Stable Free Radicals Formed by the Action of Sodium onto Diazomethane Derivatives or Phenyl Azide

Abstract

infrared and ultraviolet spectra and optical rotation) of the natural and synthetic products. Glycosidation of (2) was also effected when sodium iodide was used instead of silver perchlorate, or even without addition of either of these compounds, although then more vigorous reaction conditions were required. In this way we obtained a glucoside of uric acid from (2) and a-acetobromoglucose. This had the same ultraviolet spectrum (measured at pH 1, 7, and 14) as (1). This product, so far unknown in nature, is therefore a 3-glucosyluric acid. Received, January 23rd. 1963 [Z 435/263 IE] [l] Communication No. 18 on organosilicon compounds; Communication No.We have found that p-nitrosotoluene rapidly adds on one equivalent of sodium to form a deep green, apparently colloidal solution of the free radical (1) when shaken under nitrogen with powdered sodium in dry ether at 5-10°C. The multilineal electron spin resonance spectrum [l] shows that the unpaired electron is located to a considerable extent in the benzene ring. The free radical ( I ) is converted by shaking for 1 hour with excess sodium into the reddish-brown substance (3), which is insoluble in ether and which reforms the green radical when shaken with oxygen (0.5 mole). f IThe same reaction in tetrahydrofuran leads to a red solution of (3), which is transformed to a clear deep-green solution of (1) by measured addition of oxygen. In this solution, about 25 % of the monosodium adduct exist in the free radical form (ESR measurement). Hence (1) is probably in equilibrium with a dimer (5), which possesses no unpaired electrons. Hydrolysis of (1) gives a 48 % yield of 4,4'-azoxytoluene, very predominandy in the cis-form [2]; N-@-tol yl)hydroxylamine is formed by hydrolysis of (3). p-Nitrosodimethylaniline shows the same behaviour towards sodium asp-nitrosotoluene; the free radical (2) formed (ESRspectrum) is bluish-green, and the compound (4) is red and has no free radical character. We have not yet succeeded in detecting a monosodium adduct of nitrosobenzene with an unpaired electron.When its solution in ether is shaken under nitrogen at 2OoC with powdered sodium, diazofluorene ( I ) rapidly adds on a sodium atom to form a deep-blue free radical (2). which is very sensitive to oxygen. According to electron spin resonance measurements, about 60 ' %, of the sodium adduct exist in the freeradical form. Anequilibriumis therefore assumed between (2) and a dimer with no unpaired electron.When (2) is hydrolysed under nitrogen, bifluorenyl (3) is formed in 32 % yield. Hydrolysis in the presence of oxygen gives 28 % bifluorenylidene and 34 % fluorenoneazine.The deep-blue solution containing the free radical (ESRspectrum) of the monosodium compound with the canonical form (4) obtained from diphenyldiazomethane [l] behaves similarly upon hydrolysis. Unlike other comparable free radicals [2,3], the radicals (2) and (4) do not take up a second sodium atom under the roaction conditions stated. I J ) (4)Om mole of nitrogen is rapidly released from phenyl azide (5) by the action...

Iron and Cobalt Diazoalkane Complexes Supported by β-Diketiminate Ligands: A Synthetic, Spectroscopic, and Computational Investigation

“…More recently an intermediate bonding situation has been discovered, in which the diazoalkane accepts only one electron. Although single electron reduction of diazofluorene with sodium metal was reported as early as the 1960s, 8 ligand radical character in transition metal or f-block metal diazoalkane complexes is rarely identified. 9 We have reported the cobalt diazoalkane complex L tBu Co(η 1 -N 2 CPh 2 ), 1-Co (L tBu = [{(Dipp)NC(tBu)} 2 CH] − where Dipp = 2,6-iPr 2 C 6 H 3 ), 10 which X-ray crystallographic and computational studies showed was best described as high-spin cobalt(II) antiferromagnetically coupled to the radical anion of diphenyldiazomethane.…”