Photochemical reaction of magnesium tetraphenyl porphyrin with sulfur dioxide

<正>The photochemical reaction of magnesium tetraphenyl porphyrin(MgTPP) with sulfur dioxide(SO_2) was investigated in dichloromethane(CH_2Cl_2) by steady-state fluorescence,UV-vis absorption,MS,and XRD spectroscopic techniques.These spectra showed that under irradiation MgTPP reacted with SO_2 to form 1:1 molecular adduct at first step.During the process of keeping irradiation and maintaining the flow of SO_2,SO_2 was reduced into S~(2-) by MgTPP and the results were detected using MS and XRD techniques.Understanding the photochemical reaction of MgTPP with SO_2 is of key interest in elucidating fundamental photochemical reaction mechanisms associated with this class of chlorophyll in the presence of SO_2.     

Photochemical reaction of sulfur hexafluoride with water in low-temperature xenon matrices

Sulfur hexafluoride SF(6) is a very stable molecule with which very few reactions with other molecules have been reported. Here, we report a photochemical reaction of SF(6) with water molecules using a matrix-isolation technique, where SF(6) and H(2)O were co-condensed in Xe matrices, and the products were observed using infrared spectroscopy. Irradiation at 193 nm from an ArF excimer laser caused the simultaneous decomposition of SF(6) and H(2)O, which resulted in the production of novel species. Infrared spectra and molecular orbital calculations of the species showed that the product was a SF(4)?HF?HOF complex, which consists of hydrogen bonds and charge transfer interaction between S and F atoms. The assignment of the species was confirmed by isotope shifts using D and (18)O isotope substitutions.     

Stable sulfinic acids from the ene reaction of methyl-substituted allenes with sulfur dioxide

Allenes 2,4-dimethyl-2,3-pentadiene and 3-methyl-1,2-butadiene in liquid sulfur dioxide undergo ene addition with the solvent giving the stable 3-(2,4-dimethyl-1,2-pentadienyl) and 2-(3-methyl-1,2-butadienyl) sulfinic acids.     

The photochemically induced reaction of sulfur dioxide with alkanes and carbon monoxide

Abstract— The gas phase photochemical reactions of SO₂ induced by 3130 Å radiation have been studied in the presence of added alkanes or added CO. The quantum yields obtained in the reactions with the low molecular weight alkanes employed are lower than those obtained by previous workers. The quantum yields were found to be pressure dependent increasing slowly with increasing pressure. A stoichiometric ratio of one SO₂ removed per molecule of hydrocarbon consumed was observed only under experimental conditions of [SO₂] < [RH]. For reaction mixtures where [SO₂] < [RH] the ratio of [SO₂]/[RH] reacted always exceeded unity. The quantum yields decreased slightly with increasing temperature. In all the alkane reaction systems studied, the deposition of viscous, nonvolatile reaction products was observed. In the experiments with added CO, the quantum yields were computed with respect to the rate of CO₂ formation. At 25°C and equal pressures of SO₂ and CO, φco₂ was observed to be 0.005 and it decreased slightly with increasing temperature. The results obtained are interpreted in terms of the sulfoxidation of the alkanes and the oxidation of CO proceeding by way of a ³SO₂ reaction intermediate.     

A study of the reaction of sulfur with organic compounds

The reaction of sulfur with isomeric exo-polychloro derivatives of iso- and n-propylbenzenes containing from 4 to 6 chlorine atoms in the side chain at 200°–300° C has been studied. The reaction of sulfur with , , , -tetrachloro- and , , , , -pentachlorocumenes leads to the formation of the previously unknown thianaphtheno-[2, 3-d]-1, 2-dithiole-3-thione (yield 48%) and thionaphtheno[2,3-d]-3-chloro-1, 2-dithiolium chloride (yield 65%), respectively. The sulfuration reaction of the isomeric exo-tetrachloro-and exo-pentachloro-n-propylbenzenes leads to the formation of 4-chloro-5-phenyl-1, 2-dithiole-3-thione (yield 5–35%). The exo-hexachloro derivatives of iso- and n-bromobenzenes, on being heated with sulfur, form only resinous sulfuration products.For part XVI, see [1].     

