Kinetic Studies of Solvent and Pressure Effects on Thermochromic Behavior of 6-Nitrospiropyran
Kinetic Studies of Solvent and Pressure Effects on Thermochromic Behavior of 6-Nitrospiropyran
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溶剂和压力对 6-硝基螺吡喃热致变色行为影响的动力学研究
DOI：
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发表时间：
1985
期刊：
影响因子：
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通讯作者：
N. Nishimura
中科院分区：
文献类型：
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作者：
Y. Sueishi;Masanobu Ohcho;N. Nishimura
研究了6-硝基螺吡喃在不同溶剂和高压下从汞型到螺型的热转化。热转化率显着延迟在极性溶剂中，和柯克伍德图的速率常数显示了一个大的向下偏差作为溶剂极性的增加。速率常数（在对数标度上）与Kosower的Z值线性相关。活化体积的值为正值，并分为两组：ΔV = 10 cm 3 mol−1（在非极性溶剂中）和ΔV = 20 cm 3 mol−1（在极性溶剂中）。这些研究结果表明，在极性溶剂中的反应，特定的相互作用的操作和热转化过程中通过一个过渡态，这是极性比初始状态少得多。
The thermal conversion of 6-nitrospiropyran from a merocyanine form to a spiro form was studied in various solvents and under high pressures. The rates of the thermal conversions were remarkably retarded in polar solvents, and a Kirkwood plot of the rate constants showed a large downward deviation as the solvent polarity increased. The rate constants (on a logarithmic scale) were linearly related to Kosower’s Z-values. The values of the activation volumes were positive and divided into two groups: ΔV≠≈10 cm3 mol−1 (in nonpolar solvents) and ΔV≠≈20 cm3 mol−1 (in polar solvents). These findings suggest that for the reaction in polar solvents, specific interactions are operating and that the thermal conversion proceeds via a transition state which is much less polar than the initial state.