Institut de Ciència de Materials de Barcelona

Multivariate metal-organic frameworks (MTV MOFs) incorporate various metals and/or linkers within a periodic backbone, offering structural diversity and emergent functionalities.Typically, conventional one-pot synthesis does not allow for any control over the spatial arrangement, or sequencing, of metals within the framework.Here, we present a synthetic strategy to alter metal sequencing in multi-metallic MTV MOFs, yielding materials with identical composition yet distinct local metal arrangements and properties.Using isostructural mCB-Co and mCB-Ni MOFs, we generate two MTV MOFs with different Ni/Co sequences, resulting in distinct semiconducting and magnetic properties.High-resolution electrospray ionization mass spectrometry (ESI-HRMS) reveals the formation of distinct precursor species in solution, suggesting that prenucleation chemistry influences the final metal arrangement.This work establishes a new approach for modulating/altering metal organization in MTV MOFs, enabling tunable functional properties in multi-metallic frameworks for applications in catalysis, electronics, and quantum materials.

While biocatalysisin ionic liquids (ILs) using a single enzymeis well known, the successful performance of enzyme cascade reactions(ECRs) using multiple enzymes in ILs is limited by the incompatiblestabilization of more than one enzyme in a single IL. Here, we introducean innovative approach where stoichiometric precision of ILs createspH-switchable media that dynamically modulate multienzyme microenvironmentsand maintain the functional integrity of ECR without requiring anyproximity-engineered scaffolds. Cholinium-based ILs, with phosphateand carboxylate anions, were synthesized with varying molar ratiosof cholinium to realize pH-switchable aqueous platforms for ECR. Usingglucose oxidase (GOx)–horseradish peroxidase as (HRP) an enzymaticcascade, we demonstrate that under optimized conditions aqueous solutionsof ILs significantly enhance both the individual enzyme (GOx and HRP)activities and ECR (GOx–HRP) efficiencies compared to the control,phosphate-buffered saline (PBS) (pH 7.4). Molecular docking, moleculardynamics simulations, UV–vis, and circular dichroism spectroscopystudies reveal that ILs are involved in soft interactions with enzymes,stabilizing catalytically favorable conformations, and protectingenzymes against thermal-stress. Remarkably, a 25-fold increase inthe ECR efficiency was achieved in 10 wt % of [Ch]2[PAA]through [Ch]2[PAA] assisted improved substrate channelingand reduced transition-state energy barriers. Moreover, an ∼16%increase in the half-life temperature (T50) of GOx–HRP cascade in the presence of 10 wt % [Ch]2[PAA] with an enhanced melting temperature (Tm) of the enzymes suggested improved thermal stability relativeto PBS. The results of improved enzyme stability in hydrated ILs werefurther investigated by the thermodynamic stability curves (ΔG vs T). Overall, this work provides abasis for multienzyme biocatalysis in aqueous solution of ILs withan accelerated ECR rate and improved thermodynamic stability, envisagingsustainable biocatalysis and metabolic engineering.

Controlling the oxidation state of redox-active ligands during the assembly of Porous Coordination Polymers (PCPs) is a key challenge toward the design of electronically functional frameworks.Herein, we report a galvanostatic solvothermal strategy that enables the in situ electrochemical generation of an open-shell gold(III) bis(dithiolene) ligand during the formation of the network.The reduced tetrabenzoate-functionalized precursor undergoes anodic oxidation under constant current conditions, allowing precise control of the ligand's electronic state during the assembly of the framework.Magnetic measurements reveal regular S = 1/2 antiferromagnetic chains arising from one unpaired electron per Au(III)-dithiolene unit, in agreement with band structure calculations.While the room-temperature conductivity is comparable to that of closed-shell analogues, the charge transport proceeds through a Mott-insulating regime rather than a band-gap-activated mechanism, in agreement with band structure calculations.This electrochemical programming approach provides a general route to open-shell PCPs with electronically correlated ground states.

