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oai:riuma.uma.es:10630/344602026-02-03T11:07:36Zcom_10630_2254col_10630_37953

Salcedo, Inés R. Bazaga-García, Montse Pérez-Colodrero, Rosario Mercedes Vílchez-Cózar, Álvaro Cañamero-Cebrián, Fernando Olivera-Pastor, Pascual Zareba, Jan K. Cabeza-Díaz, Aurelio 2024-10-07T12:53:12Z 2024-10-07T12:53:12Z 2024 Inés R. Salcedo, Montse Bazaga-García, Rosario M. Pérez Colodrero, Álvaro Vílchez-Cózar, Fernando Cañamero-Cebrián, Pascual Olivera Pastor, Jan K. Zaręba, and Aurelio Cabeza. Structural Landscape and Proton Conduction of Lanthanide 5-(Dihydroxyphosphoryl)isophthalates. Crystal Growth & Design 2024 24 (19), 7910-7918 DOI: 10.1021/acs.cgd.4c00786 https://hdl.handle.net/10630/34460 https://doi.org/10.1021/acs.cgd.4c00786 Metal phosphonate-carboxylate compounds repre-sent a promising class of materials for proton conductionapplications. This study investigates the structural, thermal, andproton conduction properties of three groups of lanthanide-basedcompounds derived from 5-(dihydroxyphosphoryl)isophthalic acid(PiPhtA). The crystal structures, solved ab initio from X-raypowder diffraction data, reveal that groups Ln-I, Ln[O3P−C6H3(COO)(COOH)(H2O)2] (Ln = La, Pr), and Ln-II,Ln2{[O3P−C6H3(COO)(COOH)]2(H2O)4}·2H2O (Ln = La, Pr,Eu), exhibit three-dimensional frameworks, while group Ln-III,Ln[O3P−C6H3(COO)(COOH)(H2O)] (Ln = Yb), adopts alayered structure with unbonded carboxylic groups orientedtoward the interlayer region. All compounds feature carboxylicgroups and coordinating water molecules. Impedance measurements demonstrate that these materials exhibit water-mediated protonconductivity, initially following a vehicle-type proton-transfer mechanism. Upon exposure to ammonia vapors from a 14 or 28%aqueous solution, compounds from groups II and III adsorb ammonia and water, leading to an enhancement in proton conductivityconsistent with a Grotthuss-type proton-transfer mechanism. Notably, group II of the studied compounds undergoes the formationof a new expanded phase through the internal reaction of carboxylic groups with ammonia, coexisting with the as-synthesized phase.This postsynthetic modification results in a significant increase in proton conductivity, from approximately ∼5 × 10−6 to ∼10−4 S·cm−1 at 80 °C and 95% relative humidity (RH), attributed to a mixed intrinsic/extrinsic contribution. Remarkably, the NH3(28%)-exposed Yb-III compound achieves an enhancement in proton conductivity, reaching ∼ 5 × 10−3 S·cm−1 at 80 °C and 95% RH,primarily through an extrinsic contribution spa http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional Química inorgánica Protones Conductividad Iones Structural Landscape and Proton Conduction of Lanthanide 5-(Dihydroxyphosphoryl)isophthalates journal article