Copper in the marine environment∗ ‐ Part II

Schmidt, R.L.; Forster, W.O.

doi:10.1080/10643387709381664

Cited by 13 publications

(9 citation statements)

References 184 publications

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“…On the other hand, the EC50 value of copper was not observed to vary greatly with salinity in spite of the fact that its chloro complexes are more stable than those of zinc (Martell and Smith, 1971). Therefore, if the observed variation in zinc and cadmium toxicity was due simply to the formation of less-toxic chloro complexes, then the copper chloro species must be just as toxic as the fully aquated Cu" ion, but this observation is at variance with commonly held views (Allen et al, 1980;Bender et al, 1970;Daly et al, 1986;Schmidt, 1978).…”

Section: Effect O F Ionic Solutes On Ecsovalues/455mentioning

confidence: 95%

The effect of ionic solutes on EC₅₀ values measured using the microtox test

Hinwood

McCormick

1987

Environ. Toxicol. Water Qual.

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The Microtox test uses the marine luminescent bacterium, Photobacterium phosphoreum. To provide the organism with osmotic protection, sodium chloride (2.0%) is usually added to freshwater samples before analysis. This procedure is shown to cause a dramatic lowering of measured toxicity where ionic compounds are the major toxicants present. The reason for this is the consequent variation in ionic strength upon addition of NaCl rather than formation of less-toxic chloro complexes. Data are given for the toxicants Zn, Cd, Cu, NH4+, and phenol.It was found that measurements on aqueous samples could be made without adjustment provided that the salinity was in the range of 1.0-7.0%. Freshwaters can also be analyzed without adjustment of ionic strength by adding sucrose (20.4%) to provide the necessary osmotic protection.It is therefore recommended that the ionic strength of aqueous samples should not be altered as part of the test and that receiving waters should be used as the diluent wherever possible.

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Section: Effect O F Ionic Solutes On Ecsovalues/455mentioning

confidence: 95%

The effect of ionic solutes on EC₅₀ values measured using the microtox test

Hinwood

McCormick

1987

Environ. Toxicol. Water Qual.

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“…Particularly large quantum yields QA result in triplet sensitizers with strong ISC, negligible CT interactions and ET > Ex because then two channels via O2('Cg', and 02('Agf) to singlet oxygen formation exist; see Scheme 1. Phenalenone is such a sensitizer, with QT = 1 .OO, E,, = 1.96 V vs SCE in ACN, AGCET -C = 78 kJ mol-', and ET = 186 kJ mol-' (47), for which QA is close to unity in an airsaturated solution independent of solvent polarity and proticity (88). However, increasing CT interactions lead to lower values of SA down to the minimum value of 0.25, and thus to a decrease of QA.…”

Section: Singlet Oxygen Quantum Yieldsmentioning

confidence: 99%

Photosensitized Generation of Singlet Oxygen

Schmidt

2007

Photochemistry and Photobiology

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This work gives an overview of what is currently known about the mechanisms of the photosensitized production of singlet oxygen. Quenching of ππ* excited triplet states by O2 proceeds via internal conversion of excited encounter complexes and exciplexes of sensitizer and O2. Both deactivation channels lead with different efficiencies to singlet oxygen generation. The balance between the deactivation channels depends on the triplet‐state energy and oxidation potential of the sensitizer, and on the solvent polarity. A model has been developed that reproduces rate constants and efficiencies of the competing processes quantitatively. Sensitization by excited singlet states is much more complex and hence only qualitative rules could be elaborated, despite serious efforts of many groups. However, the most important deactivation paths of fluorescence quenching by O2 are again directed by excess energies and charge‐transfer interactions similar to triplet‐state quenching by O2. Finally, two recent developments in photo‐sensitization of singlet oxygen are reviewed: Two‐photon sensitizers with particular application potential for photodynamic therapy and fluorescence imaging of biological samples and singlet oxygen sensitization by nanocrystalline porous silicon, a material with very different photophysics compared to molecular sensitizers.

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“…The (Di values were also determined by the IR luminescence technique using perinaphthenone (phenalenone. Aldrich) as a reference (22). When excited at 337 nm, perinaphthenone sensitizes the formation of lo2 with a quantum yield of 0.98 2 0.15 in CHCI,.…”

Section: Photophysical Measurementsmentioning

confidence: 99%

Photochemistry and Photophysical Properties of Novel, Unsymmetrically Substituted Metallophthalocyanines

Lawrence

Whitten

1996

Photochem & Photobiology

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A series of novel, unsymmetrically substituted metallophthalocyanines was synthesized, along with their symmetrically substituted analogs, and the effects of structure and metal substitution on their photophysical and photoredox properties were investigated. The macrocycles were synthesized using a mixed-condensation method followed by chromatographic separation of the resulting soluble products. They possess a catechol "active site" and three tert-butyl groups for enhanced solubility. The ground-and excited-state photophysical properties of the free-base, Zn(I1) and Pd(I1) macrocycles were measured and compared with their symmetrically substituted (tetra[tert-butyl]) analogs. The efficiency with which these macrocycles sensitize the formation of singlet oxygen was determined and discussed in the context of the excitedstate photophysical properties. Several examples of photoinduced electron transfer reactions with one-and twoelectron acceptors are demonstrated and discussed. These soluble molecules can be tuned to optimize their photochemical and redox properties by varying the central metal, axial ligands and other substituents, thereby providing a series of molecules for the investigation of photodynamic therapy and photoinduced electron transfer mechanisms.

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Copper in the marine environment∗ ‐ Part II

Cited by 13 publications

References 184 publications

The effect of ionic solutes on EC₅₀ values measured using the microtox test

The effect of ionic solutes on EC₅₀ values measured using the microtox test

Photosensitized Generation of Singlet Oxygen

Photochemistry and Photophysical Properties of Novel, Unsymmetrically Substituted Metallophthalocyanines

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Copper in the marine environment∗ ‐ Part II

Cited by 13 publications

References 184 publications

The effect of ionic solutes on EC50 values measured using the microtox test

The effect of ionic solutes on EC50 values measured using the microtox test

Photosensitized Generation of Singlet Oxygen

Photochemistry and Photophysical Properties of Novel, Unsymmetrically Substituted Metallophthalocyanines

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Product

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The effect of ionic solutes on EC₅₀ values measured using the microtox test

The effect of ionic solutes on EC₅₀ values measured using the microtox test