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Description:

While crystalline metal–organic frameworks (MOFs) benefit from precise structural programmability, achieving comparable control in amorphous MOFs (aMOFs) remains underexplored. Most reported aMOFs are obtained via top-down amorphization of crystalline frameworks, whereas the limited bottom-up approaches typically rely on linker substitution-based assembly that inherently restricts node-level functionalization. Here, we present a bottom-up strategy for constructing proton-conductive aMOFs using sulfonate-rich metal–organic polyhedra (MOPs) as predesigned molecular building units. Discrete Rh-based MOPs with accessible axial coordination sites are crosslinked with flexible ditopic linkers to form extended amorphous networks while preserving 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 proton conductivities 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 the sulfonate-free aMOF analog exhibits insulating behavior. These results establish a general strategy for the rational design of functionally programmable aMOFs using chemically predefined building units.

Rights:

• Creative Commons BY-NC Attribution-NonCommercial 4.0 International
  

Keyword: amorphous materials, metal-organic frameworks, bottom-up, metal-organic polyhedra, proton conductivities

Date published: 2026-05-13

Publisher: Wiley

Journal:

• Small (ISSN: 16136810) vol. 22 issue. 36 e73752

Funding:

• Japan Science and Technology Agency JPMJPR25MB
• Japan Science and Technology Agency JPMJNX25B4
• Iketani Science and Technology Foundation 0371207‐A
• Japan Society for the Promotion of Science JP24K23109
• Japan Society for the Promotion of Science JP25K18055
• Sumitomo Foundation 2402150

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1002/smll.73752

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Updated at: 2026-06-29 15:25:12 +0900

Published on MDR: 2026-06-30 10:26:53 +0900