Some Spectroscopic Changes Connected with the Stereoisomerization of Diphenylbutadiene

Sandoval, Arturo León; Ƶechmeister, L.

doi:10.1021/ja01195a025

Cited by 37 publications

(20 citation statements)

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“…4 The electronic character and state ordering of polyenes is very sensitive to the length of the polyene chain, and therefore the electronic spectroscopy and dynamics of the set of polyenes with n = 1-4 have been the subject of numerous previous studies aimed at establishing this ordering and characterizing each of the excited states. [5][6][7][8][9][10][11][12][13][14] These state ordering effects also apply to phenyl-substituted polyenes. The smallest diphenyl derivative, stilbene (diphenylethene), has been the subject of many spectroscopic investigations and studies of the dynamics of cis-trans isomerization.…”

Section: Introductionmentioning

confidence: 90%

The excited states and vibronic spectroscopy of diphenyldiacetylene and diphenylvinylacetylene

Sebree

Zwier

2012

Phys. Chem. Chem. Phys.

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Laser induced fluorescence (LIF) excitation scans and dispersed fluorescence (DFL) spectra have been recorded for two four-carbon α,ω-diphenyl systems, diphenyldiacetylene (DPDA, φ-C≡C-C≡C-φ) and trans-diphenylvinylacetylene (DPVA, φ-CH≡CH-C≡C-φ) as isolated molecules cooled in a supersonic expansion. While these molecules have similar conjugation length, they exhibit strikingly different vibronic spectroscopy and photophysics. The near-UV LIF excitation spectrum of diphenyldiacetylene has its electronic origin at 32,158 cm(-1), and a strong progression in the C≡C stretch (2156 cm(-1)). All transitions are inherently broad, with widths of ~30 cm(-1) fwhm or greater. The S(1) origin DFL spectrum is composed of sharp transitions with Franck-Condon activity mirroring that in the excitation spectrum, and broad emission shifted well to the red ascribable to phosphorescence on the μs timescale. Using ab initio calculations, it is possible to show that DPDA exists as a single, planar conformer with D(2h) symmetry. In contrast, trans-diphenylvinylacetylene shows intense sharp transitions in both LIF and DFL spectra with an S(0)-S(1) origin of 31,183.2 cm(-1) and long progressions involving the in-plane fundamentals ν(53) (bridge-phenyl bending) and ν(51) (bridge-phenyl stretch). A sharp reduction in fluorescence yield in DPVA occurs within 300 cm(-1) of the S(1) origin. Possible causes for the photophysical processes occurring in the two molecules are discussed.

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Section: Introductionmentioning

confidence: 90%

The excited states and vibronic spectroscopy of diphenyldiacetylene and diphenylvinylacetylene

Sebree

Zwier

2012

Phys. Chem. Chem. Phys.

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“…A re-investigation of the diphenylbutadienes was carried out in collaboration with SANDOVAL, PINCKARD and WILLE (395,355) by means of chromatographic and fluorescence methods. The STRAUS data concerning the crystalline cis isomer were confirmed but the oily isomer revealed on the column the presence of impurities.…”

Section: Cis-illmentioning

confidence: 99%

Cis-trãns Isomeric Carotenoids Vitamins A and Arylpolyenes

Ƶechmeister¹

1962

324

272

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“…Pioneering studies by Zechmeister's group demonstrated trans,trans-DPB (3) and cis,cis-DPB (1) upon irradiation converted to the corresponding cis,trans-DPB (2). 4,5 Approximately 25 years later, Whitten's group confirmed these results and by measuring quantum yields of isomerization suggested an excited singlet state decay of 3 consisting of isomerization, fluorescence, and possibly a radiationless process. They also pointed out for the first time that cis,cis-DPB (1) may also be formed during light-initiated isomerization and that the process could be solvent-dependent.…”

Section: Continuing Our Longstanding Interestmentioning

confidence: 93%

Photoisomerization and Photooxygenation of 1,4-Diaryl-1,3-dienes in a Confined Space

2014

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Geometric isomerization of light-activated olefins plays a significant role in biological events as well as in modern materials science applications. In these systems, the isomerization occurs in highly confined spaces, and concepts derived from solution investigations are only partially applicable. This study makes contributions in understanding the excited-state behavior of olefins in confined spaces by investigating the excited-state behavior of 1,4-diphneyl-13-butadiene (DPB) and 1,4-ditolyl-1,3-butadiene (DTB) encapsulated in a well-defined organic capsule made up of the octa acid (OA) host. Both of these dienes that exist in three isomeric forms (trans,trans; trans,cis; and cis,cis) formed 1:2 guest-host complexes with OA in aqueous borate buffer. Competition experiments monitored by (1)H NMR signals revealed that among the three isomers the cis,cis isomer of DPB and DTB formed the most stable complex with OA. Molecular modeling studies suggested that all six isomers of DPB and DTB preferred the cisoid conformation within the OA capsule. Irradiation (>280 nm) of the diene-OA complex (diene@OA2) resulted in geometric isomerization, and the photostationary state consisted of cis,trans isomer as major and cis,cis as minor products. The photostationary state could be enriched with the cis,cis isomer in yields close to 70% with proper cutoff filters because the cis,cis isomer absorbs at shorter wavelength than the other two isomers. Consistent with the MD simulation prediction that trans,trans-DPB and trans,trans-DTB existed in cisoid conformation within OA capsule, the generation of singlet oxygen in the presence of OA encapsulated DPB or DTB resulted in facile [4 + 2] addition between the diene and the singlet oxygen.

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Some Spectroscopic Changes Connected with the Stereoisomerization of Diphenylbutadiene

Cited by 37 publications

References 0 publications

The excited states and vibronic spectroscopy of diphenyldiacetylene and diphenylvinylacetylene

The excited states and vibronic spectroscopy of diphenyldiacetylene and diphenylvinylacetylene

Cis-trãns Isomeric Carotenoids Vitamins A and Arylpolyenes

Photoisomerization and Photooxygenation of 1,4-Diaryl-1,3-dienes in a Confined Space

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