MTCiting: Metal–Organic Frameworks (MOFs)

October 2025

The 2025 Nobel Prize in Chemistry was recently awarded to Professors Robson, Yaghi, and Kitagawa for their seminal work in developing metal–organic framework (MOF) molecules. The exponential growth of research in these molecules is driven by their potential range of applications including those addressing some of the most pressing issues facing humanity.

MOFs are crystalline, porous materials that are synthesized by linking metal ions and organic molecules into three-dimensional frameworks. These frameworks have extremely high surface areas as well as pore sizes that can be contracted or expanded via customized synthesis. In this way, they are different from other porous framework molecules such as zeolites, which have fixed pore sizes. Because of the flexibility and functionalization of MOF molecules, they can be precisely modified to meet specific applications in gas storage and separation, catalysis, energy storage, drug delivery and environmental sustainability.

METTLER TOLEDO analytical systems, including in-situ FTIR and Raman spectroscopy, automated synthesis workstations, in-situ crystallization/imaging devices, and DSC/TGA, support synthesis and crystallization studies of MOFs and related organic framework compounds. Applications are discussed in the following examples from the literature below.

Process elucidation and hazard analysis of the Metal–Organic Framework Scale-Up Synthesis

The HAZOP Hero: Preventing MOF Thermal Runaway

ReactIR and RC1mx measurements are used to better understand the kinetics and heat transfer in the synthesis, crystallization, and scale-up of ZIF-8 MOF.

There are a number of methods to produce MOFs, but the most practical and controllable method for industrial production of MOFs is solvothermal synthesis in reactors. Reaction temperature is critical in MOF synthesis and influences surface area and particle size distribution. In order to safely scale-up and achieve the desired product attributes, understanding temperature and heat-release behaviors is necessary.

In the research described in this article, zeolitic imidazolate framework-8 (ZIF-8) was used as an example to study MOF scale-up synthesis. Various stages of ZIF-8 formation at room temperature, including nucleation, growth, and stationary, were investigated using in-situ FTIR to identify the 2-methylimidazole concentration evolution over time. The data from these experiments was then used in the Avrami equation, which describes how solids transform from one phase to another at constant temperature, to correlate the reaction kinetics based on the obtained concentration results. From these experiments, it was determined that Avrami’s constant for ZIF-8 crystallization varies with the reactor volume. The FTIR experiments were performed in an RC1e reactor system, which facilitated simultaneous identification of the reaction temperature and heat-release behaviors. These measurements enabled avoidance of inconsistent product properties from thermal runaway when scaling up the ZIF-8 production from the milliliter to liter scale. Furthermore, a full HAZOP analysis for each synthesis step was performed to investigate the effect of deviations and to ensure safe operations in production facilities.

Quan, Y., Parker, T. F., Hua, Y., Jeong, H., & Wang, Q. (2023). Process elucidation and hazard analysis of the Metal–Organic Framework Scale-Up Synthesis: A case study of ZIF-8. Industrial & Engineering Chemistry Research, 62(12), 5035–5041. https://doi.org/10.1021/acs.iecr.2c04570

Metal‐Dependent and Selective Crystallization of CAU‐10 and MIL‐53 Frameworks through Linker Nitration

Metal-Dependent MOF Mayhem

ReactIR measurements are used to show that the linker molecules are nitrated prior to MOF framework formation and can affect the structure.

MOFs are constructed from inorganic (metal ions or metal-oxygen clusters) and organic building units (ligands or linkers). In the work described in this article, the researchers found that the reaction of the V-shaped linker molecule 5-hydroxyisophthalic acid (H₂L⁰) with Al(NO₃)₃ and Ga(NO₃)₃ as reactants resulted in nitration of the linker with compounds of composition [Al(OH)(C₈H_2.08O₅(NO₂)_0.92)] and [Ga(OH)(C₈H₂O₃(NO₂)] crystallizing in the CAU-10 and MIL-53 type structure, respectively. The Al-MOF contains the original linker L⁰ as well as three different nitration products (L², L⁴, and L^4/6), whereas the Ga-MOF mainly incorporates the linker L². In-situ and ex-situ studies were carried out to follow the nitration and crystallization, as well as the composition of the MOFs.

Furthermore, they commented that since nitrated linkers are found in the final reaction products, in-situ nitration of the linker H₂L⁰ must take place. To confirm this observation for both MOFs, ReactIR measurements and light scattering measurements were performed. They determined that the nitration of the ligand H₂L⁰ occurs prior to the formation of the framework by the appearance of a band at 1550 cm^-1 after 5 minutes which is assigned to the anti-symmetric stretching vibration of the aromatic nitro group. This nitro-band increases with reaction time and after 30 minutes the vibrational band of the anti-symmetric stretching vibration of the carboxylate group also becomes visible. At this point in time, the Faraday–Tyndall effect from colloidal particles in solution indicates the start of product formation.

