Chemistry of singlet oxygen. 42. Effect of solvent, solvent isotopic substitution, and temperature on the lifetime of singlet molecular oxygen (1.DELTA.g)

Ogilby, Peter R.; Foote, Christopher S.

doi:10.1021/ja00349a007

Cited by 396 publications

(332 citation statements)

References 1 publication

Supporting

Mentioning

300

Contrasting

Unclassified

Order By: Relevance

“…µs 19 whereas it is ~ 3.5 µs in H 2 O, 20 and this difference is manifested in the quantum efficiency of singlet oxygen phosphorescence. 2 16 In most of our previous singlet oxygen work in cells, we used a hydrophilic cationic porphyrin as a photosensitizer: 5,10,15,20-tetrakis(N-methyl-4-pyridyl)-21H, 23H-porphine (TMPyP).…”

Section: Introductionmentioning

confidence: 95%

Singlet Oxygen in a Cell: Spatially Dependent Lifetimes and Quenching Rate Constants

2008

Self Cite

View full text Add to dashboard Cite

Singlet molecular oxygen, O 2 (a 1 ∆ g ), can be created in a single cell from ground state oxygen, O 2 (X 3 Σ g -), upon focused laser irradiation of an intracellular sensitizer. This cytotoxic species can subsequently be detected by its 1270 nm phosphorescence (a 1 ∆ g → X 3 Σ g -) with subcellular spatial resolution. The singlet oxygen lifetime determines its diffusion distance and, hence, the intracellular volume element in which singlet-oxygen-initiated perturbation of the cell occurs. In this study, the time-resolved phosphorescence of singlet oxygen produced by the sensitizers chlorin (Chl) and 5,10,15,20-tetrakis(N-methyl-4-pyridyl)-21H,23H-porphine (TMPyP) was monitored. These molecules localize in different domains of a living cell. The data indicate that (i) the singlet oxygen lifetime and (ii) the rate constant for singlet oxygen quenching by added NaN 3 depend on whether Chl or TMPyP was the photosensitizer.These observations likely reflect differences in the chemical and physical constituency of a given subcellular domain (e.g., spatially-dependent oxygen and NaN 3 diffusion coefficients) and, as such, are evidence that singlet oxygen responds to the inherent heterogeneity of a cell.Thus, despite a relatively long intracellular lifetime, singlet oxygen does not diffuse a great distance from its site of production. This is a consequence of an apparent intracellular viscosity that is comparatively large.3

show abstract

Section: Introductionmentioning

confidence: 95%

Singlet Oxygen in a Cell: Spatially Dependent Lifetimes and Quenching Rate Constants

2008

Self Cite

View full text Add to dashboard Cite

show abstract

“…Though there may be technical difficulties with measurements in water due to the short singlet oxygen lifetime in this solvent (ca. 4 s) the effect of this is small since the substitution of water by deuterated water had no effect on the ˚ value although the lifetime in deuterated water is 20 times higher than in H 2 O [60]. A comparison of the ˚ for NAD in the various solvents and the corresponding ˚T values (see Table 5) indicates that the former are much lower than the ˚T values, providing evidence of a relatively low efficiency of energy transfer from 3 NAD* to molecular oxygen to produce 1 O 2 .…”

Section: Singlet Oxygen Measurementsmentioning

confidence: 95%

Photophysical characterization of the plant growth regulator 2-(1-naphthyl) acetamide

