Delocalization of Electrons in the Dodecahedrane Cage—A D_2h‐Symmetrical 4c‐3e Radical Cation as a Structural Borderline Case

Abstract

How far apart can CC bonds be and still interact through space? An ESR investigation on the radical cation of 1,16‐dodecahedradiene (1) gives an answer to this question. On the hyperfine timescale 1•+ has a delocalized structure with D2h symmetry. The π, π distances in 1 and 1•+ are almost identical.

Secododecahedradienes - Syntheses, Reactivity, in-Plane Homoconjugated 3C/2e Cations, 4C/3e Radical Cations, andσ-Bishomoaromatic 4C/2e Dications?

“…(18)). (3')); 128.9 (C(2'), C(4')); 128.5 (C(5'), C(6')); 126.9 (C(1')); 116.5 (C (20) (2'), HÀC(2''), HÀC(4'), HÀC(4'')); 7.36 (m, HÀC(5'), HÀC(5''), HÀC(6'), HÀC(6'')); 4.45 (m, HÀC (17) (24)); 135.5 (C(3'), C(3'')); 129.0 (C(2'), C(2''), C(4'), C(4'')); 128.2 (C(5'), C(5''), C(6'), C(6'')); 126.6 (C(1'), C(1'')); 113.6 (C(1), C (5) (18) (14)); 79.6 (C(2)); 79.3 (C (1) .0 2,18 .0 3,7 .0 4,17 .0 5,15 .0 6,13 .0 8,12 .0 16,20 ]icosane (52a). To a soln.…”

“…2128 (dec.). (7)); 3.36 (dd, HÀC(11)); 3.18 (m, HÀC(3), HÀC (18) (15)); 170.7 (MeOOCÀC(9)); 152.5 (C(3')); 151.8 (C(5') at C(12)); 151.6 (C(5') at C(4)); 150.9 (C(13)); 145.4 (C(17)); 140.3 (C(16)); 136.8 (C(20)); 130.0 (C(1'') at C(12)); 129.9 (C(1'') at C(4)); 128.1 (C(3'') at C(12)); 128.0 (C(3'') at C(4)); 127.21 (C(4'') at C(12)); 127.20 (C(4'') at C(4)); 124.5 (C(2'') at C(12)); 124.4 (C(2'') at C(4)); 100.5 (CN (12) .0 5,9 .0 6,16 .0 7,14 .0 8,12 .0 13,20 ]-icosa-16-ene (65a). A soln.…”

“…12-Bromodecacyclo[9.9.0.0 2,18 .0 3,10 .0 4,17 .0 5,9 .0 6,16 .0 7,14 .0 8,12 .0 13,20 ]icos-13(20)-ene (60a). To a soln.…”

“…The combined org. phase was dried (MgSO 4 ), filtered (silica gel), and evaporated and the uniform residue purified by CC (silica gel, cyclohexane): 52a ( .0 2,18 .0 3,7 .0 4,17 .0 5,15 .0 6,13 .0 8,12 .0 16,20 ]icosane (52b). As described for 52a, with 2a (26 mg, 0.10 mmol), CH 2 Cl 2 (10 ml), and HBr/CH 2 Cl 2 .…”

“…was not observable at all [6]. Photoelectron (PE) and electrochemical (CV) studies, extended to derivatives such as the diesters 1b and 3b, furnished thermodynamically meaningful estimates of the conjugative (p-bis-homoaromatic) stabilization of these ions [7] [8].…”