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[Nattapol Ma](https://orcid.org/0000-0002-6162-1834), Daiki Umeyama, Hiroki Yamada, Soracha Kosasang

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[Bottom‐Up Assembly of Amorphous Metal–Organic Frameworks From Proton Conductive Metal–Organic Polyhedra](https://mdr.nims.go.jp/datasets/c6a45352-a3ac-4dc6-9c83-e0c4be5d5ad5)

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Bottom‐Up Assembly of Amorphous Metal–Organic Frameworks From Proton Conductive Metal–Organic PolyhedraSmallwww.small-journal.comRESEARCH ARTICLEBottom-Up Assembly of Amorphous Metal–OrganicFrameworks From Proton Conductive Metal–OrganicPolyhedraNattapol Ma1 Daiki Umeyama2 Hiroki Yamada3 Soracha Kosasang11International Center for Young Scientists (ICYS), National Institute for Materials Science, Tsukuba, Ibaraki, Japan 2Research Center for Macromolecules andBiomaterials, National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, Japan 3Diffraction and Scattering Division, Japan Synchrotron RadiationResearch Institute (JASRI), Sayo, Hyogo, JapanCorrespondence: Nattapol Ma (ma.nattapol@nims.go.jp)Received: 4 March 2026 Revised: 1 May 2026 Accepted: 5 May 2026Keywords: amorphous | coordination polymers | metal–organic frameworks | metal–organic polyhedra | proton conductivitiesABSTRACTWhile crystalline metal–organic frameworks (MOFs) benefit from precise structural programmability, achieving comparablecontrol in amorphous MOFs (aMOFs) remains underexplored. Most reported aMOFs are obtained via top-down amorphizationof crystalline frameworks, whereas the limited bottom-up approaches typically rely on linker substitution-based assembly thatinherently restricts node-level functionalization.Here, we present a bottom-up strategy for constructing proton-conductive aMOFsusing sulfonate-rich metal–organic polyhedra (MOPs) as predesigned molecular building units. Discrete Rh-based MOPs withaccessible axial coordination sites are crosslinked with flexible ditopic linkers to form extended amorphous networks whilepreserving intrinsic node functionality. Variation of linker identity modulates network connectivity, free volume, water stability,and proton transport behavior. Retention of the sulfonate group from the MOP building units affords aMOFs with protonconductivities of up to 4.8 mS cm−1 at 85◦C and 90% relative humidity, with a low activation energy of 0.20 eV, whereas thesulfonate-free aMOF analog exhibits insulating behavior. These results establish a general strategy for the rational design offunctionally programmable aMOFs using chemically predefined building units.1TtmprnWeblTm©ShIntroductionhe precise spatial organization of molecular building blockshrough coordination bonding underpins the development ofetal–organic frameworks (MOFs) and porous coordinationolymers (PCPs) [1–3]. This modular design strategy enables theational assembly of extended architectures by linking inorganicodes with organic linkers into predictable, long-range networks.hile framework topology is dictated by the coordination geom-try of the constituent units, the local chemical environment cane systematically tuned through the choice of metal centers andinker functionalities [4, 5]. The use of predetermined secondaryhis is an open access article under the terms of the Creative Commons Attribution-NonCedium, provided the original work is properly cited and is not used for commercial purp2026 The Author(s). Small published by Wiley-VCH GmbHmall, 2026; 22:e73752ttps://doi.org/10.1002/smll.73752building units (SBUs), synthesized prior to framework formation,significantly expands the structural and chemical design spaceof MOFs and PCPs [6]. Such versatile structural and chemicalcontrol has established MOFs as a promising platform for a widerange of applications, including gas storage and separation [7–9], catalysis [10, 11], charge and ion transport [12–14], magnetism[15, 16], and more.In contrast, extending comparable levels of structural pro-grammability and functional control to the emerging classof amorphous MOFs (aMOFs) remains relatively underex-plored [17]. The absence of long-range periodicity can impartommercial License, which permits use, distribution and reproduction in anyoses.1 of 10http://www.small-journal.comhttps://doi.org/10.1002/smll.73752https://orcid.org/0000-0002-6162-1834mailto:ma.nattapol@nims.go.jphttp://creativecommons.org/licenses/by-nc/4.0/https://doi.org/10.1002/smll.73752http://crossmark.crossref.org/dialog/?doi=10.1002%2Fsmll.73752&domain=pdf&date_stamp=2026-05-13FIGURE 1 Schematic representation of the bottom-up assembly of functionally programmable aMOFs. This modular approach utilizes Rh-basedMOPs as chemically designable nodes. Crosslinking occurs exclusively at open axial metal sites, ensuring that intrinsic node-bound functionalities areretained within the resulting aMOFs.abaehreoastldigdwmHiocmcfbwftatfbidafbsba 32 16136829, 2026, 36, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/smll.73752 by National Institute For, Wiley Online Library on [28/06/2026]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creatdvantageous properties, including enhanced processability,road compositional compatibility, tunable optical responses,nd, in some cases, improved ion mobility [18–24]. How-ver, only a limited number of bottom-up synthetic strategiesave been reported that employ predefined building blocks toationally introduce functionality into aMOFs [25–29]. Thesexamples rely on direct coordination between metal ions orxo-clusters and multitopic organic linkers, forming extendedmorphous networks through metal–linker crosslinking in aimilar manner to the predetermined SBUs of crystalline sys-ems. For instance, zirconium-based aMOFs are synthesized viainker exchange between acetate-capped Zr clusters and ditopicicarboxylate linkers [28]. Such substitution-based approachesnherently restrict node-level functionalization, as functionalroups initially associated with the metal building units areisplaced during framework formation, limiting the extent tohich functionality can be preprogrammed into the resultingaterials.ere, metal–organic polyhedra (MOPs) are introduced as chem-cally designable and structurally complex building units tovercome the design limitations of aMOFs. MOPs are discrete,age-like architectures, some of which feature