Two Copper(II)Complexes Built from a Novel Redox-Active Bipyridinium Dimer Ligand and Oxalate Anions:Synthesis,Crystal Structure and Magnetic Properties

摘要

The synthesis of a novel V-shaped redox-active bipyridinium dimer ligand,2,6-bis(4'-pyridyl-l'-pyridiniumyl)pyrazine(Bpypr)dichloride and its copper complexes,(H_2Bpypr)[Cu_2(C_2O_4)_4](1)and {[(Bpypr)Cu_2(C_2O_4)_3-(H_2O)_2]centre dot 5H_2O}_n(2),are described.Single-crystal X-ray diffraction studies confirm that complex 1 contains one V-shaped H_2Bpypr cation and two essentially planar [Cu(C_2O_4)_2]~(2-)anions,which participate in two hydrogen bonds through the two N-H moieties.Complex 2 has a ID zigzag chain structure composed of [Cu_2(C_2O_4)_3]~(2-)units bridged by V-shaped Bpypr cations.The magnetic study revealed the occurrence of a weak ferromagnetic interaction within the dinuclear copper unit of complex 2.