Structural Diversity And Argentophilic Interactions In Small Phosphine Silver(I) Thiolate Clusters

Silver(I) coordination compounds display an interesting geometrical diversity, the possibility of having distinct coordination numbers (typically from 2 to 4) and the capability of forming argentophilic (Ag...Ag) interactions. These properties complicate the accurate prediction of structures of silver complexes under certain experimental conditions. In this work, we show how subtle modifications in thiolate and phosphine ligands exert important effects on the nuclearity and geometry of phosphine caped clusters [Ag(SR)](n) (n=4, 6 and 8). We rationalize these effects in terms of the electronic environment of silver centers by analyzing the electronic density of the single-crystal X-ray structures via the Quantum Theory of Atoms in Molecules (QTAIM) and the Non-Covalent Interaction (NCI)-Index. Furthermore, we characterized attractive and repulsive argentophilic contacts by means of the Interacting Quantum Atoms (IQA) energy partition. Our results provide insights on the effects of ancillary ligands in controlling the structure of silver-thiolate clusters. Such control is relevant towards a bottom-up approach to the atomic precise construction of higher nuclearity clusters.