- Temperature deactivation of excited Tb3+ in the presence of 1,2-dioxetane in acetonitrile
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Quenching the fluorescence (FL) of terbium perchlorate by 2,2'-adamantane-2,2'-dioxide (1) was shown to have a chemical character and was caused by the formation of the 3+> complex.The dependence of the lifetime (τ) of FL of Tb.3+ in acetonitrile on the temperature and concentration of 1 has been studied.The temperature dependence of τ is caused by rearrangement of the inner sphere of the aquasolvate complexes of Tb3+, which leads to the replacement of H2O with MeCN and 1.The energy of replacing the H2O molecule in the inner sphere of complexes with a solvent molecule has been calculated. - Key words: chemiluminiscence, fluorescence, Tb(ClO4)3*6H2O, 2,2'-adamantane-2,2'-dioxide, lifetime, quenching.
- Ableeva, N. Sh.,Voloshin, A. I.,Ostakhov, S. S.,Kukovinets, A. G.,Korobeinikova, V. N.,et al.
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- Contrasting reactions of ketones and thioketones with alkyllithiums: A coordinated experimental and computational investigation
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The reaction of ketones with organolithium reagents generally proceeds by addition of the organometallic to the electrophilic carbon of the C=O group to give the lithium salt of a tertiary alcohol. The seemingly analogous reaction of thioketones with organolithiums is a fundamentally different process: such reactions typically afford a variety of products, and addition of the organolithium to carbon of the C=S group to give a thiol is a relatively unimportant component. Reactions of the stable thioketone, adamantantanethione (1), with several alkyllithiums (MeLi, n-BuLi and t-BuLi) in a variety of solvents have been studied in the first comprehensive investigation of the reactions of organolithiums with a representative alkyl-substituted thione. Reactions of 1 with n-BuLi or t-BuLi afforded 2-adamantanethiol (2) as the major product. In an effort to explain the marked difference in behavior of ketones and thioketones in reactions with organolithiums, transition states for both the addition and reduction reactions have been located at the B3LYP/6-311+G* level using acetone and thioacetone as model substrates. The transition states for the addition of dimeric MeLi to the C=O and C=S carbons of acetone and thioacetone were significantly different as a result of the small bond angles preferred by divalent sulfur, and this accounts for the much slower addition to a C=S carbon vis-a-vis a C=O group. Transition states for reduction of acetone and thioacetone by EtLi were similar, but the greater exothermicity of the reduction of the thioketone results in an earlier transition state and lower activation energy for this process than that for the reduction of a ketone. The possible role of radical-mediated processes in this chemistry is also discussed.
- Bailey, William F.,Bartelson, Ashley L.,Wiberg, Kenneth B.
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- Solvent-cage effect (viscosity dependence) as a diagnostic probe for the mechanism of the intramolecular chemically initiated electron-exchange luminescence (CIEEL) triggered from a spiroadamantyl-substituted dioxetane
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The excitation step of the intramolecular CIEEL generation in the triggered cleavage of spiroadamantyl-substituted dioxetane has been studied. The electron back-transfer (BET) process versus the direct chemiexcitation of the phenolate-anion emitter have been considered as mechanistic alternatives. The observed solvent-cage effect on the CIEEL generation, manifested by the increase of the singlet chemiexcitation yield at increased viscosity, provides evidence that the BET process operates in the intramolecular CIEEL mechanism.
- Adam, Waldemar,Bronstein, Irena,Trofimov, Alexei V.,Vasil'ev, Rostislav F.
