pH-Dependent Structural Engineering of Sulfonate-Carboxylate Cu-MOFs for High Proton Conductivity

IF 4.3 2区化学 Q1 CHEMISTRY, INORGANIC & NUCLEAR

Inorganic Chemistry Pub Date : 2025-04-23 DOI:10.1021/acs.inorgchem.5c01194

Shiyu Wei, Tingting Cui, Shunlin Zhang

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引用次数: 0

Abstract

Metal–organic frameworks (MOFs) with free carboxylic acid (COOH) groups are promising for solid-state proton-conducting materials, owing to the Brønsted acidity, polarity, and the hydrogen-bonding ability of COOH groups. In this work, two Cu-MOFs with different dimensions were synthesized by adjusting the pH of the reaction solution using disodium-2,2′-disulfonate-4,4′-oxidibenzoic acid (Na₂H₂DSOA) and 4,4′-bipyridine (4,4′-bpy) as ligands to coordinate with Cu(II). The resulting compounds, CuDSOA-1 (([Cu(4,4′-bpy)₂(H₂O)₂][Cu(H₂DSOA)₂(4,4′-bpy)(H₂O)₂]·12H₂O)) and CuDSOA-2 ([Cu₂(DSOA)(4,4′-bpy)₂(H₂O)₂]·4H₂O), have distinct dimensionalities and structures, mainly due to the pH’s effect on carboxylic acid deprotonation. Notably, CuDSOA-1 with abundant COOH groups, uncoordinated sulfonate groups, and water molecules shows a significantly enhanced proton conductivity of 2.46 × 10^–2 S cm^–1 at 95 °C and 98% RH, surpassing CuDSOA-2 (3.40 × 10^–5 S cm^–1 at 85 °C and 98% RH). The conductivity mechanism was found to be a Grotthuss mechanism, confirmed by deuterium–hydrogen isotopic effects. This study offers a method to control the coordination of sulfonic-carboxylic acid ligands with Cu(II) by pH adjustment, aiming to create MOFs with ultrahigh proton conductivity.

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来源期刊

Inorganic Chemistry 化学-无机化学与核化学

CiteScore

7.60

自引率

13.00%

发文量

1960

审稿时长

1.9 months

期刊介绍： Inorganic Chemistry publishes fundamental studies in all phases of inorganic chemistry. Coverage includes experimental and theoretical reports on quantitative studies of structure and thermodynamics, kinetics, mechanisms of inorganic reactions, bioinorganic chemistry, and relevant aspects of organometallic chemistry, solid-state phenomena, and chemical bonding theory. Emphasis is placed on the synthesis, structure, thermodynamics, reactivity, spectroscopy, and bonding properties of significant new and known compounds.