Preparation of tert-butyl-capped polyenes containing up to 15 double bonds

Knoll, Konrad; Schrock, Richard R.

doi:10.1021/ja00202a045

Cited by 168 publications

(104 citation statements)

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“…It also is interesting to compare the data for the S 0 f S 2 transition with that obtained from a series of R,ω-di-tert-butyl polyenes in room temperature n-pentane (A ) 14 350 ( 150 cm -1 and B ) 76 000 ( 1200 cm -1 ). 62 (See dashed line in Figure 6.) The systematic red shifts in the carotenoids can be explained by the preferential stabilization of the ππ* excited states by the isoprene methyl groups, though the two sets of polyene S 0 f S 2 transitions converge to almost identical limits as N f ∞.…”

Section: Discussionmentioning

confidence: 99%

Spectroscopic and Photochemical Properties of Open-Chain Carotenoids

et al. 2002

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The spectroscopic properties of open-chain, all-trans-C 30 carotenoids having seven, eight and nine π-electron conjugated carbon-carbon double bonds were studied using steady-state absorption, fluorescence, fluorescence excitation and time-resolved absorption spectroscopy. These diapocarotenes were purified by high performance liquid chromatography (HPLC) prior to the spectroscopic experiments. The fluorescence data show a systematic crossover from dominant S 1 f S 0 (2 1 A g f 1 1 A g ) emission to dominant S 2 f S 0 (1 1 B u f 1 1 A g ) with increasing extent of conjugation. The low temperatures facilitated the determination of the spectral origins of the S 1 f S 0 (2 1 A g f 1 1 A g ) emissions, which were assigned by Gaussian deconvolution of the experimental line shapes. The lifetimes of the S 1 states of the molecules were measured by transient absorption spectroscopy and were found to decrease as the conjugated chain length increases. The energy gap law for radiationless transitions is used to correlate the S 1 energies with the dynamics. These molecules provide a systematic series for understanding the structural features that control the photochemical properties of open-chain, diapocarotenoids. The implications of these results on the roles of carotenoids in photosynthetic organisms are discussed.

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Section: Discussionmentioning

confidence: 99%

Spectroscopic and Photochemical Properties of Open-Chain Carotenoids

et al. 2002

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“…Its spectrum is directly comparable to the most intense transition recorded in dichloromethane of an all trans-polyene with 10 double bonds. 69 Given that alkyl side groups change the optical absorption of polyenes by less than 10 nm, 70 suggesting that their electronic effect on the transition is minimal, a polymer such as trans-poly-sbutylCOT displays the highest observed effective conjugation length for a soluble polyacetylene.…”

Section: Structure/property Relationships For the Polymers In Solumentioning

confidence: 99%

“…After isomerization, the majority of the trans material will not pass through a 5 gim filter. Polyenes containing cis double bonds have been observed to be more soluble than all trans polyenes, 69 although the latter insolubility was attributed to covalent cross-linking. If such cross-links are present in the trans-polyRCOT's, they do not result in a decrease in Xma compared to polyacetylene, and the conclusion that unsubstituted, conjugated all-trans polyenes are insoluble because they are crosslinked implies that trans-polyacetylene is crosslinked in the solid state.…”

Section: Structure/property Relationships For the Polymers In Solumentioning

confidence: 99%

Soluble, highly conjugated derivatives of polyacetylene from the ring-opening metathesis polymerization of monosubstituted cyclooctatetraenes: synthesis and the relationship between polymer structure and physical properties

Gorman¹,

Ginsburg²,

Grubbs³

1993

J. Am. Chem. Soc.

122

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“…At present, the common characterization techniques for most of the newly synthesized oligomers are NMR, IR, and UV [11][12][13]. The spectroscopic techniques 1 H and 13 C NMR can provide the main structural information of the oligomers.…”

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The cationization mechanism study of novel oligo (p-phenyleneethynylene)s

Chen

et al. 2005

J. Am. Soc. Mass Spectrom.

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Two series of new oligo(p-phenyleneethynylene)s (OPEs) O1-O4 and O5-O8, which have been proven to be one of the chief classes of molecules mainly used as the wires and other potential backbones of molecular electronic devices, have been synthesized by stepwise synthetic approach. The characterization of these oligomers was performed on MALDI TOF MS. Different cationization salts have been applied to investigate the ionization processes of these series of oligomers under MALDI conditions. The experimental results show that these oligomers display a strong tendency to undergo radical cationization and varied ionization efficiency with different cationization agents attributable to their difference in cationic diameters. Furthermore, we found that these two series of oligomers differed in ionization properties because of their different end-groups even when the same cationization agent was used. (J Am Soc Mass Spectrom 2005, 16, 1695-1701

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Preparation of tert-butyl-capped polyenes containing up to 15 double bonds

Cited by 168 publications

References 0 publications

Spectroscopic and Photochemical Properties of Open-Chain Carotenoids

Spectroscopic and Photochemical Properties of Open-Chain Carotenoids

Soluble, highly conjugated derivatives of polyacetylene from the ring-opening metathesis polymerization of monosubstituted cyclooctatetraenes: synthesis and the relationship between polymer structure and physical properties

The cationization mechanism study of novel oligo (p-phenyleneethynylene)s

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