[2]Pseudorotaxane and [2]Rotaxane Molecular Shuttles: Self-Assembly through Second-Sphere Coordination of Thiocyanate Ligands

A Pd(Py)2(SCN)2 complex is shown to form a [2]pseudorotaxane complex with a macrocyclic tetralactam, which binds in the solid state through an unexpected complexation geometry. The intermolecular complexation is further applied to template the formation of a [2]rotaxane. The interlocked product acts as a degenerate molecular shuttle in solution, which is consistent with the co-conformation observed in the solid state.