Calculation of relative nonradiative decay rate constants from emission spectral profiles. Polypyridyl complexes of Ru(II)

• Published in: Journal of physical chemistry (1952) Vol. 95; no. 1; pp. 47 - 50
• Main Authors: BARQAWI, K. R, ZAKIR MURTAZA, MEYER, T. J
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 10.01.1991
• Subjects: 400102 - Chemical & Spectral Procedures; Atomic and molecular physics; COMPLEXES; COUPLING CONSTANTS; DATA; EMISSION SPECTRA; ENERGY LEVELS; Exact sciences and technology; EXCITED STATES; EXPERIMENTAL DATA; Fluorescence and phosphorescence; radiationless transitions, quenching (intersystem crossing, internal conversion); INFORMATION; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; LOW TEMPERATURE; MEASURING METHODS; Molecular properties and interactions with photons; NUMERICAL DATA; Physics; PYRIDYL RADICALS; RADICALS; RUTHENIUM COMPLEXES; SPECTRA; TRANSITION ELEMENT COMPLEXES; Lifetime; Nitrogen heterocycle; Organic ligand; Molecular dynamics; Theoretical study; Ruthenium Complexes; Transition metal Complexes; Emission spectrum; Inorganic compound; Excited state
• ISSN: 0022-3654; 1541-5740
• DOI: 10.1021/j100154a013

Low temperature emission spectra, lifetimes, and emission quantum yields have been acquired at 157 K in 4:1 (v:v) ethanol-methanol for a series of polypyridyl complexes of Ru{sup II}. At this low temperature, excited state behavior is free of complications arising from dd or higher lying MLCT states. Emission spectral profiles have been fit by using a model that includes contributions from an averaged medium frequency ring stretching mode, a low frequency mode, and the solvent. Linear correlations exist between: (1) the electron-vibrational coupling constant for the medium frequency mode and the energy gap between the excited and ground states (E{sub 0}), (2) In (k{sub nr} {times} 1s) and E{sub 0} where k{sub nr} is the nonradiative decay rate constant, (3) In (k{sub nr} {times} 1s) and vibrational overlap factors for nonradiative decay, calculated by using the parameters obtained by emission spectral fitting. Compared to earlier correlations at room temperature, the quality of the energy gap law correlations is greatly improved. This illustrates the importance of making equivalent state to state comparisons when discussing the excited state properties of these complexes.