2 edition of Metal complex photo-activators for the time-controlled, photo-oxidation of polyolefins. found in the catalog.
Metal complex photo-activators for the time-controlled, photo-oxidation of polyolefins.
Awni Mikha Marogi
Thesis (PhD) - University of Aston in Birmingham, 1983.
In higher plants, photosystem I is a unit containing several hundred molecules of chlorophyll (mostly chlorophyll a), about 50 carotenoids, one cytochrome f, one plastocyanin, two cytochrome 6 molecules, one or two ferredoxin molecules, and one molecule or a dimer of chlorophyll P Photosystem II has about molecules of chlorophylls a and b absorbing light at a wavelength . However, it will rarely only be a single mechanism that will contribute to the photo-oxidation of a complex food system, but more likely it will be a combination of both (Pattison et al.,
Photo-oxidation is the degradation of a polymer surface in the presence of oxygen or ozone. The effect is facilitated by radiant energy such as UV or artificial light. This process is the most significant factor in weathering of -oxidation is a chemical change that reduces the polymer's molecular a consequence of this change the material becomes more brittle, with a. Photo-oxidation - Photochromic Glass. Many people who wear eye glasses prefer those made with photochromic lenses or glass lenses which darken when exposed to bright light. These eyeglasses eliminate the need for sunglasses as they can reduce up to 80% of transmitted light.
Abstract— From time‐resolved measurements of the decay of singlet molecular oxygen phosphorescence at nm in D 2 O, direct estimates have been gained for the rate constants of the singlet oxygen reactions with a group of sulphur compounds in the pD range 5 to In the case of most of the thiols, the results are consistent with singlet oxygen reacting exclusively with the thiolate anions. The triplet excited state of a new crystalline form of a tetranuclear coordination d 10 –d type complex, Ag 2 Cu 2 L 4 (L = 2-diphenylphosphinomethylindole ligand), containing Ag I and Cu I metal centers has been explored using the Laue pump–probe technique with ≈80 ps time resolution. The relatively short lifetime of 1 μs is accompanied by significant photoinduced structural Cited by:
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Metal complex photo-activators for the time-controlled, photo-oxidation of polyolefins Author: Marogi, Awni M. ISNI: Awarding Body: University of Aston in Birmingham Current Institution: Aston University Date of Award: Author: Awni M. Marogi. Metal complex photo-activators for the time-controlled, photo-oxidation of polyolefins By Awni M.
Marogi OAI identifier: oai:or: Awni M. Marogi. Combinations of iron and nickel dithiocarbamates approach the ‘ideal’ delayed action photo-activators for polypropylene. They give an induction period to photo-oxidation which can be controlled by the amount of the nickel complex and a rapid rate of photo-oxidation at the end of the induction period which is primarily determined by the iron by: Metal complex photo-activators for the time-controlled, photo-oxidation of polyolefins.
PHD thesis, Aston University. McDonald, Ian R. The effect of hot deformation on the strength of precipitation hardened steels. PHD thesis, Aston University. Mhando, Joseph R. Controlled release of drugs from polymer films. The products formed from the zinc dibutyl dithiocarbamate autoretarded photo-oxidation after the disappearance of the metal complex.
This is in agreement with previously published results on this 30 a n t i o x i d a n t in which it was shown that the zinc complex is not itself an antioxidant but that a Lewis acid formed from it is responsible Cited by: 2.
Particular emphasis is laid on reactions involving electron transfer. Evidence for direct oxidation of the DNA bases, production of DNA-damaging reactive species, direct hydrogen abstraction from the DNA ribose and formation of adducts between the metal complex and DNA are by: The mechanism of the photo-oxidation of both low density and high density polyethylenes has been studied kinetically.
The kinetics are consistent with the view that when substantial quantities of carbonyl compounds are present in the polymers by photolysis of thermally formed hydroperoxides, they are intimately involved as initiators in the photo-oxidation by Norrish I photolysis of by: The low molar mass oxidation products formed during photo-oxidation and thermal oxidation are biodegradable and oxo-biodegradable polyolefins are now widely used in agricultural applications and.
