Inert Carbon Free Radicals. 9. The First Perchlorinated Triarylmethyl and Fluorenyl Radicals with a Heteroaromatic Ring, and Related Compounds

Article abstract of DOI:10.1021/jo00241a026

Perchlorodiphenyl(4-pyridyl)methyl (13), perchlorodiphenyl(2-pyridyl)methyl (14), and perchloro-9-(4-pyridyl)fluorenyl (15) radicals, the first inert carbon free radicals with a heteroaromatic ring, have been synthesized from αH-tetradecachlorodiphenyl(4-pyridyl)methane (3), αH-tetradecachlorodiphenyl(2-pyridyl)methane (7), and 9H-dodecachloro-9-(4-pyridyl)fluorene (12), respectively.The thermal and chemical stabilities of these radicals have been studied.The thermolysis of radical 13 gives a mixture of radical 15 and perchloro-3-aza-9-phenylfluorenyl radical (16).The oxidative hydrolysis of radicals 13 and 15 with oleum yields perchloor-4-(phenyl(4-pyridyl)methylene)cyclohexa-2,5-dienone (17) and perchloro-9-(pyridyl)fluoren-3-one (18), respectively.While the oxidation of radical 14 with concentrated HNO3 affords perchloro-2-(diphenylmethylene)pyridin-5(2H)-one (19), with concentrated H2SO4 it gives a mixture of perchloro-9-phenylindeno<2,1-b>pyridin-3-one (22) and perchloro-10-phenylpyrido<1,2-a>indole (9), a cyclization product that is also obtained in the thermolysis of radical 14 or αH compound 7.The ESR, IR, and UV-vis spectra of the radicals and other compounds here synthesized are reported and studied.The variation of the magnetic susceptibility of those radicals with temperature has been measured, giving purities nearly 100percent.