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- In Vivo Chemiluminescent Imaging Agents for Nitroreductase and Tissue Oxygenation
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Tissue oxygenation is a driving parameter of the tumor microenvironment, and hypoxia can be a prognostic indicator of aggressiveness, metastasis, and poor response to therapy. Here, we report a chemiluminescence imaging (CLI) agent based on the oxygen-dependent reduction of a nitroaromatic spiroadamantane 1,2-dioxetane scaffold. Hypoxia ChemiLuminescent Probe 2 (HyCL-2) responds to nitroreductase with ~170-fold increase in luminescence intensity and high selectivity for enzymatic reductase versus other small molecule reductants. HyCL-2 can image exogenous nitroreductase in vitro and in vivo in living mice, and total luminescent intensity is increased by ~5-fold under low oxygen conditions. HyCL-2 is demonstrated to report on tumor oxygenation during an oxygen challenge in H1299 lung tumor xenografts grown in a murine model as independently confirmed using multispectral optoacoustic tomography (MSOT) imaging of hemoglobin oxygenation.
- Cao, Jian,Campbell, James,Liu, Li,Mason, Ralph P.,Lippert, Alexander R.
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- Bimodal Evans-Polanyi Relationships in Hydrogen Atom Transfer from C(sp3)-H Bonds to the Cumyloxyl Radical. A Combined Time-Resolved Kinetic and Computational Study
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The applicability of the Evans-Polanyi (EP) relationship to HAT reactions from C(sp3)-H bonds to the cumyloxyl radical (CumO?) has been investigated. A consistent set of rate constants, kH, for HAT from the C-H bonds of 56 substrates to CumO?, spanning a range of more than 4 orders of magnitude, has been measured under identical experimental conditions. A corresponding set of consistent gas-phase C-H bond dissociation enthalpies (BDEs) spanning 27 kcal mol-1 has been calculated using the (RO)CBS-QB3 method. The log kH′ vs C-H BDE plot shows two distinct EP relationships, one for substrates bearing benzylic and allylic C-H bonds (unsaturated group) and the other one, with a steeper slope, for saturated hydrocarbons, alcohols, ethers, diols, amines, and carbamates (saturated group), in line with the bimodal behavior observed previously in theoretical studies of reactions promoted by other HAT reagents. The parallel use of BDFEs instead of BDEs allows the transformation of this correlation into a linear free energy relationship, analyzed within the framework of the Marcus theory. The ΔG?HAT vs ΔG°HAT plot shows again distinct behaviors for the two groups. A good fit to the Marcus equation is observed only for the saturated group, with λ = 58 kcal mol-1, indicating that with the unsaturated group λ must increase with increasing driving force. Taken together these results provide a qualitative connection between Bernasconi's principle of nonperfect synchronization and Marcus theory and suggest that the observed bimodal behavior is a general feature in the reactions of oxygen-based HAT reagents with C(sp3)-H donors.
- Bietti, Massimo,Dilabio, Gino A.,Galeotti, Marco,Groff, Benjamin D.,Mayer, James M.,Romero-Montalvo, Eduardo,Salamone, Michela,Van Santen, Jeffrey A.
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- Highly selective production of 2-adamantanone by photocatalytic oxidation of adamantane
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2-Adamantanone was selectively produced by photocatalytic oxidation of adamantane in acetic acid using TiO2 powders. The reactions were carried out at ambient and acetic acid reflux temperatures with and without an oxidant. Adding oxidant in refluxing acetic acid under irradiation remarkably increased conversion and selectivity. Rutile TiO2 powders showed better conversion and selectivity in the presence of H2O2. The total conversion was 67% and the highest selectivity of 2-adamanta-none was 89%. Copyright
- Song, Sun-Jung,Kim, Kyoung Seok,Kim, Kyung Hwan,Kim, Jong Beom,Kim, Jong-Ho,Kim, Keun-Sik,Shin, Honghyun,Cho, Dong Lyun
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- MECHANISM OF ACTIVATION AND CATALYSIS OF CHEMILUMINESCENCE BY Eu(fod)3 CHELATE IN THERMAL DECOMPOSITION OF ADAMANTYLIDENEADAMANTANE-1,2-DIOXETANE
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Complexation of the chelate both with dioxetane and with adamantanone (2), the product of decomposition of dioxetane, have an important effect on chemiluminescence (CL) in thermal decomposition of adamantylideneadamantane-1,2-dioxetane (1) in the presence of Eu(fod)3 chelate.The stability constants of Eu(fod)3*1 and Eu(fod)3*2 complexes were obtained.It was found that Eu(fod)3 catalyzes and activates chemiluminescent decomposition of 1.The rate constant (k2) of decomposition of the Eu(III)*1 complex was determined from the kinetics of quenching of CL, and the activation parameters were determined from the temperature curve.Luminescence from the 5D1- level of the Eu(III) ion was detected in the CL spectrum and was correlated with direct (bypassing the triplet of the ligand) transfer of excitation energy from 2t* to the luminescent levels of Eu(III) in the geometrically distorted complex Eu(fod)3*2. Keywords: chemiluminescence, adamantylideneadamantane-1,2-dioxetane, Eu(fod)3, catalysis.
