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

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(IPT^2-)(Ade)(DMF)]_n (IPT^2- = isophthalate; Ade = adenine; DMF = N,N'-dimethylformamide). The analysis of isosteric heat (Q_st) 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 E_a 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.