TY - JOUR
T1 - Effect of larger pore size on the sorption properties of isoreticular metal-organic frameworks with high number of open metal sites
AU - Dietzel, Pascal D. C.
AU - Georgiev, Peter A.
AU - Frøseth, Morten
AU - Johnsen, Rune E.
AU - Fjellvåg, Helmer
AU - Blom, Richard
PY - 2020
Y1 - 2020
N2 - We show that four isostructural CPO-54-M metal-organic frameworks based on the larger organic linker 1,5-dihydroxynaphthalene-2,6-dicarboxylic acid and divalent cations (M = Mn, Mg, Ni, Co) are isoreticular to the CPO-27 (MOF-74) materials. Desolvated CPO-54-Mn contains a very high concentration of open metal sites, which has a pronounced effect on the gas adsorption of N 2 , H 2 , CO 2 and CO. Initial enthalpies of adsorption are significantly higher than for MOFs without open metal sites and are slightly higher than for CPO-27. The plateau of high enthalpy of adsorption decreases earlier in CPO-54-Mn as a function of loading per mole than in CPO-27-Mn. Cluster and periodic Density Functional Theory based calculations of the adsorbate structures and energetics show that the larger adsorption energy at low loadings, when only open metal sites are occupied, is mainly due to larger contribution of dispersive interactions for the materials with the larger, more electron rich bridging ligand.
AB - We show that four isostructural CPO-54-M metal-organic frameworks based on the larger organic linker 1,5-dihydroxynaphthalene-2,6-dicarboxylic acid and divalent cations (M = Mn, Mg, Ni, Co) are isoreticular to the CPO-27 (MOF-74) materials. Desolvated CPO-54-Mn contains a very high concentration of open metal sites, which has a pronounced effect on the gas adsorption of N 2 , H 2 , CO 2 and CO. Initial enthalpies of adsorption are significantly higher than for MOFs without open metal sites and are slightly higher than for CPO-27. The plateau of high enthalpy of adsorption decreases earlier in CPO-54-Mn as a function of loading per mole than in CPO-27-Mn. Cluster and periodic Density Functional Theory based calculations of the adsorbate structures and energetics show that the larger adsorption energy at low loadings, when only open metal sites are occupied, is mainly due to larger contribution of dispersive interactions for the materials with the larger, more electron rich bridging ligand.
U2 - 10.1002/chem.202001825
DO - 10.1002/chem.202001825
M3 - Journal article
C2 - 32428361
SN - 0947-6539
VL - 26
SP - 13523
EP - 13531
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
IS - 59
ER -