A study of the reaction of sulfur with organic compounds

The reaction of sulfur with isomeric exo-polychloro derivatives of iso- and n-propylbenzenes containing from 4 to 6 chlorine atoms in the side chain at 200°–300° C has been studied. The reaction of sulfur with α, β, β, β′-tetrachloro- and α, β, β, β′, β′-pentachlorocumenes leads to the formation of the previously unknown thianaphtheno-[2, 3-d]-1, 2-dithiole-3-thione (yield 48%) and thionaphtheno[2,3-d]-3-chloro-1, 2-dithiolium chloride (yield 65%), respectively. The sulfuration reaction of the isomeric exo-tetrachloro-and exo-pentachloro-n-propylbenzenes leads to the formation of 4-chloro-5-phenyl-1, 2-dithiole-3-thione (yield 5–35%). The exo-hexachloro derivatives of iso- and n-bromobenzenes, on being heated with sulfur, form only resinous sulfuration products.     

A study of the reaction of sulfur with organic compounds

The reactions of sulfur with alip-halogen derivatives of 1,2-diphenylethane, 1,2-diphenylethylene, and tetraphenylethane have been studied. A new method for the production of tetraphenylthiophene (from C₆H₅CHClCHClC₆H₅), benzothieno[3,2-b]benzothiophene (from C₆H₅CHClCCl₂C₆H₅), and of 2-phenylbenzo[b] thiophene (from C₆H₅CHBrCHBrC₆H₅) has been developed. On being treated with sulfur, tetraphenyl-1,2-dichloroethane is converted into tetraphenylethylene. 1,2-Diphenylethylene reacts with sulfur in the presence of hydrogen bromide forming 2-phenylbenzo[b]thiophene and tetraphenylthiophene.For part XVII, see [1].     

The reaction of CO2 dimer ions with sulfur dioxide

The rate coefficient and the product distribution have been determined for the reaction CO₂-CO⁺₂ with sulfur dioxide.     

Stereochemistry at titanium in the sulfur dioxide insertion reaction of titanocene compounds

The insertion reaction of SO₂ has been studied for the two diastereoisomeric forms of η⁵-C₅H₅-η⁵-C₅H₄ CHMePhTi(C₆F₅)CH₃. The reaction is regioselective and stereospecific. Arguments that it involves a retention at the titanium atom are given.     

Thermostimulated formation of silver and gold nanoparticles in porous silicon dioxide matrices

Manifestations of thermostimulated formation and subsequent transformation of silver and gold nanoparticles in porous opal and Vycor glass matrices are studied using optical spectroscopy. Two temperature ranges for silver nanoparticles are revealed, where first-type particles transform into another type of particles. With gold nanoparticles in these matrices, a temperature range in which one type of particles transforms into another type is established. An effect of complete blackening of Vycor glass samples, caused by their annealing, is revealed, and a rationalization of this effect is given.     

A Kinetic study of the reaction of nitrogen dioxide with tetrafluoroethylene

The reaction of NO₂ with C₂F₄ was studied at 30°, 68°, 114°, and 157°C by in situ monitoring the infrared absorption bands of the products. The major primary products of the reaction are O₂NCF₂CFO and FNO. Smaller amounts of CF₂O (and presumably NO) are also produced. There was no evidence for other primary products, though they may have been produced in minor amounts. The rate laws for the production of both O₂NCF₂CFO and CF₂O are first order in both [NO₂] and [C₂F₄]. CF₂O production is at least partly heterogeneous as demonstrated by packing the quartz reaction vessel with Pyrex beads and by using a Monel cell. The homogeneous rate constant obtained from the high-temperature results gives a rate constant of 3.4 × 10⁸ exp (minus;17000/RT) M^?1sec^?1 for CF₂O production. Actually these Arrhenius parameters represent lower limits, since the heterogeneous reaction may still be playing a significant role. The production rate of O₂NCF₂CFO is not much affected by changing the nature of the surface or the surface to volume ratio. However the reaction may be heterogeneous, since the rate constant for its formation of 1.3 × 10⁴ e×p (?7500/RT) M^?1sec^?1 has an abnormally low pree×ponential factor. E×periments in the presence of NO indicate that the mechanism for O₂NCF₂CFO formatlon is The intermediate can also react with NO: with k₁₃/k₁₂ = 1.3.     

