The Energetic Significance of Metallophilic Interactions

Metallophilic interactions are increasingly recognized as playing an important role in molecular assembly, catalysis, and bio‐imaging. However, present knowledge of these interactions is largely derived from solid‐state structures and gas‐phase computational studies rather than quantitative experimental measurements. Here, we have experimentally quantified the role of aurophilic (Au^I???Au^I), platinophilic (Pt^II???Pt^II), palladophilic (Pd^II???Pd^II), and nickelophilic (Ni^II???Ni^II) interactions in self‐association and ligand‐exchange processes. All of these metallophilic interactions were found to be too weak to be well‐expressed in several solvents. Computational energy decomposition analyses supported the experimental finding that metallophilic interactions are overall weak, meaning that favorable dispersion and orbital hybridization contributions from M???M binding are largely outcompeted by electrostatic or dispersion interactions involving ligand or solvent molecules. This combined experimental and computational study provides a general understanding of metallophilic interactions and indicates that great care must be taken to avoid over‐attributing the energetic significance of metallophilic interactions.     

Selective Arene Cleavage by Direct Insertion of Iridium into the Aromatic Ring

We report an unprecedented selective cleavage of aromatic C−C bonds through the insertion of well‐defined iridium complexes into the aromatic ring of simple alkylarenes. The insertion occurs at 50–100 °C without the activation of weaker C−H and C−C bonds and gives unique metallacycles in high yields. Key to the success of this approach is metal‐induced deformation of the arene ring, which creates temporary ring strain and promotes direct and selective insertion of the metal into the otherwise inert arene ring C−C bonds.