Research Group for NMR Signal Enhancement, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.
Center for Biostructural Imaging of Neurodegeneration, Von-Siebold-Str.3 A, 37075, Göttingen, Germany.
Chemistry. 2022 Feb 7;28(8):e202104158. doi: 10.1002/chem.202104158. Epub 2022 Jan 5.
Bimodal molecular probes combining nuclear magnetic resonance (NMR) and fluorescence have been widely studied in basic science, as well as clinical research. The investigation of spin phenomena holds promise to broaden the scope of available probes allowing deeper insights into physiological processes. Herein, a class of molecules with a bimodal character with respect to fluorescence and nuclear spin singlet states is introduced. Singlet states are NMR silent but can be probed indirectly. Symmetric, perdeuterated molecules, in which the singlet states can be populated by vanishingly small electron-mediated couplings (below 1 Hz) are reported. The lifetimes of these states are an order of magnitude longer than the longitudinal relaxation times and up to four minutes at 7 T. Moreover, these molecules show either aggregation induced emission (AIE) or aggregation caused quenching (ACQ) with respect to their fluorescence. In the latter case, the existence of excited dimers, which are proposed to use in a switchable manner in combination with the quenching of nuclear spin singlet states, is observed.
双模分子探针结合了磁共振（NMR）和荧光，已在基础科学以及临床研究中得到广泛研究。自旋现象的研究有望拓宽现有探针的范围，使人们对生理过程有更深入的了解。本文介绍了一类在荧光和核自旋单重态方面具有双模特性的分子。单重态在 NMR 中是静音的，但可以通过间接探测。报道了具有对称、氘代特征的分子，其中单重态可以通过非常小的电子介导偶联（低于 1Hz）来填充。这些状态的寿命比纵向弛豫时间长一个数量级，在 7T 下可达四分钟。此外，这些分子的荧光表现出聚集诱导发射（AIE）或聚集导致猝灭（ACQ）。在后一种情况下，观察到了激发二聚体的存在，据推测，这些二聚体可以与核自旋单重态猝灭一起以可切换的方式使用。