Silva

Wong-Wah-Chung

Sarakha

2013

Journal of Photochemistry and Photobiology A: Chemistry

View full text Add to dashboard Cite

a b s t r a c tThe photophysical properties of the widely used plant growth regulator 2-(1-naphthyl) acetamide (NAD) were studied in water and representative organic solvents (ethanol, ethylene glycol, acetonitrile, chloroform, 1,4-dioxane) employing steady-state and time-resolved spectroscopy. Quantum yields and lifetimes of fluorescence, phosphorescence and triplet formation and triplet-triplet absorption spectra were obtained. From these, all radiative and radiationless rate constants have been determined, together with singlet and triplet excited state energies (4.00 and 2.69 eV, respectively). The fluorescence quantum yield and lifetime increased on going from water (˚F 0.066, F 35.0 ns) to non-hydrogen bonding solvents (˚F 0.357, F 51.0 ns in 1,4-dioxane), probably due to decreased internal conversion. Fluorescence was quenched by several anions through an electron transfer process. A limit on the reduction potential of 1 NAD* of E 0 2.1 ± 0.2 V was estimated. The attribution of the transient absorption seen in nanosecond laser flash photolysis to 3 NAD* was confirmed by energy transfer and oxygen quenching. Quenching of triplet states leads to singlet oxygen formation, with quantum yields varying from 0.097 in water to 0.396 in chloroform. However, these are lower than the triplet state quantum yields, particularly in water (˚T 0.424), indicating competing quenching pathways, probably involving electron transfer. The relevance of these results to the photoreactivity of NAD under environmental conditions is discussed.

show abstract

“…On the basis of the Mulliken's prediction [7] [2,[13][14][15][16][17][18][19][20]. The stationary concentration of singlet O 2 * in solvents is very low as well as intensity of the a→X emission; thus, a highly sensitive cooled photomultiplier (FEU-83) [13][14][15][16][17][18] or Ge-photodiode are necessary for its detection [25][26][27][28][29][30][31][32]. The low radiative rate constant (k r ) for 1270 nm a→X emission at low pressure in gases [21] and its essential enhancement in solvents [15,18] have been explained in a number of old papers [10,22,23].…”

Section: Romentioning

confidence: 99%

“…The low radiative rate constant (k r ) for 1270 nm a→X emission at low pressure in gases [21] and its essential enhancement in solvents [15,18] have been explained in a number of old papers [10,22,23]. Nowadays the total theoretical backgrounds of this theory are supported by numerous experimental studies [26][27][28][29][30][31][32] including recent experiments [33][34][35][36][37][38] on direct oxygen excitation. Thus, it can be interesting to present a short review of such backgrounds accounting a great importance of singlet oxygen photochemistry in solvents for modern medical diagnostics and therapy [39,40] as well as for some braches of chemical technology [5,32].…”

Section: Romentioning

confidence: 99%

See 1 more Smart Citation

Photochemistry and Spectroscopy of Singlet Oxygen in Solvents. Recent Advances which Support the Old Theory

Минаев¹

2016

ChChT

View full text Add to dashboard Cite

Abstract. Molecular oxygen is a paramagnetic gas with the triplet O 2 ( ) has attracted great attention of chemists during half-century studies of its reactivity and spectroscopy, but unusual properties of singlet oxygen makes it difficult to unravel all mysterious features. The semiempirical theory of spin-orbit coupling in dioxygen and in collision complexes of O 2 with diamagnetic molecules proposed in 1982 year has explained and predicted many photochemical and spectral properties of dioxygen produced by the dye sensitization in solvents. Recent experiments with direct laser excitation of O 2 in solvents provide a complete support of the old theory. The present review scrutinizes the whole story of development and experimental verification of this theory.

show abstract

Chemistry of singlet oxygen. 42. Effect of solvent, solvent isotopic substitution, and temperature on the lifetime of singlet molecular oxygen (1.DELTA.g)

Cited by 396 publications

References 1 publication

Singlet Oxygen in a Cell: Spatially Dependent Lifetimes and Quenching Rate Constants

Singlet Oxygen in a Cell: Spatially Dependent Lifetimes and Quenching Rate Constants

Photophysical characterization of the plant growth regulator 2-(1-naphthyl) acetamide

Photochemistry and Spectroscopy of Singlet Oxygen in Solvents. Recent Advances which Support the Old Theory

Contact Info

Product

Resources

About