Photolysis Of Bis Research Articles

Photolysis of bis(2-ethylhexyl) phthalate in aqueous solutions at the presence of natural water photoreactive constituents under simulated sunlight irradiation.

The photolysis of bis(2-ethylhexyl) phthalate (DEHP) under simulated sunlight in the presence of the natural water photoreactive constituents was investigated. The presence of nitrate or ferric ions facilitated the photodegradation of DEHP via oxidation by generation of •OH. The fulvic acids (FAs), at low concentrations, promoted the photolysis of DEHP via energy transfer from the photoreaction-generated 3FA*. However, the DEHP photolysis was inhibited with high concentrations of FAs since the excess FAs at the surface of solution could act as light screening agents to keep FAs in bulk solution from the light irradiation, further reducing the 3FA* generation. When low concentrations of FAs and chloride ions coexist, the reactive chloride species Cl• and Cl2•- could generate via energy transfer from 3FA* to chloride ions and react with DEHP to enhance its degradation. Furthermore, the direct and •OH-initiated DEHP photodegraded intermediates and end products were identified by HPLC-MS2 and its corresponding photolysis pathways were proposed.

Special features of photolytic transformation of tin heteropolymetallic catecholate complexes

The photolysis of bis(dicarbonylcyclopentadienyliron)(3,6-di-tert-butylcatecholato)tin(IV), bis(dicarbonylcyclopentadienylmolybdenum)(3,6-di-tert-butylcatecholato)tin(IV), and bis(dicarbonylcyclopentadienyltunsten)(3,6-di-tert-butylcatecholato)tin(IV) in solutions of saturated hydrocarbons was studied. Kinetic parameters of the transformation of these compounds under the action of a monochromatic radiation with a wavelength of 313 nm were determined. Products of their transformation formed in the course of the irradiation were identified, and the probable mechanism of their photodecomposition was proposed.

Magnetic isotope effect for mercury nuclei in photolysis of bis(p-trifluoromethylbenzyl)mercury

Magnetic isotope effect for mercury nuclei in photolysis of bis(p-trifluoromethylbenzyl)mercury

Alkoxy-substituted group 6 allenylidene complexes – Synthesis and properties

Bis(alkoxy)allenylidene complexes, [(CO) 5M C C C(OR′)OR], as well as mono(alkoxy)allenylidene complexes, [(CO) 5M C C C(OR′)Ph], of chromium and tungsten are accessible from propynones [H C C C( O)Ph] or propynoic acid esters [H C C C( O)OR; R = Et, (−)-menthyl, endo-bornyl] by the following reaction sequence: (a) deprotonation of the alkynes, (b) reaction with [(CO) 5M-THF] (M = Cr, W), and (c) alkylation of the resulting alkynyl metallate, [(CO) 5M C C C( O)R], with Meerwein salts. Vinylidene complexes, [(CO) 5M C C(R′)C( O)OR], are formed as a by-product by C β-alkylation of the alkynyl metallate. Dimethylamine displaces one alkoxy substituent of the bis(alkoxy)allenylidene complexes to give dimethylamino(alkoxy)allenylidene complexes, [(CO) 5M C C C(OR)NMe 2]. The analogous reaction of dimethylamine with a mono(alkoxy)-substituted allenylidene complex affords the aminoallenylidene complex [(CO) 5Cr C C C(NMe 2)Ph]. When the amine is used in large excess, the α,β-unsaturated aminocarbene complex [(CO) 5Cr C(NMe 2) C(H) C(NMe 2)Ph] is additionally formed by addition of the amine across the C α C β-bond of the allenylidene ligand. The reaction of [(CO) 5M C C C(OEt) 2] with dimethyl ethylenediamine offers access to bis(amino)allenylidene complexes, in which C γ is part of a five-membered heterocycle. Photolysis of bis(alkoxy)allenylidene complexes in the presence of triphenylphosphine yields tetracarbonyl- and tricarbonyl{bis(phosphine)}allenylidene complexes. Diethylaminopropyne inserts into the C β C γ bond of [(CO) 5M C C C(OEt)OMethyl] to give alkenylallenylidene complexes. Subsequent acid-catalyzed intramolecular cyclization affords a pyranylidene complex.

