Dimerization of indenocorannulene radicals: imposing stability through increasing strain and curvature. Issue 22 (22nd July 2020)

• Record Type: Journal Article
• Authors: Rogachev, Andrey Yu.; Zhu, Yikun; Zhou, Zheng; Liu, Shuyang; Wei, Zheng; Petrukhina, Marina A.
• Is Part Of: Organic chemistry frontiers. Volume 7:Issue 22(2020)
• Page Start: 3591
• Page End: 3598
• Publication Date: 2020-07-22
• Subjects: Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1039/d0qo00686f
• Languages: English
• ISSNs: 2052-4110

Abstract

Abstract : One-electron reduction of bowl-shaped indenocorannulene affords a new stable dimeric dianion, as confirmed by single-crystal X-ray diffraction, NMR and UV-vis spectroscopy, and DFT calculations. Abstract : One-electron reduction of bowl-shaped indenocorannulene, C26 H12, with Rb metal in THF affords [{Rb + (18-crown-6)}2 (C26 H12 –C26 H12 ) 2− ]·4THF, as confirmed by single-crystal X-ray diffraction. The product consists of a dimeric σ-bonded dianion (C–C, 1.568(7) Å) having two endo -η 6 coordinated {Rb + (18-crown-6)} moieties (Rb–C, 3.272(4)–3.561(4) Å). The (C26 H12 –C26 H12 ) 2− dimer represents the first crystallographically confirmed example of spontaneous coupling for indenocorannulene monoanion radicals, C26 H12 ˙ − . Comprehensive theoretical investigation of the new dimer confirms the single σ-bond character of the linker and reveals a significant increase of both thermodynamic and kinetic stability of [σ-(C26 H12 )2 ] 2− in comparison with analogues formed by such π-bowls as corannulene and its dibenzo-derivative. The in-depth computational analysis and direct comparison of the series demonstrates the effect of curvature on radical coupling processes, allowing control over stability and reactivity of bowl-shaped π-radicals.