A brief review on gold nanoclusters: Beautiful structures and practical aspects

This brief review introduces the unique structural motifs of several small gold-based clusters, then followed by a profound analysis of their binding mechanism with two typical antitumor drugs. At the equilibrium point, both Au₁₇ and Au₁₈ species are found to prefer the star-like forms that have never been located for both gold and other transition metal clusters. Although the pure gold cluster tends to exist under a flat-cage shape, a tube-like shape composed of three Au₅ rings encapsulated with an M₂ unit inside has been identified as the global energy minima for the doubly doped counterparts  (M = Mo, W). Then, we present a thorough analysis on the molecular interaction between the tetrahedral Au₂₀ cluster and two anti-tumor drug molecules, that is mercaptopurine and pramipexole. Internal triggering elements including the presence of amino acids like cysteine residues and low pH of cancerous tissues that induce the drug releasing will be discussed in the last section.

From Atomic Structure to Functional Properties: Orthorhombic Disphenoidal NaAlBr4 as a Solid-State Electrolyte

This paper presents a comprehensive computational investigation of the orthorhombic P212121 phase of NaAlBr4 as a halide-based solid-state electrolyte for sodium-ion batteries. Symmetry lowering from the conventional Pnma phase generates one-dimensional Na⁺ conduction ribbons along the b-axis, enabling highly directional transport. Thermodynamic stability, confirmed through computed decomposition energies, global instability index values, and convex-hull analysis, demonstrates its strong bonding, resistance to elemental breakdown and intrinsic synthesizability. Mechanical analysis reveals moderate elastic anisotropy and high compressibility, supporting interface compatibility. Electronic structure calculations show a wide band gap (4.3-4.7 eV) which corresponds to an electrochemical stability window of 0-4.5 V, ensuring an insulating behaviour and a compatibility with Na metal anodes and high-voltage cathodes. Defect energetics identify NaBr Schottky and Na+ Frenkel defects as the most favourable intrinsic configurations, while Li+ substitution and divalent doping with Zn2+ and Mg2+ at Na+ sites further promote vacancy formation. Transport analysis, evaluated by bond valence computations, yields exceptionally low migration barriers (~0.10 eV) and room-temperature conductivities up to 0.11 S/cm. Although the orthorhombic P212121 phase of NaAlBr4 has not been observed experimentally yet, these results predict the P212121 phase of NaAlBr4 as a symmetry-enabled, defect-tunable halide electrolyte, advancing design strategies for next-generation sodium-ion batteries.

Divalent ion exchange in Na₂MgCl₄ double chloride enabling new effective solid-state electrolytes for sodium ion batteries

The search for new solid-state electrolytes for sodium-ion batteries is essential to enhance energy storage performance and stability. This study explores the potential of Na2MCl4 (M2+ = Mg2+, Zn2+, Ca2+ and Sr2+) as battery materials using advanced atomistic simulations. Structural analysis reveals that Na2SrCl4 has the largest unit cell due to its larger cationic radius, followed by Na2CaCl4, both introducing subtle octahedral distortions. Energy gap trends highlight the impact of cation selection on electronic properties, while polyhedral volume variations influence lattice stability. Defect analysis confirms the NaCl Schottky defect as the most favourable, with decreasing solution energy as the cation size increases, reinforcing ambient stability. Na2ZnCl4 emerges as the most stable compound based on defect formation energies. Mechanical properties show a decrease of both bulk and shear modulus with respect to an increase of cation size, where most compounds meet the shear modulus threshold for dendrite suppression, except for Na2SrCl4. Pugh’s ratio confirms their ductile nature, supporting their viability as solid-state electrolytes. Transport property evaluations reveal that smaller cations such as Mg2+ and Zn2+ enhance Na+ mobility by reducing activation barriers and improving ionic conductivity. Specifically, Na2MgCl4 exhibits the lowest activation energy for conductivity at 0.17 eV, while Na2ZnCl4 shows the highest conductivity at 0.215 mScm−1, reinforcing their efficiency for Na+ transport. Optimizations of lattice interactions can further enhance the sodium ion diffusion, making these materials strong candidates for solid-state battery applications.

