Self-Assembly and Substituent Effect of Copper(I) Complexes with 1,2-Bis(2-pyridylethynyl)benzene Ligands

The reaction of 1,2-bis(2-pyridylethynyl)benzenes (L1-L5) with copper(I) ions proceeded smoothly to afford mononuclear copper(I) chelate complexes CL1-CL3 or dinuclear copper(I) molecular rectangular boxes, CL4 and CL5, in excellent yields, depending on the size of the substituent. If a ligand with a small substituent was used, the self-assembly of a mononuclear copper(I) chelate complex was achieved. If a ligand with a bulky substituent was used, the self-assembly of dinuclear copper(I) molecular rectangular boxes was achieved. The equilibrium between these two copper(I) complexes was also observed in solution.