Stauch Tim, Dreuw Andreas
Interdisciplinary Center for Scientific Computing, Im Neuenheimer Feld 205, 69120 Heidelberg, Germany.
Phys Chem Chem Phys. 2016 Jun 21;18(23):15848-53. doi: 10.1039/c6cp02395a. Epub 2016 May 27.
The photochemical cis→trans-isomerization of stiff-stilbene (1-(1-indanyliden)indan) was previously used to trigger the ring opening of cyclobutene, i.e. the retro [2+2] cycloaddition leading to butadiene, mechanically. However, the forces generated by stiff-stilbene during photoisomerization are limited, so it is unclear in how far the mechanical properties of stiff-stilbene determine the efficiency of the bond rupture. Here we present a computational study in which we investigate the mechanochemical properties of this reaction. We show that the mechanical work transmitted from stiff-stilbene to cyclobutene is much too low to account for the observed facilitation of the ring opening. Hence, local heating resulting from the absorption of a photon by stiff-stilbene and efficient non-radiative decay are the key elements initiating this reaction.
刚性二苯乙烯（1-（1-茚满叉基）茚）的光化学顺式→反式异构化先前被用于机械触发环丁烯的开环反应，即导致丁二烯生成的逆[2+2]环加成反应。然而，刚性二苯乙烯在光异构化过程中产生的力是有限的，因此尚不清楚刚性二苯乙烯的机械性能在多大程度上决定了键断裂的效率。在此，我们展示了一项计算研究，其中我们研究了该反应的机械化学性质。我们表明，从刚性二苯乙烯传递到环丁烯的机械功过低，无法解释所观察到的环开环促进作用。因此，刚性二苯乙烯吸收光子导致的局部加热和有效的非辐射衰变是引发该反应的关键因素。
