108-67-8Relevant articles and documents
ON THE REACTIVITY OF V(η-C6H3Me3-1,3,5)2I
Aviles, T.,Teuben, J.H.
, p. 39 - 44 (1983)
V(η-C6H3Me3-1,3,5)2I reacts with reducing agents such as MeLi, Na or Na to yield the neutral complex V(η-C6H3Me3-1,3,5)2 in 70-75percent yield.Reaction of V(η-C6H3Me3-1,3,5)2I with compounds containing suitable donor atoms such as THF,
Radioactive hydrocarbons [6]
Grosse,Weinhouse
, p. 402 - 403 (1946)
-
Catalytic Reduction of Alkyl and Aryl Bromides Using Propan-2-ol
Haibach, Michael C.,Stoltz, Brian M.,Grubbs, Robert H.
, p. 15123 - 15126 (2017)
Milstein's complex, (PNN)RuHCl(CO), catalyzes the efficient reduction of aryl and alkyl halides under relatively mild conditions by using propan-2-ol and a base. Sterically hindered tertiary and neopentyl substrates are reduced efficiently, as well as more functionalized aryl and alkyl bromides. The reduction process is proposed to occur by radical abstraction/hydrodehalogenation steps at ruthenium. Our research represents a safer and more sustainable alternative to typical silane, lithium aluminium hydride, and tin-based conditions for these reductions.
One-Electron Oxidation of Alkylbenzenes in Acetonitrile by Photochemically Produced NO3.: Evidence for an Inner-Sphere Mechanism
Giacco, Tiziana Del,Baciocchi, Enrico,Steenken, Steen
, p. 5451 - 5456 (1993)
The reaction between NO3. and polyalkylbenzenes was studied using 308-nm laser flash photolysis of cerium(IV) ammonium nitrate in the presence of the alkylbenzenes in acetonitrile solution.For all benzenes, with the exception of monoalkylbenzenes and o- and m-xylene, the reaction with NO3. was found to yield the corresponding radical cations and to proceed in an apparently straightforward bimolecular manner.For monoalkylbenzenes and o- and m-xylene, radicals were seen which are derived from the parents by formal loss of H. from the side chain of the aromatic.This reaction proceeds via a complex between the aromatic and NO3. with the decomposition of the complex being rate determining at higher concentrations of aromatic (rate constants for decomposition between 6 * 105 and 4 * 107 s-1).In the complex, electron transfer from the aromatic to NO3. is suggested to be concerted with deprotonation of the incipient radical cation.Formation of a complex between NO3. and aromatics is likely even in those cases where radical cations are observed, with the assumption that in these cases the complex decomposition rate is greater than 6 * 107 s-1.
Accessing Pincer Bis(carbene) Ni(IV) Complexes from Ni(II) via Halogen and Halogen Surrogates
Martinez, Gabriel Espinosa,Ocampo, Cristian,Park, Yun Ji,Fout, Alison R.
, p. 4290 - 4293 (2016)
This communication describes the two-electron oxidation of (DIPPCCC)NiX (DIPPCCC = bis(diisopropylphenyl-benzimidazol-2-ylidene)phenyl); X = Cl or Br) with halogen and halogen surrogates to form (DIPPCCC)NiX3. These complexes represent a rare oxidation state of nickel, as well as an unprecedented reaction pathway to access these species through Br2 and halogen surrogate (benzyltrimethylammonium tribromide). The NiIV complexes have been characterized by a suite of spectroscopic techniques and can readily reduce to the NiII counterpart, allowing for cycling between the NiII/NiIV oxidation states.
Selective and Mild Deacylation of Hindered Acylarenes with Aqueous Trifluoroacetic Acid
Keumi, Takashi,Morita, Toshio,Inui, Yoko,Teshima, Naomi,Kitajima, Hidehiko
, p. 979 - 980 (1985)
Sterically hindered acylarenes are deacylated to arenes in quantitative yields on heating in boiling 85percent trifluoroacetic acid.Hindered arenecarboxylic acids undergo decarboxylation under the same conditions to give arenes in high yields.
