Optical control on the nanoscale via photoresponsive compounds

分子光开关通过光触发不同物理化学性质的状态之间的转换，提供了一种高度选择性、时空精确和非侵入性的纳米级控制方式。因此，光开关对于化学和生物技术中的各种应用变得非常有吸引力。尽管如此，光开关的应用还是相对初级的。选择性和效率通常通过详尽搜索适当的取代基来实现，并且光开关通过简单的激发场来触发。此外，光开关的应用通常是一维的，即实现光开关控制单一的反应或property.Previously，我们研究了各种光开关和大的光响应构建的光致变色性，并调查其在分子水平上的控制潜力。特别有趣的方面，我们的研究是i）相干波包运动的光开关的激发态动力学和ii）的检测不同的相互作用的亚基之间的多光致变色化合物（激子耦合，空间位阻等）的观察。为了解决这些现象，我们建立了一个瞬态吸收装置，用于泵浦-转储/再泵浦-探测和相干控制实验。在新项目中，我们将使用我们的新装置来研究相干振动运动在光开关光化学中的作用。实验将揭示反应振动模式，这将有助于合理设计定制的光开关。此外，使用多脉冲实验，我们将研究反应性和非反应性途径的存在，以深入了解光响应系统的复杂反应机制。借助多脉冲激发方案，我们还将研究多光致变色体系中各组分之间复杂的分子相互作用。此外，这样的激发方案将使我们能够执行多光致变色化合物的状态的光学编程，以展示其作为分子逻辑的潜力。这些类型的分子逻辑将提供多维度的控制，以实现复杂的控制方案。除了这些项目，我们将继续开发新的光电开关设计。我们将探索偶氮杂芳烃和腙作为超快光致变色振荡器的性质，这些振荡器对于从纳米级肌肉和马达，通过信息处理器到生物药理学的各种应用都有意义。我们还开始了手性光开关的工作，利用这种分子特性施加光学控制。最后，我们正在努力将超快光谱学和时间分辨晶体学相结合，以深入了解光开关仿生蛋白质配体的动力学和操作机制。

Molecular photoswitches undergo a light-triggered transformation between states with different physicochemical properties, which offers a highly selective, spatiotemporally precise and non-invasive way of nanoscale control. Therefore, photoswitches have become extremely attractive for various applications in chemistry and biotechnology. Nevertheless, the application of photoswitches is relatively rudimentary. Selectivity and efficiency are typically achieved via exhaustive search of appropriate substituents, and photoswitches are triggered via simple excitation fields. Moreover, the application of photoswitches is generally unidimensional, i.e. photoswitches are implemented to control single reactions or properties.Previously, we studied the photochromism of various photoswitches and large photoresponsive constructs and investigated their potential for control at the molecular level. Particularly intriguing aspects of our research are i) the observation of coherent wavepacket motion during the excited state dynamics of photoswitches and ii) the detection of different interactions between the subunits of multiphotochromic compounds (excitonic coupling, steric hindrance, etc.). To address these phenomena, we built a transient absorption set-up for pump-dump/repump-probe and coherent control experiments.Within the new project we will employ our new set-up to investigate the role of coherent vibrational motions in the photochemistry of photoswitches. The experiments will reveal the reactive vibrational modes which will aid the rational design of tailored photoswitches. Further, using multipulse experiments we will study the presence of reactive and non-reactive pathways to gain insight into the complex reaction mechanisms of photoresponsive systems. With the help of multipulse excitation schemes, we will also investigate the intricate molecular interactions between the constituents of multiphotochromic system. Moreover, such excitation schemes will allow us to perform optical programming of the state of multiphotochromic compounds to demonstrate their potential as molecular logics. These type of molecular logics would afford control in multiple dimensions to achieve complex control scenarios.In addition to these projects, we will continue with the development of novel photoswitch designs. We will explore the properties of azoheteroarenes and hydrazones as ultrafast photochromic oscillators, which are of interest for various applications ranging from nanoscale muscles and motors, through information processors, to photopharmacology. We have also initiated work on chiral photoswitches to exploit this molecular property for exerting optical control. Finally, we are working on combining ultrafast spectroscopy and time-resolved crystallography to reach in-depth understanding of the dynamics and the mechanism of operation of photoswitchable biomimetic protein ligands.