paddlewheeletal nodes with accessible axial coordination sites, enablingrosslinking to occur without disrupting intrinsic node-boundunctionality (Figure 1) [30–36]. Using well-defined rhodium-ased MOPs as molecular nodes, extended amorphous frame-orks are constructed through post-assembly crosslinking withlexible ditopic linkers. Crucially, this strategy preserves func-ional groups embedded within the MOP building blocks,llowing molecular-level properties to be directly transferredo the resulting aMOFs. As demonstrated here using a sul-onated Rh-based MOP, crosslinking with bis-pyridinyl andis-imidazole linkers yields a series of amorphous frameworksn which the MOP units are preserved, as confirmed by pairistribution function analysis. Variations in proton conductivitycross the resulting materials, including an aMOF constructedrom functional-group-free MOP, highlight the roles of node-ound functional groups, linker flexibility, and the spatialeparation of acidic sites, underscoring the potential of MOP-ased assembly as a platform for functionally programmableMOFs.of 102 Results and Discussion2.1 Synthesis and Crystal Structure ofSO3RhMOPThe sulfonate-rich metal–organic polyhedral building unit(SO3RhMOP) was synthesized by reacting rhodium(II) acetatedimer with 5-sulfo-1,3-benzenedicarboxylic acid monosodiumsalt (NaSO3bdcH2) in a mixed solvent of N,N-dimethylacetamide(DMA) and water at 120◦C for 24 h (Figure 2A, see detailedmethods in the ESI). The resulting purple solution was leftto stand at room temperature for one month, during whichpurple single crystals suitable for single-crystal X-ray diffraction(SCXRD) analysis were obtained (Figure 2B). In this work,SO3RhMOP was synthesized using the sodium salt NaSO3bdcH2rather than the protonated ligand isophthalate-5-sulfonic acid(HSO3bdcH2) in order to prevent undesired self-polymerizationinto crystalline MOF, which potentially occurs when the sulfonicgroups are present in their protonated form [37, 38].SCXRD analysis revealed that SO3RhMOP crystallizes in theI4/m space group, the same space group as SO3RhMOP pre-pared from HSO3bdcH2 [37], with two polyhedral moleculesper unit cell (Table S1 and Figure S1). Each discrete moleculeis composed of twelve Rh2 paddlewheel units interconnectedby twenty-four sodium 5-sulfo-1,3-benzenedicarboxylate ligands,forming a cuboctahedral architecture (Figure 2C,D). The externalaxial sites are occupied by DMA and water molecules, whereasinternal axial sites of all the Rh2 paddlewheels are coordinated bydimethylamine (Me2NH) molecules, which are generated in situvia hydrolysis of DMA under solvothermal reaction conditions.These structural features are essentially the same as SO3RhMOPprepared from HSO3bdcH2 [37].Although the positions of Na+ cations could not be refinedcrystallographically, their presence was confirmed by inductivelycoupled plasma-optical emission spectroscopy (ICP-OES), whichindicated a Na+:Rh2+ ratio to be approximately 0.8:1 (Table S2).Combined results from SCXRD and ICP-OES analyses establishthe chemical formula of the polyhedron in its single-crystal formas H4.8Na19.2[Rh24(SO3bdc)24(Me2NH)12(H2O)4(DMA)8]. Chargeneutrality must be achieved by partial protonation of the –SO −Small, 2026ive Commons LicenseFIGURE 2 Crystal structure of SO3RhMOP. (A) The structure of the dirhodium paddlewheel and the sodium 5-sulfo-1,3-benzenedicarboxylateligands (NaSO3bdc)2−. (B) Optical microscopy image of the as-synthesized SO3RhMOP in the original solution. (C) The crystal structure and (D) packingstructure of SO3RhMOP. Rh, S, O, C, and N atoms are represented in green, yellow, red, gray, and light blue, respectively. H atoms are omitted for clarity.[oHniuÅt(W(oycatiataopFsctSS 16136829, 2026, 36, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/smll.73752 by National Institute For, Wiley Online Library on [28/06/2026]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creat37], where protons are assumed to originate from the hydrolysisf DMA. Compared to previously reported crystal structures of24[Rh24(SO3-bdc)24(Me2NH)12(H2O)4(DMA)8], which containso Na+ cations, the unit cell volume observed in this studys significantly larger. The former has a larger unit cell vol-me than that of the latter at lower temperature (36919.9(4)3 at 170 K versus 35930.3(7) Å3 at 200 K), which is consis-ent with the incorporation of Na+ cations into the structureTable S1).e further synthesized SO3RhMOP powder on a larger scalesee detailed method in ESI). After washing the sample thor-ughly with fresh DMA and acetone, subsequent drying at 85◦Cielded a purple amorphous powder. The loss of crystallinity wasonfirmed by powder X-ray diffraction (PXRD, Figure S2). Themorphous nature of SO3RhMOP in the powder form is attributedo its hygroscopicity and the inherently weak intermolecularnteractions between discrete polyhedral units [39]. Notably, thes-synthesized crystals also lose crystallinity upon removal fromheirmother liquor. Synchrotron pair distribution function (PDF)nalysis revealed that the short- to intermediate-range structuref amorphous SO3RhMOP closely resembles the simulated PDFattern derived from the single-crystal model (Figures S3, S4).urther discussion of the PDF analysis is provided in a laterection. The overall composition of the bulk SO3RhMOP washaracterized by 1H nuclear magnetic resonance (NMR) spec-roscopy (Figures S5, S6) and thermogravimetric analysis (Figure7 and Table S3).mall, 20262.2 Synthesis of Crosslinked SO3RhMOPTo construct aMOFs, SO3RhMOPs were employed as sulfonate-rich molecular building units and crosslinked via ditopic linkers.Rh–Rh paddlewheel clusters in Rh-based MOPs are known to beinert at their equatorial sites but readily exchange coordinationbonds at their axial positions, particularly with N-donor linkers[40, 41]. Three flexible ditopic linkers, 1,4-bis[(1H-imidazol-1-yl)methyl]benzene (BIX), 1,3-di(4-pyridyl)-propane (DPP), and1,2-bis(4-pyridyl)ethane (DPE), were selected to promote theformation of amorphous products (Figure 3A).For the synthesis of aMOFs, SO3RhMOP and each ditopic linkerwere first dissolved separately in DMF to afford clear solutions.The SO3RhMOP-DMF solution was then added to the vigorouslystirring linker-DMF solution, producing red solutions containingkinetically trapped species (Figure S8), inwhich each SO3RhMOPis coordinated by the ditopic linker