Nanocluster Rearrangement Forms a Family of Ordered Cerium–Titanium Bimetallic Metal–Organic Frameworks with Three Different Nodes, Nanocavities, and Thermal Stabilities

ACS Applied Nano Materials · 2026-03-05

Metal–organic frameworks (MOFs) provide a versatile platform for incorporating multiple metal ions within a single crystalline framework, yet achieving spatial and stoichiometric order in heterometallic nodes remains a synthetic challenge. Building on our previously reported, highly thermally stable Ce/Ti bimetallic MOF NU-3000, we identified and isolated two additional crystalline phases, NU-2998 and NU-2999, that arise from the same Ce/Ti nanocluster precursor under modified solvothermal conditions. Systematic variation of reaction temperature, time, solvent ratio, and modulator concentration directs the assembly of these distinct frameworks. Structural analysis and comprehensive characterization studies reveal that these MOFs each feature an unreported nodal geometry with nanocavities of different sizes. NU-2998 even adopts an unreported topology, denoted nui, that features an elongated pore spanning 4 nm. Together, these findings establish a synthesis route that starts with a nanocluster and ends with a set of bimetallic MOFs, offering a glimpse into the pathway-dependent assembly of multimetallic porous materials. We evaluated the thermal stability of each additional analogue and compared them to NU-3000, providing further insight into material stability. NU-3000 maintained the highest thermal stability and was evaluated as a catalyst for CO oxidation at elevated temperatures.

Organophosphorus Binding Thermodynamics in Metal–Organic Frameworks: Interplay between Oxidation State, Lewis Acidity, and Node Structure

ACS Applied Materials & Interfaces · 2025-06-24 · 1 citations

Organophosphorus compounds, including nerve agents and pesticides, represent a class of toxic chemicals causing harm to troops, civilians, and the environment. Metal–organic frameworks (MOFs) have emerged as a class of highly porous, crystalline, tunable materials adept at both capturing and catalytically neutralizing these harmful toxins. In particular, MOFs whose nodes display strong Lewis acidic character can hydrolyze such chemicals nearly instantaneously. However, without the help of a basic buffer to regenerate the active site, the benign organophosphorus product strongly binds to the node and prevents catalyst turnover. Here, we investigate a series of MOFs whose nodes contain metals of varying Lewis acidities and employ isothermal titration calorimetry (ITC) to directly measure the heat from the binding of an organophosphorus probe molecule, allowing the construction of a full thermodynamic binding profile (ΔH, ΔS, ΔG, Ka). We couple this with potentiometric titrations and solid state 31P magic angle spinning (MAS) NMR to gain a clearer picture of how node identity, structure, and Lewis acidity interplay to impact binding strength and favorability. This study is the first to integrate these three complementary techniques to investigate binding interactions in MOFs, further showcasing the viability of ITC for probing MOF systems, which is still relatively underexplored.

Blueprints for crystallinity: Coordination templates enable synthesis of atomically resolved covalent-organic frameworks

Chem · 2025-07-16 · 3 citations

Programming Local Confinements in Crystalline Frameworks through Reticular Chemistry

Research Square · 2025-12-01

Hydrolytically Stable Phosphonate‐Based Metal–Organic Frameworks for Harvesting Water from Low Humidity Air

Small · 2025-04-18 · 9 citations

Abstract Harvesting water from air offers a promising solution to the global water crisis. However, existing sorbents often struggle in arid climates due to limitations such as low sorption capacities, hydrolytic instability, slow mass transport, high desorption enthalpy, and costly operation. Phosphonate‐based metal–organic frameworks (MOFs), known for their exceptional water stability, have not been extensively explored for water harvesting. This study systematically investigates the performance of STA‐12 (M═Co, Ni, Mg) and STA‐16 (M═Co, Ni), a series of stable phosphonate‐based MOFs, as water sorbents. STA‐12 MOFs demonstrate remarkable adsorption at ultra‐low humidity (<10%), while STA‐16(Co) exhibits a high water uptake capacity of 0.54 g g −1 at 10–50% relative humidity (RH) and 0.72 g g −1 at 34% RH. Molecular simulations and solid‐state NMR identified liquid‐like water, critical for harvesting applications, as the key contributor to the superior sorption performance of STA‐16(Co). Scalable aqueous synthesis methods are developed, producing tens of grams of MOFs per batch without high‐pressure equipment. A prototype device incorporating STA‐12(Ni) demonstrated the feasibility of these materials for real‐world water harvesting, showcasing their potential to address water scarcity in arid regions.

Computer vision for high-throughput materials synthesis: a tutorial for experimentalists

Digital Discovery · 2025-12-23 · 3 citations

Computer vision enables the rapid identification of chemical phases, such as solid metal–organic framework (MOF) materials, from images of sample vials.