Reactivity of 17-, 18-, and 19-Electron Cationic Complexes Generated by the Electrochemical Oxidation of Tricarbonyl(mesitylene)tungsten
Zhang, Yun,Gosser,Rieger,Sweigart
, p. 4062 - 4068 (1991)
The electrochemical oxidation of (mesitylene)W(CO)3 (W) in MeCN produces the 17-electron complex W+, which reacts very rapidly with solvent (S) or tri-n-butyl phosphite (P) to give 19-electron species (WS+, WP+) that undergo spontaneous further oxidation to the 18-electron analogues (WS2+, WP2+). The identities of WS2+ and WP2+ were established by voltammetric, IR spectroelectrochemical, and NMR experiments. Although the 17-electron ? 19-electron transformation is not directly observable, digital simulation techniques allowed selection of a probable mechanism and semiquantitative determination of the rate and equilibrium parameters describing the interconversion of the 17-, 18-, and 19-electron species: W+ + S ? WS+, k ? 105 M-1 s-1, Keq ? 10-1 M-1; W+ + P ? WP+, k ? 107 M-1 s-1, Keq ? 3 × 103 M-1 at 298 K. The related 18-electron complex WS2+ is quite reactive, but orders of magnitude less so than W+ and WS+. Experiments with (mesitylene)Cr(CO)3 (Cr) suggest that associative attack by MeCN at the 17-electron Cr+ is 104 times slower than attack at the W+ analogue. This study illustrates the power of digital simulation techniques for interpreting complex mechanistic schemes and characterizing important but unobservable reaction intermediates. Electrochemical oxidation of (arene)W(CO)3 occurs without loss of arene or CO ligands, suggesting that the electroactivation of these complexes may have useful synthetic applications; this contrasts sharply with (arene)Cr(CO)3 analogues, which decompose with loss of arene and CO ligands upon oxidation in MeCN.
Grignard reagents in ionic solvents: Electron transfer reactions and evidence for facile Br-Mg exchange
Ramnial, Taramatee,Taylor, Stephanie A.,Clyburne, Jason A. C.,Walsby, Charles J.
, p. 2066 - 2068 (2007)
Grignard reagents form persistent solutions in phosphonium ionic liquids possessing O-donor anions and these solutions are excellent reaction media for electron transfer processes and transmetallation reactions. The Royal Society of Chemistry.
Temperature resolved FTIR spectroscopy of Cr2+/SiO2 catalysts: Acetylene and methylacetylene oligomerisation
Zecchina,Bertarione,Damin,Scarano,Lamberti,Prestipino,Spoto,Bordiga
, p. 4414 - 4417 (2003)
Results related to time-resolved FTIR spectroscopy at variable temperature of acetylene and methylacetylene oligomerization on a model Phillips catalyst were presented. Acetylene and methylacetylene resulted in the immediate formation of benzene and 1,3,5-trimethylbenzene, respectively, without evidence of any measurable intermediate product. This indicated that the active Cr sites were able to coordinate simultaneously three monomers and thus must display a high unsaturative coordination. The results could be an insight of chromium species active in the Phillips catalyst.
Highly active, well-defined (cyclopentadiene)(N-heterocyclic carbene)palladium chloride complexes for room-temperature Suzuki-Miyaura and Buchwald-Hartwig cross-coupling reactions of aryl chlorides and deboronation homocoupling of arylboronic acids
Jin, Zhong,Guo, Su-Xian,Gu, Xiao-Peng,Qiu, Ling-Ling,Song, Hai-Bing,Fang, Jian-Xin
, p. 1575 - 1585 (2009)
A new class of well-defined N-heterocyclic carbene (NHC)-(cyclopentadiene) palladium chloride complexes such as CpPd(NHC)Cl wasw synthesized from the readily available starting NHC-palladium(II) chloride dimers. These air-stable, coordinatively saturated NHC-Pd complexes bearing the cyclopentadiene (Cp) unit exhibit high catalytic activity in the room temperature Suzuki-Miyaura and Buchwald-Hartwig cross-coupling reactions involving unactive aryl chlorides as the substrates. In addition, they are found to be extremely efficient catalysts in the deboronation homocoupling of arylboronic acids at room temperature.
Characterization of the extra-large-pore zeolite UTD-1
Lobo, Raul F.,Tsapatsis, Michael,Freyhardt, Clemens C.,Khodabandeh, Shervin,Wagner, Paul,Chen, Cong-Yan,Balkus Jr., Kenneth J.,Zones, Stacey I.,Davis, Mark E.
