Heterotopic assemblage of two different disk-shaped ligands through trinuclear silver(I) complexation: Ligand exchange-driven molecular motion

The sandwich-shaped heterotopic trinuclear Ag+ complex Ag(3)1.2 was exclusively formed from two different tris(thiazolyl) and hexa(thiazolyl) disk-shaped ligands, 1 and 2, with the aid of three Ag+ ions. The variable-temperature H-1 NMR study on its complexation behavior revealed that metal-ligand exchanges between the two neighboring thiazolyl nitrogen donors of 2 take place at the three Ag+ centers in concert. DeltaH(double dagger) and DeltaS(double dagger) for the exchange process were calculated to be 50.5 kJ mol(-1) and -26.7 J mol(-1) K-1, respectively, and its energy barrier at 298 K was estimated to be 58.5 kJ mol(-1). Each concerted metal-ligand exchange leads to an intramolecular 60degrees-rotational motion ((P)reversible arrow(M) conversion) between the two disk-shaped ligands.