Are Noncovalent C─H⋯ Au Bonds Comparable to C─H⋯ π Bonds? A Theoretical Perspective

Herein, we have theoretically studied and compared the physical nature of C─H···Au and C─H···π bonds at the PBE0-D3/def2-TZVP level of theory. To achieve this, we have used a series of alkanes exhibiting i) linear, ii) cyclic, and iii) branched geometries and Au and C layers, mimicking a decahedral Au nanoparticle's face and a graphene surface portion, respectively. The calculated supramolecular complexes were compared in terms of their geometry and stability, unveiling interesting trends regarding the i) length, ii) shape, and iii) substitution degree of the aliphatic chain. In addition, they were characterized using the Quantum Theory of Atoms in Molecules (QTAIM) and Non-Covalent Interaction plot (NCIplot) methodologies, which shed light on the aliphatic C─H bond distribution along the complexes as well as the extension in real space of the interactions. Lastly, the Energy Decomposition Analysis (EDA) technique was useful to unveil resemblances/differences in the energetic contributors of both supramolecular forces. We believe that this conceptual study will be of interest to both supramolecular and materials science scientists, owing to the implications of these noncovalent interactions in molecular recognition, catalysis, and solid-state chemistry.