Pressure and temperature effects on the excited state of the tris(2,2 prime -bipyridine)ruthenium(II) complex

Journal Article · Thu Apr 20 04:00:00 EDT 1989 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100345a019· OSTI ID:5143514

Hiraga, Takashi; Kitamura, Noboru; Kim, Haengboo; Tazuke, Shigeo ^[1]; Mori, Nobuo ^[2]

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1. Tokyo Institute of Technology (Japan)
2. Univ. of Tokyo (Japan)

The pressure (P = 0.06-1.1 GPa) and temperature (T = 100-200 K) dependence of the emission spectrum and lifetime of Ru(bpy){sub 3}{sup 2+} (bpy = 2,2{prime}-bipyridine) was studied in ethanol-methanol (4/1, v/v) by means of nanosecond time-resolved emission spectroscopy. In contrast to a pressure-induced lower energy shift of the emission spectrum at room temperature, application of pressure brings about a distinct sharpening and a higher energy shift of the spectrum at low temperature (100-200 K). The phenomena observed with increasing P were quite analogous to the spectral changes upon cooling at a fixed pressure. Both P and T effects on the emission characteristics are explained by the variation of solvent viscosity. A time-dependent lower energy shift of the emission was observed in the T regions between 100 and 200 K depending on P while it was observed in a narrow T region between 115 and 150 K at atmospheric pressure. Although the emission lifetime of Ru(bpy){sub 3}{sup 2+} increases sharply upon cooling, the lifetime was found to be almost independent of P up to {approx} 1 GPa (100-160 K). The energy and band shapes of the emission spectrum of Ru(bpy){sub 3}{sup 2+} are exclusively determined by viscosity-dependent solvent relaxation while the lifetime is governed by deactivation processes involving the upper lying metal-to-ligand charge-transfer (MLCT) excited state(s) and therefore directly by T. The important role of viscosity-dependent solvent relaxation in the MLCT excited state is also discussed.

• OSTI ID: 5143514
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 93:8; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
AZINES
BIPYRIDINES
CHEMISTRY
COMPLEXES
DATA
EMISSION SPECTROSCOPY
ENERGY LEVELS
EXCITED STATES
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
INFORMATION
LIFETIME
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMISTRY
PRESSURE DEPENDENCE
PYRIDINES
RELAXATION
RUTHENIUM COMPLEXES
SOLVENT PROPERTIES
SPECTRAL SHIFT
SPECTROSCOPY
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPLEXES
VERY HIGH PRESSURE
VISCOSITY