Competing ionic and radical photobehaviour has been observed for 2-halogeno-1,1-diphenylethylenes... more Competing ionic and radical photobehaviour has been observed for 2-halogeno-1,1-diphenylethylenes. Irradiation of 2-fluoro-1,1-diphenylethylene in cyclohexane or ether afforded cis- and trans-fluorostilbene. Irradiation of the chloro, bromo, or iodo analogues gave a complex mixture of up to eight products, the three major products being diphenylacetylene, 1,1-diphenylethylene, and 1,1,4,4-tetraphenylbutadiene. The product distribution proved to depend on the halogen and on the solvent. Benzophenone or xanthone sensitised irradiation of 2-fluoro-1,1-diphenylethylene in cyclohexane gave 1-cyclohexyl-1-fluoro-2,2-diphenylethane, while irradiation of 2-chloro 1,1-diphenylethylene gave 2-cyclohexyl-1,1-diphenylethylene.
Acta Crystallographica Section C Crystal Structure Communications, 1994
The structure contains discrete molecules of the 1:2 adduct of octafluoronaphthalene with indene:... more The structure contains discrete molecules of the 1:2 adduct of octafluoronaphthalene with indene: (4bα,4cα,8bβ,8cβ,13bβ,13cβ,13dα,13eα)-4c,5,6,7,8,8b,13c,13d-octafluoro-4b,4c,8b,8c,9,13b,13c,13d,13e,14-decahydrobis(indeno[1',2':3,4]cyclobuta)[1,2-α:1',2'-c]naphthalene [Chem. Abstr. (1992). 116, 3468f]. The bond lengths and angles are normal for this type of compound and there are no unusual close intermolecular contacts in the structure
Photoaddition of indene or 1,2-dihydronaphthalene to hexafluorobenzene in cyclohexane solution re... more Photoaddition of indene or 1,2-dihydronaphthalene to hexafluorobenzene in cyclohexane solution results in the formation of cis-syn-cis-2 + 2-cycloadducts.
Journal of the Chemical Society, Perkin Transactions 1, 1987
The stereochemistry of photocycloaddition reactions of various cycloalkenes to hexafluorobenzene ... more The stereochemistry of photocycloaddition reactions of various cycloalkenes to hexafluorobenzene in cyclohexane solution depends on the structure of the cycloalkene, and [2 + 2] cycloadducts are mainly observed. [1,3]-Photocycloaddition is observed only when a large excess of the cycloalkene is used (hexafluorobenzene: cyclopentene, 1 :8) and at higher concentrations. Photoreactions with indene and 1,2-dihydronaphthalene occur stereospecifically syn, and a cis–syn–cis[2 + 2] cycloadduct is isolated. The photocycloaddition reaction with norbornene proceed exclusively exo, with preferential syn addition accompanied by 5%anti-addition. The stereochemistry of the [2 + 2]-photocycloaddition reactions is changed completely in the case of cyclopentene, where 85%anti addition is observed. The course of anti-photocycloaddition diminishes with increasing ring size of the cycloalkene until in the case of cyclooctene, it is reduced to 53%. The quantum yields of [2 + 2]-photocycloadditions, depend on the structure of the cycloalkene and on the concentration of hexafluorobenzene, the greatest effect being observed during [2 + 2]-cycloaddition with indene.
Phosphorus and Sulfur and the Related Elements, 1979
Abstract Leong and Peach (J. Fluorine Chem., 6, 145 (1975) have shown that at room temperature pe... more Abstract Leong and Peach (J. Fluorine Chem., 6, 145 (1975) have shown that at room temperature pentafluorothiophenol readily reacted with 1-hexene and phenylacetylene forming adducts, the reactions following anti-Markovnik type regio-selectivity, and suggested a free radical mechanism.
