Nucleophilic trapping of intermediates in the singlet oxygenations of isomeric 1,4-di-t-butoxy-1,3-butadienes

Clennan, Edward L.; Lewis, K. K.

doi:10.1021/jo00369a037

Cited by 7 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The UV absorption of the precursor fraction disappeared during the course of the 1 -h photolysis. Furthermore, irradiation of the precursor fraction for 1 h after it had been separated from most of the unreacted ammonia and acetylene also gave an HCN yield comparable to an 8-h photolysis at room temperature (Table III, run 5). These experiments establish that precursors to HCN condense from the photolysis mixture at 178 K, thus explaining the low yield of HCN at that temperature.…”

Section: Resultsmentioning

confidence: 81%

“…It was recently suggested that photochemically generated organic polymers should be considered as the source of the chromophores on Jupiter.24 The photopolymerization of acetylene is one source of organic oligomers that absorb visible light (5)(6)(7)(8). HC=CC=CH* + C2H2 -C6H2 + H2 (8) The extent of chromophore formation is decreased markedly by the addition of hydrogen.26 This inhibition is probably due to the rapid rate of reaction of the acetylenic radical intermediates with hydrogen so that they do not react appreciably with the lower concentration of acetylene present. The photochemical condensation of any diacetylene formed by reaction 7 proceeds by excited state and not radical species to form oligomers,27 so this route to chromophores may not be inhibited by hydrogen.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Formation of hydrogen cyanide and acetylene oligomers by photolysis of ammonia in the presence of acetylene: applications to the atmospheric chemistry of Jupiter

Ferris¹,

Ishikawa²

1988

J. Am. Chem. Soc.

View full text Add to dashboard Cite

HCN is formed by the photolysis of ammonia in the presence of acetylene at room temperature. There is a 70% decrease in the yield of HCN when the temperature is lowered to 178 K and two new reaction products, acetonitrile and acetaldehyde ethylidenehydrazone (6), are formed. Photolysis of 6 yields acetonitrile, and the hydrogen atom initiated deeompasition of acetonitrile yields HCN. Aziridine, a predicted reaction intermediate, was not detected at 298 or 178 K. Oligomers of acetylene are also formed. Oligomers formed by the photolysis of ammonia in the presence of acetylene were shown by Fourier transform infrared spectroscopy to contain NH groupings and to differ from those produced by the direct photolysis of acetylene. The possible role of these photochemical processes on the formation of HCN and chromophores on Jupiter, Titan, and comets is discussed. 10-38765 from NASA. The Model 1800 FT-IR was a gift to the Chemistry Department from Perkin-Elmer. Preliminary studies were performed by Dr. H. Khwaja, and we thank him for the design of the CaF2 cell. We thank Dr. F. Raulin for bringing the abstract of Masanet et al. (1982) to our attention. Registry No. 1, 151-56-4; 6 , 592-56-3; HCN, 74-90-8; NH,, 7664-41-7; CH,CN, 75-05-8; HCECH, 74-86-2; acetylene (homopolymer), 25067-58-7. (70) Wijnen, M. H.

show abstract

Section: Resultsmentioning

confidence: 81%

mentioning

confidence: 99%

Formation of hydrogen cyanide and acetylene oligomers by photolysis of ammonia in the presence of acetylene: applications to the atmospheric chemistry of Jupiter

Ferris¹,

Ishikawa²

1988

J. Am. Chem. Soc.

View full text Add to dashboard Cite

show abstract

“…Additionally, the resonance-delocalized positive charge renders the molecule susceptible to hydration to form hydroperoxyethanol 11 . This step is reminiscent of the reaction of 2,4-hexadienes with 1 O 2 , wherein alcoholysis of the zwitterionic peroxy intermediate provides hydroperoxyalkoxyethenols. − On forming the hydroperoxyethanol 11 , facile rotation about the C2′–C1′ sets up an intramolecular attack by the vinylogous enamine to provide the hydroperoxycyclobutanol 12 . Intermediate 12 subsequently releases hydroperoxyethenol 13 to afford cyanine 3 .…”

