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Controlling the Direction of the Molecular Axis of Rod‐Shaped Binuclear Ruthenium Complexes on Single‐Walled Carbon Nanotubes
Author(s) -
Ozawa Hiroaki,
Kosaka Kazuma,
Kita Tomomi,
Yoshikawa Kai,
Haga Masaaki
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201504678
Subject(s) - ruthenium , valence (chemistry) , x ray photoelectron spectroscopy , carbon nanotube , electrochemistry , pyrene , photochemistry , materials science , chemistry , crystallography , composite material , chemical engineering , organic chemistry , electrode , catalysis , engineering
We report the synthesis of a mixed‐valence ruthenium complex, bearing pyrene moieties on one side of the ligands as anchor groups. Composites consisting of mixed‐valence ruthenium complexes and SWNTs were prepared by noncovalent π–π interactions between the SWNT surface and the pyrene anchors of the Ru complex. In these composites, the long axis of the Ru complexes was aligned in parallel to the principal direction of the SWNT. The optimized conformation of these complexes on the SWNT surface was calculated by molecular mechanics. The composites were examined by UV/Vis absorption and FT‐IR spectroscopy, XPS, and SEM analysis. Furthermore, their electrochemical properties were evaluated. Cyclic voltammograms of the composites showed reversible oxidation waves at peak oxidation potentials ( E p ox ) = 0.86 and 1.08 V versus Fc + /Fc, which were assigned to the Ru II ‐Ru II /Ru II ‐Ru III and the Ru II ‐Ru III /Ru III ‐Ru III oxidation events of the dinuclear ruthenium complex, respectively. Based on these observations, we concluded that the electrochemical properties and mixed‐valence state of the dinuclear ruthenium complexes were preserved upon attachment to the SWNT surface.