Arnaboldi Serena, Cauteruccio Silvia, Grecchi Sara, Benincori Tiziana, Marcaccio Massimo, Biroli Alessio Orbelli, Longhi Giovanna, Licandro Emanuela, Mussini Patrizia Romana
Dipartimento di Chimica , Università degli Studi di Milano , Via Golgi, 19 , 20133 Milano , Italy . Email:
Dipartimento di Scienza e Alta Tecnologia , Università degli Studi dell'Insubria , Via Valleggio 11 , 22100 Como , Italy.
Chem Sci. 2018 Nov 29;10(5):1539-1548. doi: 10.1039/c8sc03337d. eCollection 2019 Feb 7.
Chiral electroanalysis could be regarded as the highest recognition degree in electrochemical sensing, implying the ability to discriminate between specular images of an electroactive molecule, particularly in terms of significant peak potential difference. A groundbreaking strategy was recently proposed, based on the use of "inherently chiral" molecular selectors, with chirality and key functional properties originating from the same structural element. Large differences in peak potentials have been observed for the enantiomers of different chiral molecules, also of applicative interest, using different selectors, all of them based on atropisomeric biheteroaromatic scaffolds of axial stereogenicity. However, helicene systems also provide inherently chiral building blocks with attractive features. In this paper the enantiodiscrimination performances of enantiopure inherently chiral films obtained by electrooxidation of a thiahelicene monomer with helicoidal stereogenicity are presented for the first time. The outstanding potentialities of this novel approach are evaluated towards chiral probes with different chemical nature and bulkiness, in comparison with a representative case of the so far exploited class of inherently chiral selectors with axial stereogenicity. It is also verified that the high enantiodiscrimination ability holds as well for electron spins, as for atropisomeric selectors.
手性电分析可被视为电化学传感中识别程度最高的方法，这意味着能够区分电活性分子的镜像，特别是在显著的峰电位差方面。最近提出了一种开创性的策略，该策略基于使用“固有手性”分子选择剂，其手性和关键功能特性源自同一结构元素。使用不同的选择剂，已观察到不同手性分子的对映体在峰电位上存在很大差异，这些选择剂均基于具有轴向立体异构性的阻转异构双杂芳族支架，且都具有实际应用价值。然而，螺旋烯体系也提供了具有吸引人特性的固有手性结构单元。本文首次展示了通过对具有螺旋立体异构性的硫杂螺旋烯单体进行电氧化而获得的对映体纯固有手性薄膜的对映体识别性能。与迄今为止所开发的具有轴向立体异构性的固有手性选择剂的典型案例相比，评估了这种新方法针对具有不同化学性质和体积的手性探针的卓越潜力。还证实了，与阻转异构选择剂一样，这种高对映体识别能力对电子自旋也同样适用。
