Anion-Dependent Cu(II) Coordination Polymers: Geometric, Magnetic and Luminescent Properties

Abstract

A one-dimensional (1D) coordination polymer [Cu2(bpba)(CH3COO)4] (1) and a two-dimensional (2D) coordination polymer [Cu(bpba)2(H2O)(NO3)](NO3)∙2H2O∙MeOH (2) were synthesized by the reaction between Cu(CH3COO)2∙H2O/Cu(NO3)2∙3H2O and bis(4-pyridyl)benzylamine (bpba). The Cu(II) ions of 1 and 2 have distorted-square pyramidal coordination with a paddle-wheel structure and an octahedral geometry, respectively. By coordinating the Cu(II) ions and bpba ligands, 1 and 2 formed zigzag 1D and puckered 2D coordination polymers, respectively. Polymer 1 exhibits strong emissions at 355 and 466 nm, whereas polymer 2 exhibits strong emissions only at 464 nm. The emissions are strongly dependent on the geometry of the Cu(II) ions linked by the bpba and anionic ligands. Polymer 1 exhibits a very strong antiferromagnetic interaction within the paddle-wheel dimer, whereas polymer 2 exhibits a very weak antiferromagnetic interaction through the bpba linkers and/or space.

Keywords

• crystal engineering
• coordination polymer
• Cu(II) ion
• photoluminescence
• structure
• magnetism