- Voloshin, A. I.,Sharipov, G. L.,Kazakov, V. P.,Tolstikov, G. A.
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- Chemiluminescence and catalysis of decomposition of dispiro(diadamantane-1,2-dioxetane) in the presence of EuIII and TbIII tris(benzoyltrifluoroacetonate) complexes
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Catalysis of decomposition of dispiro(diadamantane-1,2-dioxetane) (1) in the presence of EuIII and TbIII tris(benzoyltrifluoroacetonate) complexes (Ln(btfa)3) accompanied by the formation of adamantanone (2) and chemiluminescence (CL) was studied. The rate constants (k2) of decomposition of compound 1 in the 1 · Ln(btfa)3 complexes and their stability constants (K1) have been determined. The Arrhenius parameters of decomposition of 1 (Ea = 22.4±0.7 kcal mol-1, logA = 10.2±0.8 for 1 · Tb(btfa)3 and Ea = 23.4±0.6 kcal mol-1, logA = 10.6±0.8 for 1 · Eu(btfa)3) and thermodynamic parameters of complex formation (ΔH = -5.5±0.5 kcal mol-1, ΔS = -10.4±0.7 e.u. for 1 · Tb(btfa)3 and ΔH = -5.8±0.5 kcal mol-1, ΔS = -10.9+0.7 e.u. for 1 · Eu(btfa)3) have been calculated from the temperature dependences of k2 and K1. The yields of excitation of the Ln(btfa)3 chelates φ*Eu = 0.021±0.006 and φ*Tb = 0.12±0.04 have been determined. A higher efficiency of the occupation of the 5D4-level of Tb3+ compared to those of the 5D1- and 5D0-levels of Eu3+ is caused by different efficiencies of the non-radiative energy dissipation in the Ln3+ ion after the intracomplex energy transfer from the 3n,π*-state of 2 to the resonance excited levels of lanthanides.
- Kazakov,Voloshin,Ostakhov,Zharinova
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- Selective and mild oxyfunctionalization of model polyolefins
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The direct oxyfunctionalization of a model polyolefin, polyethylene-alt-propylene (PEP), was achieved utilizing a straightforward, mild process. In the presence of a manganese complex, manganese meso-tetra-2,6-dichlorophenylporphyrin acetate (Mn(TDCPP)OAc), imidazole, a phase transfer agent, and potassium peroxymonosulfate (Oxone), PEP was functionalized under ambient conditions without chain degradation. The primary oxidation products contained tertiary alcohols and ketones based on IR, 1H NMR, 13C NMR, and DEPT 13C NMR spectroscopy of the oxyfunctionalized products. The oxyfunctionalization of squalane, a small molecule, structural analogue of PEP, was also demonstrated. Spectroscopic analyses of the main products from the squalane oxidation were nearly identical with the functional groups identified in the PEP oxidation products. The degree of functionalization was modulated by changing the relative concentration of the oxidant, Oxone. The degree of functionalization and the thermal properties are reported for these new polymeric materials.
- Boaen, Nicole K.,Hillmyer, Marc A.
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- Enolates in 3-D: An experimental and computational study of deprotonated 2-adamantanone
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Deprotonation of 2-adamantanone (1) in the gas phase affords the corresponding β-enolate anion. This ion was independently prepared by the fluoride-induced desilylation of 4-trimethylsilyl-2-adamantanone, and its reactivity and thermodynamic properties we
- Meyer, Matthew M.,Kass, Steven R.
