University of Limerick
Gao_2022_Robust.pdf (1.24 MB)

A robust molecular porous material for C2H2/CO2 separation

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A molecular porous material, MPM-2, comprised of cationic [Ni2(AlF6) (pzH)8(H2O)2] and anionic [Ni2Al2F11(pzH)8(H2O)2] complexes that generate a charge-assisted hydrogen-bonded network with pcu topology is reported. The packing in MPM-2 is sustained by multiple interionic hydrogen bonding interactions that afford ultramicroporous channels between dense layers of anionic units. MPM-2 is found to exhibit excellent stability in water (>1 year). Unlike most hydrogen-bonded organic frameworks which typically show poor  stability in organic solvents, MPM-2 exhibited excellent stability with respect to various organic solvents for at least two days. MPM-2 is found to be permanently porous with gas sorption isotherms at 298 K revealing a strong affinity for C2H2 over CO2 thanks to a high (ΔQst)AC [Qst (C2H2) − Qst (CO2)] of 13.7 kJ mol−1 at low coverage. Dynamic column breakthrough experiments on MPM-2 demonstrated the separation of C2H2 from a 1:1 C2H2/CO2 mixture at 298 K with effluent CO2 purity of 99.995% and C2H2 purity of >95% after temperature-programmed desorption. C-H···F interactions between C2H2 molecules and F atoms of AlF6 3− are found to enable high selectivity toward C2H2, as determined by density functional theory simulations.


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Small, 2206945


Wiley and Sons

Other Funding information

M.J.Z. acknowledges the support of the Science Foundation Ireland (SFI Awards 13/RP/B2549, 16/IA/4624, and 12/RC/2278_P2) and the Irish Research Council (IRCLA/2019/167). M.V. acknowledges the Irish Centre for High-End Computing (ICHEC) for the provision of computational facilities and support. Open access funding provided by IReL

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  • Chemical Sciences

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