Reactivity of an Aromatic σ,σ,σ‐Triradical: The 2,4,6‐Tridehydropyridinium Cation

Reactivity of the 3,4,5‐Tridehydropyridinium Cation—An Aromatic σ,σ,σ‐Triradical

“…The few studies that have been reported include thermochemical measurements on 1,3,5-tridehydrobenzene (3) [1] and matrix isolation with IR detection of 1,2,3-tridehydrobenzene (1) [6] and perfluoro-1,3,5-tridehydrobenzene. [5] Recently, we reported [8] the first reactivity study on a related s,s,s-triradical, the 2,4,6-tridehydropyridinium cation (4).…”

“…The gas-phase reactions of this triradical are compared to those of triradical 4, as well as to those of two related s,s-biradicals-the previously unreported 3,4-didehydropyridinium cation (7) and the previously reported 3,5-didehydropyridinium cation (8) [9] -and two previously reported s-monoradicals-3-dehydropyridinium cation (9) [10] and 4-dehydropyridinium cation (10; Table 1). [8] Upon collisional activation, the protonated triradical precursor, 3,4,5-triiodopyridinium cation, loses first the I atom at C4. This was verified by isolating the resulting monoradical 11 and examining its reactivity toward tetrahydrofuran.…”

“…[1][2][3][4][5][6][7][8] Theoretical studies [1][2][3][4] have predicted that the 2 A 1 state is the ground state for 1,3,5-tridehydrobenzene (3). The ground state of 1,2,3-tridehydrobenzene (1) was initially assigned [2b, c] to be 2 B 2 , but later experimental and theoretical studies [6,7] showed that the ground state is actually 2 A 1 , with the 2 B 2 state lying about 1-2 kcal mol À1 higher in energy.…”

Reactivity of the 3,4,5‐Tridehydropyridinium Cation—An Aromatic σ,σ,σ‐Triradical

“…Aromatic carbon‐centered σ,σ,σ‐triradicals ( 1 – 3 ) have been the subject of several recent studies 1–8. Theoretical studies1–4 have predicted that the 2 A 1 state is the ground state for 1,3,5‐tridehydrobenzene ( 3 ).…”

“…The few studies that have been reported include thermochemical measurements on 1,3,5‐tridehydrobenzene ( 3 )1 and matrix isolation with IR detection of 1,2,3‐tridehydrobenzene ( 1 )6 and perfluoro‐1,3,5‐tridehydrobenzene 5. Recently, we reported8 the first reactivity study on a related σ,σ,σ‐triradical, the 2,4,6‐tridehydropyridinium cation ( 4 ). Triradical 4 abstracts, for example, three SCH 3 groups from dimethyl disulfide molecules, which reveals the presence of three reactive radical sites.…”