Adenine Tagged Mn-Based Coordination Polymer for Conversion of Carbon Dioxide to Cyclic Carbonates under Atmospheric Pressure.

Natural processes collectively balance the global carbon cycle, effectively controlling atmospheric carbon dioxide (CO2) levels. However, excessive CO2 emissions due to industrialization and population growth have disrupted natural processes by increasing the atmospheric CO2 concentration. To address this issue, CO2 capture and conversion have been implemented. Metal-organic frameworks (MOFs)/coordination polymers (CPs) with bioligands, such as amino acids and nucleobases, are receiving much interest. However, bio-MOFs are not much reported due to the lack of control over their coordination with metal ions. In this work, we have developed an adenine-tagged Mn-CP with dominant basic sites, [Mn(IPT2-)(Ade)(DMF)]n (IPT2- = isophthalate; Ade = adenine; DMF = N,N'-dimethylformamide). The analysis of isosteric heat (Qst) of CO2 adsorption supported the presence of strong interactions between CO2 and Mn-CP. Mn-CP demonstrated moderate to outstanding performance in coupling CO2 with smaller and larger epoxides at ambient pressure under neat conditions. The thermodynamic activation parameters indicate that Mn-CP operates through an associative mechanism (ΔS⧧ = -283.4 J mol-1 K-1), with a reduced kinetic barrier characterized by ΔH⧧ of 17.28 kJ mol-1 and Ea of 20.5 kJ mol-1. The catalytic efficiency of Mn-CP was particularly notable in the coupling reaction of epichlorohydrin and CO2, yielding 92% of the corresponding cyclic carbonate under atmospheric pressure.