Journal of Macromolecular Science: Part A - Chemistry, 1983
Abstract Polystyrene, cross-linked with 7.8% of divinylbenzene, formed a stable complex in chloro... more Abstract Polystyrene, cross-linked with 7.8% of divinylbenzene, formed a stable complex in chloroform with boron trifluoride containing 0.11% of boron, while cross-linked polystyrene-4-vinylpyridine resins containing 2–2.5% of pyridine rings formed a stable complex with boron trifluoride, containing 1.04% of boron. Both complexes catalyze conversions of aromatic aldehydes, ketones, and acids with alcohols into corresponding acetals, cyclic ketals, and esters; diphenylmethanol converts into ether. The structure of the alcohol plays an important role, with conversions decreasing in the order 1-butanol, 2-butanol, tert-butanol. Both complexes are very stable and in most cases more reactive than the cross-linked polystyrene-A1C13 complex.
Journal of the Chemical Society, Perkin Transactions 1, 1989
The reaction of crosslinked poly (styrene-4-vinylpyridine), containing 4244% of pyridine rings, ... more The reaction of crosslinked poly (styrene-4-vinylpyridine), containing 4244% of pyridine rings, in chloroform suspension with a mixture of hydrogen chloride and iodine chloride formed the cross-linked poly {styrene-[4-vinyl pyridinium dichloroiodate (I)]}(PSVP). Better ...
ABSTRACT Solutions of maleic anhydride, occurring in the waste water of the organic chemical indu... more ABSTRACT Solutions of maleic anhydride, occurring in the waste water of the organic chemical industry in the Koper area (Slovenia) and subsequently entering the river Rižana and the Bay of Koper (Gulf of Trieste, northern Adriatic), in distilled, riverine and artificial and natural sea water were photolyzed using photochemical reactors and exposure to sunlight. The transformation of maleic anhydride under artificial light proceeds first through hydrolysis to maleic acid and then photochemical isomerization of maleic acid to fumaric acid, its partial decarboxylation and polymerization. The polymeric product formed is complex consisting of chains with methylene and methine groups and these chains connected by ether and ester bonds. The average molecular weights of the polymers formed were distributed in a broad range lower than 4200. The izomerization is catalyzed by inorganic ions and to a lesser extent by dissolved organic matter (DOM) while polymerization is inhibited by inorganic ions but DOM has a negligible effect. The quantum yields ranged between 0.03–0.04. The influence of the air atmosphere was negligible.
ABSTRACT The photodegradation rates of phthalic and maleic anhydrides in aqueous media are enchan... more ABSTRACT The photodegradation rates of phthalic and maleic anhydrides in aqueous media are enchanced in the presence of semiconductor Tio2 and ZnO oxydes. This effect is dependent on pH and concentration of catalyst. The degradation of phthalic anhydride is, in contrast to maleic anhydride, also enhanced in O2 atmosphere in the absence of catalysts.
ABSTRACT The biodegradation of 2‐halosubstituted and 4‐halosubstituted benzyl alcohols was studie... more ABSTRACT The biodegradation of 2‐halosubstituted and 4‐halosubstituted benzyl alcohols was studied using two sources of biodegrative micro‐organisms: mixed culture from the ŠTUDA waste water treatment plant, Domžale, and the white rot fungus Phanerochaete chrysosporium strain MZKI B‐223 (ATCC 24725). The results obtained by this study indicate the interrelationship between the types of micro‐organism used in the experiments and the type and position of the halogen element on the aromatic ring.
3',5&... more 3',5'-dimethoxybenzoin (DMB) is an important photoremovable protecting group. The primary photoreactions of DMB acetate and fluoride following photoexcitation by a subpicosecond laser flash were investigated by pump-probe spectroscopy. The primary photoproduct is identified as a preoxetane biradical intermediate that decays by different pathways depending on solvent polarity. In polar solvents (acetonitrile, water), the biradical decays by releasing acetate or fluoride with a lifetime of about 2 ns. Thus, DMB is an excellent protecting group for the investigation of fast processes such as protein folding.