in amonodentate fashion [42].Coordination of the linkers to SO3RhMOP inDMFwas confirmedby the λmax shifts in the UV–vis spectra [33, 41]. The absorptionmaximum at 551 nm, observed for SO3RhMOP, shifted to 528,521, and 521 nm upon addition of 12 molar equivalents of BIX,DPP, and DPE, respectively (Figure S9). Heating the solutionsto 120◦C for 24 h induced gelation. The gelation indicates thatcrosslinking between MOP units occurs upon heating, drivenby the simultaneous dissociation of excess linkers and thesubsequent crosslinking of MOPs by the remaining coordinatedlinkers (Figure S10) [43, 44]. The resulting gels were washed and3 of 10ive Commons LicenseFIGURE 3 (A) Schematic overview of the bottom-up synthesis of amorphous metal–organic frameworks (aMOFs) using metal–organic polyhedraas building units. Optical images of the resulting aMOF constructed from the ditopic linkers 1,4-bis[(1H-imidazol-1-yl)methyl]benzene (BIX), 1,3-di(4-pyridyl)propane (DPP), and 1,2-bis(4-pyridyl)ethane (DPE). Scale bar= 0.5 mm. (B) Donut-chart representation of the number of unique linkers (nlinker)coordinated to each SO3RhMOP node (maximum = 12), derived from the 1H NMR spectra of the digested aMOFs (Figures S23–S33), along withthe corresponding calculated network branch functionality, f. The f value represents the average number of linkers (bridges) emanating from eachSO3RhMOP (junction) in the aMOF, assuming that each ditopic linker preferentially coordinates to two distinct SO3RhMOPs. Given the 12 exohedralRh coordination sites per SO3RhMOP, the theoretical maximum f value is 12, corresponding to full utilization of all sites to connect 12 neighboringSO3RhMOP via 6 ditopic linkers per SO3RhMOP (see more detail in ESI Figure S34).t2ssaesoawpl4 16136829, 2026, 36, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/smll.73752 by National Institute For, Wiley Online Library on [28/06/2026]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creatihen dried at 80◦C for 24 h followed by 120◦C for an additional4 h (see detailed method in ESI), affording dense solids withmooth surfaces at both the macroscopic (Figure 3A) and micro-copic (Figures S11–S16) scales. The samples are referred to asMOF-BIX, aMOF-DPP, and aMOF-DPE, according to the linkermployed during crosslinking. The amorphous nature of allamples was confirmed by the broad, diffuse scattering featuresbserved in their PXRD patterns (Figure S17). Thermogravimetricnalysis under N2 showed an initial weight loss of 7.5–8.6t% (Figures S18–S21), attributed to dehydration, followed by alateau indicating that the aMOFs are thermally stable up to ateast 225◦C. Differential scanning calorimetry (DSC, Figure S22)of 10measurements of all samples revealed no endothermic baselineshift within the measurement temperature range, indicatingthe absence of a detectable glass transition temperature andsupporting their classification as aMOFs [45].2.3 Network Structure of aMOFs1H NMR analysis of acid-digested aMOFs reveals that the aver-age numbers of incorporated linkers per polyhedron (nlinker)are 5.6, 9.5, and 9.6 for aMOF-BIX, aMOF-DPP, and aMOF-DPE, respectively (Figure 3B; Figures S23–S33). Because eachSmall, 2026ve Commons LicenseScSfabt4tfFtticnol[aaf=dB4anofabBDpatcc(pc2RsttoroSbP(d(S 16136829, 2026, 36, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/smll.73752 by National Institute For, Wiley Online Library on [28/06/2026]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable CreatiO3RhMOP possesses 12 exohedral Rh sites available for linkeroordination, full saturation corresponds to nlinker = 12 (Figure34). Locally, all three aMOFs consist of SO3RhMOP nodes thatunction as “junctions,” interconnected by ditopic linkers actings “bridges” through coordination bonds. The average number ofridges emanating from each junction, and thereby connectinghe network, is defined as the network branch functionality, f [46,7]. Assuming that each ditopic linker preferentially coordinateso two distinct junctions, the f value can be estimated directlyrom the measured nlinker values (Figure 3B; Figure S34).or aMOF-BIX, the f value is estimated to be 11.2, approaching theheoretical maximum for this system (fmax = 12). This indicateshat nearly all the exohedral Rh sites participate in bridgingnteractionswith unique SO3RhMOPneighbors, yielding a highlyrosslinked network. The f value observed for aMOF-BIX isotably high relative to previously reported amorphous gelsr aerogels constructed from other Rh-based MOPs and BIXinkers. For example, reacting 1-dodecyl-1H-imidazole-stabilizedRh2(benzene-1,3-dicarboxylate)2]12 with BIX produces gels anderogels with f values between 3.0 and 6.6 [48]. The f value forMOF-BIX is comparable to the maximum connectivity achievedor [Rh2(5-dodecoxybenzene-1,3-dicarboxylate)2]12, for which f12 was reported under optimized synthesis conditions andepending on the physical form of the product [33, 49].oth aMOF-DPP and aMOF-DPE exhibit lower f values (5.0 and.8, respectively) than aMOF-BIX. This reduction arises becausesubstantial fraction of the linkers coordinate to the SO3RhMOPode in a monodentate fashion, thereby decreasing the numberf bridging connections per node and consequently lowering thevalues [49]. A plausible explanation for the difference betweenMOF-BIX and aMOF-DPP/aMOF-DPE lies in the differingasicities of their N-donor sites. During the crosslinking process,IX, whose conjugate acid has a higher pKa than those ofPP and DPE, is more readily protonated. For reference, theKa values reported for 1-methylimidazole and 4-methylpyridinere 7.20 and 6.02, respectively [50, 51]. Protonation facilitateshe temporary generation of additional vacant Rh sites, whichan subsequently be occupied by other BIX molecules alreadyoordinated to neighboring SO3RhMOP nodes. This equilibriumthe site-opening and re-coordination processes mediated byrotons) promotes a higher degree of crosslinking in aMOF-BIX,onsistent with its larger f value [49, 52]..4 Short-Range Structureetention of SO3RhMOP building units in amorphous aMOFamples was characterized using synchrotron X-ray total scat-ering combined with PDF analysis (Figure 4A,B) [53]. Fourierransformation of the total structure factor, S(Q), with applicationf the Lorch modification yields the PDF, G(r), which provideseal-space structural information by describing the probabilityf finding