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Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
Impact of Metal Heterogeneity on Multivariate and High-Entropy MOF SBUs
Rajan R Bhawnani1, Prem K Reddy1, Meagan Phister2
1Department of Chemical Engineering, University of Illinois Chicago, Chicago, Illinois 60607, United States.
Journal of the American Chemical Society
|July 6, 2026
Summary
Metal heterogeneity in high-entropy metal-organic frameworks (MOFs) creates specific distortions in secondary building units (SBUs). These distortions propagate to cause predictable changes in the crystal lattice, linking metal identity to structural behavior.
Area of Science:
- Materials Science
- Chemistry
- Crystallography
Background:
- Understanding local coordination asymmetry in complex multimetal systems is crucial.
- High-entropy metal-organic frameworks (MOFs) exhibit chemical disorder alongside crystallographic order.
- A quantitative link between metal identity, local geometry, and bulk structure in MOFs is missing.
Purpose of the Study:
- To investigate how metal heterogeneity in MOFs influences local coordination geometry and lattice-scale structural changes.
- To establish a relationship between metal composition and structural distortions in high-entropy MOFs.
- To explore the dynamic incorporation of metals during MOF formation.
Main Methods:
- Synthesis of porphyrinic TCPP frameworks with varying metal compositions (Fe, Co, Ni, Cu, Zn).
- Extended X-ray absorption fine structure (EXAFS) spectroscopy for metal-dependent bond distance analysis.
- Time-resolved X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP-MS), and molecular dynamics (MD) simulations.
Main Results:
- Metal heterogeneity induces composition-dependent, asymmetric distortions in trinuclear secondary building units (SBUs).
- Local distortions propagate coherently, causing measurable, reproducible lattice-parameter shifts.
- EXAFS signatures show persistent local heterogeneity in multi-metal MOFs, not an averaged geometry.
- Dynamic, metal-dependent incorporation and substitution trends were observed during framework formation.
Conclusions:
- Metal identity directly influences local coordination asymmetry and lattice response in high-entropy MOFs.
- The study provides an experimentally validated framework connecting local structure to bulk properties.
- Findings advance the understanding and design of multivariate and high-entropy MOFs.
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