Singlet Sigma: The “Other” Singlet Oxygen in Solution

  title={Singlet Sigma: The “Other” Singlet Oxygen in Solution},
  author={Dean Weldor and Tina D. Poulsen and Kurt V. Mikkelsen and Peter R. Ogilby},
  journal={Photochemistry and Photobiology},
The lowest excited electronic state of molecular oxygen, O2(a1‐DLg), is often called simply singlet oxygen. This singlet delta state is an acknowledged and well‐studied intermediate in many solution‐phase photosystems. However, the second excited electronic state of oxygen, O2(b1δg+), is also a singlet. It has recently become possible to monitor this singlet sigma state in solution, which, in combination with studies of the singlet delta state, contributes to a better understanding of a variety… 
Singlet oxygen: there is indeed something new under the sun.
  • P. Ogilby
  • Chemistry, Medicine
    Chemical Society reviews
  • 2010
In this critical review, recent work on singlet oxygen is summarized, focusing primarily on systems that involve light.
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The reaction between CH2OO and 1Δg O2 has been investigated by means of high level quantum chemical and chemical kinetic calculations, implying that the reaction rate would be limited by the upper limit of bimolecular collision frequency.
Singlet oxygen photogeneration efficiencies of a series of phthalocyanines in well-defined spectral regions
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Direct 1O2 optical excitation: A tool for redox biology
The direct optical excitation of O2 to produce 1O2 will be introduced, in order to present its main advantages and drawbacks for biological studies.
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The quantum chemical study of the MeOOH/(MeO)3Al model system has been carried out in order to predict the mechanism of the catalytic decomposition of t-BuOOH under mild conditions for the
Independent Control of Singlet Oxygen and Radical Generation via Irradiation of a Two-Color Photosensitive Molecule
Free-radical polymerizations are used for a wide range of applications but are detrimentally impacted by the presence of oxygen. Zinc phthalocyanines have been previously used as singlet oxygen


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The relative fraction F Σ of excited state oxygen formed as b 1 Σ g + was determined for a series of triplet state photosensitizers in CCl 4 solutions. Oxygen excited states were formed by energy
Radiationless Deactivation of the Second Excited Singlet State 1Σg+ of O2 in Solution
The deactivation of the upper excited singlet oxygen O2(1Σg+) by 22 different quenchers has been studied in the liquid phase by time-resolved emission experiments. Radiationless deactivation occurs
Oxygen quenching of aromatic triplet states in solution. Part 2
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Rate constants k q T ranging between 0.3×10 9 and 15×10 9 M -1 s -1 for quenching of the lowest excited triplet state of several substituted aromatic hydrocarbons and ketones by molecular oxygen were
The perturbing effect of solvents on the luminescence rate constant of singlet molecular oxygen
Abstract The quantum yield of porphyrin singlet-oxygen luminescence in water, D 2 O, benzene and toluene at photoexcitation by argon laser light has been measured and, based on these data, the
Definition of the nature of ketone triplet states on the basis of singlet oxygen generation efficiency
The efficiency of singlet oxygen generation (S Δ ) was measured for acetophenone, p-aminobenzophenone, and Michler's ketone by the time-resolved O 2 ( 1 Δ g ) phosphorescence method in various
Factors governing the efficiency of singlet oxygen production during oxygen quenching of singlet and triplet states of anthracene derivatives in cyclohexane solution
The efficiencies of singlet oxygen production from the first excited singlet and triplet states of a range of substituted anthracenes in cyclohexane are reported. For all of the anthracene
Chemical Reactivity of Singlet Sigma Oxygen (b1Σg+) in Solution
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Radiative Transitions of Singlet Oxygen: New Tools, New Techniques and New Interpretations
The near‐IR phosphorescence of singlet delta oxygen, O2(a1Δg), has provided a wealth of information since it was first observed in solution‐phase systems. The techniques employed and the quality of