The photolysis of bis(dithiobenzil)nickel in chloroform

Bis(dithiobenzil)nickel, although photoinert in nonhalogenated solvents as well as in chloroform under 313 nm irradiation, reacts in CHCl3 under 254 nm irradiation to yield 2,3,5,6-tetraphenyl-1,4-dithiin and a water-soluble nickel(II) species. The reaction is driven through absorption of light by both the solvent and the metal complex.

The photolysis of bis(benzene)chromium(I) in chloroform

Irradiation of [Cr(C 6H 6) 2]Cl in chloroform at 254 nm yields CrCl 3. The reaction occurs primarily through the photodissociation of CHCl 3, followed by attack by CCl 3 radicals or HCl on the complex.

Sensitive Wavelength Dependence of PdC And Pd Formation from Photolysis of Bis(hexafluoroacetylacetonato)palladium(II)

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTADDITION / CORRECTIONThis article has been corrected. View the notice.Sensitive Wavelength Dependence of PdC And Pd Formation from Photolysis of Bis(hexafluoroacetylacetonato)palladium(II)Peter Muraoka, Daniel Byun, and Jeffrey I. ZinkView Author Information Department of Chemistry and Biochemistry University of California, Los Angeles, California 90095 Cite this: J. Am. Chem. Soc. 2000, 122, 6, 1227–1228Publication Date (Web):January 29, 2000Publication History Received27 September 1999Published online29 January 2000Published inissue 1 February 2000https://doi.org/10.1021/ja993476vCopyright © 2000 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views167Altmetric-Citations10LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (38 KB) Get e-AlertsSUBJECTS:Ions,Molecules,Palladium,Quantum mechanics,Resonance structures Get e-Alerts

Sensibilisierte Photolyse von Bis(dimethylglyoximato)cobalt(III)-Komplexen mit axial koordiniertem Azid bzw. Thiophenolat als photochemischen Opferliganden

Sensitized Photolysis of Bis(dimethylglyoximato)cobalt(III) Complexes with Axially Coordinated Azide or Thiophenolate as Photochemical Sacrificial Ligands The photolysis of [N3Co(dmg)2pyr] 1a and [PhSCo(dmg)2pyr] 1b (dmg = dimethylglyoxime, pyr = pyridine) is sensitized by both [Ru(bpy)3]Cl22 (bpy = 2,2′-bipyridine) and Michler's thioketone 3 (4,4′-bis(dimethyl-amino)-thiobenzophenone). Quenching of 2 by the cobalt(III) chelates 1a and 1b was studied by luminescence spectroscopy. The quenching rate constants calculated are in the order of magnitude of kq ≅ 106 mol−1 s−1. Polychromatic irradiation (> 250 nm) of 1b and 3 in the presence of thiophenole (PhSH) leads to hydrogen evolution, whereas long-wavelength (546 nm) irradiation does not. The results of these sensitization experiments support strongly a mechanism of catalyzed photolysis of PhSH as proposed earlier.

Copper Fluoride Luminescence during UV Photofragmentation of Bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)copper(II) in the Gas Phase.

