ under mild conditions.