Effect of Metal Coordination on Two-dimensional Assemblies in Curcumin Derivatives

Two-dimensional (2D) structures of Cu(II)-coordinated curcumin derivatives were revealed by scanning tunneling microscopy at the solid/liquid interface. The Cu(II)-coordination resulted in the formation of dimerized structure, which was different from the pristine curcumin derivatives. The appearance and disappearance of 2D structure modulation due to odd-even effect were dependent on the number of alkyl chain substituents. In addition, the appearance of the odd-even was found to be maintained before and after the Cu(II) coordination. Scanning tunneling microscopy observations revealed the two-dimensional (2D) structures of Cu(II)-coordinated curcumin derivatives at a solid/liquid interface. A dimerized structure was formed due to Cu(II) coordination, and the 2D structures of metallated curcumin derivatives were different from the pristine ones. Appearance of odd-even effect was dependent on the alkyl chain substituents, and was maintained before and after the Cu(II) coordination.