Two-dimensional open structures of transition metal(II) coordination polymers constructed from 3-fluorophthalic acid and 4,4′-bipyridine

Six complexes Cu(fpht)(bpy)0.5 (1), [Zn(fpht)(bpy)·H2O]·2H2O (2), [M(fpht)(bpy)·2H2O]·2H2O (M = Co 3, Mn 4, and Cd 5), and [Ni(fpht)(bpy)·2H2O]·0.5H2O (6) (H2fpht = 3-fluorophthalic acid and bpy = 4,4′-bipyridine) have been synthesized and structurally characterized by X-ray single crystal diffraction. 1 possesses a 2D structure constructed from [Cu2O2] units, and fpht and bpy linkers. 2 shows a 2D structure formed from the Zn2(fpht)2 clusters and bpy linkers. Complexes 3–6 have similar rectangular grid structures assembled from the M–fpht–M and M–bpy–M chains. The different 3D architectures of 1–3 with channels are formed by different noncovalent interactions, C–H⋯F in 1, O–H⋯O and C–H⋯F in 2 and O–H⋯O in 3. The fluorescence of the complexes arises from the π∗–π transition of the ligands.

Graphical abstractReactions of transition metal(II) salts with 3-fluorophthalic acid and 4,4′-bipyridine afforded six complexes. Three different types of 2D structures are assembled by different M–fpht–M and M–bpy–M connectivities. The different 3D architectures are formed by noncovalent interactions.Figure optionsDownload full-size imageDownload as PowerPoint slide