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

A porous metal−organic framework [Co(SCN)2(EDPC)2(H2O)3]n (1; EDPC = 1,2-ethanediyl di-3-pyridinecarboxylate) has been synthesized and structurally characterized. Immersing the crystals of 1 in THF solution led to the dynamic framework of 1 undergoing a crystal-to-crystal guest-exchange process to afford the helical metallacyclic polymer [Co(SCN)2(EDPC)2(THF)]n [1⊃THF]. 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.