Mario Sánchez

Curcumin, a natural polyphenol with neuroprotective potential for Alzheimer's disease (AD), suffers from limited bioavailability due to poor solubility and rapid degradation. To address this, we employed dispersion‐corrected density functional theory (DFT‐D3, PBE0‐D3/def2‐TZVP) to investigate graphitic carbon nitride (gC ₃ N ₄ ) functionalized with Fe ^{2 +} , Cu ^{2 +} , and Zn ^{2 +} as a nanocarrier for curcumin. Metallation of the gC ₃ N ₄ heptazine cavity significantly enhances curcumin adsorption, with energies increasing from −43.93 kcal mol ⁻¹ for pristine gC ₃ N ₄ to −122.32 to −144.30 kcal mol ^{− 1} upon metal incorporation. This enhanced binding arises from bidentate M–O coordination through curcumin's keto‐enol moiety and cooperative O―H···N hydrogen bonds with the gC ₃ N ₄ framework. The Fe ^{2 +} ‐functionalized system exhibits the strongest adsorption (−144.30 kcal mol ^{− 1} ), surpassing Cu ^{2 +} and Zn ^{2 +} analogues. In aqueous solution (SMD model), adsorption energies remain robust (−56.29 to −90.10 kcal mol ^{− 1} ), suggesting that metallated gC ₃ N ₄ is a promising nanocarrier for improving curcumin's stability and delivery under physiological conditions. These findings provide a theoretical basis for designing advanced nanocarriers for AD and other therapeutic applications, and highlight experimentally testable predictions, such as isothermal titration calorimetry, spectroscopic binding studies, and in vitro release assays under physiological and pH‐varied conditions.

Hydrogen storage technologies are improving over time, such as in the case of hydrogen adsorption in systems, which has been investigated in various experimental ways, as well as with theoretical methods. The design of systems that meet the needs of their experimental application is one of the challenges of these days. There are different strategies to generate adsorption of more hydrogen molecules, and several research groups have chosen to use alkali metal atoms to cause better interactions between surfaces and hydrogen molecules. Carbon, silicon, boron, phosphorus, and other systems have been reported, with carbon nanostructures being the most widely used. This review describes theoretical studies based on the addition of lithium atoms to various materials to increase the adsorption properties of hydrogen molecules.

A series of three symmetric, hollow spherical, and shape-persistent molecular organic cages analogous to C₂₀ and C₆₀ were examined by computational modeling, analyzing structural elements, strain indicators, and physical properties relevant for potential applications. The compounds are covalent aromatic cages based on 1,3,5-substituted benzene nodes linked by para-phenylene or para-pyrenylene-connectors, with diameters varying from 2.3 to 4.2 nm. The apertures in the cage interior are varied by virtue of the cage type (C₂₀- or C₆₀-type cage) and the linear connectors placed between the C₆H₃-units. NBO and MESP analyses indicate the presence of electrophilic and nucleophilic sites in the molecular skeleton. In the cages with the phenylene-connectors, the HOMO–LUMO gaps are close to 4.0 eV. In the cage coated with an enlarged polyaromatic spacer (pyrene-unit), the gap is reduced by approximately 0.4 eV.

Dye-sensitized solar cell (DSSC, DSC, DYSC, or Grätzel cell) are a semiconductor photovoltaic device that directly converts solar radiation into electric current. In contrast to conventional systems in which the semiconductor takes on both the task of absorbing light and transporting charge carriers, the two functions are separated in the DSSCs. The light is absorbed by a sensitizer, which is anchored to the surface of a broadband semiconductor. A typical DSSC consists of a mesoporous photoanode with a dye-sensitized titanium dioxide (TiO2) film, an electrolyte containing iodide/triiodide (I-1/I3-1) redox couple, and a counter electrode with platinum (Pt) catalyst. Upon the absorption of light energy, a photo-excited electron is injected from the excited state of the dye into the conduction band of the TiO2. However, the immobilization of the adsorbing dye molecules onto the surface of semiconducting metal oxide nanoparticles is crucial for initiating an electrical current, via the injection of electrons, which collectively act as the working electrode of a DSSC. Herein we report the synthesis, characterization, and evaluation of the compound 5-(4-octyloxyphenyl)tetrazole (LTz-5) as dye co-adsorbente to DSSCs. This dye was incorporated in DSSCs as a co-sensitizer with different other dyes (HD-2, HD-14, and MH-13), to evaluate the effect of interaction between dye and co-adsorbent on the energy conversion efficiency (%η). The energy conversion efficiency of the DSSC was 8.78 % from HD-2 – LTz-5 (4.9 % increase compared to CDCA), 9.20 % from HD-14 – LTz-5 (0.66 % increase compared to CDCA), and 5.01 % from MH-13 – LTz-5 (1.0 % reduction compared to CDCA). The latter results suggest that steric effects restrict the anchoring ability of the tetrazole groups, by hindering their approach to TiO2 surface and by restricting the coplanarity of the system.