atomic pairs at specific interatomic distances (Figures35–S41) [54–56]. Assignment of the PDF features was supportedy comparison with the simulated PDF pattern and partialDFs calculated from the single-crystal structure of SO3RhMOPFigure S4). The observed PDF peaks can be grouped into fouristinct regions, as highlighted in Figure 4A and B. Region I1.5–2.5 Å) corresponds to interatomic distances within the Rh2mall, 2026paddlewheel units. Region II (2.5–7.5 Å) comprises distancesbetween Rh atoms and portions of the coordinated linkers.Region III (7.5–12 Å) covers distances between neighboring Rh2paddlewheel units. Region IV (12–24 Å) represents correlationswithin a single SO3RhMOP polyhedron [57]. The PDF features ofaMOF-BIX, aMOF-DPP, and aMOF-DPE closely resemble thoseof SO3RhMOP, including retention of the Rh⋯Rh4 correlationsat interatomic distances of approximately 16–17 Å. Together withthe comparable Fourier transform infrared (FTIR, Figure S42)spectra observed for SO3RhMOP and the corresponding aMOFs,these results confirm that the SO3RhMOP building units remainintact in all aMOFs [28]. This behavior contrasts with zeoliticimidazolate framework glasses, where the melt-quenching pro-cess induces short-range disorder arising from distortions of theZn[ligand]4 tetrahedral units [58]. At higher r values, the PDFsbecome largely featureless due to signal damping originatingfrom the amorphous nature of the samples [59].2.5 Free Volume of aMOFsChanges in the average pore radius and free volume betweenSO3RhMOP and the corresponding aMOFs with different linkeridentities under ambient conditions, without sample activation,weremonitored using positron annihilation lifetime spectroscopy(PALS, Figure 5; Figure S43). The orthopositronium (o-Ps) life-time (τ3) and its relative intensity (I3), corresponding to thelongest-lived component, are correlated with the average poreradius and the relative number of free-volume cavities, respec-tively [60]. The estimated pore radii (and corresponding τ3 values)for SO3RhMOP, aMOF-BIX, aMOF-DPP, and aMOF-DPE are0.282 nm (1.96 ns), 0.290 nm (2.04 ns), 0.271 nm (1.84 ns), and0.275 nm (1.89 ns), respectively. The PALS-derived free-volumeparameters (τ33I3) are 20.7, 18.9, 14.1, and 15.5 ns3%, respectively.Among the aMOF samples, these trends are consistent with theN2 gas-accessible porosity data, indicating that the free volumeis strongly influenced by linker rigidity (see detail in ESI, FigureS44). Considering that all samples are predominantly composedof SO3RhMOP units, the comparatively higher free-volumeparameter observed for pristine SO3RhMOP likely originatesfrom external cavities formed by loosely packed SO3RhMOPunitsand incorporated interstitial water molecules [37, 61].2.6 Water Stability and Proton ConductivityThe presence of a high density of hydrophilic moieties inSO3RhMOP and the corresponding aMOFs, including sulfonategroups and Na+ ions, motivated us to evaluate their pro-ton conductivity [62, 63]. Previous studies have shown thatMOPs containing sulfonic acid groups exhibit promising protonconductivities, reaching approximately 15 mS cm−1 at 85◦C and90% relative humidity (RH), and up to 25 mS cm−1 at 95◦C [37].Although high proton conductivity can be achieved with discreteMOPs, their practical application is limited by their high watersolubility, which leads to a significant risk of dissolution uponexposure to liquid water during condensation events [64].Water stability was therefore assessed by immersing all materialsin deionizedwater at 25◦Cunder static conditions for twomonths(Figure S45). SO3RhMOP remained solid without undergoing5 of 10ve Commons LicenseFIGURE 4 (A) Local coordination environment and pair-distance labeling in SO3RhMOP. Rh, S, O, and C atoms are represented in green, yellow,red, and gray, respectively. H atoms and solvent molecules are omitted for clarity. (B) Experimental pair distribution functions (PDFs) of SO3RhMOP,aMOF-BIX, aMOF-DPP, and aMOF-DPE. Peaks are grouped into four main regions, highlighted in (A). Peak labels are assigned based on partial PDFs(Figure S4) simulated from crystal structures of SO3RhMOP. Additional S(Q) data and extended PDF data up to 40 Å are provided in Figures S35–S41 ofthe ESI.FIGURE 5 Pore radius of SO3RhMOP, aMOF-BIX, aMOF-DPP,aMOF-DPE, and PALS parameter (τ33I3). These cavity sizes were derivedfrom the orthopositronium (o-Ps) lifetime component (τ3) obtained viaPositron Annihilation Lifetime Spectroscopy (PALS). See Figure S43 forthe PALS spectra and Table S4 for the complete parameters.dwddvaat(drr6 16136829, 2026, 36, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/smll.73752 by National Institute For, Wiley Online Library on [28/06/2026]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creatieliquescence at 90% RH and 85◦C. However, upon direct contactith liquid water, it dissolved immediately and was completelyissolved within 2 h. Similarly, aMOF-DPP exhibited substantialissolution and fully dissolved after 7 days. In contrast, noisually detectable dissolution was observed for aMOF-BIX orMOF-DPE over the two-month period. The water stability ofMOF-BIX and aMOF-DPE was further evaluated at elevatedemperature by immersing the samples in water at 70◦C for 24 hFigure S46). Under these conditions, aMOF-DPE completelyissolved, indicating that the apparent water stability observed atoom temperature is kinetically limited. In contrast, aMOF-BIXemained stable, with no detectable dissolution observed by UV–of 10vis spectroscopy (Figure S47). This difference in water stabilitycorrelates well with the pKa values of the linkers employed.Based on their water stability at room temperature, aMOF-BIXand aMOF-DPE were selected for further proton conductivityevaluation under humidified conditions, in comparison withpristine SO3RhMOP (Figure 6A). All samples were preparedas pressed pellets from powder, and their proton conductivitieswere measured using alternating-current (AC) impedance spec-troscopy under a humidified atmosphere at 90% RH. PristineSO3RhMOPexhibits a proton conductivity of 2.0mS cm−1 at 30◦C,which increases to 16.7 mS cm−1 as the temperature is raisedto 85◦C. The activation energy (Ea) for proton conduction wasdetermined to be 0.40 eV, which lies at the empirical boundarycommonly used to distinguish between the Grotthuss and vehiclemechanisms [65–67, 13]. Notably, negligible