Date of Award

1-1-1985

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Abstract

The radical anions of 2, 3, and 4-cyanoanisole and 2 and 4-cyanodiphenyl ether have been electrochemically generated and shown to react by a variety of pathways in dry N,N-dimethylformamide (DMF). The 2-cyanoanisole radical anion dimerizes (k = 320 M('-1) s('-1)) to a dimeric dianion which undergoes carbon-oxygen bond cleavage (k = 0.019 s('-1)) to 2-cyanophenoxide, methide, and 2-cyanoanisole. The 3-cyanoanisole radical anion is relatively stable (t(, 1/2) > 10('3) s). The 4-cyanoanisole radical anion undergoes unimolecular fragmentation (k = 7 s('-1)) to yield 4-cyanophenoxide and methyl radical. The radical anion of 4-cyanodiphenyl ether undergoes dimerization (k = 110 M('-1) s('-1)) to yield a 2-4 coupled dimeric dianion and a 4-4 coupled dimeric dianion with respect to the cyano substituent. The 4-4 coupled dianion undergoes loss of phenoxide ions (k = 0.038 s('-1)) to form 4,4'-dicyanobiphenyl. The 2-4 coupled dianion undergoes rapid loss of one phenoxide to yield, upon workup, 2,4'-dicyano-5-phenoxybiphenyl. The radical anion of 2-cyanodiphenyl ether reversibly dimerizes (k(,f) = 1200 M('-1) s('-1), k(,b) = 0.095 s('-1)). The radical anion also undergoes a slow, irreversible dimerization (2-4 coupled dimeric dianion respective to the cyano substituent) with subsequent loss of phenoxide to yield, upon workup, 2', 4-dicyano-3-phenoxybiphenyl.Selective generation of the 2-(3-butenyl)phenyl anion and radical was accomplished by direct electrode reduction or by homogeneous reduction with electrochemically generated m-tolunitrile radical anion, respectively, of 2-(3-butenyl)bromobenzene. Reaction of the 2-(3-butenyl)phenyl radical in dry DMF yielded a ratio of 8:1 for 1-methylindan:(3-butenyl)benzene. Formation of the 2-(3-butenyl)phenyl anion in dry DMF yielded ratios of 2:1 and 1:1 on Pt and Hg electrodes, respectively, for 1-methylindan:(3-butenyl)benzene. Cyclization of the anion can be prevented by the presence of proton-donor additives. Cyclization of the radical (unaffected by proton-donor additives) was affected by the addition of a H-atom donating species, sodium isopropylate, allowing a minimum rate constant of 1 x 10('7) s('-1) to be estimated for 2-(3-butenyl)phenyl radical cyclization.

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