Metal(II) Complexes Based on Benzene-1,2,3-triyldioxy-triacetate: Structures and Photoluminescence Properties

Abstract

Using a novel hemirigid multitopic ligand, benzene-1,2,3-triyldioxy-triacetic acid (H3L), five metal(II) complexes formulated as Cd3L2(H2O)3·H2O (1), Zn(L)(BPPA)1/2·(HBPPA) (BPPA = N,N′-bis-(4-pyridyl)phthalamide) (2), M(HL)(phen)(H2O)2·H2O (phen = phenanthroline) (M = Zn (3) and Co (4)) and Cd(HL)(2,2′-bpy)(H2O)·5H2O (2,2′-bpy = 2,2′-bipyridine) (5) have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Complex 1 features a 2-nodal (4, 5)-connected three-dimensional (3D) LIBNIU net with a (3.42.5.6.7)(32.43.5.62.7.8) topology. Complex 2 exhibits a 2-nodal (3, 4)-connected two-dimensional (2D) framework with a novel (4.7.8)(4.74.8) topology, in which the μ2-BPPA is self-penetrated into a cage of the 2D layer constructed by neighboring six Zn(II) ions and six L3–. Complexes 3 and 4 are isostructural, and they are mononuclear Zn(II) and Co(II) complexes, respectively, in which strong intramolecular π–π stacking interactions are observed between phen and the phenyl ring of HL2–. Complex 5 is a mononuclear Cd(II) complex, which is assembled into 3D supramolecular architecture via strong intermolecular π–π stacking interactions and H bonds. L3– or HL2– displays different coordination modes in the five complexes. Complexes 1–3 and 5 show different UV absorptions, emission spectra, and photoluminescence lifetimes.