conductivity wasobserved at 100◦C under dry N2 atmosphere, indicating thatcharge transport is predominantly mediated by incorporatedwater [68]. Protonmigration is therefore likely to proceed via hop-ping through a hydrogen-bonding network composed primarilyof water molecules, stabilized by interactions with hydrophilicsulfonate groups and hydrated Na+ ions [69].Crosslinking the proton-conductive moiety (in this caseSO3RhMOP) typically decreases conductivity dramatically,often due to an increase in spatial separation and a decrease inthe degree of freedom in motion caused by crosslinking [70].However, aMOF-DPE exhibits conductivity of 1.6 mS cm−1 at30◦C, comparable to that of SO3RhMOP at 30◦C (Figure 6A). Weattribute this suppression of the negative impact of crosslinkingto the relatively small spatial separation of aMOF-DPE (Figure 5).In addition, the presence of non-coordinated pyridyl groups onthe monodentate DPE linker, as suggested by the smaller fvalue of aMOF-DPE, may provide additional hopping sites thatfacilitate proton migration. The proton conductivity of aMOF-DPE reaches 4.8 mS cm−1 at 85◦C with an Ea of 0.20 eV. Thebenefit of crosslinking (enhanced water stability) is remarkablein aMOF-DPE, considering the limited drop of conductivitySmall, 2026ve Commons LicenseFIGURE 6 (A) Variable temperature proton conductivity at 90%relative humidity (RH) of SO3RhMOP, aMOF-BIX, aMOF-DPE, andHRhMOP. Nyquist plots are provided in Figures S48–S54. The activationenergy (Ea) values were calculated from Arrhenius plots (Figure S55).Conductivity values are provided in Table S9. (B) Schematic illustrationof the contributions of node-bound functional groups to humidity-dependent proton conductivity. Rh, S, O, and C atoms are represented ingreen, yellow, red, and gray, respectively. H atoms and solvent moleculesare omitted for clarity.aaoRTa3(apsbnutfFtNtspS 16136829, 2026, 36, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/smll.73752 by National Institute For, Wiley Online Library on [28/06/2026]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creatind lowered Ea compared to those of SO3RhMOP. Notably,MOF-DPE retains its fine powder morphology without anybservable swelling after 8 h under humidified conditions (90%H and 85◦C, Figure S57).he drop in conductivity is more prominent in aMOF-BIX.MOF-BIX exhibits a proton conductivity of 0.016 mS cm−1 at0◦C, increasing to 1.4 mS cm−1 at 85◦C with Ea of 0.76 eVFigure 6A). The substantial decrease in proton conductivity,ccompanied by an increase in Ea relative to SO3RhMOP, isotentially attributed to the larger spatial separation betweenulfonate groups (Figure 5) and the restricted mobility imposedy the relatively rigid BIX linker and the highly crosslinkedetwork (f = 11.2). In addition, aMOF-BIX shows lower waterptake compared to aMOF-DPE. For example, aMOF-BIX con-ains 26.3wt% H2O, which is lower than the 32.2 wt% observedor aMOF-DPE under identical conditions (30◦C and 90% RH,igure S58). The higher hydration level in aMOF-DPE is expectedo facilitate proton transport under humidified conditions [71].onetheless, the conductivity of aMOF-BIX is comparably higho the best value of the previously reported Zr-based aMOFsynthesized via bottom-up approaches, where water-mediatedroton conductivity is governed predominantly by the acidity ofmall, 2026functional groups on the organic linkers (0.031 mS cm−1 at 30◦Cand 95% RH) [28]. The superior performance of aMOF-DPE andaMOF-BIX suggests the advantage of the material design usingthe node-bound functionality.The importance of node-bound functionality is further high-lighted by an analogous aMOF without a functional group. Weprepared this aMOF (hereafter aMOF-H-BIX) from a sulfonate-free MOP [72], [Rh24(Hbdc)24] (hereafter HRhMOP) and theditopic BIX linker (see ESI Figures S59–S66 for detailed synthesisand characterization). Notably, the proton conductivity of aMOF-H-BIX (f = 5.5, see ESI) was below the instrumental limit,effectively making it an insulator (Figure 6B; Figure S67). Theproton conductivity of discrete HRhMOP at 90% RH exhibitedvalues of 0.013 and 0.13 mS cm−1 at 30 and 85◦C, respectively,which is lower than the values of aMOF-DPE and aMOF-BIX throughout the measured temperature range. The observeddifference in conductivity demonstrates the effectiveness of ourbottom-up strategy, where we can preserve functional groupsembedded within the MOP building blocks.Millimeter-scale, self-standing aMOF-BIX films can be fabricatedby reducing the thickness of the kinetically trapped solutionwithin an enclosed container during gelation without modifyingother synthesis parameters. This approach reduces the thicknessof the resulting cross-linked gel and, consequently, the finalaMOFmaterial after drying. For example, maintaining a solutionheight of 4 mm yields aMOF-BIX films with a thickness ofapproximately 11 µm(Figure S68). In contrast, aMOF-DPE ismoredifficult to process into large-area films (Figure S69), likely dueto its lower degree of cross-linking. Nevertheless, these resultsindicate that film formation is feasible through geometric controlof the reaction medium. With further optimization of synthesisconditions, particularly solution thickness and drying protocols,the fabrication of application-ready, self-standing aMOF films isachievable.3 ConclusionsIn conclusion, we have demonstrated a bottom-up approach toamorphous metal–organic frameworks that decouples networkformation from node functionalization by employing sulfonate-rich metal–organic polyhedra as molecular building units. Thisstrategy enables the preservation of well-defined Rh-basedMOP architectures within extended amorphous networks whileallowing modulation of network connectivity, free volume, andtransport properties through the choice of linkers. The resultingaMOFs exhibit enhanced water stability relative to the discreteMOPprecursor and display tunable proton conductivity governedby linker flexibility, sulfonate spatial arrangement, and water-mediated transport pathways. The aMOFs constructed fromsulfonated Rh-based MOPs exhibit proton conductivities exceed-ing those of previously reported aMOFs from the bottom-upapproach, whereas aMOFs synthesized from functional-group-free MOPs display insulating behavior. These results underscorethe important role of node-level functionality in amorphousframework