Five M(ii) coordination polymers assembled from various polynuclear units spaced by semirigid carboxyphenylpropionate and N-donor coligand

Abstract

A series of five metal(II) coordination polymers are hydrothermally synthesized by employing dual linkers of semirigid 3-(4-carboxyphenyl)propionic acid and various N-donor coligands. The single crystal X-ray diffractions give a diversity of topology nets manifesting various inorganic polynuclear units as the nodes spaced by organic linkers. Their structural dimensionalities span a wide range from 2D layer, 2D → 3D interpenetrated network, to 3D self-interpenetrated framework. Among them, the 3D self-interpenetrating frameworks for {[Cu₂(cpp)₂(4,4′-bpy)]}_n (1) and {[Co(cpp)(bpe)_1.5(H₂O)]}_n (2) are based on {Cu₂(OCO)₄} paddlewheel binuclear and CoO₃N₃ octahedron mononuclear as the nodes, respectively. The 2D layers for {[Zn(Hcpp)(trz)]}_n (3) and {[Cd(cpp)(2,2′-bpy)]}_n (4) contain different dinuclear units featuring trz-bridged [ZnN₃O₂] tetragonal pyramids and edge-shared CdO₄N₂ octahedra, respectively. The 2D → 3D interpenetrated framework for {[Cd₃(cpp)₃(bpp)₂(H₂O)₂]}_n (5) are assembled from 6-connected [Cd₃] clusters as the nodes (H₂cpp = 3-(4-carboxyphenyl)propionic acid, 4,4′-bpy = 4,4′-bipyridyl, bpe = 1,2-di(4-pyridyl)ethylene, Htrz = 1,2,4-triazole, 2,2′-bpy = 2,2′-bipyridyl, and bpp = 1,3-di(4-pyridyl)propane). It is shown that the semirigid carboxyphenylpropionate can bear diverse structures of metal–organic frameworks regulated by various N-donor coligands. Fluorescence properties of complexes 3–5 are also investigated.