dcm-pyran

omlc

dcm-pyran
The chemical structure of 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM), acetonitrile is shown at the right. The absorption and fluorescence emission spectra are shown below. The structure, absorption, and fluorescence data were all obtained from the PhotochemCAD package by Jonathan Lindsey. This excellent program allows rapid comparison of spectra and enables one to do a variety of photochemically relevant calculations.
Absorption This is a graph of the molar extinction coefficient of 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) dissolved in acetonitrile. It was measured by R. A. Fuh on 6/23/95 [H. Du, R. A. Fuh, J. Li, A. Corkan, J. S. Lindsey, "PhotochemCAD: A computer-aided design and research tool in photochemistry," Photochemistry and Photobiology, 68, 141-142, 1998]. 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM), acetonitrile has a molar extinction coefficient of 44,900 M^-1cm^-1 at 459.5 nm [J. Bourson and B. Valeur, "Ion-responsive fluorescent compounds. 2. Cation-steered intramolecular charge transfer in a crowned merocyanine.," J. Phys. Chem., 93, 3871-3876, 1989]. The fluorescence yield also has been reported to be 0.44 in acetonitrile [J. M. Drake, M. L. Lesiecki, and D. M. Camaioni, "Photophysics and cis-trans isomerization of DCM," Chem. Phys. Lett., 113, 530-534, 1985]. The quantum yield is highest in DMSO, where the dye exists predominantly (92%) in the trans form. In chloroform, the cis-trans ratio is 45:55, and the fluorescence yield is 0.35 [J. M. Drake, M. L. Lesiecki, and D. M. Camaioni, "Photophysics and cis-trans isomerization of DCM," Chem. Phys. Lett., 113, 530-534, 1985]. Original Data \| Extinction Data
Fluorescence This is the fluorescence emission spectrum of 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) dissolved in acetonitrile. The spectrum was taken by R. A. Fuh on 6/23/95 using an excitation wavelength of 430 nm [H. Du, R. A. Fuh, J. Li, A. Corkan, J. S. Lindsey, "PhotochemCAD: A computer-aided design and research tool in photochemistry," Photochemistry and Photobiology, 68, 141-142, 1998]. The quantum yield is 0.60 [J. Bourson and B. Valeur, "Ion-responsive fluorescent compounds. 2. Cation-steered intramolecular charge transfer in a crowned merocyanine.," J. Phys. Chem., 93, 3871-3876, 1989]. Original Data

This page and graphs were created by Scott Prahl.