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- Photocatalytic decomposition of dispiro(diadamantane-1,2-dioxetane) initiated by Ce(ClO4)3 in the excited state
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Photocatalytic decomposition of dispiro(diadamantane-1,2-dioxetane) (1) to adamantanone (2) initiated by Ce(ClO4)3 in the excited state in the MeCN-CHCl3 (2 : 1) mixture was studied. The bimolecular rate constants of quenching kq were determined from the kinetics of quenching of Ce3+* by dioxetane at different temperatures. The Arrhenius parameters of the quenching were calculated from the temperature dependence of kq: Ea = 3.2±0.3 kcal mol-1 and logA = 11.6±0.6. The quantum yields of photolysis of 1 depending on its concentration and the rate constant of the chemical reaction of Ce3+* with 1 were determined. The latter coincides with kq: kch = (2.6±0.3) · 109 L mol-1 s-1 (T = 298 K). The fact that the maximum quantum yield or decomposition of dioxetane is equal to 1 indicates the absence of physical quenching of Ce3+* by dioxetane. It is believed that the electron transfer occurs in the reaction of Ce3+* with 1. Nonradiative deactivation of Ce3+* in solutions of MeCN and in MeCN-CHCl3 mixtures was studied. It is caused by the replacement of H2O molecules in the nearest coordination surroundings of Ce3+ by solvent molecules and reversible transfer of an electron to the ligand. The activation parameters of the nonradiative deactivation of Ce3+* were determined.
- Kazakov,Voloshin,Ostakhov,Khusainova,Zharinova
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- Kinetic Study of the Nitrolysis of Haloadamantanes
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Abstract: The kinetics of nitrolysis of haloadamantanes containing halogen atoms in the bridging and bridgehead positions with fuming nitric acid have been studied. The effective nitrolysis constants of eight haloadamantane derivatives have been determine
- Ivleva, E. A.,Klimochkin, Yu. N.,Skomorokhov, M. Yu.
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- Photochemistry of spiro[6H-[1,3]oxathiin-2,2′-tricyclo[3.3.1.1 3.7]decan]-6-one
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On irradiation (300 nm) in the solid state, the title compound 8 affords tricyclo[3.3.1.13.7]decan-2-one (=adamantan-2-one; 9) selectively via [4+2] cycloreversion. A similar result is obtained on photolysis in solution (MeCN or acetone), also in the presence of added alkenes. On irradiation in MeOH, a solvent adduct 11 is isolated in addition to 9. From experiments in CD3OD, it can be inferred that 11 is formed via syn-addition of MeOH to the ground-state (E)-heterocycle 16.
- Schmidt, Kerstin,Margaretha, Paul
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- Zirconia-supported 11-molybdovanadophosphoric acid catalysts: effect of the preparation method on their catalytic activity and selectivity
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The oxidation of adamantane with hydrogen peroxide catalyzed by zirconia-supported 11-molybdovanadophosphoric acid is shown to be a suitable green route for the synthesis of adamantanol and adamantanone. This work evaluates how the catalyst activity and selectivity are affected by some of its preparative parameters, such as the method for supporting the catalytically active heteropoly acid over the zirconia matrix or the pretreatments applied to the resulting materials before being used as heterogeneous catalysts. Our results indicate that the most effective catalysts able to maintain their activity after several reaction runs are those prepared by following the sol-gel route, whereas the most selective catalysts are those obtained by impregnation methods. Moreover, the calcination temperature has also been identified as a relevant parameter influencing the performance of catalysts based on supported heteropoly acids. The increasing catalytic activity observed over several consecutive reaction runs has been attributed to the formation of peroxo derivatives of polyoxometalate clusters at the surface of the catalyst and their accumulation after each reaction cycle.
