Synthesis and Single‐Molecule Conductance Study of Redox‐Active Ruthenium Complexes with Pyridyl and Dihydrobenzo[b]thiophene Anchoring Groups. Issue 36 (29th July 2016)

• Record Type: Journal Article
• Authors: 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
• Is Part Of: Chemistry. Volume 22:Issue 36(2016)
• Page Start: 12732
• Page End: 12740
• Publication Date: 2016-07-29
• Subjects: anchoring groups -- electrochemistry -- molecular wires -- ruthenium -- STM-break junction; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201600616
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: 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 β PY =2.07±0.1 nm −1 and β BT =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. Abstract : Anchor management : The peripheral ligands with pyridine and 2, 3‐dihydrobenzo[ b ]thiophene were used to synthesize two series of complexes with different lengths and anchoring groups. The electrochemical and single‐molecular conductance properties of these two series of ruthenium complexes were studied experimentally by employing cyclic voltammetry and the scanning tunneling microscopy‐break junction technique (STM‐BJ) and theoretically by using density functional theory (DFT).