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Author Hecker, C. R. ♦ Fanwick, P. E. ♦ McMillin, D. R.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword SOLAR ENERGY ♦ INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY ♦ ALKANES ♦ CRYSTAL STRUCTURE ♦ AROMATICS ♦ BIPYRIDINES ♦ RUTHENIUM COMPLEXES ♦ CHEMICAL PREPARATION ♦ EXPERIMENTAL DATA ♦ PHOTOCHEMISTRY ♦ AZINES ♦ CHEMISTRY ♦ COMPLEXES ♦ DATA ♦ HETEROCYCLIC COMPOUNDS ♦ HYDROCARBONS ♦ INFORMATION ♦ NUMERICAL DATA ♦ ORGANIC COMPOUNDS ♦ ORGANIC NITROGEN COMPOUNDS ♦ PYRIDINES ♦ SYNTHESIS ♦ TRANSITION ELEMENT COMPLEXES ♦ Solar Energy Conversion- Photochemical, Photobiological, & Thermochemical Conversion- (1980-) ♦ Photochemistry ♦ Chemical & Physicochemical Properties
Abstract In acetonitrile and in the presence of appropriate nucleophiles, the complex (Ru(trpy)(bpy)(NCCH{sub 3})){sup 2+} undergoes a ligand substitution reaction when irradiated into the metal-to-ligand absorption band system (trpy = 2,2{prime}:6{prime},2{double prime}-terpyridine, and bpy = 2,2{prime}-bipyridine.) At 25C quantum yields for displacement of the acetonitrile ligand are 0.0013 (1), 0.0013 (1), and 0.0026 (5) for 1.0 M solutions of pyridine, 4-phenylpyridine, and 2-methylpyridine, respectively. No photochemistry is observed for the osmium(II) analogue, and all findings can be understood in terms of a dissociative reaction mechanism involving a reactive {sup 3}d-d state. The {sup 3}d-d state is accessed from a {sup 3}CT state, which is emissive below ca. 180 K. From measurements of the temperature dependence of the emission lifetime, the barrier to population of the {sup 3}d-d state is approximately 1,500 cm{sup {minus}}. Finally, the crystal structure of (Ru(trpy)(bpy)(py))(PF{sub 6}){sub 2}{center dot}(CH{sub 3}){sub 2}CO has been determined with a diffractometer. The compound crystallizes with two independent formula units in a triclinic unit cell, and the crystal structure is reported. The structure was solved by the full-matrix least-squares method, and after the final stage of refinement, R = 0.0055. There is evidence of interligand steric strain within the coordination sphere, and the bpy ligand is coordinated asymmetrically with a difference in Ru-N bond lengths of about 0.04 {Angstrom}. The internal strain probably explains why the authors have been unable to prepare the 2-methylpyridine analogue by standard methods.
ISSN 00201669
Educational Use Research
Learning Resource Type Article
Publisher Date 1991-02-20
Publisher Place United States
Journal Inorganic Chemistry
Volume Number 30
Issue Number 4


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