Three dinuclear Cu⁺ complexes based on Cu₂X₂ core (X-=Cl^-, Br^- and I^-): Syntheses, crystal structures, absorption and emission spectra

Three dinuclear Cu⁺ complexes [Cu₂(μ-X₂)(deebq)₂] (where deebq =4,4'-diethylester-2,2'-biuinoline; X=Cl (1), Br (2) or I (3)), have been synthesized and characterized spectroscopically. The isostructural 1∼3 crystallize in triclinic system with space group P₁, and show uite similar lattice parameters and packing structures. Two Cu⁺ ions in a dinuclear unit are related to each other via an inversion center; each Cu⁺ ion are coordinated by two N atoms form one deebq ligand and two X^- anions, which act as a μ₂-bridge mode to link two Cu⁺ ions, to form a distorted tetrahedral coordination geometry. The dinuclear units are aligned into a supramolecular chain via the intermolecular π···π interactions between the neighboring phenyl rings in deebq ligands, and the supramolecular chains are held together through weakly intermolecular van der Waals forces.