, p. 8474 - 8484 (1997)
The molecular sieve UTD-1 is investigated using scanning and transmission electron microscopies (TEM), solid-state NMR spectroscopy, electron (ED) and X-ray diffraction (XRD), adsorption studies, and catalytic test reactions. The results confirm that UTD-1 is the first high-silica zeolite to contain a one;dimensional, extra-large 14-ring pore system. TEM and ED show that UTD-1 is faulted along the (002) planes. Simulations of XRD patterns of faulted structures using DIFFaX indicate that the XRD pattern of a framework containing the so-called double crankshaft chains is in better agreement with the experimental pattern than a framework with the narsarsukite chains previously reported. Thermal/hydrothermal stability studies show that UTD-1 has similar stability to other medium- and large-pore, high-silica zeolites. The ratio of isomerization to disproportionation, and the distribution of trimethylbenzene isomers in the m-xylene isomerization test reaction from UTD-1 are similar to those obtained from other large-pore zeolites (zeolites Y or L). However, UTD-1 shows a p-/o-xylene ratio of products below one.The molecular sieve UTD-1 is investigated using scanning and transmission electron microscopies (TEM), solid-state NMR spectroscopy, electron (ED) and X-ray diffraction (XRD), adsorption studies, and catalytic test reactions. The results confirm that UTD-1 is the first high-silica zeolite to contain a one-dimensional, extra-large 14-ring pore system. TEM and ED show that UTD-1 is faulted along the (002) planes. Simulations of XRD patterns of faulted structures using DIFFaX indicate that the XRD pattern of a framework containing the so-called double crankshaft chains is in better agreement with the experimental pattern than a framework with the narsarsukite chains previously reported. Thermal/hydrothermal stability studies show that UTD-1 has similar stability to other medium-and large-pore, high-silica zeolites. The ratio of isomerization to disproportionation, and the distribution of trimethylbenzene isomers in the m-xylene isomerization test reaction from UTD-1 are similar to those obtained from other large-pore zeolites (zeolites Y or L). However, UTD-1 shows a p-/o-xylene ratio of products below one.
Strategy for Selective Csp2-F and Csp2-Csp2Formations from Organoplatinum Complexes
Sarkissian, Elin,Golbon Haghighi, Mohsen
, p. 1016 - 1020 (2021)
By changing the parameters of fluorination reaction of bisaryl-platinum(II) complexes, each possible competitive pathway of Ar-Ar and Ar-F formation can be selectively controlled. It was discovered that steric hindrance, type of fluorinating reagent, and
Tailoring the Morphology of MTW Zeolite Mesocrystals: Intertwined Classical/Nonclassical Crystallization
Zhao, Yang,Zhang, Hongbin,Wang, Peicheng,Xue, Fangqi,Ye, Zhaoqi,Zhang, Yahong,Tang, Yi
, p. 3387 - 3396 (2017)
The morphology and porosity of zeolite play a significant role in the activity and selectivity of catalytic reactions. It is a dream to optionally modulate zeolite morphology by regulating the crystallization process on the basis of comprehensively understanding the mechanisms. Herein, a series of MTW zeolite mesocrystals can be consciously fabricated with morphologies from a dense structure to a loose one of an oriented nanocrystallite aggregate by changing the H2O/SiO2 ratio. Their intertwined classical/nonclassical crystallization processes are investigated comprehensively. The results indicate that the crystallization of MTW zeolite takes place by a chain of events, including the formation of wormlike particles (WLPs), their aggregation, and crystallization of aggregates. MTW with a loose structure mainly crystallizes by an internal reorganization after a fast aggregation of WLPs in a concentrated system. On the other hand, the dense structure of MTW is realized via the co-occurrence of a coalescence of the participating WLPs during its crystal growth with a slower rate in a dilute system. Moreover, the advantages of MTW with a loose structure are confirmed through cumene cracking and 1,2,4-trimethylbenzene transformation. This method could pave the way for the synthesis of other zeolites with diverse morphologies and/or mesoporosities via subtle regulation of the crystallization pathway.
