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We have developed a class of phosphido-boranes (BoPh’s) with formula X+[R2PBH3–] that bind CO2 with exceptional strength (ΔG = −8.2 to −24.0 kcal/mol) at ambient conditions. We use quantum mechanics (QM) to determine how the choice of electron-donating versus electron-withdrawing ligand impacts the CO2 binding strength, in the presence of a donating borane moiety. We also examine the role of the cation in CO2 binding, finding that the ion position relative to the bound CO2 dramatically alters binding strength. We find that the BoPh with two ethyl ligands Li[Et2PBH3] leads to ΔG = −24.0 kcal/mol upon CO2 binding while Li[Ph2PBH3] leads to ΔG = −12.8 kcal/mol. We synthesized the BoPh with two phenyl ligands Li[Ph2PBH3] to validate the QM-predicted stability and predicted pKa. 

Synthesis of amine incorporated hierarchical metal organic framework (MOF) MIL-101(Cr)/SBA-15, meso/ micro-porous composites, with tailored properties for CO 2 capture is reported. The synthesized composites were characterized in terms of their crystallinity, morphology, functional groups, and textural properties. Isothermal adsorption of CO 2 from concentrated sites as well as ambient conditions were evaluated by gravimetric and volumetric measurements. The optimized composite i.e., MIL-101(Cr)/SBA-15/PEI-25 showed improved pseudo- equilibrium adsorption capacity of 3.2 mmol/g at 303 K and 1 bar, compared to nascent SBA-15 (0.8 mmol/g) and the MOF, i.e., MIL-101(Cr) (1.3 mmol/g). Such adsorption performance can be attributed to the basic sites of the impregnated polyethyleneimine (PEI), unsaturated Cr(III) metal sites, and the hierarchical pore structure of the composite which imparts chemical as well physical adsorption forces towards CO 2 lower amine loading of 25 wt% in the composite resulted in facile CO 2 uptake. Interestingly, desorption at much lower temperature of