title: A high molar extinction coefficient mono-anthracenyl bipyridyl heteroleptic ruthenium(II) complex: synthesis, photophysical and electrochemical properties.
abstract: In our quest to develop good materials as photosensitizers for photovoltaic dye-sensitized solar cells (DSSCs), cis-dithiocyanato-4-(2,3-dimethylacrylic acid)-2,2'-bipyridyl-4-(9-anthracenyl-(2,3-dimethylacrylic)-2,2'-bipyridyl ruthenium(II) complex, a high molar extinction coefficient charge transfer sensitizer, was designed, synthesized and characterized by spectroscopy and electrochemical techniques. Earlier studies on heteroleptic ruthenium(II) complex analogues containing functionalized oligo-anthracenyl phenanthroline ligands have been reported and documented. Based on a general linear correlation between increase in the length of π-conjugation bond and the molar extinction coefficients, herein, we report the photophysical and electrochemical properties of a Ru(II) bipyridyl complex analogue with a single functionalized anthracenyl unit. Interestingly, the complex shows better broad and intense metal-to ligand charge transfer (MLCT) band absorption with higher molar extinction coefficient (λ(max) = 518 nm, e = 44900 M⁻¹ cm⁻¹), and appreciable photoluminescence spanning the visible region than those containing higher anthracenyl units. It was shown that molar absorption coefficient of the complexes may not be solely depended on the extended π-conjugation but are reduced by molecular aggregation in the molecules.
authors.affiliation: Department of Chemistry, Faculty of Science and Agriculture, University of Fort Hare, P.M.B. X1314, Alice 5700, South Africa. aadeloye@ufh.ac.za
authors.forename: Adewale O
authors.initials: AO
authors.lastname: Adeloye
authors.forename: Peter A
authors.initials: PA
authors.lastname: Ajibade
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry*; D000873:Anthracenes / Q000138:chemical synthesis* / Q000737:chemistry*; D004563:Electrochemistry; D008024:Ligands; D019906:Nuclear Magnetic Resonance, Biomolecular; D010777:Photochemistry; D056951:Photoelectron Spectroscopy; D017319:Photosensitizing Agents / Q000138:chemical synthesis / Q000737:chemistry; D012428:Ruthenium / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000873:Anthracenes; D008024:Ligands; D017319:Photosensitizing Agents; D015082:2,2'-Dipyridyl; D012428:Ruthenium