Rabe, T., Grape, E. S., Engesser, T. A., Inge, A. K., Ströh, J., Kohlmeyer‐Yilmaz, G., Wahiduzzaman, M., Maurin, G., Sönnichsen, F. D., & Stock, N. (2021). Metal‐Dependent and Selective Crystallization of CAU‐10 and MIL‐53 Frameworks through Linker Nitration. Chemistry - a European Journal, 27(28), 7696–7703. https://doi.org/10.1002/chem.202100373

Keggin-type polyoxometalates molecularly loaded in Zr-ferrocene metal organic framework nanosheets for solar-driven CO2 cycloaddition

The Case of the Missing Polymer: ReactIR Catches the Intermediate That Proves the MOF Mechanism

ReactIR measurements of a hybrid solar-driven MOF for CO₂ cycloaddition provides key insight and support for a proposed reaction mechanism.

Due to their unique structural and chemical properties, MOFs are promising candidates for CO₂ cycloaddition through solar-driven catalytic reduction of CO₂. The authors comment that designing a MOF has both good light-harvesting and excellent catalytic activity for CO₂ cycloaddition is quite challenging and that a possible approach is to decorate catalyst into photothermal MOFs or incorporate photothermal components into catalytic MOFs. With this in mind, they developed a hybrid solar-driven catalyst by decorating a typical POMs, PMo₁₂ (phosphomolybdate, PMo₁₂O₄₀^-3), into photothermal Zr-Fc (Ferrocene) MOFs nanosheets for CO₂ cycloaddition reactions. The resulting structure, POMs@Zr-Fc MOFs, demonstrated high solar-driven catalytic performance for CO₂ cycloaddition. The catalyst has both the excellent stability and photothermal property of Zr-Fc MOF and many active sites of PMo₁₂ for a highly efficient catalyst in CO₂ cycloaddition.

To gain further insight into the cycloaddition mechanism, the reaction of CO₂ and styrene oxide in the presence of POMs@Zr-Fc MOF and co-catalyst tetra butyl ammonium bromide under artificial sunlight to produce styrene carbonate was monitored by in-situ FTIR spectroscopy at 80 ℃ and ambient pressure. A peak arising from the cyclic carbonate at 1801 cm^-1 intensified as the reaction progressed, as did a peak at 1815 cm^-1 assigned to a Br-styrene oxide intermediate. It was noted that the 1815 cm^-1 peak of the intermediate appeared before the 1801 cm^-1 product peak. Furthermore, there was no evidence of polymer carbonate forming, as indicated by the absence of a 1760 cm^-1 peak. From this information, a plausible reaction mechanism was proposed.

Fang, Z., Deng, Z., Wan, X., Li, Z., Ma, X., Hussain, S., Ye, Z., & Peng, X. (2021). Keggin-type polyoxometalates molecularly loaded in Zr-ferrocene metal organic framework nanosheets for solar-driven CO₂ cycloaddition. Applied Catalysis B Environment and Energy, 296, 120329. https://doi.org/10.1016/j.apcatb.2021.120329

MOFs, COFs, and MCOFs

In addition to MOFs, there are other classes of customizable, high porosity, high surface area organic framework molecules. These include non-metallic, covalent organic frameworks (COFs) that have covalent bonds between organic building blocks and metal-covalent organic frameworks (MCOFs) that have metal species integrated into a covalent organic framework leading to COF-covalent connectivity with metal functionality. These compounds have an exceptional range of applications in catalysis, electro-optics, gas storage etc. The following example is of a novel MCOF catalyzed reaction:

ReactIR measurements on a Ru based MCOF catalyst provides insight and support for the proposed tandem heterogeneous reaction mechanism.

A ruthenium porphyrin-based covalent organic framework (Ru-COF-1) catalyst was synthesized and characterized. The catalyst activates the C-H bond of cumene to generate alkyl peroxide in situ, and is coupled to a downstream air (O₂) epoxidation of olefins. This is a heterogenous tandem approach, which generates an intermediate/reactive species that yields the selective epoxidation. The carbonyl-ruthenium COF (Ru-COF-1) is reported to have excellent performance, with 98% epoxide selectivity for 1-hexene. The researchers state that the superior performance, when compared with Ru-porphyrins and metal-free COFs, results from the presence of the Ru metal. They determined that the porous structure aids oxygen enrichment, forming active peroxy radicals, with the cumene carbon-centered radicals formed on the catalyst surface. Ru-H sites then accelerate active oxygen transfer from peroxy radicals, enabling olefin tandem epoxidation. The proposed reaction mechanism was supported by DFT calculations.

