Cytosine |
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| The chemical structure of Cytosine 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. |
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Absorption
This is a graph of the molar extinction coefficient of Cytosine dissolved in water. It was measured by R. A. Fuh on summer, 97 [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]. Cytosine has a molar extinction coefficient of 6,100 M-1cm-1 at 220 nm [G. D. Fasman, Handbook of Biochemistry and Molecular Biology, Nucleic Acids, I, 65-215, CRC Press, 3 ed., 1975]. Due to the expected low fluorescence yield, estimated to be 0.000082 [P. R. Callis, "Polarized fluorescence and estimated lifetimes of the DNA bases at room temperature," Chem. Phys. Lett., 61, 563-567, 1979] a fluorescence spectrum was not collected. For fluorescence studies of the nucleic acid bases and related heterocyclic compounds, see [J. W. Longworth, R. O. Rahn, and R. G. Shulman, "Luminescence of pyrimidines, purines, nucleosides and nucleotides at 77K. The effect of ionization and tautomerization.," J. Chem. Phys, 45, 2930-2939, 1966]. |
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