Promising process for synthesis of 3,5-xylenol from isophorone
Kirichenko,Glazunova,Kirichenko,Dzhemilev
, p. 434 - 438 (2006)
A thermocatalytic process for the synthesis of 3,5-xylenol from isophorone over a silicon dioxide catalyst promoted by iron oxides was developed. The process holds promise for commercialization. Nauka/Interperiodica 2006.
Hastings,Nicholson
, p. 730,734 (1957)
Eichhorn, Bryan W.,Haushalter, Robert C.,Pennington, William T.
, p. 8704 - 8706 (1988)
Product Ratios Dependent on and Independent of the Left Group in a Single Series: Potassium Metal Provoked Reactions of Aryl Halides with Amide and Acetone Enolate Ions That Occur during Mixing
Tremelling, Michael J.,Bunnett, J. F.
, p. 7375 - 7377 (1980)
-
A new peroxo-route for the synthesis of Mg-Zr mixed oxides catalysts: Application in the gas phase acetone self-condensation
Krivtsov, Igor,Faba, Laura,Díaz, Eva,Ordó?ez, Salvador,Avdin, Viacheslav,Khainakov, Sergei,Garcia, Jose R.
, p. 26 - 33 (2014)
We propose in this manuscript a new peroxo-mediated procedure for preparing magnesia-zirconia mixed oxides, with Mg/Zr molar ratio between 1 and 3, with enhanced distribution of basic sites. The mixed magnesia-zirconia oxides have been prepared from the gelled complex by Pechini-type method. The MgO-ZrO 2 materials have been characterized and used as catalysts for acetone aldol condensation. The proposed preparation method provides a high degree of molecular homogeneity and favours the formation of magnesia-stabilized zirconia phase. Acetone gas-phase self-condensation was carried out over these catalysts as model reaction requiring the presence of basic sites. The condensation yields diacetone alcohol and mesityl oxide as mean C6 products, and phorones, isophorones and mesitylene as C9 products. In comparison to Mg-Zr oxide prepared by co-precipitation, these new materials present better conversions and higher selectivity to linear dimers and trimers (as mesitylene), whereas the selectivity for isophorones is significantly lower.
Relative Reactivities of Amide, Diphenylphosphide, and Diphenylarsenide Ions toward Aryl Radicals
Alonso, Ruben A.,Bardon, Alicia,Rossi, Roberto A.
, p. 3584 - 3587 (1984)
Competition experiments have been carried out in liquid ammonia at reflux temperature to determine the relative rate constants for the coupling reactions of amide (NH2-), diphenylphosphide (Ph2P-), and diphenylarsenide (Ph2As-) toward aryl radicals.It is proposed that these nucleophiles react under photostimulation with halo aromatic substrates through an SRN1 mechanism of aromatic substitution.Relative rate constants of NH2- vs.Ph2P- ions toward 2,4,6-trimethylphenyl radicals and Ph2P- vs.Ph2As- ios toward 2-quinolyl radicals have been determined.The results here reported indicate that NH2- (1.00) - (6.4) = Ph2As- (6.4).The fact that there is not a difference in the rate constants of Ph2P- vs.Ph2As- suggests that both nucleophiles react at diffusion-controlled rate.In competition experiments of Ph2P- vs.Ph2As- ions toward phenyl radicals, it was found that Ph2P- (1.00) > Ph2As- (0.44).The decrease of the Ph2As- ion reactivity is attributed to the reversible coupling of this nucleophile with phenyl radicals.
-
Sucharda,Kuczynski
, (1935)
-
-
Tsutsui, M.,Zeiss, H.
