Guest-Induced Helical Metallacyclic Chains in a Porous Coordination Solid Constructed from a Flexible Ester-Containing Ligand

A porous metal−organic framework [Co(SCN)<sub>2</sub>(EDPC)<sub>2</sub>(H<sub>2</sub>O)<sub>3</sub>]<i><sub>n</sub></i> (<b>1</b>; EDPC = 1,2-ethanediyl di-3-pyridinecarboxylate) has been synthesized and structurally characterized. Immersing the crystals of <b>1</b> in THF solution led to the dynamic framework of <b>1</b> undergoing a crystal-to-crystal guest-exchange process to afford the helical metallacyclic polymer [Co(SCN)<sub>2</sub>(EDPC)<sub>2</sub>(THF)]<i><sub>n</sub></i> [<b>1</b>⊃<b>THF</b>]. The guest THF molecules were accommodated in the cavities of the metallacyclic chains and showed the handness of the helical chains by their oxygen atoms as probes.