Química Inorgànica i Orgànica

Gold(I) Complexes with Bulky Phosphanes: A Dual Approach to Triplet Harvesting and Hydroamination Catalysis

Wed, 08 Apr 2026 15:10:55 GMT

Gold(I) Complexes with Bulky Phosphanes: A Dual Approach to Triplet Harvesting and Hydroamination Catalysis Aquino Samper, Araceli de; Santamaría, Nazaret.; Moro, Artur J.; Aguilà Aviles, David; Nicasio, M. Carmen; Lima, João Carlos; Rodríguez Raurell, Laura; Prieto, Auxiliadora Two families of mononuclear gold(I) complexes featuring Au-chromophore units, with chromophores being carbazole (a), phenanthrene (b), or dibenzofuran (c), were synthesized. The Au(I) atoms are coordinated to two phosphanes, either $PMe_{2}Ar^{Xyl2}(Ar^{Xyl2} = 2,6-C_{6}H{_3}-(2,6-C_{6}H{3}-Me_{2})_{2})$ (P1) or the bulkier $PCyp_{2}Ar^{Xyl2}(Cyp = cyclopentyl)$ (P2). The photophysical properties of these complexes were extensively studied, with a particular focus on the effects of phosphane bulkiness and chromophore electron-donating capacity on triplet state quantum yields ($\Phi_{T}$). Nanosecond-laser flash photolysis measurements were employed to calculate $\Phi_{T}$. Time-dependent density functional theory (TD-DFT) calculations supported the absorption and emission assignments, providing insights into the electronic state gaps involved in photophysical processes and their relative populations. The parent complex AuCl (P2) in combination with ${NaBAr_{4}}^F$, as a chloride scavenger, served as an efficient catalyst for the hydroamination of a variety of alkynes and amines, under mild conditions and with low Au loading (0.1–0.2 mol %). Luminescent studies allowed us to check the active catalytic species.

Short Antimicrobial Peptides Based on Arginine and Tryptophan: Agents with Potential in Combating Resistant Pathogens

Wed, 08 Apr 2026 08:03:51 GMT

Short Antimicrobial Peptides Based on Arginine and Tryptophan: Agents with Potential in Combating Resistant Pathogens Fernández de la Cruz, Eric; Mhlongo, Jessica T.; Kumar, Ashish; Albericio Palomera, Fernando; Viñas, Miquel; Espinal, Paula; Fusté i Domínguez, Ester; Torre, Beatriz G. de la The limitations of conventional antibiotics due to the rise of antimicrobial resistance demand new therapeutic strategies. Antimicrobial peptides represent a promising alternative because of their broad-spectrum activity and low propensity for inducing resistance. In this study, we designed and evaluated a set of seven-residue Arg/Trp-based peptides. All peptides were successfully synthesized and characterized, and their activities were assessed against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, including clinical isolates. Among the sequences tested, (WRW)2F exhibited the strongest antimicrobial activity, displaying bactericidal effects. Growth inhibition and timekill assays showed dose-dependent effects, and SYTOX Green uptake, AFM, and TEM analyses confirmed rapid membrane permeabilisation and structural disruption as the primary mode of action, while it has been demonstrated not to act as an efflux pump inhibitors. Importantly, the three more active peptides synergized with linezolid against E. coli, and (WRW)2F was able to resensitize MRSA to oxacillin, demonstrating their potential for combined therapies. The toxicity studies in eukaryotic cells and the C. elegans survival model have shown a favorable safety profile. Overall, this work highlights short Arg/Trp-rich peptides, especially (WRW)2F, as affordable, easy-to-synthesize, and biocompatible compounds with significant potential to enhance antibiotic efficacy and counteract resistant pathogens.

Confronting positions: para- vs. meta-functionalization in triindole for p-type air-stable OTFTs

Mon, 13 Oct 2025 17:21:12 GMT

Confronting positions: para- vs. meta-functionalization in triindole for p-type air-stable OTFTs Cuadrado Santolaria, Alba; Bujaldón Carbó, Roger; Fabregat, Clara; Puigdollers i González, Joaquim; Velasco Castrillo, Dolores The 5,10,15-trihexyl-10,15-dihydro-5H-diindolo[3,2-a:3′,2′-c]carbazole core, namely triindole, is well-known for its prominent hole-transporting properties and air stability. The functionalization of this core is also rather versatile, which allows the modulation of its properties by anchoring targeted scaffolds to different positions, e.g. 3,8,13 (para with respect to the nitrogens), 2,7,12 (analogously meta) or the nitrogen heteroatoms. Therefore, triindole excels as a pivotal semiconductor to be exploited in long-lasting organic thin-film transistors (OTFTs). This report aims to shed light on the effect of functionalizing whether para or meta positions with sulfurated moieties, in the pursuit of an enhanced performance in OTFTs. Remarkably, meta-substituted derivatives outshone their para- counterparts in terms of thermal, optical, intermolecular arrangement and semiconductor properties, claiming mobility values up to 2 × 10−3 cm2 V−1 s−1 and a shelf lifetime beyond the analyzed period of 5 months. Analysis of the thin films by grazing incidence X-ray diffraction (GIRXD) and atomic force microscopy (AFM) revealed that the meta-substitution also induces a higher degree of order and better morphology, further corroborating the potential of this structural approach.

Crystallographic and Computational Analysis of Oxyma B Cocrystals with Nitrogen-Containing Coformers: The Relevant Role of n → π* Interactions in Their Diverse Supramolecular Architectures

Thu, 30 Oct 2025 09:42:49 GMT

Crystallographic and Computational Analysis of Oxyma B Cocrystals with Nitrogen-Containing Coformers: The Relevant Role of n → π* Interactions in Their Diverse Supramolecular Architectures Jemai, Mahdi; Barbas Cañero, Rafael; Barceló-Oliver, Miquel; Marouani, Houda; Albericio Palomera, Fernando; Frontera, Antonio; Prohens López, Rafael Three new cocrystals of Oxyma-B, an important racemization suppressor for peptide synthesis, with 6-methylquinoline (I), 2,3,5,6-tetramethylpyrazine (II), and 1,10-phenanthroline (III) were synthesized and their single crystal structures analyzed. They show a rich network of noncovalent interactions, including classical and nonclassical hydrogen bonds (CH···O, OH···N, CH···N), CH···π, π-stacking, and, notably, lone pair···π (n → π*) interactions. Distinctive supramolecular synthons were identified, including the R22(7) motif found in both 6-methylquinoline/Oxyma-B and 2,3,5,6-tetramethylpyrazine/Oxyma-B cocrystals. In 1,10-phenanthroline/Oxyma-B, larger ring motifs such as R44(20) and R55(24) were observed, further supported by additional synthons of types R12(5) and R12(6). Hirshfeld surface analysis and density functional theory (DFT) calculations, including MEP surface, QTAIM, and NCIplot analyses, were carried out to quantify the intermolecular contributions and rationalize the experimental findings with a focus on the cooperative role of hydrogen bonding, π-stacking, and lone pair···π (n → π*) interactions in stabilizing and shaping the architectures of these new multicomponent crystalline materials.