71998-51-1Relevant academic research and scientific papers
The Synthesis of a Double-Layered Annulene with 10?-Rings. 1,1:2,2-Bis(annulene-1,6-diyl)ethylene
Yamamoto, Koji,Ojima, Juro,Morita, Noboru,Asao, Toyonobu
, p. 1281 - 1284 (1988)
The synthesis of the title compound, a double-layered annulene with 10?-rings, is described.The examination of 1H NMR and electronic spectra suggests that the layered compound exhibits appreciable interaction between two annulene rings.
Replacing platinum with tungsten carbide for decalin dehydrogenation
Qi, Suitao,Yue, Jiaqi,Li, Yingying,Huang, Jun,Yi, Chunhai,Yang, Bolun
, p. 1443 - 1449 (2014)
Pt was replaced with tungsten carbide (WC) in the Ni-Pt structure for decalin dehydrogenation on base of their similar properties. The catalytic performance of Ni-WC catalyst was predicted by density functional theory (DFT) calculations and further confirmed by dehydrogenation reaction. Replacing Pt with WC significantly reduces the side reactions such as ring-opening and coking. The highest conversion of decalin is about 93 % and the selectivity to naphthalene is nearly 100 % over Ni-WC/AC catalyst. The improved catalytic activity of Ni-WC/AC demonstrates the feasibility to replace Pt with WC as an active and less expensive dehydrogenation catalyst. Graphical Abstract: [Figure not available: see fulltext.].
Measurement of Internal Energies by Hot Ultraviolet Absorption Spectroscopy: Spectra of Excited Azulene Molecules
Brouwer, L.,Hippler, H.,Lindemann, L.,Troe, J.
, p. 4608 - 4612 (1985)
The gas-phase absorption spectrum of azulene in the wavelength range λ = 220-300 nm has been measured in shock waves between 600 and 1750 K.Combined with the room-temperature spectrum, a dependence of the absorption coefficients ε(λ) on the average thermal energy over the range 10-420 kJ mol-1 is established.The "canonically hot" UV spectra are compared with "microcanonically hot" UV spectra obtained by laser excitation of azulene at 337 and 308 nm, corresponding to excitation energies of 367 and 400 kJ mol-1. "Microcanonically hot" and "canonically hot" absorption spectra agree perfectly when the average internal energies of the ensembles are the same.This experimental observation is rationalized.Various applications of hot UV absorption spectroscopy in chemical kinetics are reviewed.
Chiral diaminocarbene palladium(II) complexes: Synthesis, reduction to Pd(0) and activity in the Mizoroki-Heck reaction as recyclable catalysts
Pytkowicz, Julien,Roland, Sylvain,Mangeney, Pierre,Meyer, Gilbert,Jutand, Anny
, p. 166 - 179 (2003)
A preparation of chiral palladium(II) bis-diaminocarbene complexes was developed from the corresponding silver(I) diaminocarbenes and bis(acetonitrile)dichloropalladium(II). Crystal structure details of trans -diiodo bis[(4 R ,5 R )-1,3-dibenzyl-4,5-di-tert- butylimidazolin-2-ylidene] palladium(II) are presented. Mixed diaminocarbene-phosphine complexes were also prepared in two steps from the corresponding imidazolidinium salts and palladium acetate. The very high air, moisture and thermal stability of such complexes were confirmed. These two families of complexes were tested in the Mizoroki-Heck reaction. Their ability to be reduced into Pd(0) which undergoes oxidative addition with aryl halides was studied by cyclic voltammetry. The ability of different agents to generate Pd(0) complexes and the reactivity of these latters with aryl halides were also studied in situ. The obtained results allowed us to perform Heck reactions at temperatures starting from 40 °C in DMF, by activation of the palladium(II) catalyst precursor. Moreover, in the case of the bis-diaminocarbene complexes, the Pd(0) catalysts were totally re-oxidized during the work-up and the starting Pd(II) complexes could be quantitatively recovered.
3-Benzotellurepines: The First Examples of Tellurepines
Sashida, Haruki,Kurahashi, Hideshi,Tsuchiya, Takashi
, p. 802 (1991)
Reaction of o-diethynylbenzene with sodium telluride in the presence of hydrazine hydrate gives 3-benzotellurepine 2, which is converted into the 3,3-dihalogeno derivatives 3 by treatment with sulphuryl chloride or bromine; these compounds are the first examples of tellurepines.
147. Photodissociation of Halonaphthalenes in Solution: Comparative Photochemistry of 1-Iodo-, 1-Bromo-, and 1-Chloronaphthalenes
Haselbach, Edwin,Rohner, Yves,Suppan, Paul
, p. 1644 - 1652 (1990)
Fluorescence measurements have been used to follow the build-up of photoproducts during the direct and benzophenone-sensitized irradiation of the title compounds 1-IN, 1-BrN, and 1-ClN (HN = naphthalene).Compounds 1-IN and 1-BrN react by homolytic dissociation through their lowest triplet and singlet excited states, respectively.Compound 1-ClN does not undergo C-Cl bond fission, except through electron transfer in the presence of an amine A, 1(1-ClN)* + A -> (1-ClN)-. + A+, then (1-ClN)-. -> N. + Cl-. In the absence of this electron tranfer, 1-ClN reacts only through substitution and oxidation processes.
Mechanistic Aspects of the Triethylamine Assisted Photo-induced Dehalogenation of Halogeno-aromatic Compounds
Davidson, R. Stephen,Goodin, Jonathan W.
, p. 163 - 166 (1981)
Criteria for the intervention of radical ions in the photoreactions of aromatic halides with triethylamine is given and where appropriate evidence for the intermediary of such species is presented.
PHOTODECHLORINATION OF CHLOROAROMATICS BY ELECTRON TRANSFER FROM AN ANIONIC SENSITIZER
Soumillion, J. Ph.,Vandereecken, P.,Schryver, F. C. De
, p. 697 - 700 (1989)
A novel photosensitized process for dechlorination of chloronaphtalene, chlorobiphenyl and, potentially, polychlorinated aromatics uses naphtoxide anion as excited donor.This process proceeds through the radical anion of the chloroaromatic and presents characteristics comparing favorably with other sensitized systems.
THE AMINE ASSISTED PHOTO-DEHALOGENATION OF HALO-AROMATIC HYDROCARBONS
Beecroft, Richard A.,Davidson, R. Stephen,Goodwin, Dean
, p. 5673 - 5676 (1983)
The rate constants for quenching the triplet states of 4-chloro-biphenyl, 1-chloronaphthalene and 1-methylnaphthalene have been determined by use of the technique of laser flash photolysis.Evidence in favour of the quenching occuring by a charge transfer process, is presented.
Photosensitizers covalently anchored to the silica surface: Enhanced efficiency of heterogeneous photodechlorination of chlorinated aromatics
Ayadim,Soumillion
, p. 381 - 384 (1996)
A naphthol sensitizer is covalently anchored on silica. The so obtained heterogeneous as well as the corresponding homogeneous photosensitizer, under anionic form, have been tested in the reductive dechlorination of chloroaromatics. In these photoinduced electron transfer (PET) sensitized reactions, interactions between the sensitizer and the surface are shown to enhance their reactivity. The grafted silica is shown to work in the dechlorination of a tetrachlorobiphenyl and sunlight reactions have been performed.