Competing ionic and radical photobehaviour has been observed for 2-halogeno-1,1-diphenylethylenes... more Competing ionic and radical photobehaviour has been observed for 2-halogeno-1,1-diphenylethylenes. Irradiation of 2-fluoro-1,1-diphenylethylene in cyclohexane or ether afforded cis- and trans-fluorostilbene. Irradiation of the chloro, bromo, or iodo analogues gave a complex mixture of up to eight products, the three major products being diphenylacetylene, 1,1-diphenylethylene, and 1,1,4,4-tetraphenylbutadiene. The product distribution proved to depend on the halogen and on the solvent. Benzophenone or xanthone sensitised irradiation of 2-fluoro-1,1-diphenylethylene in cyclohexane gave 1-cyclohexyl-1-fluoro-2,2-diphenylethane, while irradiation of 2-chloro 1,1-diphenylethylene gave 2-cyclohexyl-1,1-diphenylethylene.
Acta Crystallographica Section C Crystal Structure Communications, 1994
The structure contains discrete molecules of the 1:2 adduct of octafluoronaphthalene with indene:... more The structure contains discrete molecules of the 1:2 adduct of octafluoronaphthalene with indene: (4bα,4cα,8bβ,8cβ,13bβ,13cβ,13dα,13eα)-4c,5,6,7,8,8b,13c,13d-octafluoro-4b,4c,8b,8c,9,13b,13c,13d,13e,14-decahydrobis(indeno[1',2':3,4]cyclobuta)[1,2-α:1',2'-c]naphthalene [Chem. Abstr. (1992). 116, 3468f]. The bond lengths and angles are normal for this type of compound and there are no unusual close intermolecular contacts in the structure
Photoaddition of indene or 1,2-dihydronaphthalene to hexafluorobenzene in cyclohexane solution re... more Photoaddition of indene or 1,2-dihydronaphthalene to hexafluorobenzene in cyclohexane solution results in the formation of cis-syn-cis-2 + 2-cycloadducts.
Journal of the Chemical Society, Perkin Transactions 1, 1987
The stereochemistry of photocycloaddition reactions of various cycloalkenes to hexafluorobenzene ... more The stereochemistry of photocycloaddition reactions of various cycloalkenes to hexafluorobenzene in cyclohexane solution depends on the structure of the cycloalkene, and [2 + 2] cycloadducts are mainly observed. [1,3]-Photocycloaddition is observed only when a large excess of the cycloalkene is used (hexafluorobenzene: cyclopentene, 1 :8) and at higher concentrations. Photoreactions with indene and 1,2-dihydronaphthalene occur stereospecifically syn, and a cis–syn–cis[2 + 2] cycloadduct is isolated. The photocycloaddition reaction with norbornene proceed exclusively exo, with preferential syn addition accompanied by 5%anti-addition. The stereochemistry of the [2 + 2]-photocycloaddition reactions is changed completely in the case of cyclopentene, where 85%anti addition is observed. The course of anti-photocycloaddition diminishes with increasing ring size of the cycloalkene until in the case of cyclooctene, it is reduced to 53%. The quantum yields of [2 + 2]-photocycloadditions, depend on the structure of the cycloalkene and on the concentration of hexafluorobenzene, the greatest effect being observed during [2 + 2]-cycloaddition with indene.
Phosphorus and Sulfur and the Related Elements, 1979
Abstract Leong and Peach (J. Fluorine Chem., 6, 145 (1975) have shown that at room temperature pe... more Abstract Leong and Peach (J. Fluorine Chem., 6, 145 (1975) have shown that at room temperature pentafluorothiophenol readily reacted with 1-hexene and phenylacetylene forming adducts, the reactions following anti-Markovnik type regio-selectivity, and suggested a free radical mechanism.