, p. 1367 - 1369 (1959)
-
A new method to prepare functional phosphines through steady-state photolysis of triarylphosphines
Yasui, Shinro,Ando, Taro,Ozaki, Masashi,Ogawa, Yuya,Shioji, Kosei
, (2018)
The steady-state photolysis of triarylphosphine, Ar3P, was carried out using a xenon lamp or a high-pressure mercury lamp under an argon atmosphere in a solvent containing a functional group, CH3X. Gas chromatograph-mass spectroscopic analysis on the photolysis showed that a phosphine to which the functional group from the solvent is incorporated, Ar2PCH2X, was formed in a moderate yield, along with tetraaryldiphosphine, Ar2PPAr2. The product, Ar2PCH2CN, from the photolysis in acetonitrile (X=CN) was isolated by column chromatography. In the photolysis in other solvents tried here (ethyl acetate, acetone, 2-butanone, and 3,3-dimethyl-2-butanone), Ar2PCH2X formed in the reaction mixture was so labile on a silica-gel column that it was treated with S8 powder to convert to the corresponding phosphine sulfide, Ar2P(=S)CH2X. The resulting phosphine sulfide was isolated by column chromatography. The isolated products in these reactions, Ar2PCH2CN and Ar2P(=S)CH2X, were characterized by 1H, 13C, and 31P NMR spectroscopy, IR spectroscopy, and elemental analysis or high-resolution mass spectroscopy. The formation of Ar2PCH2X as well as Ar2PPAr2 is explained by homolytic cleavage of a P-C bond of Ar3P in the photoexcited state. This reactivity of Ar3P in the photoexcited state is in sharp contrast to that exerted under aerobic conditions, where Ar3P in the photoexcited state donates readily an electron to oxygen producing the radical cation, Ar3P·+. This photoreaction, which affords a functional phosphine, Ar2PCH2X, in one-pot with generating very small amounts of unidentified side products, has potential for use in preparing functional phosphines.
Infrared and Raman spectra, ab initio calculations and conformational studies of ethyl iodosilane
Aleksa, Valdemaras,Powell, David L.,Gruodis, Alytis,Hassler, Karl,Hummeltenberg, Reinhard,Herzog, Klaus,Salzer, Reiner,Klaeboe, Peter,Nielsen, Claus J.
, p. 105 - 118 (2003)
Ethyl iodosilane (CH3CH2-SiH2I) was synthesized for the first time. Infrared spectra were recorded in the vapour, amorphous and crystalline solid phases in MIR and FIR regions. Additional MIR spectra of the compound isolated in argon and nitrogen matrices were obtained at 5 K. Raman spectra of the liquid, excited by argon and by Nd3+ YAG lasers, were recorded at room temperature including polarization measurements. The spectra were studied in an extended temperature range 173-353 K and a ΔH value of 1.2 ± 0.3 kJ mol-1 was obtained with gauche being the low energy conformer. Spectra of the amorphous and crystalline solids were obtained at liquid nitrogen temperature. Ethyl iodosilane exists in an equilibrium between anti and gauche conformers, in the vapour, liquid and amorphous states. After careful annealing the amorphous solid on a cold Cu finger (Raman) or on a CsI or Si window (infrared) to 160 K a partly crystalline solid was formed. A number of IR and Raman bands were reduced in intensity after annealing, although they did not vanish completely. From comparison between the observed and calculated vibrational modes it was apparent that the gauche conformer was present in the crystal. The sample was mixed with argon and nitrogen in a ratio 1:1000, deposited on a window at 5 or 10 K and annealed to temperatures between 5 and 36 K (argon) and 5-30 K (nitrogen). IR bands attributed to the anti and gauche conformers were reduced and increased in intensities, respectively. Thus, the gauche conformer was the low energy conformer in the matrices and probably also in the vapour phase. Ab initio calculations were performed at the RHF/3-21 G* and 6-311G* B3LYPs and gave optimized geometries, IR and Raman intensities and vibrational frequencies for the anti and gauche conformers. An enthalpy difference of 0.9 kJ mol-1 was obtained from the calculations with gauche being the low energy conformer. After scaling, a reasonably good agreement between the experimental and calculated wavenumbers for the anti and gauche conformer was obtained. The spectra of ethyl iodosilane were closely related to those of the corresponding ethyl fluoro, ethyl chloro and ethyl bromosilane.
Perfluoroalkylated Main-Group Element Lewis Acids as Catalysts in Transfer Hydrogenation
Bader, Julia,Maier, Alexander F. G.,Paradies, Jan,Hoge, Berthold
, p. 3053 - 3056 (2017)
Transfer hydrogenation plays an important part in organic chemistry. Recently, strong Lewis acids like B(C6F5)3 have been introduced as a catalyst for these reactions. We successfully employed the Lewis acid (C2F5)3PF2 as a catalyst in the transfer hydrogenation between 1,3,5-trimethylcyclohexa-1,4-diene and 1,1-diphenylethylene. Surprisingly, the treatment of the diene alone with a catalytic amount of (C2F5)3PF2 led to a quantitative dismutation to mesitylene and 1,3,5-trimethylcyclohexane. With B(C6F5)3, there was a solvent-dependency: in CH2Cl2 mainly the dismutation products were obtained, while in toluene the evolution of H2 was observed. Additionally, the catalytic activity of various perfluoroalkylated germanes and silanes was tested.
