Insights into Unconventional Intramolecular CH⋅⋅⋅CO Interaction in Os3(CO)9(μ‐H)2(μ3‐η1: η1: η2‐C16H8) Crystal: A QTAIM, NCI, and NBO Exploration

Abstract

AbstractThis work presents a study investigating the inter‐ and intra‐molecular interactions within the Os3(CO)9(μ‐H)2(μ3‐η1: η1: η2‐C16H8) 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 Os3(CO)9(μ‐H)2(μ3‐η1: η1: η2‐C16H8) crystal, enriching our understanding of crystal interactions and offering perspectives for further exploration in this field.