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Brooker's merocyanine (''1-methyl-4-()-1,4-dihydropyridine'', 'MOED')〔L.G.S. Brooker, G.H. Keyes, R.H. Sprague, R.H. VanDyke, E. VanLare, G. VanZandt, and F.L. White: "Studies in the Cyanine Dye Series. XI. The Merocyanines", ''Journal of the American Chemical Society'', Volume 74. Number 11., November 1951, p. 5350 (link )〕 is an organic dye belonging to the class of merocyanines. MOED is notable for its solvatochromic properties, meaning it changes color depending on the solvent it is dissolved in. As shown in the structural formula, MOED can exist in two resonance forms: A neutral molecule and a zwitterion. Research indicates that the zwitterion form is most representative when the compound exists in polar solvents such as water, and the neutral form when it exists in nonpolar solvents such as chloroform. 〔"Fundamental Studies on Brooker’s Merocyanine", Morley et al., ''J. Am. Chem. Soc.'', 1997, 119 (42), 10192-10202 • 〕 ==Solvatochromic effects== When MOED is dissolved in various liquids, its colour will vary, depending on the solvent and its polarity. In general, the more polar the solvent, the shorter the wavelengths of the light absorbed will be. When light of a certain colour (wavelength) is absorbed, the solution will appear in the complementary colour of the one absorbed. Therefore, in water, a highly polar solvent, MOED appears yellow (corresponding to absorbed blue light of wavelengths 435-480 nm), but is purple or blue (corresponding to absorbed green to yellow light of wavelengths 560-595 nm) in acetone, a less polar solvent. The effect stems in part from the stabilization of the ground state of the merocyanine molecule in polar solvents, which increases the energy gap between the ground state and excited states, which corresponds to shorter wavelengths (increased energy) of the absorbed light. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Brooker's merocyanine」の詳細全文を読む スポンサード リンク
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