- Bakkali, Bouchra El,Trautwein, Guido,Alca?±iz-Monge, Juan,Reinoso, Santiago
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- Electron exchange luminescence of spiroadamantane-substituted dioxetanes triggered by alkaline phosphatases. Kinetics and elucidation of pH effects
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Intramolecular chemically initiated electron exchange luminescence (CIEEL) was studied in the alkaline phosphatase triggering of the spiroadamantyl-substituted 1,2-dioxetanes AMPPD and CSPD, which are widely employed in modern chemiluminescent bioassays, particularly in clinical immunoassay applications. Experimental data on the pH dependence of the CIEEL efficiency, the CIEEL emitter fluorescence lifetime, the rate of cleavage of the dephosphorylated dioxetane 2a, the turnover number, and the Michaelis constant are reported and kinetically rationalized. Through this detailed kinetic analysis, the pH effects on the various steps of the CIEEL process were elucidated. Although every step of the triggering involves H+ or HO- ions, it was shown that at alkaline pH and steady-state conditions only enzymatic dephosphorylation of AMPPD and CSPD depends on pH in this CIEEL process. The turnover number is affected only at pH below 9, which reflects a switchover of the rate-determining step of the enzyme dephosphorylation to its phosphorylation at increasing pH. The Michaelis constant depends on pH within the entire range used, which is attributed to the pH effect on the concentration of the catalytically active enzyme form. The present model kinetic studies on the important alkaline-phosphatase-triggered CIEEL reaction provide the necessary mechanistic insights to understand pH effects in such enzymatic processes for the rational design of more effective CIEEL systems.
- Adam, Waldemar,Bronstein, Irena,Edwards, Brooks,Engel, Thomas,Reinhardt, Dirk,Schneider, Friedemann W.,Trofimov, Alexei V.,Vasil'ev, Rostislav F.
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- Chemiluminescence and catalysis of the decomposition of dispiro(diadamantane-l,2-dioxetane) in solutions of lanthanide perchlorates 1: Catalysis of the 1,2-dioxetane decomposition
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Decomposition of dispiro(diadamantane-l,2-dioxetane) u1, Cd1, Tb1, Pr1, and Ce1 perchlorates was studied by the chemiluminescencc method. The rate constants of decomposition of 1 in complexes of composition 1 Ln"1 and stability constants of these complexes, as well as activation parameters of the decomposition of 1 and thermodynamic parameters of the complexation were determined. A correlation between the thermodynamic parameters of complexation and ionic radii of Ln"1 was found.
- Kazakov,Voloshin,Ostakhov,Khusainova
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- Adamantane Selective Hydroxylation by 2,6-Dichloropyridine N-Oxide and Organoruthenium(II) Polyoxometalates as Catalyst Precursors
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Organoruthenium polyoxometalates with general formula [{Ru(C6Me6)}3M5O18], M=Mo, W, serve as catalyst precursors, together with 2,6-dichloropyridine N-oxide, to effect the hydroxylation of adamantane with conversion up to 94%, and C3-H/C2-H selectivity > 100. Under analogous conditions, hydroxylation of cis-decalin occurred with complete stereoretention. Control experiments and kinetic evidence suggest the in-situ formation of a high valent Ru-oxo species as the competent oxidant.
- Bonchio, Marcella,Scorrano, Gianfranco,Toniolo, Paolo,Proust, Anna,Artero, Vincent,Conte, Valeria
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- Mechanism of RuO4-mediated oxidations of saturated hydrocarbons, isotope effects, solvent effects and substituent effects
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Adamantane and 1,3,5,7-tetradeuterioadamantane were oxidized by RuO4 in two solvent systems, CCl4-CH3CN-H2O and acetone-water, yielding two kinetic deuterium isotope effects (KIEs), 4-8 ± 0-2 and 7.8 ± 0.l, respectively, very similar to those obtained in analogous reactions with cu-decalin and perdeuteriocis-decalin, 4-8 and 6-8. These results were interpreted as primary KIEs and small or negligible secondary KIEs. From this, sp2-hybridized intermediates were not involved in the reaction path. The kinetic effect of the solvent was investigated by performing the reaction in aqueous acetone and acetonitrile. The rates were correlated with Grunwald-Winstein Y values and with Reichardt ET(30) values. Both correlations showed the reaction to be only moderately dependent on the solvent polarity. 1-Substituted adamantanes were oxidized in CCl4-CH3CN giving a Taft ρ* value of -2.5 ± 0.1. These results were regarded as support for a reaction consisting of a pre-equilibrium with formation of a substrate-RuO4 complex followed by a rate-determining concerted reaction. Chemical Equation Presented. The results did not support a reaction mechanism with a carbocation or radical intermediate, or a scheme with two competing reactions, one with a carbocation intermediate and the other with a concerted mechanism.
