Alkaline earth metal ion doped Zn(ii)-terephthalates

Abstract

Alkaline earth metal ion doped Zn(II)-terephthalates, [Zn₂Mg(PBDC)₃(DMA)₂]_n (1), [ZnCa(PBDC)₂(DMA)₂]_n (2), [ZnSr(PBDC)₂(DMA)₂]_n (3) and [Zn₂Ba(PBDC)₃(μ₂-O1w)₂(DMF)]_n·n(DMF) (4) (H₂PBDC = terephthalic acid, DMA = N,N′-dimethylacetamide, DMF = N,N′-dimethylformamide), have been solvothermally synthesized and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, elemental analyses, IR spectra, and thermal analyses. Different secondary building subunits, [Zn₂Mg(μ₂-COO)₃] for 1, [ZnCa(μ₂-COO)₃] for 2, [ZnSr(μ₂-COO)₃] for 3, and [Zn₂Ba(μ₂-COO)₄(μ₂-O1w)₂] for 4, are realized by the introduction of different alkaline earth ions. Compound 1 is a two-dimensional (2D) layer structure with 6-connected hxl topology. Compounds 2 and 3 are isostructural and exhibit a three-dimensional (3D) framework with (3,5)-connected {4.6²}{4.6⁶.8³} topology owing to their similar secondary building subunits. Compound 4 is a three-dimensional (3D) opened framework with the channels occupied by the disordered lattice DMF molecules and can be simplified into a (3,8)-connected {4².6}₂{4⁴.6¹⁴.7⁸.8²} topology. Moreover, the solid-state fluorescence of compounds 1–4 have also been investigated at room temperature.