Cyclopentadienyl–lithium complexes are fundamental to organometallic chemistry, with broad applications in catalysis, materials science, and synthetic chemistry, powering advances in catalysis, materials design, and synthesis. To engineer better materials, a deeper grasp of how Cp ligands bond with lithium atoms is required. In this study, density functional theory, natural bond orbital analysis, and natural energy decomposition analysis are employed to investigate the bonding interactions in Cp _n Li _n ( n = 1–6) and characterize their structural and electron properties. The results show that neutral complexes form significantly stronger CpLi bonds, with interaction energies ranging from −175.22 to −184.52 kcal mol ⁻¹ , compared to their anionic counterparts. NEDA demonstrates that electrostatic and charge transfer contributions are the primary stabilizing forces, while steric and core repulsions introduce minor destabilization. Second−order donor−acceptor stabilization energies ( E(2) ) further subtle but stabilizing contributions, in neutral complexes, primarily involving σ (CH) bonds coordinated to lithium atoms. These insights into bonding and stability offer a strategic foundation for designing materials with tailored electronic and structural properties. Future studies should expand to larger clusters, alternative charge states, and functionalized ligands to unlock new reactivity and behaviors.

Spherical and hollow molecular cages based on planar triazine (C₃N₃) hubs and aromatic phenylene connectors have been developed. The cages exhibit topologies akin to C₂₀, C₆₀, and C₇₀ fullerenes with diameters that range from 2.3 to 4.9 nm. Apertures into the cage interiors are tuned by varying the aromatic connectors situated between the C₃N₃-units. The stabilities of the C₃N₃ cages increase with size owing to reduced bending strain of planar nodes and connectors that make up the spherical aromatic networks. Doping of the cages with Li⁺ reveals the capacity of the cages for significant adsorption of gaseous H₂ and CO₂. The design of graphene-like spherical cages is also discussed.

Metformin (N, N-dimethylbiguanidine) is a drug with many biological functions. In certain cases, it is necessary for this compound to interact with some molecules in order to increase the efficacy of administration in the human body. For this purpose, density functional theory was used to study the intermolecular interactions between binuclear boron Schiff complexes and metformin (charged and neutral). All structures herein, have been studied by using Natural and Mulliken charges, Natural Bond Orbitals (NBO), and quantum molecular descriptors. The adsorption energies (Eads) for the most stable structures with neutral metformin are -27.02 to -53.34 kcal/mol in gas phase. The Eads for two monoprotonated metformin shows -39.71 kcal/mol in gas phase and -84.08 kcal/mol in water. The NBO results showed that the donor orbitals belong to the nitrogen atoms of metformin, while the acceptor orbitals belong to the C-H atoms of tert-butyl groups in binuclear boron Schiff complexes. The binuclear structure could be used as an adsorber and as a carrier of metformin molecules. Resumen. La metformina(N,N-dimetilbiguanidina) es un fármaco con múltiples funciones biológicas. En ciertos casos, es necesario que este compuesto interactúe con ciertas moléculas para aumentar la eficacia de su administración en el cuerpo humano. Para ello, se empleó la teoría del funcional de la densidad para estudiar las interacciones intermoleculares entre los complejos de Schiff de boro binucleares y la metformina (con carga y neutra). Todas las estructuras aquí descritas se han estudiado utilizando cargas naturales y de Mulliken, orbitales de enlace naturales (NBO) y descriptores moleculares cuánticos. Las energías de adsorción (Eads) para la mayoría de las estructuras estables con metformina neutra son de -27.2 a -53.34 kcal/mol en fase gaseosa. Las Eads para dos metforminas monoprotonadas muestran -39.71 kcal/mol en fase gaseosa y -84.08 kcal/mol en agua. Los resultados del NBO mostraron que los orbitales donantes pertenecen a los átomos de nitrógeno de la metformina, mientras que los orbitales aceptores pertenecen a los átomos C-H de los grupos ter-butilos en los complejos de Schiff de boro binucleares. La estructura binuclear podría utilizarse como adsorbente y transportador de moléculas de metformina.

Boroxine- and borazine-cage analogs to C₂₀, C₆₀, and C₇₀ were calculated and compared in terms of structure, strain indicators, and physical properties relevant to nanoscale applications. The results show C₆₀ and C₇₀ type cages are less strained than the smaller congener, primarily due to minimized bending in the B-arylene-B segments. The smallest cage calculated has a diameter of 2.4 nm, which increases up to 4.9 nm by either variation of the polyhedron (C₂₀ < C₆₀ < C₇₀-type cage) or organic spacer elongation between boron centers. All calculated cages are porous (apertures ranging from 0.6 to 1.9 nm). Molecular electrostatic potential and Hirshfeld population analysis revealed both nucleophilic and electrophilic sites in the interior and exterior cage surfaces. HOMO-LUMO gaps range from 3.98 to 4.89 eV and 5.10-5.18 eV for the boroxine- and borazine-cages, respectively. Our findings provide insights into the design and properties of highly porous boroxine and borazine cages for nanoscience.