van Wilderen Luuk J G W, Kern-Michler Daniela, Neumann Carsten, Reinfelds Matiss, von Cosel Jan, Horz Maximiliane, Burghardt Irene, Heckel Alexander, Bredenbeck Jens
Johann Wolfgang Goethe-University, Institute of Biophysics Max-von-Laue-Str. 1 60438 Frankfurt am Main Germany
Johann Wolfgang Goethe-University, Institute of Organic Chemistry and Chemical Biology Max-von-Laue-Str. 7 60438 Frankfurt am Main Germany.
Chem Sci. 2023 Feb 8;14(10):2624-2630. doi: 10.1039/d2sc06259c. eCollection 2023 Mar 8.
Photocages are light-triggerable molecular moieties that can locally release a pre-determined leaving group (LG). Finding a suitable photocage for a particular application may be challenging, as the choice may be limited by for instance the optical or physicochemical properties of the system. Using more than one photocage to release different LGs in a reaction mixture may even be more difficult. In this work an experimental strategy is presented that allows us to hand-pick the release of different LGs, and to do so in any order. This is achieved by using isotopologue photocage-LG mixtures in combination with ultrafast VIbrationally Promoted Electronic Resonance (VIPER) excitation. The latter provides the required molecular selectivity simply by tuning the wavenumber of the used IR pulses to the resonance of a specific photocage isotopologue, as is demonstrated here for the -hydroxyphenacyl (HP) photocage. For spectroscopic convenience, we use isotopologues of the infrared (IR) spectroscopic marker -SCN as different LGs. Especially for applications where fast LG release is required, HP is found to be an excellent candidate, as free LG formation is observed to occur with a 10 ps lifetime. The devised strategy may open up new complex uncaging applications, where multiple LGs can be formed locally on a short time scale and in any sequence.
光笼是可光触发的分子部分，能够局部释放预先确定的离去基团（LG）。为特定应用找到合适的光笼可能具有挑战性，因为选择可能会受到例如系统的光学或物理化学性质的限制。在反应混合物中使用不止一种光笼来释放不同的LG甚至可能更加困难。在这项工作中，我们提出了一种实验策略，该策略使我们能够挑选不同LG的释放，并可以按任何顺序进行。这是通过将同位素光笼-LG混合物与超快振动促进电子共振（VIPER）激发相结合来实现的。后者只需将所用红外脉冲的波数调至特定光笼同位素的共振频率，即可提供所需的分子选择性，本文以对羟基苯甲酰（HP）光笼为例进行了说明。为了光谱学上的便利，我们使用红外（IR）光谱标记物 -SCN的同位素作为不同的LG。特别是对于需要快速释放LG的应用，发现HP是一个极佳的候选物，因为观察到游离LG的形成寿命为10皮秒。所设计的策略可能会开辟新的复杂解笼应用，其中可以在短时间内以任何顺序在局部形成多个LG。
