Cobalt(ii) and zinc(ii)-coordination polymers constructed from ether-linked tetracarboxylic acid and isomeric bis(imidazole) linkers: luminescence-based Fe(iii) detection in aqueous media†
Abstract
Four Co(II) and Zn(II)-coordination polymers, formulated as {[Co2(μ4-L)(μ-mbix)2]·2H2O}n (1), {[Co2(μ4-L)(μ-pbix)2]·4H2O}n (2), {[Zn2(μ4-L)(μ-mbix)2]·2H2O}n (3) and {[Zn2(μ4-L)(μ-pbix)2]·4H2O}n (4) (H4L: (E)-5,5′-(but-2-ene-1,4-diylbis(oxy))diisophthalic acid, mbix: 1,3-bis((imidazol-1-yl)methyl)benzene and pbix: 1,4-bis((imidazol-1-yl)methyl)benzene), were synthesized and characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction techniques. The single crystal X-ray diffraction analyses reveal that 1 and 3 display a 2D structure with a kgm topology with a point symbol of 32·62·72, while 2 and 4 exhibit 3D frameworks with a new topology with a point symbol of (86). The detection ability of 3 which showed high luminesce intensity towards Fe3+ ions was investigated and compound 3 exhibited sensitive and selective detection towards Fe3+ ions in the presence of other competing agents with a detection limit of 3.23 ppm. Moreover, the topological and thermal properties of the compounds were also studied.