1120-89-4Relevant academic research and scientific papers
Phenyl Silicates with Substituted Catecholate Ligands: Synthesis, Structural Studies and Reactivity
Levernier, Etienne,Jaouadi, Khaoula,Zhang, Heng-Rui,Corcé, Vincent,Bernard, Aurélie,Gontard, Geoffrey,Troufflard, Claire,Grimaud, Laurence,Derat, Etienne,Ollivier, Cyril,Fensterbank, Louis
, p. 8782 - 8790 (2021)
While the generation of aryl radicals by photoredox catalysis under reductive conditions is well documented, it has remained challenging under an oxidative pathway. Because of the easy photo-oxidation of alkyl bis-catecholato silicates, a general study of phenyl silicates bearing substituted catecholate ligands has been achieved. The newly synthesized phenyl silicates have been fully characterized, and their reactivity has been explored. It was found that, thanks to the substitution of the catecholate moiety, notably with the 4-cyanocatecholato ligand, the phenyl radical could be generated and trapped. Computational studies provided a rationale for these findings.
Photo-CIDNP and Nanosecond Laser Flash Photolysis Studies on the Photodecomposition of Triarylsulfonium Salts
Welsh, Kevin M.,Dektar, John L.,Garcia-Garibaya, Miguel A.,Hacker, Nigel P.,Turro, Nicholas J.
, p. 4179 - 4184 (1992)
The direct and sensitized photodecomposition of triarylsulfonium salts have been investigated by nanosecond laser flash photolysis and steady-state photo-CIDNP.The direct photoreaction of triphenylsulfonium salts was shown to proceed via a singlet diphenylsulfinyl radical cation-phenyl radical pair which is produced by internal electron transfer from the initially formed phenyl cation-diphenyl sulfide pair.Recombination of both sets of intermediates gives protonated (phenylthio)biphenyls, identified as a broad transient absorption centered at 465 nm, which lose H+ to give 2-, 3-, and 4-(phenylthio)biphenyl.The acetone-sensitized photoreaction gave a triplet excited state of the salt, which then dissociated to give the triplet diphenylsulfinyl radical cation (λ max 750, 340 nm)-phenyl radical pair and subsequently underwent escape reactions with the solvent.Anthracene-, 9,10-diphenylanthracene-, naphthalene-, and perylene-sensitized photoreactions of triphenylsulfonium salts proceeded by electron transfer from the singlet excited state of the aromatic hydrocarbon to give the singlet aromatic hydrocarbon radical cation-triphenylsulfur radical pair, which dissociates to the in-cage triad of diphenyl sulfide, phenyl radical and the aromatic hydrocarbon radical cation.In the solvent cage naphthalene radical cation can oxidize diphenyl sulfide to diphenylsulfinyl radical cation, identified by transient absorptions at 750 and 340 nm, whereas the other hydrocarbon radical cations cannot.In contrast to the triphenylsulfonium salts, the diphenylsulfonium salt decomposed via the triplet excited state upon both direct and triplet-sensitized photolysis.Photo-CIDNP gave a strong enhanced absorption which was quenched upon the addition of oxygen and also gave transients, identified as diphenylsulfinyl radical cation (λ max 750, 340 nm), upon both direct and triplet-sensitized photolysis.
Stereochemistry of Dehydrogenation of 1,4-cyclohexadiene with 2,3-dichloro-5,6-dicyano-p-benzoquinone
Mueller, Paul,Joly, Daniel,Mermoud, Francois
, p. 105 - 112 (1984)
cis- and trans-(3,6-D2)-1,4-cyclohexadienes 1a and 1b have been synthesized from cis-3,4-dichlorocyclobutene (5).Aromatization to benzene with DDQ is cis-stereospecific with an uncertainty of 5percent.This results is discussed in relation to concerted or stepwise mechanisms for aromatization of 1,4-dihydroaromatics with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ).
Simulation of vibrational spectra of isotopic benzenes by an extended molecular mechanics method
Miwa, Yoshihisa,Mimura, Norio,Machida, Katsunosuke,Nakagawa, Tetsuo,Umemura, Junzo,Hayashi, Soichi
, p. 1629 - 1646 (1994)
Vibrational spectra of benzene and benzene-d6 in the gas and liquid phase have been simulated by a molecular mechanics method including the calculation of equilibrium structures, thermodynamic quantities, normal frequencies and vibrational transition probabilities.The potential parameters have been estimated by referring to the observed frequencies of benzene, benzene-d6 and 1,3,5-benzene-d3 and also to results of ab initio, calculations.Four and ten independent parameters are required, respectively, for elucidating the infrared absorption and Raman intensities of these compounds in the gas and liquid phase.The infrared absorption spectrum of benzene-d1 is reproduced well by using the potential and the intensity parameters estimated for benzene and benzene-d6.The change of relative band intensities on the phase change has been elucidated in terms of the change of various intensity parameters.
C-C bond Activation: Cycloheptatriene Reaction on W(100), W(100)-(5X1)-C,and W(100)-(2X1)-O
Pearlstine, K. A.,Friend, C. M.
