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 (H 2 O) 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.