Pseudorotaxane based on tetraazamacrocyclic copper complex and dibenzocrown ether

Host–guest interactions between two electron-rich dibenzocrown ethers and electron deficient macrocyclic copper(II) tetraimine complexes lead to the formation of pseudorotaxane in solution. The interactions are enhanced with the copper(III) complex compared to that of the copper(II) form as shown by the electrochemical studies. The larger – 30-membered dibenzocrown donor interacted with the copper complex stronger than the smaller ones as revealed by NMR and electrochemical methods. The thiolated form of the copper(II) tetraimine complex was self-assembled at the gold electrode forming an electroactive monolayer able to interact with the crown ether in the solution. These donor–acceptor interactions lead to an increase of the barrier properties of the layer and decreased the electron transfer rate between the copper centre and the gold electrode surface as proved by the voltammetric data.