Solid-state polymerization in a polyrotaxane coordination polymer via a [2+2] cycloaddition reaction

Alternate bpeb ligands in the polyrotaxane 2D coordination polymer [Cd(bpeb)(sdb)]·DMA (1) selectively undergo polymerization via a [2+2] cycloaddition reaction to form a polyrotaxane based 3D structure [Cd(bpeb)0.5(poly-bppcb)0.5(sdb)]·DMA (2) in a single-crystal-to-single-crystal manner.