Electronically Tunable Low-Valent Uranium Metallacarboranes

Inorganic Chemistry · 2025-03-03

Uranium metallocenes have played a pivotal role in advancing the understanding of low-valent uranium chemistry since the inception of this field, and they still find continued use today. Functionalization strategies for cyclopentadienyl (Cp) ligands used in uranium metallocenes have predominately focused on modifying the steric properties of the ligand through the incorporation of alkyl or silyl groups, which offer limited control over the electronic properties. Moreover, due to the flat, two-dimensional nature of Cp, functional groups will affect the coordination geometry of the uranium metallocene and can potentially present challenges in decoupling steric and electronic effects. In comparison, uranium metallacarboranes, which are boron cluster-based metallocene analogues that feature three-dimensional dianionic dicarbollide (dc) ligands, present a versatile platform that is potentially capable of not only stabilizing the low-valent uranium center but also providing control over the electronic properties of the resulting complex without significantly modifying the coordination geometry through the incorporation of a diverse range of groups onto the dc ligand at vertices directed away from the uranium center. In this work, we synthesized a series of uranium metallacarboranes featuring B-functionalized dc ligands with increasingly electron withdrawing aryl groups. A combination of cyclic voltammetry and density functional theory studies confirms that this strategy offers predictable control over the electronic properties of the uranium center. More broadly, this work establishes uranium metallacarboranes as a highly tunable class of complexes potentially capable of unlocking new insights into low-valent uranium chemistry.

Interrogating the Metal Identity Effect of Isostructural NU-1801 Frameworks on Toxic Gas Capture with Moisture-Enhanced Feature

ACS Applied Materials & Interfaces · 2025-11-17 · 2 citations

The effective capture of toxic industrial chemicals (TICs), particularly at low concentrations and under humid conditions, is essential for industrial chemical waste management and environmental hazard remediation. Among existing sorbents, metal–organic frameworks (MOFs) are promising materials for TIC capture, yet a significant gap remains in the design principles. Herein, we leveraged reticular chemistry to construct isostructural NU-1801 frameworks with Y6, Zr6, Hf6, Ce6, and Th6 clusters, providing a systematic platform to elucidate the structure–property relationships among metal identity, framework stability, and adsorption performance for TICs. Among the five analogs, NU-1801(Zr) had the highest structural stability and adsorption performance for SO2 and NH3. Breakthrough experiments demonstrated that NU-1801(Zr) exhibited moisture-enhanced behavior for SO2 and NH3 capture driven by the formation of sulfate and ammonium species, respectively. Molecular studies revealed that the binding pockets of SO2 and NH3 were located at the metal carboxylic cluster, with μ3–OH species serving as the main binding sites. Additionally, coadsorption binding geometries of H2O + SO2 and H2O + NH3 are more thermodynamically favorable than the formation of a pure H2O network, explaining the experimentally observed formation of sulfate and ammonia species. This work demonstrates the critical role of metal identity in the rational design of isostructural MOF adsorbents for practical TIC capture.

Architecting Metal–Organic Frameworks at Molecular Level toward Direct Air Capture

Journal of the American Chemical Society · 2025-02-07 · 67 citations

Escalating carbon dioxide (CO2) emissions have intensified the greenhouse effect, posing a significant long-term threat to environmental sustainability. Direct air capture (DAC) has emerged as a promising approach to achieving a net-zero carbon future, which offers several practical advantages, such as independence from specific CO2 emission sources, economic feasibility, flexible deployment, and minimal risk of CO2 leakage. The design and optimization of DAC sorbents are crucial for accelerating industrial adoption. Metal–organic frameworks (MOFs), with high structural order and tunable pore sizes, present an ideal solution for achieving strong guest–host interactions under trace CO2 conditions. This perspective highlights recent advancements in using MOFs for DAC, examines the molecular-level effects of water vapor on trace CO2 capture, reviews data-driven computational screening methods to develop a molecularly programmable MOF platform for identifying optimal DAC sorbents, and discusses scale-up and cost of MOFs for DAC.

Solvent-Directed Assembly of π-Stacked 3D Metal–Organic Frameworks with Tunable Conductivity Enhanced by C₆₀ Encapsulation

Journal of the American Chemical Society · 2025-06-04 · 8 citations

Metal–organic frameworks (MOFs) with tunable structures and unique host–guest chemistry have emerged as promising candidates for conductive materials. However, the tunability of conductivity and porosity in conductive MOFs, as well as their interrelationship, still lacks a systematic study. Herein, we report the synthesis of a series of 3D copper MOFs (NU-4000 to NU-4003) using a triphenylene-based hexatopic carboxylate linker. By modulating the ratio of mixed solvents, distinct structural topologies and π–π stacking arrangements were achieved, resulting in electrical conductivities ranging from insulators (<10–6 S/cm) to semiconductors (10–8∼102 S/cm). Among them, NU-4003 features continuous π–π stacking and exhibits a conductivity of 1.7 × 10–6 S/cm. To further enhance the conductivity, we encapsulated C60, a strong electron acceptor, within the circular channels of NU-4003, resulting in a remarkable conductivity increase to 140 S/cm with approximately 100% pore occupancy. Even at lower C60 loadings that leave 54% of the pore volume accessible, the conductivity remains exceptionally high at 104 S/cm. This represents an eight-order magnitude enhancement and positions NU-4003-C60 as one of the most conductive 3D MOFs reported to date. This work integrates two charge transport pathways (through-space and electron donor-acceptor interactions) into a single MOF host–guest material, achieving a significant enhancement in conductivity. This study demonstrates the potential of combining host–guest chemistry and π–π stacking to design conductive MOFs with permanent porosity maintained, providing a blueprint for the development of next-generation materials for electronic and energy-related applications.