A New Preparation of 1,3,5-Hexatriene and the Separation of its Geometrical Isomers

Hwa, Jesse C. H.; Benneville, Peter L. de; Sims, Homer J.

doi:10.1021/ja01495a036

Cited by 72 publications

(26 citation statements)

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“…19 the band at about 1800 cm-1 may be characteristic of vinyl groups or conjugated polyenes. Although such bands have been observed in all trans or trans rich polyenes except cis-1,3,5-hexatrene, 11 we could find no such bands in trans poly( acetylene. We have tentatively assigned the band at 1800 cm-1 to combinations of C-C-C deformation and C-Hin-plane vibrations.…”

Section: Assignments and Discussioncontrasting

confidence: 71%

“…In the C-H deformation frequency region, Lunde, et a/., 5 have shown that the spectrum of cis isomer of various diphenylpolyenes contain two bands absent from all trans spectra. One is the weak to moderate band assigned to in-plane vibrations of hydrogen attached to cis C-C double bonds located at roughly the same wave number, 1430 -1410 em-\ but in the spectrum of cis, cis-1,4-236 diphenylbutadiene-1 ,3 the band is shifted to 1368 cm-1 • The other band is assigned to outof-plane vibrations of hydrogen attached to cis C-C double bonds which appear at 779-772 em -1 • Hwa, et a/., 11 have shown that the cis out-ofplane deformation band of cis-hexatriene-1 ,3,5 appears at 818 cm-1 by comparison with the spectrum of the trans isomer. The two bands at 1329 and 1249 em-\ on this basis, may be assigned to cis C-H in-plane deformation of B1u and B3u modes predicted from the analysis of cis-transoid (or trans-cisoid) skeleton models.…”

Section: Assignments and Discussionmentioning

confidence: 96%

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Infrared Spectra of Poly(acetylene)

Shirakawa

Ikeda

1971

Polym J

747

195

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ABSTRACT:The infrared spectra of poly(acetylene), poly(acetyiene-d2), copoly(acetylene+acetylene-d2), and copoly(acetylene tacetylene-d1 +acetylene-d2) prepared by the Ti(OC4H9)4-Al(C2Hs)3 system over a wide temperature range (ca. -100 to 180°C) are reported. A tentative assignment of the observed spectra is made on the basis of model structures in which infinite planar chains of all trans, all trans-cisoid, and all cistransoid configurations are assumed. The spectral data are best interpreted on the basis of an all cis-transoid (or an all trans-cisoid) structure for the polymers prepared at temperatures lower than -78°C, and an all trans structure for the polymers prepared at temperatures higher than 150°C.Simplified calculations of the C-H and C-D out-of-plane deformation frequencies are made for various model chains. It has been concluded from a comparison of the observed and calculated frequencies that the cis-opening of the triple bond occurs in a polymerization reaction with the Ti(OC4H9)4-Al(CzHs)3 catalyst system at low temperatures.KEY WORDS Infrared SpectrajPoly(acetylene)/Deuterated Acetylene/ Ziegler Catalyst/Configuration/cis-Opening/Factor Group Analysis/ Normal Vibration/ Structure and properties of poly( acetylene) prepared with Ziegler-Natta catalysts have been investigated by several groups. Natta, et a!./ presented evidence from chemical properties and X-ray diffraction data, indicating that the poly-(acetylene) obtained had linear chains of conjugated double bonds of trans configuration along the chains. poly(acetylene) containing a 60-70% cis content obtained by a catalyst system of thermally decomposed iron dimethylglyoximate-2-pyridine and triethylaluminum at 25°C or below.

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Section: Assignments and Discussioncontrasting

confidence: 71%

Section: Assignments and Discussionmentioning

confidence: 96%

Infrared Spectra of Poly(acetylene)

Shirakawa

Ikeda

1971

Polym J

747

195

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“…The all-trans isomer has greater relative intensity in the origin peak at 302 nm and the monocis isomer exhibits slightly more intensity in the 215-nm "cis-band" region. The same relationship is observed for cis-and trans-hexatriene (11). At room temperature, the absorbance and emission spectra of the two isomers were remarkably similar.…”

supporting

confidence: 75%

cis-trans photoisomerization of 1,3,5,7-octatetraene in n -hexane at 4.2 K

Granville

Holtom

Kohler

1980

Proc. Natl. Acad. Sci. U.S.A.