design. Additionally, dual-mode functionality canbe developed to enhance proton conductivity by introducingfunctional groups in both the crosslinkers and the nodes.More broadly, this work establishes MOP-based assembly as a7 of 10ve Commons LicensevftpANfJ(StAaBe2(ptF(DPfKCTDDmvCsRiAj2“I3pfC4FS15J(6t8 16136829, 2026, 36, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/smll.73752 by National Institute For, Wiley Online Library on [28/06/2026]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicabersatile and general paradigm for the rational construction ofunctionally programmable aMOFs, opening new avenues forhe design of disordered solids with precisely encoded molecularroperties.cknowledgements.M. acknowledges the support from ICYS for a research fellowship,rom the Japan Science and Technology Agency (JST) PRESTO grantPMJPR25MB, from the Japan Society of the Promotion of ScienceJSPS) KAKENHI Grant Numbers JP24K23109 and JP25K18055, from theumitomo Foundation basic science grant number 2402150, and fromhe Iketani Science and Technology Foundation grant number 0371207-. S.K. acknowledges the support from ICYS for a research fellowshipnd from JST NEXUS (JPMJNX25B4). The authors acknowledge theL04B2 beamlines at SPring-8 for the synchrotron X-ray total scatteringxperiments with the approval of JASRI (Proposal Numbers 2024B1167,025A1067, and 2025B1248). The authors thank Dr. Takashi NakanishiNIMS), Dr. Renzhi Ma (NIMS), and Dr. Michio Matsumoto (NIMS) forroviding access to equipment. The authors acknowledge support fromhe NIMS Surface and Bulk Analysis Unit and NIMS Nanofabricationacilities. N.M. acknowledges the discussionswithDr. TakashiNakanishiNIMS), Dr. Michio Matsumoto (NIMS), Dr. Shinsuke Ishihara (NIMS),r. Mizuki Tenjimbayashi (NIMS), Dr. Kazuhiko Nagura (NIMS), androf. Rob Ameloot (KU Leuven). Finally, N.M. acknowledges the supportromDr. Koichi Tsuchiya,Ms. Chikako Enari,Ms. Imanishi Yuko, andMr.enichiro Kono.onflicts of Interesthe authors declare no conflict of interest.ata Availability Statementeposition number 2529690 (for SO3RhMOP) contains the supple-entary crystallographic data for this paper. These data are pro-ided free of charge by the joint Cambridge Crystallographic Dataentre and Fachinformationszentrum Karlsruhe Access Structureservice.eferences1. B. F. Hoskins and R. Robson, “Infinite Polymeric Frameworks Consist-ng of Three Dimensionally Linked Rod-Like Segments,” Journal of themerican Chemical Society 111 (1989): 5962–5964, https://doi.org/10.1021/a00197a079.. M. Kondo, T. Yoshitomi, H. Matsuzaka, S. Kitagawa, and K. Seki,[M2(4, 4′-bpy)3(NO3)4]⋅xH2O}n (M = Co, Ni, Zn),” Angewandte Chemienternational Edition 36 (1997): 1725–1727.. H. Li, M. Eddaoudi, T. L. Groy, and O. M. Yaghi, “Establishing Micro-orosity in Open Metal−Organic Frameworks: Gas Sorption Isothermsor Zn(BDC) (BDC= 1,4-Benzenedicarboxylate),” Journal of the Americanhemical Society 120 (1998): 8571–8572.. M. Eddaoudi, J. Kim, and N. Rosi, “Systematic Design of Pore Size andunctionality in Isoreticular MOFs and Their Application in Methanetorage,” Science 295 (2002): 469–472, https://doi.org/10.1126/science.067208.. O. M. Yaghi, M. O’Keeffe, N. W. Ockwig, H. K. Chae, M. Eddaoudi, and. Kim, “Reticular Synthesis and theDesign of NewMaterials,”Nature 4232003): 705–714, https://doi.org/10.1038/nature01650.. C. Serre, F. Millange, S. Surblé, and G. Férey, “A Route to the Syn-hesis of Trivalent Transition-Metal Porous Carboxylates With Trimericof 10Secondary Building Units,” Angewandte Chemie International Edition 43(2004): 6285–6289, https://doi.org/10.1002/anie.200454250.7. S. Kitagawa, R. Kitaura, and S. Noro, “Functional Porous Coordi-nation Polymers,” Angewandte Chemie International Edition 43 (2004):2334–2375, https://doi.org/10.1002/anie.200300610.8. G. Férey, “Hybrid Porous Solids: Past, Present, Future,” ChemicalSociety Reviews 37 (2008): 191–214.9. L. J. Murray, M. Dincă, and J. R. Long, “Hydrogen Storage inMetal–organic Frameworks,” Chemical Society Reviews 38 (2009): 1294–1314.10. J. Lee, O. K. Farha, J. Roberts, K. A. Scheidt, S. T. Nguyen, and J.T. Hupp, “Metal–organic Framework Materials as Catalysts,” ChemicalSociety Reviews 38 (2009): 1450–1459.11. Y.-S. Wei, M. Zhang, R. Zou, and Q. Xu, “Metal–Organic Framework-Based Catalysts With Single Metal Sites,” Chemical Society Reviews 120(2020): 12089–12174.12. P. Ramaswamy, N. E. Wong, and G. K. H. Shimizu, “MOFs as ProtonConductors – challenges and Opportunities,”Chemical Society Reviews 43(2014): 5913–5932.13. D.-W. Lim and H. Kitagawa, “Proton Transport in Metal–OrganicFrameworks,” Chemical Review 120 (2020): 8416–8467.14. L. S. Xie, G. Skorupskii, andM.Dinca, “Electrically ConductiveMetal–Organic Frameworks,” Chemical Reviews 120 (2020): 8536–8580, https://doi.org/10.1021/acs.chemrev.9b00766.15. G. M. Espallargas and E. Coronado, “Magnetic Functionalities inMOFs: From the Framework to the Pore,” Chemical Society Reviews 47(2018): 533–557, https://doi.org/10.1039/C7CS00653E.16. A. E. Thorarinsdottir and T. D. Harris, “Metal–Organic FrameworkMagnets,” Chemical Review 120 (2020): 8716–8789.17. T. D. Bennett and S. Horike, “Liquid, Glass and Amorphous SolidStates of Coordination Polymers andMetal–organic Frameworks,”NatureReviews Materials 3 (2018): 431–440, https://doi.org/10.1038/s41578-018-0054-3.18. W. Chen, S. Horike, and D. Umeyama, “Glass Formation of aCoordination Polymer Crystal for Enhanced Proton Conductivity andMaterial Flexibility,” Angewandte Chemie International Edition 55 (2016):5195–5200, https://doi.org/10.1002/anie.201600123.19. L. Frentzel-Beyme, M. Kloß, P. Kolodzeiski, R. Pallach, and S. Henke,“rom Melting Point Engineering to Selective Hydrocarbon Sorption,”Journal of the American Chemical Society 141 (2019): 12362–12371, https://doi.org/10.1021/jacs.9b05558.20. Y. Wang, H. Jin, and Q. Ma, “A MOF Glass Membrane for Gas Sepa-ration,” Angewandte Chemie International Edition 59 (2020): 4365–4369,https://doi.org/10.1002/anie.201915807.21. M. Liu, A. H. Slavney, and S. Tao, “Designing Glass and CrystallinePhases of Metal–Bis(acetamide) Networks to Promote High OpticalContrast,” Journal of the American Chemical Society 144 (2022): 22262–22271.22. N. Ma, S. Impeng, S. Bureekaew, N. Morozumi, M. Haga, and S.Horike, “Photoexcited Anhydrous Proton Conductivity in CoordinationPolymer Glass,” Journal of the American Chemical Society 145 (2023):9808–9814, https://doi.org/10.1021/jacs.3c01821.23. M. Kim, H.