Trends in Metallophilic Bonding in Pd–Zn and Pd–Cu Complexes

Metallophilic interactions stabilize the bond between closed-shell metal centers, which electrostatically repel one another. Since their introduction, the origin of these interactions has been argued to be either London dispersion forces or dative bonding, but as yet, there is no definitive answer. Insight into the nature of metallophilic bonding would provide the key for rational tuning of the stabilizing interaction, for example, in specific transmetalation transition states. We now report on a computational study focused on the metallophilic d8–d10 bond in recently published families of Pd­(II)–Cu­(I) and Pd­(II)–Zn­(II) heterobimetallic compexes. We show that dative bonding outweighs dispersion interaction in controlling the metallophilic bonding energy in the studied heterobimetallic complexes, and elucidate the governing orbital interactions.