Journal of Macromolecular Science: Part A - Chemistry, 1983
Abstract Polystyrene, cross-linked with 7.8% of divinylbenzene, formed a stable complex in chloro... more Abstract Polystyrene, cross-linked with 7.8% of divinylbenzene, formed a stable complex in chloroform with boron trifluoride containing 0.11% of boron, while cross-linked polystyrene-4-vinylpyridine resins containing 2–2.5% of pyridine rings formed a stable complex with boron trifluoride, containing 1.04% of boron. Both complexes catalyze conversions of aromatic aldehydes, ketones, and acids with alcohols into corresponding acetals, cyclic ketals, and esters; diphenylmethanol converts into ether. The structure of the alcohol plays an important role, with conversions decreasing in the order 1-butanol, 2-butanol, tert-butanol. Both complexes are very stable and in most cases more reactive than the cross-linked polystyrene-A1C13 complex.
Journal of the Chemical Society, Perkin Transactions 1, 1989
The reaction of crosslinked poly (styrene-4-vinylpyridine), containing 4244% of pyridine rings, ... more The reaction of crosslinked poly (styrene-4-vinylpyridine), containing 4244% of pyridine rings, in chloroform suspension with a mixture of hydrogen chloride and iodine chloride formed the cross-linked poly {styrene-[4-vinyl pyridinium dichloroiodate (I)]}(PSVP). Better ...
ABSTRACT Solutions of maleic anhydride, occurring in the waste water of the organic chemical indu... more ABSTRACT Solutions of maleic anhydride, occurring in the waste water of the organic chemical industry in the Koper area (Slovenia) and subsequently entering the river Rižana and the Bay of Koper (Gulf of Trieste, northern Adriatic), in distilled, riverine and artificial and natural sea water were photolyzed using photochemical reactors and exposure to sunlight. The transformation of maleic anhydride under artificial light proceeds first through hydrolysis to maleic acid and then photochemical isomerization of maleic acid to fumaric acid, its partial decarboxylation and polymerization. The polymeric product formed is complex consisting of chains with methylene and methine groups and these chains connected by ether and ester bonds. The average molecular weights of the polymers formed were distributed in a broad range lower than 4200. The izomerization is catalyzed by inorganic ions and to a lesser extent by dissolved organic matter (DOM) while polymerization is inhibited by inorganic ions but DOM has a negligible effect. The quantum yields ranged between 0.03–0.04. The influence of the air atmosphere was negligible.
ABSTRACT The photodegradation rates of phthalic and maleic anhydrides in aqueous media are enchan... more ABSTRACT The photodegradation rates of phthalic and maleic anhydrides in aqueous media are enchanced in the presence of semiconductor Tio2 and ZnO oxydes. This effect is dependent on pH and concentration of catalyst. The degradation of phthalic anhydride is, in contrast to maleic anhydride, also enhanced in O2 atmosphere in the absence of catalysts.
ABSTRACT The biodegradation of 2‐halosubstituted and 4‐halosubstituted benzyl alcohols was studie... more ABSTRACT The biodegradation of 2‐halosubstituted and 4‐halosubstituted benzyl alcohols was studied using two sources of biodegrative micro‐organisms: mixed culture from the ŠTUDA waste water treatment plant, Domžale, and the white rot fungus Phanerochaete chrysosporium strain MZKI B‐223 (ATCC 24725). The results obtained by this study indicate the interrelationship between the types of micro‐organism used in the experiments and the type and position of the halogen element on the aromatic ring.
3',5&... more 3',5'-dimethoxybenzoin (DMB) is an important photoremovable protecting group. The primary photoreactions of DMB acetate and fluoride following photoexcitation by a subpicosecond laser flash were investigated by pump-probe spectroscopy. The primary photoproduct is identified as a preoxetane biradical intermediate that decays by different pathways depending on solvent polarity. In polar solvents (acetonitrile, water), the biradical decays by releasing acetate or fluoride with a lifetime of about 2 ns. Thus, DMB is an excellent protecting group for the investigation of fast processes such as protein folding.
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