Pnictogen Bonds between Electrophilic Pnictogens and Nucleophilic Metal Centers: A Combined Database Survey and Theoretical Investigation.

d8 and d10 metal centers showing nucleophilic properties can function as Lewis bases in the establishment of pnictogen bonding (PnB). In this work, PnB interactions between electrophilic pnictogens (R3Pn) and nucleophilic metal centers (Ni/Pd and Ag/Au) were systematically studied by quantum chemical calculations combined with a search of the Cambridge Structural Database (CSD). Owing to the increased nucleophilicity, d8 metal centers generally form enhanced PnBs with R3Pn relative to d10 ones, leading to a partially covalent character of Pn···Ni/Pd contacts. In most cases, a certain amount of charge is transferred from the metal compounds to the donor molecules. Energy decomposition analysis revealed that the attraction of metal-involving PnBs originates mainly from the electrostatic interaction, while the orbital term and the dispersion component also play an important role. In addition, a number of crystal structures consisting of metal-participating PnBs were collected from the CSD, to provide crystallographic evidence of such interactions.