Zinc Coordination Polymers Containing the m‐(2‐thiazolyl)benzoic Acid Spacer: Synthesis, Characterization and Luminescent Properties in Aqueous Solutions

Four 1D coordination polymers have been prepared, starting from Zn II salts and the organic linker m ‐(2‐thiazolyl)benzoic acid (HL), also combined with auxiliary ligands: [Zn 2 (L) 4 (H 2 O)⋅2(MeCN)] ∞ ( 1 ), [Zn 2 (L) 3 (NO 3 )(bipy)] ∞ ( 2 ; bipy = 4,4′‐dipyridyl), [Zn 2 (L) 4 (bipy)] ∞ ( 3 ), [Zn 2 (L) 4 (PyEtPy)] ∞ [ 4 ; PyEtPy = 1,2‐bis(4‐pyridyl)ethane]. In all species, the Zn 2 (carboxylate) 4 “paddle‐wheel” dimer is the constituting inorganic node, where the carboxylate groups from L ‐ are bridging two adjacent metal centers. The square pyramidal metal coordination environment is completed by aquo ligands and the N(thiazole) atoms (in 1 ) or by the N donors from auxiliary bridging spacers like bipy (in 2 and 3 ) or PyEtPy (in 4 ). The luminescent properties in aqueous solutions of 3 and 4 have been examined. The N and S donors dangling from the thiazole rings in these polymers can engage into further supramolecular interactions with (acidic) metal cations, inducing a luminescence quenching after complexation. The interaction of 3 and 4 with Hg II (in the form of its chloride salt HgCl 2 ) has been analyzed as a representative example of this behaviour.