Cation-directed assembly of polyrotaxane and polycatenane

Abstract

Divalent metal (Pb or Zn) coordination polymers containing 1,4-bis(4-pyridyl)piperazine (bpp) and 4,4′-sulfonyldibenzoic acid (H₂sdb) exhibit different interlocked topologies. In [Pb₂(sdb)₂(bpp)]_n (1), two Pb(II) generate Pb₂(sdb)₂ metallacycles connected by bpp ligands, leading to the formation of a 1D + 1D → 1D polyrotaxane. In contrast, in {[Zn₂(sdb)₂(bpp)₂]·2DMA}_n (2), tetrameric metallacycles Zn₄(sdb)₄ are interlocked, generating 1D polycatenated chains in a parallel manner and are further pillared by bpp ligands to build a 3D framework.