From zero-dimensional complexes to one-dimensional coordination polymers adjusted by the solvents or ligand substituent groups

Abstract

A new ligand, 6-(4-carboxyphenyl)-3-(2-chloroimidazo[1,2-a]pyridin-3-yl)picolinic acid (H2L1), was used to construct two zero-dimensional (0D) complexes ([Zn(HL1)2] (1) and ([Ni(HL1)2(H2O)2] (3)), and one one-dimensional (1D) zig-zag chain coordination polymer ([Zn(L1)(H2O)2]n (2)) which was further assembled into porous three-dimensional (3D) supramolecular framework. The various dimensionality of 1–3 essentially originates from the types of organic solvents, because protic EtOH solvent resulted in completely deprotonated 2-connected L12− in 2, conversely, polar MeCN only caused partial deprotonation to give 1-connected HL1− in 1 and 3. Moreover, through changing 2-chloroimidazo[1,2-a]pyridine ring to pyridine ring, 0D Ni(II) complex (3) was adjusted to 1D ladder chain Ni(II) coordination polymer ([Ni(L2)(H2O)2]n•2H2O (4)) which should be ascribed to ligand substituent group effects. The photoluminescent or magnetic properties of 1–4 were also researched.