Decomposition Of 1a Research Articles

Electrophotocatalytic Si–H Activation Governed by Polarity-Matching Effects

Electrophotocatalytic Si–H Activation Governed by Polarity-Matching Effects

External Photocatalyst-Free Visible Light-Promoted 1,3-Addition of Perfluoroalkyl Iodides to Vinyldiazoacetates

External Photocatalyst-Free Visible Light-Promoted 1,3-Addition of Perfluoroalkyl Iodides to Vinyldiazoacetates

Generalized Synthesis and Physical Properties of Dialkoxy Disulfides

A substrate study was undertaken in order to probe the scope of S(2)Cl(2) coupling of alcohols to form dialkoxy disulfides. Compounds 1b and 1f are new; along with 1a, 1c, 1h, and 1j, all of the title compounds are fully characterized, and the yields of 1a and 1c have been optimized from previously reported syntheses. The effect of the R-substituent about the OSSO moiety has been carefully probed as yields vary. A substrate and a solvent study of the coalescence behavior of this class was carried out. The origin of the inherently large barrier to rotation and the resultant thermal decomposition pathway is discussed. Both phenomena are shown to be solvent independent; hindered rotation is substrate independent. The decomposition of 1a is ca. 7 kcal/mol higher than the barrier to rotation about the S-S bond. The combined evidence suggests acyclic unsymmetric homolytic cleavage of the dialkoxy disulfide.

Electron-Beam-Induced Fries Rearrangement and Oxidation Reactions of Sulfonic Acid Esters in Crystalline State

The electron beam (EB)-induced reactions of arylsulfonic acid esters, phenyl p-toluenesulfonate (1a), phenyl benzenesulfonate (1b), and phenyl 1-naphthalenesulfonate (1c), were examined in the balk state. The EB irradiation of 1a afforded the Fries rearrangement products, o- and p-hydroxyphenyl p-tolylsulfoes (2a and 3a), phenol (5) and the oxidation products of 2a, o,p-dihyroxyphenyl p-tolysulfon (4a), which has not been observed in photolysis. The EB-induced reaction of 1a exhibits higher ortho-regioselectivity at the early stage owing to crystal lattice control. The radiation of 1b, which is liquid at room temperature, give Fries rearrangement products with lower ortho/para regioselectivity. On the other hand, the EB-induced reaction of 1c proceeded with the lowest reactivity through crystal to crystal transformation to afford Fries rearrangement products, o- and p-hydroxyohenyl 1-naphthylsulfones (2c and 3c), and 5, but not oxidation product. The mechanistic study reveals that oxidation rpoduct 4a generated by the oxidation reaction of ortho-Fries rearrangement product 2a but not para-isomer 3a with an active oxidant, which should result from the decomposition of 1a.

Application of Photo Acid Generators for .GAMMA. Rays Detective Materials.

The sensitivities to γ rays were investigated for photo acid generators: N-sulfonyloxy phthalimide 2, N-sulfonyloxy succinimide 3, N-sulfonyloxy 1, 8-naphthalimide 4, N-tosyloxy 5-norbomene-2, 3-dicarboximide 5, triphenylsulfonium trifluoromethane-sulfonate 6, diphenyliodonium chloride 7 and chloroform 8. The acid generation efficiency was monitored by the use of acid sensitive dye, fluoran dye 1a. The efficiency for γ irradiation decreased in the order 7>2>6>5>3>4. In the case of 8, decomposition of 1a was accompanied. 7 and 8 were of no practical use because volatile hydrogen chloride was generated. The others (2-6) generate methanesulfonic acid, p-toluenesulfonic acid or trifluoromethanesulfonic acid which are not so volatile acid as hydrogen chloride. N-sulfonyloxy imide compounds (2-5) have an advantage for practical use as dosimeter because these reagents dissolve in either polar or nonpolar solvent.

Hydridoiridium(III) sulfoxide complexes and their reactivity toward dioxygen

Synthetic routes to hydridoiridium(III) dimethylsulfoxide complexes via oxidative addition of HCl or H2 to precursor insitu iridium(I) species are described. The complexes, trans, mer-IrHCl2(DMSO)3 (1a) and cis, mer-IrH2Cl(DMSO)3 (2), have been characterized by 1H nmr and ir, and contain only S-bonded sulphoxide, DMSO. Comparison is made with data for other isomers reported in the literature, and some discrepancies are discussed. The decomposition of 1a and 2 in chloroform leads to isomers of IrCl3(DMSO)3, while (2) with HCl generates cis,cis IrHCl2(DMSO)2(DMSO) with the O-bonded sulfoxide trans to hydride. The reaction of 1a in dichloromethane with dioxygen occurs with a 1:1 stoichiometry and generates two complexes tentatively formulated as Ir(OH)Cl2(DMSO)2H2O (3) and IrCl2(O2)(DMSO)2DMSO (4); a hydroperoxide intermediate (Ir—OOH) initially formed from 1a is considered to react with further 1a in the rate-determining step. Oxidation of coordinated DMSO to the sulphone is not observed, implying that such a catalyzed O2-oxidation reported earlier in aqueous 2-propanol proceeds via reaction of IrOOH with free DMSO, or else via free hydrogen peroxide.

Polymerization of Styrene Initiated by 1,4-Dimethyl-1,4-bis(p-anisyl)-2-tetrazene

Abstract The polymerization of styrene (St) initiated by 1,4-dimethyl-1,4-bis(p-anisyl)-2-tetrazene (1a) was studied kinetically in benzene. The polymerization proceeds through a radical mechanism. The rate of polymerization is proportional to [1a]0.5 and [St]1.0. The overall activation energy for the polymerization is found to be 81.2 kJ/mol within the temperature range of 65 to 80°C. The activation parameters for the decomposition of 1a at 70°C are kd = 1.88 × 10−5s−1, δH‡ = 133.1 kJ/mol, and δS‡ = 29.9 J/mol·deg.