Patalag Lukas J, Hoche Joscha, Mitric Roland, Werz Daniel B, Feringa Ben L
University of Groningen, Stratingh Institute for Chemistry, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
Universität Würzburg, Institute of Physical and Theoretical Chemistry, Am Hubland, 97074, Würzburg, Germany.
Angew Chem Int Ed Engl. 2022 May 23;61(22):e202116834. doi: 10.1002/anie.202116834. Epub 2022 Mar 16.
Herein we present a systematic study demonstrating to which extent exciton formation can amplify fluorescence based on a series of ethylene-bridged oligo-BODIPYs. A set of non- and weakly fluorescent BODIPY motifs was selected and transformed into discrete, chain-like oligomers by linkage via a flexible ethylene tether. The prepared superstructures constitute excitonically active entities with non-conjugated, Coulomb-coupled oscillators. The non-radiative deactivation channels of Internal Conversion (IC), also combined with an upstream reductive Photoelectron Transfer (rPET) and Intersystem Crossing (ISC) were addressed at the monomeric state and the evolution of fluorescence and (non-)radiative decay rates studied along the oligomeric series. We demonstrate that a "masked" fluorescence can be fully reactivated irrespective of the imposed conformational rigidity. This work challenges the paradigm that a collective fluorescence enhancement is limited to sterically induced motional restrictions.
在此，我们展示了一项系统研究，该研究基于一系列乙烯桥连的寡聚硼二吡咯，证明了激子形成能够在多大程度上放大荧光。我们选择了一组非荧光和弱荧光的硼二吡咯基序，并通过柔性乙烯链连接将其转化为离散的链状寡聚物。制备的超结构构成了具有非共轭、库仑耦合振荡器的激子活性实体。在单体状态下研究了内部转换（IC）的非辐射失活通道，该通道还与上游的还原光电子转移（rPET）和系间窜越（ISC）相结合，并研究了沿着寡聚体系列的荧光和（非）辐射衰减率的演变。我们证明，无论施加的构象刚性如何，“隐藏”的荧光都可以完全重新激活。这项工作挑战了集体荧光增强仅限于空间诱导的运动限制这一范式。
