High-performance carbon dioxide capture and storage by multi-functional sphingosine kinase inhibitors through a CO2-philic membrane

The "all in one" environmentally friendly sphingosine kinase inhibitor (SphKI) molecule could combine the advantages of various organic functional groups, and ambiphilic and amphipathic nature together for effective carbon dioxide (CO2) capture. The CO2 molecule interacts with various functional molecules including aromatic and multi-heteroatom (such as nitrogen and oxygen) systems through both physical and chemical absorption. In this study, the ability of SphKI with multiple reaction centers to bind CO2 is investigated using symmetry-adapted perturbation theory and a non-covalent interaction approach. The combination of these two analyses allowed us to explore the nature and strength of the SphKIMIDLINE HORIZONTAL ELLIPSISCO2 interactions. We found that the variety of functional groups in SphKI including guanidine, oxadiazole, phenyl, and alkyl groups allowed it to act as both an electrophile and a nucleophile (ambiphilic nature) for the CO2 physisorption. But on the other hand, the chemisorption of CO2 by SphKI only proceeded through the guanidine group in the polar head (hydrophilic) region. These results revealed that the interaction energy values are divided into physical interactions with a binding energy in the range of similar to 2-32 kJ mol(-1), which are mainly dominated by both electrostatic and dispersion contributions, and chemical interactions (similar to 16-45 kJ mol(-1)). Also, according to the amphipathic nature of SphKIs, a simple sphingosine-based membrane is proposed and shown to be stable by molecular dynamics simulation under aqueous conditions. By considering the chemical equilibrium between CO2 and water (H2CO3 (aq)), we used the proposed membrane to evaluate the large scale CO2-capturing efficacy of SphKIs. The simulation results showed that the CO2 molecules can diffuse into the hydrophobic phase of the SphKI membrane, while the H2CO3 molecules remain in the aqueous phase.