Solvent Dependence of Absorption and Emission Spectra of Ru(bpy)2(CN)2: Experiment and Explanation Based on Electronic Structure Theory

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• 作者：Lajos Fodor ; Gy&ouml ; rgy Lendvay ; Attila Horvá ; th
• 刊名：Journal of Physical Chemistry A
• 出版年：2007
• 出版时间：December 20, 2007
• 年：2007
• 卷：111
• 期：50
• 页码：12891 - 12900
• 全文大小：516K
• 年卷期：v.111,no.50(December 20, 2007)
• ISSN：1520-5215

文摘

Measurements in acidic media and time-dependent density functional theory and SCF calculations wereperformed for Ru(bpy)₂(CN)₂ in 11 solvents of varying polarity to determine the solvent's influence on theabsorption and emission spectra of the complex. The solvent effect caused by both the polarizable continuumnature of the solvent (characterized by the polarizable conductor model), and by the coordination of thecyano groups of the complex by solvent molecules were investigated. Both the absorption and emission maximashow a strong blue shift as the solute-solvent interaction increases, the magnitude of which is in good linearcorrelation with Gutmann's acceptor number of the solvent. The calculations reproduce the location, shape,and shift of the experimental metal-to-ligand charge transfer bands. The solvent shift is shown to be in goodcorrelation with the charge difference between the Ru atom and the bpy ligand, which in turn is closelyrelated to the HOMO energy. The coordination of the solvent molecule to the cyano group causes a smallerblue shift than the polarizable continuum solvent. The specific solute-solvent interaction becomes dominant,however, when the pH in a protic solvent is small and the complex is protonated.