June 5 , 1957
COMMUNICATIONS TO THE EDITOR
Reduction of (-)-Ie with NaBHd-AlCIs to (-)If (m.p. 95-97', [ a ] " ~-25' (EtOH); found: C, 62.0; H, 4.2; N, 10.3), followed by hydrogenation over Pd/C, afforded (-)-Ia (m.p. 153-158', [ a I z s-49" ~ (EtOH)). The melting point, 232233", of the diacetamide, [ a ] " ~4-134' (EtOH), was undepressed by admixture of authentic6diaceta[ C Y ] ~ ~+12S0 D (EtOH), mide, m.p. 233-235', prepared from authentics (-)-Ia, m.p. 156-158', [ a I z 4 D -47" (EtOH), +No ( N Hcl).' (-)-Ia and (+)-DNDBCH-6-one have thus been correlated via (-)-Ie; (-)-Ia therefore4 has the S-configuration. It would appear that the assumptions underlying the theoretical deserve re-examination. The absolute configurations of the many common hindered biphenyls related* to I a and I b will be listed in future publications.
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and a t higher temperatures, the peak sharpened and shifted in the direction of the tellurium hexafluoride resonance. The amide solution was cooled -180' displayed three broad to a glass that a t resonances of approximate intensities 1: 1: 0.4. On warming above - 180", these three peaks broadened rapidly (but a t different rates) and finally merged into a single peak. It should be noted that the weak doublet due to spin-spin coupling of fluorine with the TelZ6isotope persisted a t 25" (masked a t low temperatures by the broad resonances), and therefore no fluorine exchange was taking place in this system. The n-m-r data are consistent with the behavior of an octacovalent complex which has geometrical isomers and which undergoes amine exchange through simple dissociation of the complex. At -180°, the three fluorine resonances may be ascribed to the three possible isomers. On steric (6) J. Meisenheimer and M. Horing. Bcr., 60, 1425 (1927). (7) The sign of rotation of Ia is $H dependent (F.A. McGinn, un- grounds, the two peaks of relative intensity 1 probably arise from the 1,8- and 1,3-isomers, and published results). (8) Cf.also K. Mislow, T ~ a n r N . . Y . Acad. Sci., [Z]19, 298 (1957). the peak of relative intensity 0.4 from the 1,2-isomer. Above --180°, slight dissociation of the U'M.H. NICHOLS CHEMICAL LABORATORY KURTMISLOW complexes leads to amine exchange and this occurs NEWYORKUNIVERSITY PHILIPRUTKIN a t different rates for the three isomers. At higher NEW YORK53, N. Y. ALLANK. LAZARUS temperatures the three isomers are indistinguishRECEIVED APRIL18, 1957 able in the n-m-r spectrum because of fast amine exchange. At temperatures above 25O, the complex is highly dissociated in solution and the position of LEWIS ACID CHARACTER OF TELLURIUM resonance is a measure of the equilibrium constant HEXAFLUORIDE for the dissociation. Without supporting data, Sir: these conclusions cannot be considered rigorously I n a previous communication,1 the formation of established. Unfortunately, the rapid amine exfluorotellurate salts from tellurium hexafluoride change will not permit isolation of the postulated and certain alkali metal fluorides was described. isomers by conventional techniques. We have now found that tellurium hexafluoride CONTRIBUTION No. 418 DEPARTMENT E. L. MUETTERTIES will react exothermally with tertiary amines to CHEMICAL STATION W. D. PHILLIPS form stable adducts of the composition TeF8.- EXPERIMENTAL I. DU PONTDE NEMOURS AND COMPANY 2R3N. Analysis of the n-m-r data suggests that E. WILMINGTON, DELAWARE geometrical isomers are present in solutions of the RECEIVED APRIL15, 1957 trimethylamine complex. Trimethyl- and triethylamines were added to A CRYSTALLIZABLE ORGANOMETALLIC COMPLEX tellurium hexafluoride in a vacuum system. The CONTAINING TITANIUM AND ALUMINUM trimethylamine adduct was a white solid, but the Sir: ethyl analog had a dark color that apparently was Following our previous researches' concerning due to minor secondary reactions. The pressure- the nature of the catalytic agent promoting the avolume relationships indicated a stoichiometry of olefins polymerization, we have isolated a crystaltwo molecules of amine for one of the hexafluoride lizable compound containing titanium, aluminum and analysis of the trimethylamine complex conorganometallic bonds, which causes the polyfirmed the indicated composition (Anal. Calcd. and merization of ethylene. for TeFs*2N(CH&: C, 20.0; H, 5.04; F, 31.7. By treating 0.01 mole of bis-(cyclopentadieny1)Found: C, 19.56; H, 5.10; F, 29.14). Pyridine titanium dichloride2 suspended in 50 ml. of n-hepformed a complex that was highly dissociated a t tane with 0.025 mole of triethylaluminum a t 70°, 25", but amides, ethers and nitriles did not absorb in the absence of air and of moisture, a slow gas tellurium hexafluoride a t this temperature. This evolution takes place, the titanium compound is low acceptor strength and the previously cited' and the solution becomes dark blue, By low stability of fluorotellurate salts indicate that dissolved the solution a t -50°, a blue crystalline tellurium hexafluoride is a relatively weak Lewis cooling solid has been obtained in good yield. acid. The macroscopic blue needles of the compound, The Fl9 magnetic resonance spectrum of the recrystallized four times from n-heptane, melt a t molten trimethylamine adduct showed only one 126-130' without appreciable decomposition. sharp peak; amine exchange through simple dis(1) G. Natta, P. Pino, E. Mantica, F. Danusso. G. Mazzanti and sociation of the complex was therefore indicated. M. Peraldo, La Chimica e I'lndustria, 38, 124 (1956); G. Natta, P. A dimethylformamide solution of the trimethyl- Pino,G. Mazzanti, U. Giannini, E. Mantica and M. Peraldo, ibid., 39, amine adduct gave a single broad resonance a t 25O, 19 (1957). (1) E. L. Muetterties, THIS JOURNAL, '79, 1004 (1967).
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(2) G. Wilkinson and G. M. Birmigam, THIS JOURNAL, 76, 4281 (1954).