, p. 5898 - 5901 (1985)
The adsorption and reaction of cycloheptatriene (c-C7H8) was investigated on W(100), W(100)-(5X1)-C, and W(100)-(2X1)-O surfaces under ultra-high-vacuum conditions with use of thermal desorption spectroscopy and isotope exchange reactions.Irreversible dehydrogenation yielding gaseous H2 was the only reaction observed on clean W(100).Cycloheptatriene dehydrogenation was suppressed on W(100)-(5X1)-C, allowing reactions involving C-C bond activation to produced.Benzene formation was uniquely observed on the -(5X1)-C surface.Reaction of cycloheptatriene-7d1 on W(100)-(5X1)-C demonstrated that the 7-position was initially dehydrogenated, yielding a coordinated C7H7 adsorption intermediate which subsequently eliminated one carbon to yield benzene.
Nucleophilic Aromatic Substitution at Benzene with Powerful Strontium Hydride and Alkyl Complexes
R?sch, Bastian,Gentner, Thomas Xaver,Elsen, Holger,Fischer, Christian A.,Langer, Jens,Wiesinger, Michael,Harder, Sjoerd
, p. 5396 - 5401 (2019)
Key to the isolation of the first alkyl strontium complex was the synthesis of a strontium hydride complex that is stable towards ligand exchange reactions. This goal was achieved by using the super bulky β-diketiminate ligand DIPePBDI (CH[C(Me)N-DIPeP]2, DIPeP=2,6-diisopentylphenyl). Reaction of DIPePBDI-H with Sr[N(SiMe3)2]2 gave (DIPePBDI)SrN(SiMe3)2, which was converted with PhSiH3 into [(DIPePBDI)SrH]2. Dissolved in C6D6, the strontium hydride complex is stable up to 70 °C. At 60 °C, H–D isotope exchange gave full conversion into [(DIPePBDI)SrD]2 and C6D5H. Since H–D exchange with D2 is facile, the strontium hydride complex served as a catalyst for the deuteration of C6H6 by D2. Reaction of [(DIPePBDI)SrH]2 with ethylene gave [(DIPePBDI)SrEt]2. The high reactivity of this alkyl strontium complex is demonstrated by facile ethylene polymerization and nucleophilic aromatic substitution with C6D6, giving alkylated aromatic products and [(DIPePBDI)SrD]2.
Formation of α-[KSiH3] by hydrogenolysis of potassium triphenylsilyl
Leich,Spaniol,Okuda
, p. 14772 - 14774 (2015)
Hydrogenation of easily accessible potassium triphenylsilyl [K(Me6TREN)SiPh3] gave the hydrogen storage material α-[KSiH3] in high yields by an unusual hydrogenolytic cleavage of silicon-phenyl bonds.
Ag-Mediated Radical Cyclization of 2-Alkynylthio(seleno)anisoles: Direct Synthesis of 3-Phosphinoylbenzothio(seleno)phenes
Cai, Tao,Liu, Jian,Zhang, Huimiao,Wang, Xiaolong,Feng, Jing,Shen, Runpu,Gao, Yuzhen
, p. 4605 - 4608 (2019)
A new method for the direct synthesis of 3-phosphinoylbenzothio(seleno)phenes has been achieved through an Ag-mediated radical addition-cyclization of 2-alkynylthio(seleno)anisoles with secondary phosphine oxides in good yields under mild conditions. In this single reaction, benzenethiophene or benzeneselenophene skeleton, C(sp2)-P and C(sp2)-S bonds can be constructed with the cleavage of the C(sp3)-S bond, highlighting the efficiency and step-economics of this protocol.
Temperature Effect on Gas Phase Alkylbenzene Dealkylation
Perez, Giorgio
, p. 1777 - 1780 (1994)
Dealkylation of ethylbenzene, propylbenzene, and isopropylbenzene by radiolytically formed 2H+3 ions has been studied in the gaseous phase as a function of the irradiation temperature.The extent of the reaction, which increases with the temperature follows the order ethylbenzene-1 between the activation energies for dealkylation of ethylbenzene and isopropylbenzene, and of ethylbenzene and propylbenzene, respectively.
Rates and Mechanisms of Gas-Phase Desubstitution of Hexadeuteriobenzene and Benzene Derivatives C6H5X, X = CH3, CF3, OH, Cl, and F, by H Atoms between 898 and 1039 K
Manion, Jeffrey A.,Louw, Robert
, p. 4127 - 4134 (1990)
Mixtures of C6D6 and C6H5X, X = CH3, CF3, OH, Cl, and F, have been thermolyzed in H2 in a tubular flow system at atmospheric pressure between 898 and 1039 K.Removal of D or X occurs via hydrogen atom attack and lower deuterated benzenes and C6H6 are formed.Mass spectral analyses for (deuterio)benzenes have been used to determine the rates of desubstitution C6H5X + H --> C6H6 relative to H + C6D6 --> C6D5H (9).For X = D, CH3, CF3, and OH, desubstitution occurs by addition of a H atom to the ring followed by loss of X. from the substituted cyclohexadienyl intermediate.For X = Cl direct abstraction also takes place and for X = F abstraction is the only operative mechanism.No evidence for hydrogen migration around the ring in cyclohexadienyl intermediates was found.On a per-site basis, the dedeuteration rates of C6D6, C6D5H, C6D4H2, ..., C6DH5 were found to be equal.On the basis of log k9/L mol-1 s-1 = 10.69 - 2350/2.3T, we have found the following log k(benzene)/L mol-1 s-1 for C6H5X + H --> C6H6: X = CH3, 10.19 - 2914/2.3T; CF3, 9.79 - 2832/2.3T; OH, 9.93 - 2945/2.3T; Cl, 10.48 - 4148/2,3T; F, 10.31 - 5066/2.3T.Results are compared with relevant literature data.
