Syntheses, structures, magnetic properties and luminescence of four coordination polymers based on an asymmetric semirigid tricarboxylate ligand

Abstract

In this work, four new complexes, [Mn(μ3-Hcpoia)(phen)(H2O)]n1, [Mn2(μ4-Hcpoia)2(μ2-bib)(H2O)2]n2, [Zn(μ2-Hcpoia)(phen)(H2O)]n3, and [Zn2(μ2-Hcpoia)2(μ2–4,4′-bpy)(H2O)2]n·2nH2O 4 (H3cpoia = 4-(4-carboxyphenoxy)isophthalic acid, phen = phenanthroline, bib = 1,4-di(1H-imidazol-1-yl)benzene, 4,4′-bpy = 4,4′-bipyridine) have been synthesized by solvothermal reactions. Complexes 1–4 were fully characterized by IR spectroscopy, elemental analyses, thermogravimetric analyses, powder and single-crystal X-ray diffraction. Complexes 1 and 2 present two-dimensional (2D) structures based on the dinuclear Mn(II) secondary building units with the vertex symbols of (4.82) and (32.44)(34.46.64.7), respectively. Complex 3 possesses one-dimensional (1D) structure and reveals a uninodal 2-connected chain with the 2C1 topology. Complex 4 exhibits a 1D ladder-like double chain, containing a 1D metal–organic chain interconnected by the 4,4′-bpy ligand with the vertex symbol of (42.6). Such a rich structural diversity of 1–4 is driven by various factors, including the type of the metal(II) ions and the ancillary ligands, as well as the coordination mode of ligand. Complexes 1 and 2 show antiferromagnetic interactions (J = −0.719 cm−1 for 1, and J = −6.981 cm−1 for 2) in dimeric units with the Mn-Mn distances of 4.451(1) and 3.151(5) Å, respectively, that are related to double syn−anti carboxylate bridges and four bis-bidentate carboxylate groups with syn−syn and μ–oxo modes. The solid-state luminescent behaviors of 3, 4 were also investigated systematically.