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One- and two-electron reduction of triarylborane-based helical donor–acceptor compounds†‡ † This paper is dedicated to Professor Wolfgang Kaim on the occasion of his 70th birthday.‡ Electronic supplementary information (ESI) available. CCDC 2044266–2044268. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/d1sc02409d

ABSTRACT: One-electron chemical reduction of 10-(dimesitylboryl)-N,N-di-p-tolylbenzo[c]phenanthrene-4-amine (3-B(Mes)2-[4]helix-9-N(p-Tol)2) 1 and 13-(dimesitylboryl)-N,N-di-p-tolyldibenzo[c,g]phenanthrene-8-amine (3-B(Mes)2-[5]helix-12-N(p-Tol)2) 2 gives rise to monoanions with extensive delocalization over the annulated helicene rings and the boron pz orbital. Two-electron chemical reduction of 1 and 2 produces open-shell biradicaloid dianions with temperature-dependent population of the triplet states due to small singlet-triplet gaps. These results have been confirmed by single-crystal X-ray diffraction, EPR and UV/vis-NIR spectroscopy, and DFT calculations. Stepwise chemical reduction of D–π–A triarylborane-based helicenes gives the corresponding monoanions and dianions with delocalized unpaired electrons. The structures were confirmed by single crystal X-ray diffraction.

SUBMITTER: Jia X

PROVIDER: S-EPMC8442707 | biostudies-literature |

REPOSITORIES: biostudies-literature

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