-S. Lee, D.-H. Seo, S. J. Cho, E. Jeon, and H. R. Moon,“Melt-quenchedCarboxylateMetal–organic FrameworkGlasses,”NatureCommunications 15 (2024): 1174.24. F. Cao, S. S. Sørensen, and A. K. R. Christensen, “ContinuousStructure Modification of Metal-organic Framework Glasses via HalideSalts,” Nature Communications 16 (2025): 7001, https://doi.org/10.1038/s41467-025-62143-9.25. T. Ogawa, K. Takahashi, and S. S. Nagarkar, “Coordination PolymerGlass from a Protic Ionic Liquid: Proton Conductivity and MechanicalSmall, 2026le Creative Commons Licensehttps://www.ccdc.cam.ac.uk/services/structures?id=doi:10.1002/smll.73752https://doi.org/10.1021/ja00197a079https://doi.org/10.1126/science.1067208https://doi.org/10.1038/nature01650https://doi.org/10.1002/anie.200454250https://doi.org/10.1002/anie.200300610https://doi.org/10.1021/acs.chemrev.9b00766https://doi.org/10.1039/C7CS00653Ehttps://doi.org/10.1038/s41578-018-0054-3https://doi.org/10.1002/anie.201600123https://doi.org/10.1021/jacs.9b05558https://doi.org/10.1002/anie.201915807https://doi.org/10.1021/jacs.3c01821https://doi.org/10.1038/s41467-025-62143-9Ph2iC2A72tC2SN03MA3oD3NA(3MM3CL3cU(53Aa(3ES(3Och3F14S4lO44SPE2S 16136829, 2026, 36, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/smll.73752 by National Institute For, Wiley Online Library on [28/06/2026]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Croperties as an Electrolyte,” Chemical Science 11 (2020): 5175–5181,ttps://doi.org/10.1039/D0SC01737J.6. T. Ogawa, K. Takahashi, and T. Kurihara, “Network Size Controln Coordination Polymer Glasses and Its Impact on Viscosity and H+onductivity,” Chemistry of Materials 34 (2022): 5832–5841.7. Z. Zhang and Y. Zhao, “Transparent and High-porosity Aluminumlkoxide Network-forming Glasses,” Nature Communications 15 (2024):339, https://doi.org/10.1038/s41467-024-51845-1.8. N. Ma, S. Kosasang, and J. Theissen, “Systematic Design and Func-ionalisation of Amorphous Zirconium Metal–organic Frameworks,”hemical Science 15 (2024): 17562–17570.9. L. León-Alcaide, L. Martínez-Goyeneche, and M. Sessolo, “Directynthesis of an IronMetal-organic FrameworkAntiferromagnetic Glass,”ature Communications 16 (2025): 8783, https://doi.org/10.1038/s41467-25-63837-w.0. J.-R. Li, D. J. Timmons, and H.-C. Zhou, “Interconversion Betweenolecular Polyhedra and Metal−Organic Frameworks,” Journal of themerican Chemical Society 131 (2009): 6368–6369.1. H.-N. Wang, X. Meng, and G.-S. Yang, “Stepwise Assembly of Metal–rganic Framework Based on a Metal–organic Polyhedron Precursor forrug Delivery,” Chemical Communications 47 (2011): 7128–7130.2. H.-N. Wang, F.-H. Liu, X.-L. Wang, K.-Z. Shao, and Z.-M. Su, “Threeeutral Metal–organic Frameworks With Micro- and Meso-pores fordsorption and Separation of Dyes,” Journal of Materials Chemistry A 12013): 13060–13063.3. A. Carné-Sánchez, G. A. Craig, and P. Larpent, “Self-assembly ofetal–organic Polyhedra Into Supramolecular Polymers With Intrinsicicroporosity,” Nature Communication 9 (2018): 2506.4. Z. Wang, C. Villa Santos, and A. Legrand, “Multiscale Structuralontrol of Linked Metal–organic Polyhedra Gel by Aging-inducedinkage-reorganization,” Chemical Science 12 (2021): 12556–12563.5. T. Grancha, A. Carné-Sánchez, and F. Zarekarizi, “Synthesis of Poly-arboxylate Rhodium(II) Metal–Organic Polyhedra (MOPs) and Theirse as Building Blocks forHighly ConnectedMetal–Organic FrameworksMOFs),” Angewandte Chemie International Edition 60 (2021): 5729–733.6. A. Khobotov-Bakishev, L. Hernández-López, C. von Baeckmann, J.lbalad, A. Carné-Sánchez, and D. Maspoch, “Metal–Organic Polyhedras Building Blocks for Porous Extended Networks,” Advanced Science 92022): 2104753.7. J. Troyano, S. Horike, and S. Furukawa, “Reversible Discrete-to-xtended Metal–Organic Polyhedra Transformation by Sulfonic Acidurface Functionalization,” Journal of the American Chemical Society 1442022): 19475–19484.8. B. L. Ouay, T. Ohara, R. Minami, R. Kunitomo, R. Ohtani, and M.hba, “Efficient water-based purification of metal–organic polyhedra byentrifugal ultrafiltration,” Dalton Transactions 52 (2023): 15321–15325,ttps://doi.org/10.1039/D3DT01644G.9. S. Tokuda and S. Furukawa, “Three-dimensional van der Waals Openrameworks,” Nature Chemistry 17 (2025): 672–678, https://doi.org/10.038/s41557-025-01777-0.0. E.Warzecha, T. C. Berto, and J. F. Berry, “Structural and Spectroscopictudy,” Inorganic Chemistry 54 (2015): 8817–8824.1. A. Carné-Sánchez, J. Albalad, and T. Grancha, “Postsynthetic Cova-ent and Coordination Functionalization of Rhodium(II)-Based Metal–rganic Polyhedra,” Journal of the American Chemical Society 141 (2019):094–4102.2. Z. Wang, T. Aoyama, E. Sánchez-González, T. Inose, K. Urayama, and. Furukawa, “Control of Extrinsic Porosities in Linked Metal–Organicolyhedra Gels by Imparting Coordination-Driven Self-Assembly Withlectrostatic Repulsion,” ACS Applied Materials & Interfaces 14 (2022):3660–23668.mall, 202643. D. Nam, J. Huh, and J. Lee, “Cross-linking Zr-based Metal–organicPolyhedra via Postsynthetic Polymerization,” Chemical Science 8 (2017):7765–7771.44. A. Legrand, G. A. Craig, M. Bonneau, S. Minami, K. Urayama, andS. Furukawa, “Understanding the Multiscale Self-assembly of Metal–organic Polyhedra towards Functionally Graded Porous Gels,” ChemicalScience 10 (2019): 10833–10842.45. A. Qiao, T. D. Bennett, andH. Tao, “AMetal-organic FrameworkWithUltrahigh Glass-forming Ability,” Science Advances 4 (2018): aao6827,https://doi.org/10.1126/sciadv.aao6827.46. A. V. Zhukhovitskiy, M. Zhong, and E. G. Keeler, “Highly Branchedand Loop-rich Gels via Formation of Metal–organic Cages Linked byPolymers,” Nature Chemistry 8 (2016): 33–41.47. Y. Gu, J. Zhao, and J. A. Johnson, “rom Plastics and Gels to PorousFrameworks,” Angewandte Chemie International Edition 59 (2020): 5022–5049, https://doi.org/10.1002/anie.201902900.48. Z. Wang, C. Villa Santos, and A. Legrand, “Multiscale StructuralControl of Linked Metal–organic Polyhedra Gel by Aging-inducedLinkage-reorganization,” Chemical Science 12 (2021): 12556–12563.49. A. Legrand, L.