Improvement of the Proton Conduction of Copper(II)-Mesoxalate Metal−Organic Frameworks by Strategic Selection of the Counterions Gil-Hernández, Beatriz Quirós Olozábal, Miguel Supporting Information The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.inorgchem.2c01241. ACKNOWLEDGMENTS The authors would like to dedicate this publication to the memory of our good friend, scientific collaborator and former Inorganic Chemistry Department Professor Dr. Pedro Gili- Trujillo, whose wisdom, scientific knowledge, serenity, and kindness we will never forget. B.G.-H. acknowledges the SIDIX/SEGAI facility of the University of La Laguna. Threecopper(II)/mesoxalatebasedMOFswithformulas(H3O)[Cu9(Hmesox)6(H2O)6Cl]•8H2O(1),(NH2Me2)0.4(H3O)0.6[Cu9(Hmesox)6(H2O)6Cl]•8H2O(2),and(enH2)0.25(enH)1.5[Cu6(Hmesox)3(mesox)(H2O)6Cl0.5]Cl0.5•5.25H2O (3) were synthesized (H4mesox = mesoxalic acid = 2,2-dihydroxypropanedioic acid, en = ethylenediamine). Essentially, all of the compounds display the same anionic network with a different arrangement of the cations, which have a remarkable effect on the proton conduction of the materials, ranging from 1.16 × 10–4 S cm–1 for 1 to 1.87 × 10–3 S cm–1 for 3 (at 80 °C and 95% RH). These compounds also display antiferromagnetic coupling among the copper(II) ions through both the carboxylate and alkoxido bridges. The values of the principal magnetic coupling constants were calculated by density functional theory (DFT), leading to congruent values that confirm the predominant antiferromagnetic nature of the interactions. 2022-09-26T12:41:11Z 2022-09-26T12:41:11Z 2022-07-15 journal article Inorg. Chem. 2022, 61, 30, 11651–11666 [https://doi.org/10.1021/acs.inorgchem.2c01241] https://hdl.handle.net/10481/76987 10.1021/acs.inorgchem.2c01241 eng http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional American Chemical Society