Water adsorption–desorption property of stable porous supramolecular assembly composed of discrete tetranuclear iron(III) complex using π⋯π interactions

A tetranuclear FeIII complex, [FeIII4(μ-bpypz)4(μ-O)2(NO3)2(H2O)2](NO3)2·3MeOH (1) (bpypz− = 3,5-bis(2-pyridyl)pyrazolate), has been synthesized and characterized. Single-crystal X-ray structural determination reveals that the extended three-dimensional structure having the one-dimensional channel, in which the complementary FeIII tetrameric core linked together by π⋯π stacking interactions. Porous supramolecular assembly of 1 shows high thermal stability. Through water adsorption/desorption process, compound 1 is flexible, and shows the reversible structural transformation arising from the specific π⋯π stacking mode between bpypz− ligands in the crystal packing.

Graphical abstractA tetranuclear FeIII complex, [FeIII4(μ-bpypz)4(μ-O)2(NO3)2(H2O)2](NO3)2·3MeOH (1) forms that an extended three-dimensional structure having a one-dimensional channel, in which the complementary FeIII tetrameric core linked together by π⋯π stacking interactions. The porous supramolecular assembly of 1 shows high thermal stability. Through the water adsorption/desorption process, compound 1 is flexible, and shows the reversible structural transformation arising from the specific π⋯π stacking mode between bpypz− ligands in the crystal packing.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A novel tetranuclear FeIII complex is designed by using 3,5-bis(2-pyridyl)pyrazole. ► Aggregation of the discrete building units is formed by the stacking interaction. ► The assembly shows reversible structural transformation by the water sorption.