To aid in understanding the reaction process, in-situ IR spectroscopy was used to record the changes of functional groups during the epoxidation. From the data they noted that the characteristic peaks of cumene decreased as the reaction proceeded, and additional in-situ FTIR experimentation showed that the epoxidation reaction nearly reached equilibrium simultaneously with the equilibrium of cumene conversion. From this they concluded cumene functions as an oxygen transfer mediator, providing additional validation for their proposed reaction mechanism.

Li, D., Xiong, C., Mao, Q., Xi, L., Yang, T., Hu, P., & Ji, H. (2025). Boosting cumene hydrogen transfer via a Ru-based porphyrin covalent organic framework for tandem air epoxidation of olefins. Nano Research. https://doi.org/10.26599/nr.2025.94907892

Additional Examples of MOF R&D Applications

Next-generation computational and experimental tools for understanding nucleation and growth of metal–organic framework

This article discusses current techniques for studying MOF kinetics and how improved data acquisition and multiscale approaches can advance scalable applications. In-situ FTIR, Raman spectroscopy, and FBRM are among the methods discussed.

Bhawnani, R. R., Barreto, O. M., Podupu, P. K. R., Colón, Y., Giri, G., & Singh, M. R. (2025). Next-Generation Computational and Experimental Tools for understanding nucleation and growth of Metal–Organic frameworks. ACS Materials Letters, 906–927. https://doi.org/10.1021/acsmaterialslett.4c02600

One‐pot conversion of glucose into 5‐Hydroxymethylfurfural using MOFs and Brønsted‐Acid tandem catalysts

Catalyst testing for the one-pot conversion of glucose into HMF was carried out at various temperatures under stirring in an EasyMax synthesis workstation equipped with a pressurized glass stirred tank reactor.

Lara‐Serrano, M., Morales‐delaRosa, S., Campos‐Martin, J. M., Abdelkader‐Fernández, V. K., Cunha‐Silva, L., & Balula, S. S. (2022). One‐Pot Conversion of Glucose into 5‐Hydroxymethylfurfural using MOFs and Brønsted‐Acid Tandem Catalysts. Advanced Sustainable Systems, 6(5). https://doi.org/10.1002/adsu.202100444

Isomerization of glucose to fructose catalyzed by metal–organic frameworks

The isomerization reaction of glucose to fructose was studied using five selected metal–organic frameworks (MOFs) as catalysts and a mixture of γ-valerolactone and 10% H₂O as solvent. Testing of the catalysts were performed in an EasyMax synthesis workstation.

Lara-Serrano, M., Morales-delaRosa, S., Campos-Martin, J. M., Abdelkader-Fernández, V. K., Cunha-Silva, L., & Balula, S. S. (2021). Isomerization of glucose to fructose catalyzed by metal–organic frameworks. Sustainable Energy & Fuels, 5(15), 3847–3857. https://doi.org/10.1039/d1se00771h

In-situ IR monitoring to probe the formation of structural defects in Zr-fumarate metal–organic framework (MOF)

ReactIR monitors the crystallization process of Zr-fumarate (Zr-fum) MOF in both H₂O- and DMF-based systems. In DMF-based system, the acid modulator (HCOOH) was observed to be consumed while the H₂O-based system showed otherwise. This observation serves to confirm the participation of formic acid during the structural formation of Zr-fum MOF synthesized in DMF, and the presence of the solvent as the origin of structural defects.

Ren, J., Musyoka, N. M., Langmi, H. W., Walker, J., Mathe, M., & Liao, S. (2018). In-situ IR monitoring to probe the formation of structural defects in Zr-fumarate metal–organic framework (MOF). Polyhedron, 153, 205–212. https://doi.org/10.1016/j.poly.2018.07.026

FTIR Spectroscopy for Flow Chemistry

White Paper

The inherent advantages of continuous flow chemistry expand the potential for both enabling and simplifying complex processes. However, comprehensive understanding of these fast moving processes is difficult, or even impossible, with offline analytical techniques. Inline FTIR spectroscopy is widely regarded as a key technology to:

Study reaction progression including kinetics, mechanisms, pathways and steady-state
Increase product yield and/or purity by quickly discovering the impact of critical process parameters on reactions
Fingerprint and troubleshoot process mishaps in real time from research to manufacturing

Technology Used in the Study of MOFs

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This story was part of the METTLER TOLEDO AutoChem #MTCiting series. In this series we dive into the latest published research on innovative applications in research & development.

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