Gas phase 308 and 350-370 nm photolysis of bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)copper(II), Cu(hfac)(2), produces CuF as well as copper atoms and dimers. These metal-containing fragments, identified by luminescence spectroscopy, are studied under a variety of gas phase conditions ranging from 1 bar in a static chamber to 10(-4) mbar in a collision-free molecular beam. Copper atom and dimer luminescence is observed at the higher pressures, whereas at low pressures (total pressure no greater than the vapor pressure of the sample) exclusively CuF emission is observed. The a, A (omega = 0, 1, 2), B, and C excited states at 681.0, 567.6, and 505.1, and 491.7 nm are observed. The (3)Pi(0)(-) component of the A state is observed for the first time. The CuF luminescence obeys a quadratic power law with 308 nm excitation. The partitioning of excess energy into fragment degrees of freedom is determined from the intensities of the emission lines. The vibrational and rotational temperatures of the CuF fragment are in excess of 1700 K. Mechanisms of CuF formation, comparisons with the free ligand and with other volatile copper complexes, and the implications for laser-assisted chemical vapor deposition are discussed.

Decomposition of bis(silyldiazomethyl) polysilanes: formation of polysilabicyclo[1.m.n]alkane derivatives

The photolysis of bis(trimethylsilyldiazomethyl)disilane ( 4a) in tert-butyl alcohol provided the tert-butyl alcohol adducts 5, 6, 7, 8 and 9. The structures of these products revealed the stepwise formation of asymmetric silenes as intermediates. Gas-phase pyrolysis of 4a and subsequent reaction with methanol and 4-methyl-1,2,4-triazoline-3,5-dione yielded the compounds 13 and 14, which are derived from the 1,4-disilabutadiene intermediate ( 16) rather than 1,2-disilacyclobutene ( 15). The photolysis and thermolysis of bis(dimethylphenylsilyl-diazomethyl)trisilane ( 4b) afforded 21b, 22b, 23b and 24b. Formation of compound 21b is attributed to the head-to-tail [2 + 2]cycloaddition of 1,5-disila-1,4-pentadiene ( 26b), while that of 23b, 22b and 24b is attributed to head-to-head [2 + 2]cycloaddition of 26 followed by reactions with tert-butyl alcohol and oxygen. Photolysis and pyrolysis of bis(trimethylsilyldiazomethyl)trisilane ( 4c) and bis(dimethyl-phenylsilyldiazomethyl)tetrasilane ( 4d) gave 29, 30 and 21d, which is consistent with an alternative mechanism, i.e. [2 + 2]silene-diazo cycloaddition.

Development of Highly Efficient Deep-UV and Electron Beam Mediated Cross-Linkers: Synthesis and Photolysis of Bis(perfluorophenyl) Azides

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDevelopment of Highly Efficient Deep-UV and Electron Beam Mediated Cross-Linkers: Synthesis and Photolysis of Bis(perfluorophenyl) AzidesSui Xiong Cai, Denis J. Glenn, Manoj Kanskar, M. N. Wybourne, and John F. W. KeanaCite this: Chem. Mater. 1994, 6, 10, 1822–1829Publication Date (Print):October 1, 1994Publication History Published online1 May 2002Published inissue 1 October 1994https://doi.org/10.1021/cm00046a041RIGHTS & PERMISSIONSArticle Views627Altmetric-Citations28LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (3 MB) Get e-Alerts Get e-Alerts

Convenient unimolecular sources of aryloxyl radicals. III - photolysis of bis(aryloxy)phosphine azides

Photolysis of sterically hindered bis(aryloxy)phosphine azides in solution, frozen matrix, or neat solid states leads to facile unimolecular production of aryloxyl radicals.

5035244 Motion artifact minimization

The photolysis of bis(trimethylsilyldiazomethyl)disilane (4a) in tert-butyl alcohol provided the tert-butyl alcohol adducts 5, 6, 7, 8 and 9. The structures of these products revealed the stepwise formation of asymmetric silenes as intermediates. Gas-phase pyrolysis of 4a and subsequent reaction with methanol and 4-methyl-1,2,4-triazoline-3,5-dione yielded the compounds 13 and 14, which are derived from the 1,4-disilabutadiene intermediate (16) rather than 1,2-disilacyclobutene (15). The photolysis and thermolysis of bis(dimethylphenylsilyl-diazomethyl)trisilane (4b) afforded 21b, 22b, 23b and 24b. Formation of compound 21b is attributed to the head-to-tail [2 + 2]cycloaddition of 1,5-disila-1,4-pentadiene (26b), while that of 23b, 22b and 24b is attributed to head-to-head [2 + 2]cycloaddition of 26 followed by reactions with tert-butyl alcohol and oxygen. Photolysis and pyrolysis of bis(trimethylsilyldiazomethyl)trisilane (4c) and bis(dimethyl-phenylsilyldiazomethyl)tetrasilane (4d) gave 29, 30 and 21d, which is consistent with an alternative mechanism, i.e. [2 + 2]silene-diazo cycloaddition.

