Farrah Cañavera-Buelvas

This work presents a study investigating the inter‐ and intra‐molecular interactions within the Os ₃ (CO) ₉ (μ‐H) ₂ (μ ³ ‐η ¹ : η ¹ : η ² ‐C ₁₆ H ₈ ) crystal. The crystal‘s behavior is analyzed by comparing experimental distances, revealing intriguing interactions. In the isolated molecule, an unconventional pyrene‐C−H⋅⋅⋅CO interaction is observed, an electron transfer from σ(C−H) to π*(CO). Strikingly, the Quantum Theory of Atoms in Molecules identifies similarities to an intramolecular charge‐inverted hydrogen bond, despite its relatively low stability due to proximity to critical points. Energy surface scans demonstrate that the interaction arises from van der Waals strain induced by the crystal‘s packing structure. The proximity between carbonyl and pyrene facilitates electron transfer between σ(C−H) and π*(CO) at distances similar to the crystal structure. A significant correlation is established between total energy and the ratio (|V|/G) of potential energy density (V) to Lagrangian kinetic energy (G) at bond (BCP) and ring (RCP) critical points, underscoring the role of electron delocalization on the pseudo‐ring in determining the existence and characteristics of these interactions. In conclusion, this study provides valuable insights into molecular interactions within the Os ₃ (CO) ₉ (μ‐H) ₂ (μ ³ ‐η ¹ : η ¹ : η ² ‐C ₁₆ H ₈ ) crystal, enriching our understanding of crystal interactions and offering perspectives for further exploration in this field.

Within the current challenges in medicinal chemistry, the development of new and better therapeutic agents effective against infectious diseases produced by bacteria, fungi, viruses, and parasites stands out. With chemotherapy as one of the main strategies against these diseases focusing on the administration of organic and inorganic drugs, the latter is generally based on the synergistic effect produced by the formation of metal complexes with biologically active organic compounds. In this sense, Schiff bases (SBs) represent and ideal ligand scaffold since they have demonstrated a broad spectrum of antitumor, antiviral, antimicrobial, and anti-inflammatory activities, among others. In addition, SBs are synthesized in an easy manner from one-step condensation reactions, being thus suitable for facile structural modifications, having the imine group as a coordination point found in most of their metal complexes, and promoting chelation when other donor atoms are three, four, or five bonds apart. However, despite the wide variety of metal complexes found in the literature using this type of ligands, only a handful of them include on their structures tridentate SBs ligands and their biological evaluation has been explored. Hence, this review summarizes the most important antimicrobial activity results reported this far for pincer-type complexes (main group and d-block) derived from SBs tridentate ligands.

In the title compound, [NiCl(2)(C(14)H(32)P(2))]·2C(12)H(9)N, the neutral [Ni(dppe)Cl(2)] complex [dppe is 1,2-bis-(diisopropyl-phosphan-yl)ethane] consists of a tetracoordinated Ni(2+) cation and has a crystallographic twofold axis passing through the metal atom and the mid-point of the CH(2)-CH(2) bond of the dppe ligand. The metal atom shows slight tetra-hedral distortion from an ideal square-planar coordination geometry, as reflected in the dihedral angle between NiCl(2) and NiP(2) planes of 15.32 (2)°. The 9H-carbazole ring system is essentially planar (r.m.s. deviation = 0.022 Å). In the crystal packing, there are two symmetry-related 9H-carbazole mol-ecules between two adjacent Ni(II) complexes, with an angle between the carbazole mean planes of ca 77°.