SOLVATOCHROMISM AND THERMOCHROMISM OF RHODAMINE SOLUTIONS
SOLVATOCHROMISM AND THERMOCHROMISM OF RHODAMINE SOLUTIONS
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DOI：
10.1016/0584-8539(86)80095-2
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发表时间：
1986-01-01
影响因子：
4.4
通讯作者：
BORRIS, DP
中科院分区：
文献类型：
--
作者：
HINCKLEY, DA;SEYBOLD, PG;BORRIS, DP
研究了罗丹明B在16种质子溶剂和14种非质子溶剂中的电子吸收光谱。罗丹明B在溶液中以高度着色的两性离子、无色内酯和强烈着色的阳离子存在。质子溶剂稳定两性离子：内酯-两性离子平衡的位置取决于溶剂-染料氢键和溶剂介电/极化性能。根据其温度依赖性，热力学参数（Δ G °，Δ H °，Δ S °）在水、正丙醇和正辛醇中测定该平衡。两性离子在非质子溶剂中不稳定，其中根据介质的酸性或碱性，阳离子或内酯是有利的。酯化染料罗丹明6G的吸收光谱不表现出上述平衡，溶剂和温度的大多数变化仅适度改变。
Electronic absorption spectra of rhodamine B have been examined in 16 protic and 14 aprotic solvents. Rhodamine B exists in solution as a highly colored zwitterion, a colorless lactone and an intensely colored cation. Protic solvents stabilize the zwitterion: the position of the lactone-zwitterion equilibrium depends upon solvent-dye hydrogen bonding and solvent dielectric/polarizability properties. From its temperature dependence, thermodynamic parameters (.DELTA.G.degree., .DELTA.H.degree., .DELTA.S.degree.) for this equilibrium were determined in water, n-propanol and n-octanol. The zwitterion is not stable in aprotic solvents, in which the cation or lactone is favored according to the acidity or basicity of the medium. Absorption spectra of rhodamine 6G, an esterified dye which does not exhibit the above equilibria, are only modestly altered by most variations of solvent and temperature.