Pushing the intrinsic lattice thermal conductivity (LTC) in crystalline materials to lower bounds is crucial for fundamental materials research towards emerging technologies including thermoelectric energy conversion and thermal management in both hypersonic aircraft and next-generation turbine systems. However, in the ultralow LTC regime ( < 1 Wm-1K-1), the competition between propagative (particle-like) and coherent phonons—arising from off-diagonal components—poses a significant challenge in further reducing LTC. We perform quantitative analysis of 4700 materials using density functional theory (DFT), spanning all crystallographic groups, to elucidate the interplay between diagonal and off-diagonal phonon contributions. We identify a critical balance between these transport mechanisms, where intermediate phonon lifetimes ( ~ 1 ps) and slow group velocities ( ~ 1 km/s) collectively suppress both contributions, enabling ultralow LTC. Results from a large dataset of 31,058 structures by machine learning models strongly resemble the DFT trends of two-channel phonon transport. Leveraging these models, we screen 25,882 additional materials and confirm their properties with DFT, identifying 12 candidates with ultralow room-temperature LTC—including a record-low value of 0.132 Wm-1K-1. Our large-scale analysis reveals fundamental insights into dual-channel phonon transport, enabling rational design of ultralow LTC materials and accelerating the discovery of advanced phononic crystals with tailored thermal transport properties.

Lithium superionic conductors (LISICONs) are pivotal for next-generation solid-state batteries, yet rational design remains challenged by poorly understood correlations between lattice dynamics (phonons) and ion transport. We unveil phonon softness as the unifying descriptor for rapid Li+ conduction through a high-throughput computational framework combining ab initio calculations, machine learning potentials (fine-tuned MACE MPA model), and molecular dynamics across 1304 dynamically stable Li materials screened from an initial pool of 8578 candidates. We demonstrate that low-frequency phonons dominate Li+ migration, with the Li+ vibrational density of states (VDOS) center and Debye frequency exhibiting strong inverse correlations with diffusion coefficients. Phonon mode-resolved analysis reveals that delocalized, collective vibrations (<2 THz) lower activation barriers by promoting in-phase host lattice coupling. Crucially, global mechanical properties─bulk modulus, shear modulus, elastic modulus, and hardness─all inversely scale with Li+ mobility, confirming that structural compliance facilitates reduced activation barriers for Li+ hopping, consistent with prior observations that lattice softness enhances ionic migration. Using ab initio molecular dynamics simulations, we confirm superionic conduction in 25 Li structures that are screened from our workflow, including halide-based and nitrogen-containing materials. Our study establishes readily accessible lattice dynamics descriptors (VDOS center, Debye frequency) and mechanical metrics as universal screening tools, accelerating the discovery of high-performance solid electrolytes for energy-dense, safe batteries.

Radiopharmaceuticals that combine diagnostic and therapeutic isotopes are at the forefront of novel cancer treatments. A crucial element is the method of attaching radioisotopes to biomolecules using chelator-based techniques that are widely used clinically. Selection from available chelators is essential because this choice influences the physicochemical and biological characteristics of the final radiopharmaceutical. Numerous chelators exist because none fulfill all ideal conditions: rapid and complete binding to radiometals at low concentrations and with metallic impurities, high thermodynamic and kinetic stability in vivo, easy bioconjugation, and, key for this work, achieving these for many radiometals from the growing list of medical isotopes. We demonstrate how nanotechnology may change this. Ten nano-radiotracers were synthesized, incorporating radiometals such as 68Ga, 64Cu, 89Zr, 99mTc, 201Tl, 111In, 67Ga, 177Lu, 223Ra, and 225Ac into the nanoparticle core. The versatility of the platform was demonstrated through proof-of-concept experiments, including passive targeting in glioblastoma, active targeting of thrombosis, intratumoral radiotherapy in glioblastoma, and renal clearance optimization. This nanotracer addresses traditional challenges in radiopharmaceutical development, offering a single platform with consistent physicochemical and biological properties regardless of the radioisotope used for robust diagnostic and therapeutic applications.