A theoretical study of the Li₅B₃Si_x(BH)_3-x isolobal systems with x = 0–3: Remarkable materials for H₂ adsorption

In this study we investigate the stability of the isomers of the Li_nB₃Si₃ clusters with n = 0–7 using both density functional theory and coupled-cluster theory CCSD(T) calculations using both the def2-TZVPP and def2-QZVPP basis sets and the total energy is subsequently extrapolated to the complete basis set limit (CBS). Calculated results reveal closely spaced energies among the four most stable isomers for each size, except for n = 5. The Li₅B₃Si₃ isomers exhibit significant energy gaps, and a high thermodynamic stability as suggested by ΔE and Δ₂E values for its lowest-energy isomer. Of particular importance, Li₅B₃Si₃ emerges as a material able to capture a large amount of molecular hydrogen. To enhance the wt%, a substitution of Si atom by a BH unit tends to yield stabilized compounds Li₅B₃Si₂(BH), Li₅B₃Si(BH)₂ and Li₅B₃(BH)₃. Molecular dynamics simulations (BOMD) at up to 1200K confirm their thermal stability. Magnetic ring current maps identify them as doubly aromatic species, explaining their high stability. Each of these four Li₅ compounds can adsorb up to 24H₂ molecules with adsorption energies of 0.1–0.2 eV. The Li₅B₃(BH)₃ shows the most favorable wt% improvement as compared to the previously known B₁₂Li₈ cluster. A survey shows that all clusters can adsorb 24H₂ at pressures up to 100 atm and temperatures below 80 K, fitting the effective range for cryo-compressed hydrogen storage.

The Jarzynski binding free energy can effectively rank ligand-protein affinities in inadequate samplings

The use of the Jarzynski equality for estimating ligand–protein binding free energies are illustrated for cases of inadequate samplings. Data obtained from a large amount (10⁴) of work are thus converged to an incorrect value, due to creation of a distorted Gaussian-like distribution. However, even in such cases, the Jarzynski equality can effectively rank binding affinities in the early stage of rational drug design. A combination of steered molecular dynamics calculations, Jarzynski relation and block averaging can provide such relative binding free energies having significantly better correlations in the cases of the thrombin and HIV-1 complexes examined.

https://pubs.rsc.org/en/content/articlelanding/2022/RA/D1RA08527A

A theoretical study of geometric and electronic structures, stability and magnetic properties of both neutral and anionic Ge₁₆M^0/− clusters with M being a first-row 3d transition metal atom, is performed using quantum chemical approaches. Both the isoelectronic Ge₁₆Sc⁻ anion and neutral Ge₁₆Ti that have a perfect Frank–Kasper tetrahedral T_d shape and an electron shell filled with 68 valence electrons, emerge as magic clusters with an enhanced thermodynamic stability. The latter can be rationalized by the simple Jellium model. Geometric distortions from the Frank–Kasper tetrahedron of Ge₁₆M having more or less than 68 valence electrons can be understood by a Jahn–Teller effect. Remarkably, DFT calculations reveal that both neutral Ge₁₆Sc and Ge₁₆Cu can be considered as superhalogens as their electron affinities (≥3.6 eV) exceed the value of the halogen atoms and even that of icosahedral Al₁₃. A detailed view of the magnetic behavior of Ge₁₆M^0/− clusters shows that the magnetic moments of the atomic metals remain large even when they are quenched upon doping. When M goes from Sc to Zn, the total spin magnetic moment of Ge₁₆M^0/− increases steadily and reaches the maximum value of 3 μ_B with M = Mn before decreasing towards the end of the first-row 3d block metals. Furthermore, the IR spectra of some tetrahedral Ge₁₆M are also predicted.