While Xj is an intrinsic property of the binuclear complex x Q depends on the reorganization of solvent environment according to x =e2(i-+i- -!)(' -I) 0 2a 1 2a 2 d n D The parameters a^ and a 2 are the radii of the coordination spheres of both metals, d is the metal-metal distance, n and D are the refractive indexAuthor: Arnd Vogler.
The photolysis of electron-rich aryl nonaflates (ArONfs) in protic media was investigated and heterolysis of the Ar–OS bond (from 3ArONf) took place.
The reaction generated a triplet phenyl cation that added to π-bond nucleophiles. This metal-free arylation method was made further useful by Cited by: Photo-induced damage to proteins occurs via multiple pathways. Direct damage induced by UVB (λ – nm) and UVA radiation (λ – nm) is limited to a small number of amino acid residues, principally tryptophan (Trp), tyrosine (Tyr), histidine (His) and disulfide (cystine) residues, with this occurring via both excited state species and radicals.
The discovery of such a feature in a stable metal complex has since led to a considerable interest being generated in explaining the nature of this observation, and in exploiting this discovery to develop new photochemical reactions and photoinduced catalytic by: An impressive example of the possibilities of metal complex photochemistry is the substantiation of the critical step in corrin synthesis reported by Eschenmoser ): Ring closure is brought about by antarafacial cycloisomerization of a secocorrinoidic palladium complex by Cited by: The photo-antioxidant activity of these metal complexes, on the other hand, was shown to vary depending on the nature of the metal ion and their stability to UV-light; nickel is one of the most stable, while iron and manganese are least stableA41 Iron complexes, e.g.
FeDRC, showed unique behaviour in that at low concentrations it causes Cited by: Initially, the complex is stable during manufacturing processing and reacts with hydroperoxides formed from the thermal degradation of the polyolefin to inhibit further decomposition. However, when exposed to UV light the metal complex splits with the release of the metal in a photoactivated state which causes the rapid degradation of the by: Purchase Organometallic Photochemistry - 1st Edition.
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of Polymers. Polymers will change over time when exposed to UV radiation. These changes are the result of light-induced homolytic fission of chemical bonds (photolysis) and photo-oxidation. The UV resistance of unprotected polymers varies widely and depends on the structure and composition.
The first chapter contains a literature survey of the group 6 and 7 metal carbonyl complexes, also presented is a brief description of the role of transition metal complexes in some important industrial processes.
In addition, the metal carbonyl bond and the metal arene bond are described, while the nature of the absorption spectra of group 6 and. The synthesis of α-amino carbonyl/carboxyl compounds is a contemporary challenge in organic synthesis.
Herein, we present a stereoselective α-amination of amides employing simple azides that proceeds under mild conditions with release of nitrogen gas. The amide is used as the limiting reagent, and through simple variation of the azide pattern, various differently substituted aminated Cited by:.
Proton-coupled electron transfer (PCET) reactions were studied in acetonitrile for a Photosystem II (PSII)-inspired [Ru(bpy)2(phen-imidazole-Ph(OH)(tBu)2)]2+, in which Ru(III) generated by a flash–quench sequence oxidizes the appended phenol and the proton is transferred to the hydrogen-bonded imidazole base.
In contrast to related systems, the donor and acceptor are strongly coupled, as Cited by: carbonyls. The necessary condition to form a stable complex with a metal in a low oxidation state is that the ligands be able to form TT acceptor bonds in addition to a donor bonds.
The ligands must provide empty TT orbitals that are low enough to interact with lower lying filled dir orbitals of the Size: 7MB. The photo-oxidation of PET involves the formation of hydroperoxide species through oxidation of the CH 2 groups adjacent to the ester linkages and the hydroperoxides species involving the formation of photoproducts through several pathways.
For the three polymers, interaction with microbes and formation of biofilms are by: 8.