Magnetic and Optical Properties of Aromatic Hydrocarbon Cation Radical Salts

Abstract

Stable cation radical salts were prepared by oxidation of perylene, 9,10-diphenylanthracene, 9,10-dimethylanthracene, and 9,10-dichloranthracene with antimony pentachloride. Perylene perchlorate was also obtained in a stable form. From the temperature variations of their paramagnetic susceptibilities, the exchange coupling constants for these salts were found to increase in the sequence of above listing ranging from ∼0 to 8.5×10−2 eV. The absorption spectra of these solid compounds were compared with those observed with solutions. While the absorption bands of each salt in the visible region were found to correspond to those of the solution spectrum of the respective compound, an extra absorption band was observed in the near-infrared region for compounds with larger exchange coupling constants. The appearance of the new absorption band was reasonably ascribed to charge-transfer interaction between the radicals. These observations are considered to support further our previous suggestion that the magnitude of the exchange coupling constant obtained through magnetic measurements is basically determined by the stabilization energy due to the charger-transfer configurational interaction.

Dehydro coupling of aromatic nuclei by catalyst-oxidant systems: poly(p-phenylene)

“…The following tabulation is undoubtedly not exhaustive (Table II). Cations" A mctfll sfllt Mg(II) (38), Zn(II) (49), Sn(IV) (40), Hg(II) (41), Ag(II) (42,43), Fe(III) (44), Tl(II) (43), Ti(III) (45)(46)(47), Cu(III) (31), Cu(II) (48,49), As(V) (50), Cr(II) (31), Co(I) (31), Ir(IV) (31), Mo(V) (51), V(IV) (51) B. catalyst surfaces hydrogen zeolon (52), synthetic mordenite (53), alumina (54) C. other chemicals 0s04 (40), NO+ (55), N02+ (31), (C6HeC02)2 (56), XeF2 (57), R+ (31), peroxydiphosphate (58), HN03 (59,60), N02 (55,61), S2C12-A1C13 (62), I2/AgC104 (63), Mn02 (64), ferricyanide (64), aminium (31), C102 (31) "References in parentheses.…”

Role of Radical Cations in Aromatic Hydrocarbon Carcinogenesis

“…The synthesis of the radical cation perchlorates of BP and 6-methylBP has been reported (47), following a modified method of preparation of perylene radical cation (48,49). More recently, the radical cation perchlorate of 6-fluoroBP has also been synthesized (50).…”

Neutral and positively charged azonitriles. Decomposition rates and efficiencies of radical production

“…6,ll-Dihydro-ll-hydroxy-6-oxo-2,2,5-trimethyl-2JT-naphtho-[l,2-b]pyran (6).-To a stirred solution of 1.7 g (6.7 mmol) of the chromenol methyl ether 5 dissolved in dioxane (77 ml) and 85% phosphoric acid (7.7 ml) was added 2.5 g (20 mmol) of argentic oxide. After stirring for 2.5 hr at room temperature, the mixture was diluted with 200 ml of water and 100 ml of ether and worked up in the usual way.…”

“…Crystallization of the resulting gum from 4:1 hexane-ether afforded 52 mg (26.8%) of unreacted 6. The mother liquor was evaporated cold and chromatographed on Florisil. The combined 1:1 benzene-hexane eluates were evaporated and gave 57 mg (29.4%) of 8 as a yellow gum: ir (CHCla) v 1700, 1650, 1600 cm-1; mass spectrum m/e 256 (M); nmr (CDCI3, HA-100) r 8.73 (several sharp lines, 9 H, among which are two doublets at 8.83 and 8.63, J = 7.0 Hz), 6.85 (sextet representing two overlapped quartets, 1 H, J = 7.0 Hz), 4.74 and 4.14 (q, 1 H, J = 6.0 Hz), 4.45 and 4.12 (q, 1 H, J = 6.0 Hz), 2.39 (m, 2 H), and 2.05 (m, 2 H).…”

“…Antimony pentachloride is also frequently used, both for spectroscopic, solution studies4 and for precipitating cation radicals as antimony halide salts. 6 The composition of the perylene cation radical salt has been reported as C20Hi2SbCl6, for example. 6 The use of antimony pentachloride systems for chemical studies, however, does not seem to be suitable.…”