Bleaching products of rose bengal under reducing conditions

Zakrzewski, A.; Neckers, Douglas C.

doi:10.1016/s0040-4020(01)86891-5

Cited by 53 publications

(38 citation statements)

References 7 publications

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“…For both electron acceptors, the driving forces for electron transfer (DG el ) are similar (-(E red )-E oo is À90 kJ Á mol À1 for CQ and À110 kJ Á mol À1 for benzophenone, respectively). It should also be noted that electron transfer between Rose bengal (-(E red )-E oo ¼ À48 kJ Á mol À1 ) [20] and PTAA AS occurs to yield intermediates characteristic of this type of reaction. [16] The data for Rose bengal clearly show that for an electron donor, for which electron transfer to the dye triplet occurs, a similar reaction for the camphorquinone triplet state is even more thermodynamically favorable and should also occur.…”

Section: Resultsmentioning

confidence: 99%

Reinvestigation of the Mechanism of the Free Radical Polymerization Photoinitiation Process by Camphorquinone–Coinitiator Systems: New Results

Pyszka

Kucybała²,

Pączkowski

2004

Macro Chemistry & Physics

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Summary: Comparative studies of photoinitiation processes using camphorquinone (CQ) and benzophenone (BP) as light absorbers were performed. The experimental results show that after the transformation of (phenylthio)acetic acid (PTAA) into its tetrabutylammonium salt (PTAA AS), a substantial decrease of the polymerization photoinitiation ability for the CQ–PTAA AS pair in comparison to the CQ–PTAA pair is observed. The mechanism of the photoinitiated polymerization for the tested photoredox pair was clarified based on laser flash photolysis experiments obtained using benzophenone as an electron acceptor and (phenylthio)acetic acid and its tetrabutylammonium salt as electron donors in solution in MeCN. It is documented and deduced that the photoreduction of benzophenone in the presence of (phenylthio)acetic acid and its tetrabutylammonium salt occurs by a photoinduced electron transfer process, while for CQ as initiator, the free radicals are formed by hydrogen atom abstraction by the triplet state of camphorquinone.Schematic of the transients formed after an electron‐transfer process for benzophenone–PTAA and benzophenone–PTAA AS pairs.magnified imageSchematic of the transients formed after an electron‐transfer process for benzophenone–PTAA and benzophenone–PTAA AS pairs.

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Section: Resultsmentioning

confidence: 99%

Reinvestigation of the Mechanism of the Free Radical Polymerization Photoinitiation Process by Camphorquinone–Coinitiator Systems: New Results

Pyszka

Kucybała²,

Pączkowski

2004

Macro Chemistry & Physics

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“…Immobilized eosin Y on the surface of the aerogel initiated the formation of PEG diacrylate hydrogel on the surface. 47,48 Eosin was used as the photoinitiator since its spectral properties perfectly suit its application as an initiating system for an argon ion laser [49][50][51] This step resulted in the formation of a cross-linked thin PEG hydrogel coating around the hydrophobic or hydrophilic aerogels. Ketoprofen release experiments Drug release experiments were conducted at 310 K and under constant string at 100 rpm.…”

Section: Hydrogel Coating Of Silica Aerogelsmentioning

confidence: 99%

Controlled drug delivery through a novel PEG hydrogel encapsulated silica aerogel system

Giray

Bal

Kartal

et al. 2012

J Biomedical Materials Res

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A novel composite material consisting of a silica aerogel core coated by a poly(ethylene) glycol (PEG) hydrogel was developed. The potential of this novel composite as a drug delivery system was tested with ketoprofen as a model drug due to its solubility in supercritical carbon dioxide. The results indicated that both drug loading capacity and drug release profiles could be tuned by changing hydrophobicity of aerogels, and that drug loading capacity increased with decreased hydrophobicity, while slower release rates were achieved with increased hydrophobicity. Furthermore, higher concentration of PEG diacrylate in the prepolymer solution of the hydrogel coating delayed the release of the drug which can be attributed to the lower permeability at higher PEG diacrylate concentrations. The novel composite developed in this study can be easily implemented to achieve the controlled delivery of various drugs and/or proteins for specific applications.

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“…15 This reaction occurs when the photoinitiator species absorbs the incident photons of a suitable wavelength. In our analysis, the photoinitiator consists of a photosensitive dye ͑Eryth-rosin B͒ denoted by Dye, and an electron donor ͑ED͒, i.e., triethanolamine ͑HOCH 2 CH 2 ͒ 3 N. [16][17][18] The second reaction in the initiation process involves the primary radicals, which are produced due to the absorption of photons, reacting with monomer molecules to produce the chain initiating or macroradical species, M …”

Section: A Initiation Mechanismsmentioning

confidence: 99%