Ozawa Hiroaki, Baghernejad Masoud, Al-Owaedi Oday A, Kaliginedi Veerabhadrarao, Nagashima Takumi, Ferrer Jaime, Wandlowski Thomas, García-Suárez Víctor M, Broekmann Peter, Lambert Colin J, Haga Masa-Aki
Department of Applied Chemistry, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, 112-8551, Tokyo, Japan.
Department of Chemistry and Biochemistry, University of Bern, Freistrasse 3, 3012, Bern, Switzerland.
Chemistry. 2016 Aug 26;22(36):12732-40. doi: 10.1002/chem.201600616. Epub 2016 Jul 29.
The ancillary ligands 4'-(4-pyridyl)-2,2':6',2''-terpyridine and 4'-(2,3-dihydrobenzo[b]thiophene)-2,2'-6',2"-terpyridine were used to synthesize two series of mono- and dinuclear ruthenium complexes differing in their lengths and anchoring groups. The electrochemical and single-molecular conductance properties of these two series of ruthenium complexes were studied experimentally by means of cyclic voltammetry and the scanning tunneling microscopy-break junction technique (STM-BJ) and theoretically by means of density functional theory (DFT). Cyclic voltammetry data showed clear redox peaks corresponding to both the metal- and ligand-related redox reactions. Single-molecular conductance demonstrated an exponential decay of the molecular conductance with the increase in molecular length for both the series of ruthenium complexes, with decay constants of βPY =2.07±0.1 nm(-1) and βBT =2.16±0.1 nm(-1) , respectively. The contact resistance of complexes with 2,3-dihydrobenzo[b]thiophene (BT) anchoring groups is found to be smaller than the contact resistance of ruthenium complexes with pyridine (PY) anchors. DFT calculations support the experimental results and provided additional information on the electronic structure and charge transport properties in those metal|ruthenium complex|metal junctions.
辅助配体4'-(4-吡啶基)-2,2':6',2''-三联吡啶和4'-(2,3-二氢苯并[b]噻吩)-2,2'-6',2''-三联吡啶被用于合成了两个系列的单核和双核钌配合物，它们在长度和锚定基团上有所不同。通过循环伏安法和扫描隧道显微镜-断结技术（STM-BJ）对这两个系列钌配合物的电化学和单分子电导性质进行了实验研究，并通过密度泛函理论（DFT）进行了理论研究。循环伏安数据显示出对应于金属和配体相关氧化还原反应的清晰氧化还原峰。单分子电导表明，对于这两个系列的钌配合物，分子电导均随着分子长度的增加呈指数衰减，衰减常数分别为βPY =2.07±0.1 nm(-1)和βBT =2.16±0.1 nm(-1)。发现具有2,3-二氢苯并[b]噻吩（BT）锚定基团的配合物的接触电阻小于具有吡啶（PY）锚定基团的钌配合物的接触电阻。DFT计算支持了实验结果，并提供了有关那些金属|钌配合物|金属结中电子结构和电荷传输性质的额外信息。
