Capturing a Square Planar Gold(III) Complex Inside a Platinum Nanocage: A Combined Experimental and Theoretical Study

A novel synthetic procedure was set up to gain access to platinum coordination cages Pt₂L₄, which are less investigated compared to their palladium counterparts. This Pt₂L₄ nanocage exhibits an adequate cavity for guest encapsulation. Indeed, the Au(III) metal complex [Au(bdt)₂]^- (bdt = benzene-1,2-dithiolate) was successfully captured inside the cavity, in contrast to the analogous palladium cage which failed to host the gold complex. This result represents a rare example where a metal complex with thio-ligands can be encapsulated in a coordination cage. Moreover, it highlights the role of the metal center and the robustness of the platinum cage for host-guest chemistry. This discovery will inspire researchers in this area to pay more attention to Pt-cages. The host-guest system was fully characterized by NMR techniques and X-ray crystallographic analysis. Moreover, the nature of the host-guest interaction in this unique example was investigated and rationalized by DFT computational studies.