Phosphoric acid-modified commercial kieselguhr supported palladium nanoparticles as efficient catalysts for low-temperature hydrodeoxygenation of lignin derivatives in water
Cui, Yuntong,Liu, Zhaohui,Ran, Jiansu,Wang, Jianjian,Yangcheng, Ruixue
, p. 1570 - 1577 (2022/03/14)
Efficient production of high value-added chemicals and biofuels via low-temperature chemoselective HDO of lignin derivatives in water is still a challenge. Here, we construct a low-cost, active and stable Pd/PCE catalyst using phosphoric acid-modified commercial Celite (PCE) as the support, and this catalyst exhibits excellent activity in low-temperature HDO of vanillin as well as other lignin derivatives in water. The superior catalytic performance is due to the presence of P species on the surface of Pd/PCE, accelerating the selective conversion of the intermediate into the final product. Detailed experimental and mechanistic studies reveal that the rapid conversion of the intermediate to the final product proceeds via a free-radical process in an interfacial microenvironment created by intimate interacting between the P species and Pd NPs. The insights of this work provide a new low-cost catalytic system for efficient production of valuable chemicals and future biofuels from lignin derivatives. This journal is
Ceramic boron carbonitrides for unlocking organic halides with visible light
Yuan, Tao,Zheng, Meifang,Antonietti, Markus,Wang, Xinchen
, p. 6323 - 6332 (2021/05/19)
Photochemistry provides a sustainable pathway for organic transformations by inducing radical intermediates from substrates through electron transfer process. However, progress is limited by heterogeneous photocatalysts that are required to be efficient, stable, and inexpensive for long-term operation with easy recyclability and product separation. Here, we report that boron carbonitride (BCN) ceramics are such a system and can reduce organic halides, including (het)aryl and alkyl halides, with visible light irradiation. Cross-coupling of halides to afford new C-H, C-C, and C-S bonds can proceed at ambient reaction conditions. Hydrogen, (het)aryl, and sulfonyl groups were introduced into the arenes and heteroarenes at the designed positions by means of mesolytic C-X (carbon-halogen) bond cleavage in the absence of any metal-based catalysts or ligands. BCN can be used not only for half reactions, like reduction reactions with a sacrificial agent, but also redox reactions through oxidative and reductive interfacial electron transfer. The BCN photocatalyst shows tolerance to different substituents and conserved activity after five recycles. The apparent metal-free system opens new opportunities for a wide range of organic catalysts using light energy and sustainable materials, which are metal-free, inexpensive and stable. This journal is
Metal-Free Heterogeneous Semiconductor for Visible-Light Photocatalytic Decarboxylation of Carboxylic Acids
Shi, Jiale,Yuan, Tao,Zheng, Meifang,Wang, Xinchen
, p. 3040 - 3047 (2021/03/09)
A suitable protocol for the photocatalytic decarboxylation of carboxylic acids was developed with metal-free ceramic boron carbon nitrides (BCN). With visible light irradiation, BCN oxidize carboxylic acids to give carbon-centered radicals, which were trapped by hydrogen atom donors or employed in the construction of the carbon-carbon bond. In this system, both (hetero)aromatic and aliphatic acids proceed the decarboxylation smoothly, and C-H, C-D, and C-C bonds are formed in moderate to high yields (35 examples, yield up to 93%). Control experiments support a radical process, and isotopic experiments show that methanol is employed as the hydrogen atom donor. Recycle tests and gram-scale reaction elucidate the practicability of the heterogeneous ceramic BCN photoredox system. It provides an alternative to homogeneous catalysts in the valuable carbon radical intermediates formation. Moreover, the metal-free system is also applicable to late-stage functionalization of anti-inflammatory drugs, such as naproxen and ibuprofen, which enrich the chemical toolbox.