Relating the number and relative intensity of the lines in an NMR or EPR spectrum to Pascal's triangle.

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Transparent plates of a tungsten oxide-silica metathesis catalyst were prepared by hydrolyzing a WCl6-Si(OC2H6)4 mixture. From the infrared spectra of adsorbed pyridine and ammonia, it is concluded that the chemisorption sites on the catalyst surface are of the Lewis type. Strong Bronsted acid sites could not be observed: the surface hydroxyls appear to resemble the weakly Bronsted-acidic hydroxyls on dry silica gel. Temperature-programmed reduction showed that ~95% of the tungsten on the calcined catalyst is present as surface compounds and less than 5% as metathesis-inactive "free" oxide. The Lewis acidity is ascribed to these surface compounds, which are thought to be coordinatively unsaturated species resulting from the dehydration of W06 octahedra sharing edges or planes with the silica lattice.Stoichiometric reactions between superoxide ions on MgO and simple hydrocarbons were observed at 175 °C, although the 02" ions were much less reactive than either 0~or Oa~i ons. Several types of oxygen-containing products were formed, as well as other hydrocarbons and C02. The reaction of propylene with 02~gave no gaseous product at 175 °C; however, at elevated temperatures acetaldehyde and methanol were obtained. Following the reaction of propane with 02~, acetone was detected at 175 °C in addition to acetaldehyde and methanol which were observed at higher temperatures. With 1-butene as the reactant, 2-butanol was formed together with methanol, acetaldehyde, and acrolein above 300 °C. Infrared spectra of surface intermediates indicate that the reaction of 02~w ith propylene at 175 °C resulted in the simultaneous formation of formate and acetate ions which are consecutively converted to carbonate ions at elevated temperatures. It is proposed that hydrogen atom abstraction is the initial step in the reaction of Of with simple hydrocarbons. The resulting radicals react with lattice oxygen ions forming carboxylate ions or with H02~i ons forming alkoxy or epoxide intermediates.

The ene reactions of cis-and r/wis-[3-2H]-/3-pinenes with methyl phenylglyoxylate and benzyne have been examined. In each case, it has been established that the hydrogen atom of the methylene group at C3 in ßpinene which is trans to the gem-dimethyl bridge is involved, overwhelmingly, in this reaction. This remarkable degree of stereoselectivity is presented in support of earlier proposals (ref 3) that these ene reactions occur in a concerted fashion through a single, cyclic transition state. In concert with this view: (1) no difference was observed in the rate of reaction of /3-pinene with methyl phenylglyoxylate (at 140°) when polar and nonpolar solvents (e.g., nitrobenzene and oxylene) were used; and (2) no products resulting from the rearrangement of possible carbonium ion intermediates have been observed in ene reactions with /3-pinene. We believe these data cannot be rationalized in terms of a two-step mechanism involving a dipolar intermediate.

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