Molecular Stirrers in Action
Molecular Stirrers in Action
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DOI：
10.1021/ja507711h
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发表时间：
2014-10-22
影响因子：
15
通讯作者：
Feringa, Ben L.
中科院分区：
文献类型：
--
作者：
Chen, Jiawen;Kistemaker, Jos C. M.;Feringa, Ben L.
合成了一系列具有不同长度刚性取代基的第一代光驱动分子马达，用作“分子搅拌器”。通过H-1 NMR和紫外-可见吸收光谱研究了它们在多种不同极性和粘度的溶剂中的旋转运动。动力学和热力学参数的定量分析表明，旋转速度的影响，刚性取代基的刚性和长度的取代基和速度的差异是由熵效应。最明显的是溶剂粘度的旋转运动的影响时，长，刚性取代基存在。由DFT计算支持的自由体积模型获得的α值表明，在马达的旋转过程中，随着刚性取代基变长，需要增加重排体积，这导致增强的溶剂置换和马达的延迟。
A series of first-generation light-driven molecular motors with rigid substituents of varying length was synthesized to act as "molecular stirrers". Their rotary motion was studied by H-1 NMR and UV-vis absorption spectroscopy in a variety of solvents with different polarity and viscosity. Quantitative analyses of kinetic and thermodynamic parameters show that the rotary speed is affected by the rigidity of the substituents and the length of the rigid substituents and that the differences in speed are governed by entropy effects. Most pronounced is the effect of solvent viscosity on the rotary motion when long, rigid substituents are present. The alpha values obtained by the free volume model, supported by DFT calculations, demonstrate that during the rotary process of the motor, as the rigid substituent becomes longer, an increased rearranging volume is needed, which leads to enhanced solvent displacement and retardation of the motor.