Franchi Paola, Bleve Valentina, Mezzina Elisabetta, Schäfer Christian, Ragazzon Giulio, Albertini Marco, Carbonera Donatella, Credi Alberto, Di Valentin Marilena, Lucarini Marco
Dipartimento di Chimica "G. Ciamician", University of Bologna, Via Selmi 2, 40126, Bologna, Italy.
Dipartimento di Scienze Chimiche, University of Padova, Via Marzolo 1, 35131, Padova, Italy.
Chemistry. 2016 Jun 20;22(26):8745-50. doi: 10.1002/chem.201601407. Epub 2016 May 25.
Gaining detailed information on the structural rearrangements associated with stimuli-induced molecular movements is of utmost importance for understanding the operation of molecular machines. Pulsed electron-electron double resonance (PELDOR) was employed to monitor the geometrical changes arising upon chemical switching of a [2]rotaxane that behaves as an acid-base-controlled molecular shuttle. To this aim, the rotaxane was endowed with stable nitroxide radical units in both the ring and axle components. The combination of PELDOR data and molecular dynamic calculations indicates that in the investigated rotaxane, the ring displacement along the axle, caused by the addition of a base, does not alter significantly the distance between the nitroxide labels, but it is accompanied by a profound change in the geometry adopted by the macrocycle.
获取与刺激诱导的分子运动相关的结构重排的详细信息对于理解分子机器的运作至关重要。采用脉冲电子-电子双共振（PELDOR）来监测作为酸碱控制分子穿梭体的[2]轮烷化学切换时产生的几何变化。为此，在环和轴组件中都赋予了轮烷稳定的氮氧自由基单元。PELDOR数据与分子动力学计算相结合表明，在所研究的轮烷中，加入碱导致环沿轴的位移并没有显著改变氮氧标记之间的距离，但伴随着大环所采用几何形状的深刻变化。
