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.