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

Using a novel hemirigid multitopic ligand, benzene-1,2,3-triyldioxy-triacetic acid (H 3 L), five metal(II) complexes formulated as Cd 3 L 2 (H 2 O) 3 ·H 2 O ( 1 ), Zn(L)(BPPA) 1 / 2 ·(HBPPA) (BPPA = N, N ′-bis-(4-pyridyl)phthalamide) ( 2 ), M(HL)(phen)(H 2 O) 2 ·H 2 O (phen = phenanthroline) (M = Zn ( 3 ) and Co ( 4 )) and Cd(HL)(2,2′-bpy)(H 2 O)·5H 2 O (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 (3.4 2 .5.6.7)(3 2 .4 3 .5.6 2 .7.8) topology. Complex 2 exhibits a 2-nodal (3, 4)-connected two-dimensional (2D) framework with a novel (4.7.8)(4.7 4 .8) topology, in which the μ 2 -BPPA is self - penetrated into a cage of the 2D layer constructed by neighboring six Zn(II) ions and six L 3– . 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 HL 2– . 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. L 3– or HL 2– displays different coordination modes in the five complexes. Complexes 1 – 3 and 5 show different UV absorptions, emission spectra, and photoluminescence lifetimes.