Synthesis And Electrochemical Properties Of Anthraquinone Molecular Wires

With the rapidly development of electronic and sharply rise in the production cost of the chips,it is becoming more integrated and electronic components' sizes are decreased at the speed of Moore's Law.Traditional electronics of manufacturing silicon semiconductor materials are faced with challenges both in physical limitations and restrictions in the production.Compared with the conventional electronic devices,the molecular devices are smaller in size and faster in the process of electron transmission,it also has the advantages of low energy consumption and low cost.Organic molecules assembled into electronic components and even assembled into molecular computers will be our goals in the future.Quinones molecular wires have good electrochemical activities and electron transport capabilities so it could be used as advanced electron transport materials.Anthraquinone molecules could be readily chemically modified,eight sites of anthraquinone molecules could be modified to generate several types of molecular wires,such as 1-and 2-anthraquinone anthraquinone molecular wires and 1,4-,1,5-,1,8-,2,6-and 2,7-anthraquinone molecular wires to research its electrochemical activity systematically and the relationship of the single molecule conductance and the molecular structures to provide basis for designing new molecular devices.The main works and results of this paper:1.We synthsized a series of molecule wires:1,4-,1,5-,1,8-,2,6-and 2,7-ethynyl anthraquinone molecular wires and all the structures were confirmed by 1H NMR and 13C NMR.1,4-,1,5-and 2,6-ethynyl anthraquinone molecules were anchored to the surfaces of gold electrode to form monomolecular self-assembled layers(SAMs)and its electrochemical behaviors were studied in aqueous perchloric acid.By constructing metal-molecule-metal junctions,we measured 1,4,-1,5-and 2,6-ethynyl anthraquinone molecular wires' single molecule conductance both in oxidized and reduced state with the technology of STM-BJ.The results showed that the reduced state conductance values are about 70 to 80 times greater than that of the oxidation state,so anthraquinone molecular wires have good abilities to switch.2.We synthsized another series of molecule wires:1-?2-?1,4-?1,5-?1,8-?2,6-and 2,7-vinyl anthraquinone molecular wires and all the structures were confirmed by 1H NMR,13C NMR and X-ray.1-vinyl anthraquinone molecular wire was anchored to the gold electrode surface to form a single self-assembled molecular layer.Its electrochemical behaviors were studied in the ionic liquid of[BMIM]PF6 and in buffer solutions of different pH values.The study found that the electrode surface has a sub-monolayer adsorption.Two pairs of redox peaks appeared in the ionic liquid,which represent two-step electron reduction while only one pair of reversible redox peaks appeared in buffer solutions.1-vinyl anthraquinone molecular wire were reducted in two-electron step with two protons in buffer solutions whose pH values were 1?10.3 5,but pH values above 10.35,1-vinyl anthraquinone molecular wire were reducted in two-electron step with only one proton.