Self-assembly of bis-β-diketone-based [M2L2] dinuclear platforms into 2-dimensional coordination polymers

Abstract

A bis-β-diketone ligand incorporating a 3,5-substituted pyridine ring between its two β-diketone domains (1,1′-(pyridine-3,5-diyl)bis(4,4-dimethylpentane-1,3-dione), H₂L¹) and its interaction with three divalent cations (Cu²⁺, Zn²⁺ and Pd²⁺) is reported. Charge neutral dinuclear metallocycles of type [M₂L¹₂] were obtained in each case and their X-ray structures determined. [Pd₂L¹₂] incorporates two square-planar O₄-coordinated metal centres. The zinc(II) and copper(II) complexes contain five-coordinate O₄N₁-metal centres in which the pyridyl nitrogen from adjacent [M₂L¹₂] metallocycles coordinates apically forming two-dimensional coordination polymers of type {[Zn₂L¹₂]_n(dmf)_n} and {[Cu₂L¹₂]_n(dmf)_n}. Desolvation of the coordination polymers led to loss of crystallinity.