Assembly of Metal−Organic Frameworks with Helical Layer: From 2D Parallel Interpenetrated Layer to 3D Self-Penetrating Network

Two novel Co(II)-organic frameworks with helical structures, [Co(hfipbb)(py)]_n (1) and {[Co₄(OH)(H₂O)(hfipbb)₃(Hhfipbb)(bpp)₂]·H₂O}_n (2) (H₂hfipbb = 4,4′-(hexafluoroisopropylidene)bis(benzoic acid), py = pyridine, bpp = 1,3-bis(4-pyridyl)propane), have been assembled from flexible bent ligands. Complex 1 displays a 2-fold parallel interpenetrated layer network with one-dimensional double helical channels, while 2 exhibits a three-dimensional pillared helical-layer open framework with six-connected self-penetrating topology based on a mixed dinuclear paddle-wheel cluster and tetranuclear [Co₄(μ₃-OH)₂(μ₂-OH₂)₂] steplike cluster.