Site‐Directed Dimerization of Bowl‐Shaped Radical Anions to Form a σ‐Bonded Dibenzocorannulene Dimer

Abstract

Designed site-directed dimerization of the monoanion radicals of a p-bowl in the solid state is reported. Dibenzo[a,g]corannulene (C 28 H 14 )w as selected based on the asymmetry of the charge/spin localization in the C 28 H 14 C À anion. Controlled one-electron reduction of C 28 H 14 with Cs metal in diglyme resulted in crystallization of an ew dimer, [{Cs + (diglyme)} 2 (C 28 H 14 ÀC 28 H 14 ) 2À ]( 1), as revealed by single crystal X-rayd iffraction study performed in ab road range of temperatures.T he C À Cb ond length between two C 28 H 14 C À bowls (1.560 (8) )measured at À143 8 8Cdoes not significantly change upon heating of the crystal to + 67 8 8C. The single sbond character of the CÀClinker is confirmed by calculations. The trans-disposition of two bowlsi n1 is observed with the torsion angles around the central CÀCb ond of 172.3(5)8 8 and 173.5(5)8 8.Asystematic theoretical evaluation of dimerization pathwayso fC 28 H 14 C À radicals confirmed that the trans-isomer found in 1 is energetically favored.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.org/10.1002/anie.201801537. Scheme 1. Dibenzo[a,g]corannulene (left) and (C 28 H 14 ÀC 28 H 14 ) 2À dimer (right).

Interactions between Coal and Solvent during the Solvent Extraction of Coal in View of Free Radicals

“…The formation of radical ions after charge transfer can significantly relax chemical bonds. − This relaxation is beneficial to the breakage of chemical bonds and can lead to the swelling of the coal. Pruitt and Xue reported that the bond energy is significantly reduced after the formation of free radical cations or anions through charge transfer.…”

Antiaromaticity-promoted radical anion stability in α-vinyl heterocyclics

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