Kuzhelev Andrey A, Tormyshev Victor M, Rogozhnikova Olga Yu, Trukhin Dmitry V, Troitskaya Tatiana I, Strizhakov Rodion K, Krumkacheva Olesya A, Fedin Matvey V, Bagryanskaya Elena G
N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Novosibirsk 630090, Russia.
Novosibirsk State University, Novosibirsk 630090, Russia.
Z Phys Chem (N F). 2017 Apr;231(4):777-794. doi: 10.1515/zpch-2016-0811. Epub 2016 Oct 5.
Triarylmethyl (TAM) radicals are widely used in Electron Paramagnetic Resonance (EPR) spectroscopy as spin labels and in EPR imaging as spin probes for oxymetry. One of the key advantages of TAMs is extremely narrow EPR line, especially in case of deuterated analogues (~5 μT). Another advantage is their slow spin relaxation even at physiological temperatures allowing, in particular, application of pulsed dipolar EPR methods for distance measurements in biomolecules. In this paper a large series of TAM radicals and their deuterated analogues is synthesized, and corresponding spectroscopic parameters including C hyperfine constants are obtained for the first time. The negligible dependence of C hyperfine constants on solvent, as well as on structure and number of substituents at para-C atoms of aromatic rings, has been found. In addition, we have demonstrated that C signals at natural abundance can be employed for successful room-temperature distance measurements using Pulsed Electron Double Resonance (PELDOR or DEER).
三芳基甲基（TAM）自由基在电子顺磁共振（EPR）光谱中作为自旋标记被广泛使用，在EPR成像中作为用于血氧测定的自旋探针。TAM的关键优势之一是其EPR线极窄，尤其是氘代类似物的情况（约5 μT）。另一个优势是即使在生理温度下它们的自旋弛豫也很慢，这尤其使得脉冲偶极EPR方法可用于生物分子中的距离测量。本文合成了一系列大量的TAM自由基及其氘代类似物，并首次获得了包括碳超精细常数在内的相应光谱参数。已发现碳超精细常数对溶剂以及对芳环对位碳原子上取代基的结构和数量的依赖性可忽略不计。此外，我们已经证明，利用脉冲电子双共振（PELDOR或DEER），天然丰度下的碳信号可用于成功的室温距离测量。