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Photoisomerization of the linear polyene 1,3,5,7-octatetraene has been observed in an n-hexane matrix maintained at the boiling point of helium. To a good approximation, only the transtrans and cistrans isomers participate in the photochemistry. These compounds have been unambiguously identified by comparing the observed high-resolution fluorescence spectra to those of chromatographically purified reference compounds. Although the quantum yield of this process is probably low, its microscopic rate seems to compete favorably with vibrational deactivation.The cis-trans photoisomerization of linear polyenes is of considerable interest because it provides a prototypical system for studying the coupling between electronic excitation and nuclear motion and because it plays a central role in a variety of photoprocesses, including visual transduction (1, 2). In the case of visual transduction, kinetic data have indicated that bathorhodopsin, the first photoproduct obtained when the pigment rhodopsin from dark-adapted vertebrate rod cells is irradiated, is also produced at a significant rate at liquid helium temperatures (3). Because this intermediate is supposed to arise, at least in part, from photoisomerization of the 11-cis retinal chromophore, the question of the extent to which such isomerizations can take place in condensed-phase low-temperature baths assumes some importance. Although it is difficult to envision large conformational changes in a low-temperature solid, the photoisomerization of rhodopsin (11-cis retinal) through intermediates to isorhodopsin (9-cis retinal) at 5.5 K has been observed (4). Here we would like to report the observation of photochemical cis-trans isomerization of the linear polyene 1,3,5,7-octatetraene in n-hexane at 4.2 K. The occurrence of photochemistry under the conditions that are needed to obtain vibrationally resolved electronic spectra should make detailed mechanistic studies possible.MATERIALS AND METHODS trans,trans-Octatetraene (all-trans) was synthesized as described by Evans (5) and was purified by recrystallization and sublimation. cis,trans-Octatetraene (monocis) was chromatographically isolated from a photolyzed undecane solution with a Waters Associates 201 high-pressure liquid chromatograph utilizing a Schoeffel 770 absorbance detector, a 4.6 X 250 mm column packed with Macherey-Nagel ALOX 60-D5 alumina, and Burdick and Jackson UV grade hexane.Room-temperature and 77 K fluorescence spectra were recorded on a Perkin-Elmer MPF-44A spectrofluorimeter. Fluorescence spectra at 4.2 K were obtained with a Jobin-Yvon HR1500 monochromator fitted with a 2400-lines/mm holographic grating, and a broad-band excitation source consisting of a 100-W high-pressure mercury lamp, f/8 optics, a NiSO4/CoSO4 Kasha filter (6), a Corning 9863 glass, a Schott UG1-1 glass, and a 10% Balzars neutral density filter. The Balzars filter was removed during photolysis.Absorbance spectra at 4.2 K were obtained by standard excitation techniques, utilizing a 1-m Jarrell-Ash monochromator with a...

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“…4 and 6 in the IR spectra show absorption bands at 1733 and 1705 cm −1 for polymer 4 and at 1717 and 1625 cm −1 for polymer 6 because of the conjugate CC stretching vibration, which was interpreted as a trans geometry 34, 35. Moreover, a weak band at 961 cm −1 (for both 4 and 6 ), corresponding to the out‐of‐plane bending vibration of the trans CH, can also be observed.…”

Section: Resultsmentioning

confidence: 93%

Polymerization of conjugated 5‐[(5‐ethynyl‐1‐naphthyl)ethynyl]‐N,N‐dimethylnaphthalen‐1‐amine with rhodium and palladium complexes

Rodriguez

Tejedor

2007

J. Polym. Sci. A Polym. Chem.

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The monomer 5‐[(5‐ethynyl‐1‐naphthyl)ethynyl]‐N,N‐dimethylnaphthalen‐1‐amine was satisfactory obtained through the heterocoupling reaction of 5‐ethynyl‐N,N‐dimethylnaphthalen‐1‐amine and 4‐(5‐iodo‐1‐naphthyl)‐2‐methyl‐3‐butyn‐2‐ol catalyzed by a palladium–copper system, followed by acetone elimination. Poly{5‐[(5‐ethynyl‐1‐naphthyl)ethynyl]‐N,N‐dimethylnaphthalen‐1‐amine} was obtained through the reaction of the acetylene monomer with homogeneous rhodium and palladium catalyst complexes. The structure of the polymers always showed a trans–cisoidal chain configuration on the basis of IR and NMR spectra. Moreover, only for the rhodium catalyst complex in methanol was a dimeric product isolated in a very low yield, having a conjugated terminal ene–yne structure, which permitted the consideration of a metallated chain‐transfer intermediate in the polymer propagation. The mass determination of the polymers, by osmometry and gel permeation chromatography techniques, showed low average molecular weights. The kinetics of the catalyzed polymerization were analyzed. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2038–2047, 2007

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A New Preparation of 1,3,5-Hexatriene and the Separation of its Geometrical Isomers

Cited by 72 publications

References 0 publications

Infrared Spectra of Poly(acetylene)

Infrared Spectra of Poly(acetylene)

cis-trans photoisomerization of 1,3,5,7-octatetraene in n -hexane at 4.2 K

Polymerization of conjugated 5‐[(5‐ethynyl‐1‐naphthyl)ethynyl]‐N,N‐dimethylnaphthalen‐1‐amine with rhodium and palladium complexes

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