944247-90-9Relevant academic research and scientific papers
Probing donor-acceptor interactions and co-conformational changes in redox active desymmetrized [2]catenanes
Cao, Dennis,Amelia, Matteo,Klivansky, Liana M.,Koshkakaryan, Gayane,Khan, Saeed I.,Semeraro, Monica,Silvi, Serena,Venturi, Margherita,Credi, Alberto,Liu, Yi
supporting information; experimental part, p. 1110 - 1122 (2010/04/01)
We describe the synthesis and characterization of a series of desymmetrized donor-acceptor [2]catenanes where different donor and acceptor units are assembled within a confined catenated geometry. Remarkable translational selectivity is maintained in all cases, including two fully desymmetrized [2]catenanes where both donors and acceptors are different, as revealed by X-ray crystallography in the solid state, and by 1H NMR spectroscopy and electrochemistry in solution. In all desymmetrized [2]catenanes the co-conformation is dominated by the strongest donor and acceptor pairs, whose charge-transfer interactions also determine the visible absorption properties. Voltammetric and spectroelectrochemical experiments show that the catenanes can be reversibly switched among as many as seven states, characterized by distinct electronic and optical properties, by electrochemical stimulation in a relatively narrow and easily accessible potential window. Moreover in some of these compounds the oxidation of the electron donor units or the reduction of the electron acceptor ones causes the circumrotation of one molecular ring with respect to the other. These features make these compounds appealing for the development of molecular electronic devices and mechanical machines.
Templated synthesis of desymmetrized [2]catenanes with excellent translational selectivity
Liu, Yi,Klivansky, Liana M.,Khan, Saeed I.,Zhang, Xiyun
, p. 2577 - 2580 (2008/02/07)
Desymmetrized [2]catenanes ware synthesized and shown to exhibit excellent translational selectivity. The templated synthesis takes effect from the formation of pseudorotaxanes between π-rich crown ethers and a π-deficient pyromellitic (Pml) unit, followed by macrocyclization around the crown ethers with the creation of a bipyridinium (BPy) unit. The crown ethers preferably encircle the BPy unit In the resulting [2]catenanes in both solution and the solid state, as indicated by various spectroscopic analyses.