Photochemical behavior of thioxophosphoranyl diazo compounds: evidence for transient .lambda.5-phosphathiirenes and for structural isomerizations of the diazo group

Photolysis of bis[bis(diisopropylamino)thioxophosphoranyl]diazomethane (1) in the presence of a slight excess of dimethyl acetylenedicarboxylate led to 1,3λ 5 -thiaphosphole 5 in 95% yield. This compound was fully characterized including an X-ray diffraction study. Irradiation of (thioxophosphoranyl)(trimethylsilyl)diazomethane 2 gave rise to [bis(diisopropylamino)thioxophosphoranyl](trimethylsilyl)carbodiimide 6 in 60% yield

Photolysis of bis(methoxyphenyl) methylphosphonates. Their emission spectra and formation of dimethoxybiphenyl and dimethoxy-9,10-dioxaanthracene.

Upon UV-irradiation in methanol, bis(methoxyphenyl) methylphosphonates underwent an intramolecular coupling of two methoxyphenyl groups to give dimethoxybiphenyls and dimethoxy-9,10-dioxaanthracenes. The reactivities and fluorescence spectra of the phosphonates were sensitive to the position of the methoxy group. These photo-induced couplings proceed probably through the formation of the two types of singlet intramolecular excimers.

On the photolysis of bis[2-( o-chlorophenyl)-4,5-diphenylimidazole] sensitized by 2-isopropylthioxanthone or Michler's ketone

The triplet states of 2-isopropylthioxanthone (ITX) and 4,4′-bis( N,N′-dimethylamino)benzophenone (Michler's ketone, MK) react very rapidly with bis[2-( o-chlorophenyl)-4,5-diphenylimidazole] (I 1) as inferred from flash photolysis studies. The rate constants of the reaction of 3ITX * and 3MK * with I 1 (determined at room temperature in acetonitrile and benzene solution) are about 1 × 10 10 dm 3 mol −1 s −1. Imidazolyl radicals (R 1 ) are formed in these reactions as the major product (φ(R 1 ) = 1.1). By contrast, the quantum yield is higher (φ(R 1 ) ≈ 2 in the direct photolysis of I 1. With respect to the reaction mechanism, triplet—triplet energy transfer can be excluded since E T(I 1) > E T(ITX) and E T(I 1) > E T(MK). Electrical conductivity measurements reveal that, in the system MK—I 1, free ions are formed with a very low yield (φ(ion) ⩽ 0.01), which indicates that charge transfer complexes do not play a prominent role as intermediates in the reaction mechanism. It is postulated that, in the reaction of the sensitizer triplets with I 1, an encounter complex is formed which decomposes very quickly, the mutual orientation of T and I 1 determining the path of the decomposition. The latter involves either the formation of imidazolyl radicals or the formation of the starting compounds.