Section: Resultsmentioning

confidence: 99%

Defining the Basis of Cyanine Phototruncation Enables a New Approach to Single-Molecule Localization Microscopy

et al. 2021

View full text Add to dashboard Cite

The light-promoted conversion of extensively used cyanine dyes to blue-shifted emissive products has been observed in various contexts. However, both the underlying mechanism and the species involved in this photoconversion reaction have remained elusive. Here we report that irradiation of heptamethine cyanines provides pentamethine cyanines, which, in turn, are photoconverted to trimethine cyanines. We detail an examination of the mechanism and substrate scope of this remarkable two-carbon phototruncation reaction. Supported by computational analysis, we propose that this reaction involves a singlet oxygen-initiated multistep sequence involving a key hydroperoxycyclobutanol intermediate. Building on this mechanistic framework, we identify conditions to improve the yield of photoconversion by over an order of magnitude. We then demonstrate that cyanine phototruncation can be applied to super-resolution single-molecule localization microscopy, leading to improved spatial resolution with shorter imaging times. We anticipate these insights will help transform a common, but previously mechanistically ill-defined, chemical transformation into a valuable optical tool.

show abstract

“…The mechanism involving a charge transfer (path 5, Scheme 14) from the electron rich olefin, 2,3-diaryl-1,4butadiene, to the molecular singlet oxygen to yield the corresponding 2,3-diaryl-1,4-dioxetane was also proposed (94). A similar mechanism was proposed by Clennan for the [2 + 2] cycloaddition of 1 O 2 to 1, 2-di-tert-butoxy-1,3-butadiene (95). In this case, when the solvent was MeOH, the charge transfer mechanism predominates over the concerted [2 s +2 a ] cycloaddition.…”

Section: [2 + 2] Cycloadditionsmentioning

confidence: 69%

Singlet Oxygen: Discovery, Chemistry, C₆₀‐Sensitization^†

Orfanopoulos

2021

Photochem & Photobiology

View full text Add to dashboard Cite

This review article refers to the discovery of excited molecular oxygen, in particular on its lower singlet excited state ( 1 D g , 1 O 2 ). After a short report on singlet oxygen generation, the review is focused on the chemistry of this reactive species. Specifically, the three major reactions of 1 O 2 with unsaturated organic substrates, namely the [4 + 2] and [2 +2] cycloadditions as well as the ene reaction, are reviewed. The proposed mechanisms of these reactions, through the years, based on experimental and computational work, have been presented. Selected examples of singlet oxygen-synthetic applications are also mentioned. The [60]fullerene and fullereno-materials photosensitized oxidations in homogeneous, as well as in heterogeneous conditions, are also comprehensively discussed.Finally, the self-sensitized photooxidation of open cage fullerenes as well as fullerenes bearing oxidizable groups is reported.

show abstract

Nucleophilic trapping of intermediates in the singlet oxygenations of isomeric 1,4-di-t-butoxy-1,3-butadienes

Cited by 7 publications

References 0 publications

Formation of hydrogen cyanide and acetylene oligomers by photolysis of ammonia in the presence of acetylene: applications to the atmospheric chemistry of Jupiter

Formation of hydrogen cyanide and acetylene oligomers by photolysis of ammonia in the presence of acetylene: applications to the atmospheric chemistry of Jupiter

Defining the Basis of Cyanine Phototruncation Enables a New Approach to Single-Molecule Localization Microscopy

Singlet Oxygen: Discovery, Chemistry, C₆₀‐Sensitization^†

Contact Info

Product

Resources

About

Nucleophilic trapping of intermediates in the singlet oxygenations of isomeric 1,4-di-t-butoxy-1,3-butadienes

Cited by 7 publications

References 0 publications

Formation of hydrogen cyanide and acetylene oligomers by photolysis of ammonia in the presence of acetylene: applications to the atmospheric chemistry of Jupiter

Formation of hydrogen cyanide and acetylene oligomers by photolysis of ammonia in the presence of acetylene: applications to the atmospheric chemistry of Jupiter

Defining the Basis of Cyanine Phototruncation Enables a New Approach to Single-Molecule Localization Microscopy

Singlet Oxygen: Discovery, Chemistry, C60‐Sensitization†

Contact Info

Product

Resources

About

Singlet Oxygen: Discovery, Chemistry, C₆₀‐Sensitization^†