The original purpose of this study, namely, the determination of the reaction mechanism, has now become extremely complicated by the large number and type of products formed. In order to assist in the formulation and substantiation of the mechanism for this reaction, the reactions of several related compounds are presently under study. These results and the mechanism will be presented in the near future. AcknowledgmentsThe authors wish to express their thanks to the National Research Council of Canada and to the Faculty of Graduate Studies, Dalhousie University, for financial assistance. 0, CzF4 reacted; product flow rates: 0, C,F,H; e, 55, 1363 (1933 the production of C2H2 and C2F3H has dropped Can. J. Chem. 43, 1973Chem. 43, (1965 markedly and the flow rate of C2F4H2 has 8. G . 0. PRICHARD, J. R. DACEY, W. C. KENT, and C. R. become negligible.SIMONDS. Can. J. Chem. 44, 171 (1966).Detection of the triple ion (durosemiquinone-Na2)+ by electron spin resonance spectroscopy Reduction of duroquinone by sodium in tetrahydrofuran and in 2-methyltetrahydrofuran in the presence of sodium tetraphenylboride yields the triple ion (durosemiquinone-Na2)+ which shows hyperfine interaction with twelve equivalent hydrogen and two equivalent sodium nuclei. When the reduction is performed in 1,2-dimethoxyethane, the triple ion is not formed, and the electron spin resonance spectra indicate the presence of an intermolecular cation exchange process.

The formation, in tetrahydrofi~ran, of triple ions of the formula NalQ+ (Q = p-benzosemiquinone, 2,3-, 2,5-, 2,6-dimethyl-p-benzosemiquinone, durosemiquinoi~e) has been detected by electron spin resonance spectroscopy. The spectra show asymmetric broadening within the Z3Na hyperfine multiplets. From the direction of this broadening, it is deduced that the sodium ions lie in the plane of the semiquinone anion, one sodium ion associating with each oxygen.Canadian Journal of Chemistry, 47. 3393 (1969) IntroductionThe one-electron alkali metal reduction of duroquinone (D) in ethereal solution forms durosemiquinone (D-); the electron spin resonance (e.s.r.) spectra of the reaction products indicate extensive ionic association in such media (1-3) though, especially at low temperatures, an equilibrium exists between M' D -and its constituent ions. The reactions which constitute the equilibrium are sufficiently slow that well resolved spectra for M' D-and for D -are obtained. When the reduction is performed in the presence of an equimolar quantity of sodium tetraphenylboride, the e.s.r. spectra indicate the presence of Na,D', provided that the polarity of the solvent is sufficiently low (4). At higher polarities, e.g. in 1,2-dimethoxyethane, the spectra indicate the presence of intermolecular cation exchange reactions, though a complete interpretation of these spectra has not been achieved.The polarity of the solvent is not the only factor controlling the formation of triple ions. Listed below are several systems in which strong ionic association occurs, yet triple ions are not observable. All of the following systems contain a semiquinone anion and excess sodium cations dissolved in a solvent of low polarity : 9,lO-anthrasemiquinone and sodium iodide in 1,2-dimethoxyethane (5), 9,lO-anthrasemiquinone and sodium tetraphenylboride in tetrahydrof~~ran (6), 2,5-dit-butyl-p-benzosemiquinone and sodium iodide in tetrahydrof~lran (5), duroserniquinone (7) and 2,6-dimethyl-p-benzosemiquinone (8), and sodium t-pentoxide in t-pentanol.As part of an experimental survey on the

Electron spin resonance spectra of 9,lO-anthrasemiquinone as the free ion, ion-pair and triple ion (counter ion, Na+) in tetrahydrofuran, and as the triple ion in 2-methyltetrahydrofuran are presented and discussed in terms of the structures of the ionic associates. The ion-pair is " locked-in " to an asymmetric configuration at -65"C, but at 20°C intramolecular transfer of the cation between the oxygens of the anion is observed. The triple ion is symmetrical, one sodium associating with each oxygen, and occupying a position close to the 0-0 axis.

A survey of the effects, as detected by electron spin resonance spectroscopy, of adding NaX (X− = Ph4B−, ClO4−, I−) to sodium-semiquinone ion pairs is given. When X− = Ph4B− triple ion formation was observed, but when X− = ClO4− or I− intermolecular cation scrambling occurred. It is postulated that such scrambling reactions proceed via the triple ion.

The electron spin resonance (e.s.r.) spectrum of potassium durosemiquinone in tetrahydrofuran has been studied as a function of temperature and found to exhibit line-width alternation indicating the presence of an intramolecular migration of the potassium ion between the oxygens of the semiquinone. The addition of potassium tetraphenylboride to the system produces intermolecular scrambling of potassium, the spectral effects of which are superimposed upon those of the intramolecular exchange. From the spectral line-shapes approximate values of the activation energies and frequency factors were derived. The tetraphenylboride anion did not play a detectable role in the various exchange mechanisms.On a CtudiC le spectre r.p.e. du sel de potassium de la durosemiquinoneenfonction de la tempkrature et on a trouvC qu'ils prCsentent une alternation des largeurs de raie qui indiquerait que I'ion de potassium effectue des migrations intramolCculaires entre les divers atomes d'oxyg6ne de la semiquinone. L'addition de tCtraphCnylborure de potassium au systtme a comme effet de permettre une permutation des ions potassium entre les molCcules; ces migrations provoquent des changements spectraux qui se superposent a ceux provoquCes par les Cchanges intramolCculaires. A partir des formes des bandes dans les spectres, on a pu domer les energies d'activation et les facteurs de frCquence de ces rCactions. I1 ne semble pas que I'anion tCtraphCnylborure joue un rBle dttectable dans les divers mCcanismes d'Cchange.