Weak anionic ligands controlled synthesis of ZnII/CdII coordination polymers based on N-(4-pyridylmethyl)-l-threonine

A series of Zn(II)/Cd(II) coordination polymers based on the chiral ligands of N-(4-pyridylmethyl)-l-Threonine have been synthesized, which can be profoundly regulated by the different positions of carboxylate groups, hydroxyl groups, and pyridyl groups of N-(4-pyridylmethyl)-l-Threonine building blocks and acids auxiliary ligands, as well as metal centers. Their thermal stability and fluorescence properties were also investigated. [Display omitted] Four new coordination polymers based on N-(4-pyridylmethyl)-l-threonine (HL), {[Zn(L)(HCOO)](H2O)}n (1), {[Cd(L)(HCOO)](H2O)}n (2), {[Zn(L)(H2O)2](ClO4)(H2O)}n (3), and {[Cd(L)(H2O)2](ClO4)(H2O)}n (4) have been prepared and structurally characterized by X-ray crystallography. Coordination polymers 1–4 crystallize in the uniform space group orthorhombic P212121. Coordination polymers 1 and 2 display two-dimensional lattice frameworks, while 3 and 4 are one-dimensional chain motifs. Interestingly, formate anions can easily coordinate to metal ions in coordination polymers 1 and 2, while perchlorate anions lead to lower dimension of the coordination assemblies in coordination polymers 3 and 4 with the lattice counter ions. And hydrogen bonding interactions play important roles for the formation and stabilization of these three-dimensional supramolecular networks. Furthermore, the thermal stability, and photoluminescence properties have been investigated.