Electrophilic activation and the formation of an unusual Tl+/Cr3+ tetranuclear ion-complex adduct.

Reaction of TlPF(6) with the Cr(III) complex fac-[CrCl(3)(NPN)] (NPN = bis(2-picolyl)phenyl phosphine) did not lead to precipitation of TlCl but rather to addition of the Tl(+) cation to the CrCl(3) moiety, which resulted in a pseudo-dimeric adduct which has an unusual tetranuclear centrosymmetric structure in the solid state.