Carboranyl Derivatives of Phosphorus Acids with Boron-Phosphorus Bond

Abstract Carboranyl derivatives of phosphorus acids with boron-phosphorus bond can be obtained in two ways: 1. Photolysis of bis(m-carboran-9-yl)- and bis(p-carboran-2-yl)mercury in trimethylphosphite leads to the formation of dimetiiyl ester of (m-carboran-3-yl)- and (p-carboran-2-yl)phosphonic acids: 2. Photolysis of bis(o-carboran-9-yl)- and bis(m-carboran-3-yl)mercury in PC13 results in the formation of (o-carboran-9-yl)- and (m-carboran-9-yl)dichlorophosphines: Oxidation of (boron-carboranyl)dichlorophosphines by sul-phuryl chloride leads to dichloroanhydrides of (boron-carboranyl)phosphonic acids: The properties of boron-carboranyl derivatives of phosphorous acids are similar to those of organic derivatives of phosphorous acids. The obtained compounds have been characterized by IR-, 11B and 31P NMR spectra. 31P NMR chemical shift of these compounds, and those of the corresponding organo-phosphorus compounds, has the same values.

Solvation of photolytically generated p-aminophenylthiyl radicals studied by sub-picosecond transient absorption

By pump-and-probe spectroscopy, the photolysis of bis-( p-aminophenyl) disulfide in diethyl ether has been followed with sub-picosecond time resolution. The visible absorption band of generated p-aminophenylthiyl radicals rises in two stages: an unresolved fast initial rise is followed by a second, exponential rise with a time constant of 5.9 ps. During the second process, the peak absorption of the band shifts from its initial position at 557.9 to 572.0 nm. A rate-equation model quantitatively accounts for the observations. The first stage is assigned to the formation of the radical pair in a common solvent cage, and the second stage to the separation and solvation of the radicals.

Carboranyl Derivatives of Phosphorus Acids with Boron-Phosphorus Bond

Abstract Carboranyl derivatives of phosphorus acids with boron-phosphorus bond can be obtained in two ways: 1. Photolysis of bis(m-carboran-9-yl)- and bis(p-carboran-2-yl)mercury in trimethylphosphite leads to the formation of dimetiiyl ester of (m-carboran-3-yl)- and (p-carboran-2-yl)phosphonic acids: 2. Photolysis of bis(o-carboran-9-yl)- and bis(m-carboran-3-yl)mercury in PC13 results in the formation of (o-carboran-9-yl)- and (m-carboran-9-yl)dichlorophosphines: Oxidation of (boron-carboranyl)dichlorophosphines by sul-phuryl chloride leads to dichloroanhydrides of (boron-carboranyl)phosphonic acids: The properties of boron-carboranyl derivatives of phosphorous acids are similar to those of organic derivatives of phosphorous acids. The obtained compounds have been characterized by IR-, 11B and 31P NMR spectra. 31P NMR chemical shift of these compounds, and those of the corresponding organo-phosphorus compounds, has the same values.

Electron paramagnetic resonance spectroscopic study of the radicals formed during the photodecomposition of some bis(alkenoyl) peroxides, a bis(alkenoyl) peroxide and some peroxydicarbonates

Photolysis, at low temperatures in cyclopropane and/or CFCl3, of bis[(E)-4,4-dimethylpent-2-enoyl]-peroxide 1, bis(4,4-dimethylpent-2-ynoyl) peroxide 2 and dipropyl peroxydicarbonate 3 yielded the corresponding carbonyloxyl radicals,viz. Me3CCHCHC(O)O˙, Me3CCCC(O)O˙ and PrOC(O)O˙, which were identified by EPR spectroscopy. Carbonyloxyl radicals were not detected on photolysis of bis(3-methylbut-2-enoyl) peroxide 4, di[(E)-cinnamoyl] peroxide 7, and bis(1-methylpropyl) peroxydicarbonate 9. All the peroxides also give other radicals many of which were identified from their EPR spectral parameters. Thus, the two bis(alkenoyl) peroxides give the ‘corresponding’ alkenylacyl radicals, viz. s-cis- and s-trans-Me3CCHCHĊO from 1 and s-trans-Me2CCHĊO from compound 2. Evidence is presented which indicates that these acyl radicals may be formed directly during the photolysis of substrates 1 and 4via a Norrish type-1 process. This would represent a new route for the photodecomposition of acyl peroxides with C–O bond scission occurring in competition with the usual O–O bond scission.