-H. Liu, and P. Royla, “Spatiotemporal Control ofSupramolecular Polymerization and Gelation of Metal–Organic Polyhe-dra,” Journal of the American Chemical Society 143 (2021): 3562–3570.50. H. C. Brown, D. H. McDaniel, and O. Häfliger, in Determination ofOrganic Structures by Physical Methods Ed. E. A. Braude and F. C. Nachod(Academic Press, 1955), 567–662.51. R. L. Benoit, D. Boulet, L. Séguin, and M. Fréchette, “Protonationof Purines and Related Compounds in Dimethylsulfoxide and Water,”Canadian Journal of Chemistry 63 (1985): 1228–1232, https://doi.org/10.1139/v85-209.52. R. S. Forgan, “Modulated Self-assembly of Metal–organic Frame-works,” Chemical Science 11 (2020): 4546–4562.53. H. Yamada, S. Shimono, and S. Kawaguchi, “High-throughput X-rayTotal Scattering Measurement System at BL04B2 of SPring-8,” Jour-nal of Synchrotron Radiation 33 (2026): 516–522, https://doi.org/10.1107/S1600577525011294.54. T. E. Faber and J. M. Ziman, “A Theory of the Electrical Properties ofLiquidMetals,” Philosophical Magazine 11 (1965): 153–173, https://doi.org/10.1080/14786436508211931.55. E. Lorch, “Neutron Diffraction by Germania, Silica and Radiation-damaged Silica Glasses,” Journal of Physics C: Solid State Physics 2 (1969):229–237, https://doi.org/10.1088/0022-3719/2/2/305.56. S. Kohara, M. Itou, and K. Suzuya, “Structural Studies of DisorderedMaterials UsingHigh-energy X-ray Diffraction FromAmbient to ExtremeConditions,” Journal of Physics: Condensed Matter 19 (2007): 506101,https://doi.org/10.1088/0953-8984/19/50/506101.57. A. C. Ghosh, A. Legrand, and R. Rajapaksha, “Rhodium-BasedMetal–Organic Polyhedra Assemblies for Selective CO2 Photoreduction,”Journal of the American Chemical Society 144 (2022): 3626–3636.58. R. S. K. Madsen, A. Qiao, and J. Sen, “Ultrahigh-field 67 ZnNMR Reveals Short-range Disorder in Zeolitic Imidazolate FrameworkGlasses,” Science 367 (2020): 1473–1476, https://doi.org/10.1126/science.aaz0251.59. M. W. Terban and S. J. L. Billinge, “Structural Analysis of MolecularMaterials Using the Pair Distribution Function,” Chemical Reviews 122(2022): 1208–1272, https://doi.org/10.1021/acs.chemrev.1c00237.60. S. J. Tao, “Positronium Annihilation in Molecular Substances,” TheJournal of Chemical Physics 56 (1972): 5499–5510, https://doi.org/10.1063/1.1677067.61. L. O. Alimi, N. Khalfay, S. Khlifi, W. Lin, B. Moosa, and N. M.Khashab, “A Nonporous Crystalline Organic Cage for Selective WaterUptake and Storage,” Chemical Science 17 (2026): 511–515, https://doi.org/10.1039/D5SC06328K.9 of 10reative Commons Licensehttps://doi.org/10.1039/D0SC01737Jhttps://doi.org/10.1038/s41467-024-51845-1https://doi.org/10.1038/s41467-025-63837-whttps://doi.org/10.1039/D3DT01644Ghttps://doi.org/10.1038/s41557-025-01777-0https://doi.org/10.1126/sciadv.aao6827https://doi.org/10.1002/anie.201902900https://doi.org/10.1139/v85-209https://doi.org/10.1107/S1600577525011294https://doi.org/10.1080/14786436508211931https://doi.org/10.1088/0022-3719/2/2/305https://doi.org/10.1088/0953-8984/19/50/506101https://doi.org/10.1126/science.aaz0251https://doi.org/10.1021/acs.chemrev.1c00237https://doi.org/10.1063/1.1677067https://doi.org/10.1039/D5SC06328K6S26ZC16“CE6AC(6(6“Mi6P6S07aPI7dc(7h5SAIS1 16136829, 2026, 36, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/smll.73752 by National Institute For, Wiley Online Library on [28/06/2026]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-an2. R. Liu, D.-Y. Wang, J.-R. Shi, and G. Li, “Proton Conductive Metalulfonate Frameworks,” Coordination Chemistry Reviews 431 (2021):13747, https://doi.org/10.1016/j.ccr.2020.213747.3. S.-S. Liu, Q.-Q. Liu, S.-Z. Huang, C. Zhang, X.-Y. Dong, and S.-Q.ang, “Sulfonic and Phosphonic Porous Solids as Proton Conductors,”oordination Chemistry Reviews 451 (2022): 214241, https://doi.org/10.016/j.ccr.2021.214241.4. K. Takahashi, T. Ogawa, T. Itakura, K. Kami, and S. Horike,Water-Stable Al(III) Coordination Polymer Glass With High Protononductivity Toward Stable Electrolytes in a Fuel Cell,” ACS Appliednergy Materials 7 (2024): 11937–11945.5. K.-D. Kreuer, A. Rabenau, and W. Weppner, “Vehicle Mechanism,New Model for the Interpretation of the Conductivity of Fast Protononductors,” Angewandte Chemie International Edition in English 211982): 208–209, https://doi.org/10.1002/anie.198202082.6. N. Agmon, “The Grotthuss Mechanism,” Chemical Physics Letters 2441995): 456–462, https://doi.org/10.1016/0009-2614(95)00905-J.7. T. Ogawa, K. Kamiguchi, T. Tamaki, H. Imai, and T. Yamaguchi,Differentiating Grotthuss Proton Conduction Mechanisms by Nuclearagnetic Resonance Spectroscopic Analysis of Frozen Samples,” Analyt-cal Chemistry 86 (2014): 9362–9366, https://doi.org/10.1021/ac5021485.8. T. Norby, “Solid-state Protonic Conductors: Principles, Properties,rogress and Prospects,” Solid State Ionics 125 (1999): 1–11.9. K. D. Kreuer, “Phenomenon Between the Solid and the Liquid state?,”olid State Ionics 94 (1997): 55–62, https://doi.org/10.1016/S0167-2738(96)0608-X.0. M. K. Sarango-Ramírez, J. Park, J. Kim, Y. Yoshida, D.-W. Lim,nd H. Kitagawa, “Void Space versus Surface Functionalization forroton Conduction inMetal–Organic Frameworks,” Angewandte Chemienternational Edition 60 (2021): 20173–20177.1. K. Shiraishi, M. Kabaya, K. Fujihira, K. Kato, and M. Sadakiyo, “Aetailed study on the effects of adsorbed water molecules on protononduction in a metal–organic framework,” Dalton Transactions 542025): 12125–12129, https://doi.org/10.1039/D5DT01395J.2. S. Furukawa, N. Horike, andM. Kondo, “Rhodium–Organic Cubocta-edra as Porous Solids With Strong Binding Sites,” Inorganic Chemistry5 (2016): 10843–10846.upporting Informationdditional supporting information can be found online in the Supportingnformation section.upportingFile: smll73752-sup-0001-SuppMat.pdf.0 of 10 Small, 2026d-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttps://doi.org/10.1016/j.ccr.2020.213747https://doi.org/10.1016/j.ccr.2021.214241https://doi.org/10.1002/anie.198202082https://doi.org/10.1016/0009-2614(95)00905-Jhttps://doi.org/10.1021/ac5021485https://doi.org/10.1016/S0167-2738(96)00608-Xhttps://doi.org/10.1039/D5DT01395J Bottom-Up Assembly of Amorphous Metal-Organic Frameworks From Proton Conductive Metal-Organic Polyhedra 1 | Introduction 2 | Results and Discussion 2.1 | Synthesis and Crystal Structure of SO3RhMOP 2.2 | Synthesis of Crosslinked SO3RhMOP 2.3 | Network Structure of aMOFs 2.4 | Short-Range Structure 2.5 | Free Volume of aMOFs 2.6 | Water Stability and Proton Conductivity 3 | Conclusions Acknowledgements Conflicts of Interest Data Availability Statement References Supporting Information