In this study, graphdiyne (GDY) was grown in situ on sulfide surfaces derived from polyoxometalate (POM) to construct sp-C–S–M heterointerfaces between metal sulfides (Fe3S4 and MoS2) and GDY, thereby enabling highly efficient bifunctional oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) electrocatalysis. Experimental results reveal that the heterointerface configuration enhances the synergistic interaction between the POM-derived sulfides and GDY, promoting rapid charge transfer and increasing the number of active sites, which collectively boost the intrinsic catalytic activity. At a current density of 10 mA cm–2, the catalyst demonstrates low overpotentials of 132 mV for the HER and 218 mV for the OER and exhibits excellent catalytic activity. This work systematically clarifies the critical roles of electronic interaction and interfacial architecture between POM-derived components and GDY in enhancing HER and OER activities, offering an effective strategy for the design and construction of high-performance electrocatalysts.

Designing materials with tailor-made thermal propertiesis an importantchallenge in current condensed matter and nanoscience, particularlyfor the implications on efficient thermal management in electronicsand for applications related to energy harvesting such as thermoelectricity.Even more interesting is the possibility to dynamically access differentheat conduction states, as it potentially leads to the real-time controlof heat flow. Here, we leverage phase-engineering in MoTe2, a 2D van der Waals transition metal dichalcogenide, showing thatthe thermal conductivity undergoes a giant increase (∼270%at room temperature) upon the phase transition between the common2H and 1T′ polymorphs. Ourfirst-principles calculations trace back this very large change tothe different effects that four-phonon processes have on the two crystalphases. Importantly, the 2H ↔ 1T′ phase transition is ultrafast and reversible and can betriggered by external electric fields, light absorption, and THz pulses.

The development of smart, selective, and multifunctional nanotherapeutics is crucial for advancing next-generation cancer treatments. In this study, superparamagnetic iron oxide nanoclusters (SPIONCs) were coated with mesoporous silica, functionalized with folic acid (FA), and co-loaded with curcumin (CUR) and capecitabine (CAPE) to create a novel nanocarrier system. To enhance cellular internalisation, magnetophoresis was applied before exposure of the cells to cold atmospheric plasma (CAP). The resulting FA-conjugated, CUR and CAPE-loaded nanoclusters were evaluated in vitro in MCF-7 breast cancer and HME-1 normal epithelial cells at varying CAP exposure durations (0, 10, and 20 s) and incubation times (24 and 48 h). This is the first report demonstrating the co-loading of CUR and CAPE into FA-functionalised mesoporous silica-coated magnetic nanoclusters. Drug release studies revealed significantly enhanced release profiles under acidic conditions (pH 5.0 and 6.5), mimicking lysosomal and tumour microenvironments, compared to physiological pH (7.4). Drug-loaded nanoclusters exhibited substantially higher cytotoxicity than the controls with no loading, with a more pronounced effect in MCF-7 cells. Notably, the combined treatment of CAP and CUR-CAPE loaded NCs showed a synergistic cytotoxic effect. IC50 values, after 10 s CAP exposure and 24 h incubation, decreased to 0.43 µg mL-1 for MCF-7 cells and 37 µg mL-1 for HME-1 cells. The elevated levels of reactive oxygen species (ROS) induced by CAP played a key role in the observed cytotoxic effects, and both CUR and CAPE were found to enhance this process through ROS-related and potentially additional molecular pathways. These findings highlight the potential of CAP-assisted multicomponent nanocarriers as a promising platform for effective cancer therapy.

Three mixed-ligand gold bis(dithiolene) complexes involving one TTF dithiolate show a robust gap under pressure due to the reinforced dimerization of TTF dithiolate moieties in the solid state.