Counterion-Controlled Formation of Layered Honeycomb and Polythreading Uranyl Networks and the Highly Sensitive and Selective Detection of Fe in Aqueous Media.

Under hydrothermal conditions, six uranium coordination polymers were obtained by employing the ligand of tris(2-carboxyethyl) isocyanurate (Htci) and different combinations of d-block metal ions (Mn, Co, Zn, Ni) or N-donors (triethylamine (EtN), 2,2'-bipyridine (2,2'-bipy)). Three uranium polymers [(UO)(tci)]·[Mn(μ-O)(HO)]·2HO (), [(UO)(tci)]·[Co(μ-O)(HO)] (), and [(UO)(tci)]·[Zn(μ-O)(HO)]·2HO () containing transition metal hydrated ions, crystallized as two-dimensional coordination polymers with the common (6, 3) net topology. X-ray crystal structures of - display that they have similar honeycomb-like frameworks with all ligands bis-chelating. [UO(tci)]·Ni(HO)·2HO () and [UO(tci)]·[NH(CHCH)]·(2HO) () are made up of four interlocked sets and exhibit the 4-fold-interpenetrated frameworks. [UO(tci)]·(CHN)·HO () comprises the 2,2'-bipy cation as counterion and represents a 2D grid layered structure. Additional metals and the N-donors are all free in the complexes, acting as the templates and compensation of the charge equilibrium. The solid-state emission spectra indicate that all of the synthesized compounds own fluorescence emissions. Furthermore, the results of the quenching ability of Fe for complexes and exhibit their highly sensitive and selective detection for Fe ions. Moreover, the uranium complexes can be used as a potential probe for Fe in aqueous solutions.