A new chemical for measuring humidity on the basis of the reaction of sulfur dioxide oxidation with iodine

Russian Journal of Applied Chemistry -     

Simple spectrophotometry method for the determination of sulfur dioxide in an alcohol-thionyl chloride reaction

Thionyl chloride is often used to convert alcohols into more reactive alkyl chloride, which can be easily converted to many compounds that are not possible from alcohols directly. One important reaction of alkyl chloride is nucleophilic substitution, which is typically conducted under basic conditions. Sulfur dioxide, the by-product from alcohol-thionyl chloride reactions, often reacts with alkyl chloride to form a sulfonyl acid impurity, resulting in yield loss. Therefore, the alkyl chloride is typically isolated to remove the by-products including sulfur dioxide. However, in our laboratory, the alkyl chloride formed from alcohol and thionyl chloride was found to be a potential mutagenic impurity, and isolation of this compound would require extensive safety measures. As a result, a flow-through process was developed, and the sulfur dioxide was purged using a combination of vacuum degassing and nitrogen gas sweeping. An analytical method that can quickly and accurately quantitate residual levels of sulfur dioxide in the reaction mixture is desired for in-process monitoring. We report here a simple ultraviolet (UV) spectrophotometry method for this measurement.     

Sulfur dioxide mediated one-pot, three- and four-component syntheses of polyfunctional sulfonamides and sulfonic esters: study of the stereoselectivity of the ene reaction of sulfur dioxide

The ene reaction of sulfur dioxide with enoxysilanes or with allylsilanes generates silyl sulfinates that can be brominated (Br(2) or NBS) or chlorinated (NCS or Cl(2)) to produce the corresponding sulfonyl halides. They react with primary and secondary amines or alcohols to give the corresponding sulfonamides and sulfonic esters, respectively. The hetero-Diels-Alder addition of sulfur dioxide to 1-oxy- or 1,3-dioxy-1,3-dienes generates zwitterions that add to enoxysilanes or allylsilanes giving silyl sulfinates that can be converted in situ into polyfunctional sulfonamides or sulfonic esters. This realizes quick access to libraries of complicated sulfonamides and sulfonic esters applying one-pot, three- and four-component methods.     

Theoretical study on reaction mechanism of the ketenylidene radical with nitrogen dioxide

The complex doublet potential-energy surface for the reaction of CCO with NO2, including 8 minimum isomers and 17 transition states, is explored theoretically using the coupled cluster and density functional theory. The association of CCO with NO2 was found to be a barrierless process forming an energy-rich adduct a (OCCNO2) followed by oxygen shift to give b (O2CCNO). Our results show that the product P1 (CO2 + CNO) is the major product with absolute yield, while the product P4 (2CO + NO) is the minor product with less abundance. The other products may be undetectable. The product P1 (CO2 + CNO) can be obtained through R --> a --> b --> P1 (CO2 + CNO), whereas the product P4 (2CO + NO) can be obtained through two channels R --> a--> b --> c --> (d, g) --> P2 (OCNO + CO) --> P4 (2CO + NO) and R --> a --> b --> f --> P3 (c-OCC-O + NO) --> P4 (2CO + NO). Because the intermediates and transition states involved in the above three channels are all lower than the reactants in energy, the CCO + NO2 reaction is expected to be rapid, which is consistent with the experimental measurement in quality. The present study may be helpful for further experimental investigation of the title reaction.