2-Amino-7-nitro-fluorenes in Neat and Mixed SolventsOptical Band Shapes and Solvatochromism

Autor:	Jürgen Liebscher, Nikolaus P. Ernsting, Ginagunta Saroja, Tamara Senyushkina, Venugopal Karunakaran
Rok vydání:	2007
Předmět:	Solvent symbols.namesake Aqueous solution Absorption spectroscopy Chemistry Stokes shift Ultrafast laser spectroscopy Solvatochromism symbols Analytical chemistry Physical and Theoretical Chemistry Absorption (electromagnetic radiation) Spectroscopy
Zdroj:	The Journal of Physical Chemistry A. 111:10944-10952
ISSN:	1520-5215 1089-5639
DOI:	10.1021/jp073844e
Popis:	Femtosecond transient absorption spectroscopy of amino-nitro-fluorenes in the UV-visible range shows that the dynamic Stokes shift of the emission band is sensitive to infrared-active modes of the solvent. Bandshapes for stationary absorption and emission are needed to quantify the observed spectral evolution. They are reported for 2-amino-7-nitro-fluorene (ANF), 2-dimethylamino-7-nitro-fluorene (dM-ANF), and 2-di(n-butyl)amino-7-nitro-9-di(n-propyl)-fluorene (dBdP-ANF) in a variety of solvents. Bands broaden systematically with increasing solvent polarity. This effect is taken into account in an improved location of band positions. The resulting solvatochromic plots differ significantly from those that use peak positions of absorption spectra and fluorescence quantum distributions. Absorption spectra were also measured in aqueous solvent mixtures, and shifts are described by binding curves for hydrogen bonding and stepwise solvent exchange.
Databáze:	OpenAIRE
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