- Bakke, Jan M.,Frohaug, Astrid E.
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- A Highly Sensitive Chemiluminescent Probe for Detecting Nitroreductase and Imaging in Living Animals
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Hypoxia is a common characteristic of solid tumors, which is caused by the imbalance of oxygen supply and consumption. As the expression level of nitroreductase (NTR) increases in hypoxic solid tumors, NTR is one of the common biomarkers of hypoxia and widely used to evaluate the degree of tumor hypoxia. In this study, we designed and synthesized a highly water-soluble chemiluminescent probe, CL-NTR, for the detection of NTR activity in hypoxic tumors. It was found that the probe could be used to detect NTR with high sensitivity, and the total light photons increased tremendously with 6000-fold after the probe was treated with NTR. The chemiluminescence total light photons emission was directly proportional to the concentration of nitroreductase in the range of 3-55 ng/mL, with a detection limit of 0.947 ng/mL. Finally, the probe was successfully used to evaluate NTR activity in living mice by chemiluminescent imaging. In general, this probe has a remarkable response to NTR, which provides a promising method for the determination of NTR activity in vivo.
- Sun, Jinyu,Hu, Zhian,Wang, Ruihua,Zhang, Sichun,Zhang, Xinrong
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- Hydrogen-atom and oxygen-atom transfer reactivities of iron(
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A series of iron(ii) complexes with the general formula [FeII(L2-Qn)(L)]n+ (n = 1, L = F?, Cl?; n = 2, L = NCMe, H2O) have been isolated and characterized. The X-ray crystallographic data reveals that
- Banerjee, Sridhar,Haukka, Matti,Hossain, Md. Kamal,Huelsmann, Ricardo Dagnoni,Martendal, Edmar,Munshi, Sandip,Nordlander, Ebbe,Paine, Tapan K.,Peralta, Rosely,Singh, Reena,Sinha, Arup,Valiati, Andrei Felipe,Wendt, Ola F.,Xavier, Fernando,Yiga, Solomon
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supporting information
p. 870 - 884
(2022/02/01)
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- Enhancing Chemo- And Stereoselectivity in C-H Bond Oxygenation with H2O2by Nonheme High-Spin Iron Catalysts- And Role of Lewis Acid and Multimetal Centers
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Spin states of iron often direct the selectivity in oxidation catalysis by iron complexes using hydrogen peroxide (H2O2) on an oxidant. While low-spin iron(III) hydroperoxides display stereoselective C-H bond hydroxylation, the reactions are nonstereoselective with high-spin iron(II) catalysts. The catalytic studies with a series of high-spin iron(II) complexes of N4 ligands with H2O2 and Sc3+ reported here reveal that the Lewis acid promotes catalytic C-H bond hydroxylation with high chemo- and stereoselectivity. This reactivity pattern is observed with iron(II) complexes containing two cis-labile sites. The enhanced selectivity for C-H bond hydroxylation catalyzed by the high-spin iron(II) complexes in the presence of Sc3+ parallels that of the low-spin iron catalysts. Furthermore, the introduction of multimetal centers enhances the activity and selectivity of the iron catalyst. The study provides insights into the development of peroxide-dependent bioinspired catalysts for the selective oxygenation of C-H bonds without the restriction of using iron complexes of strong-field ligands.
- Das, Abhishek,Jana, Rahul Dev,Paine, Tapan Kanti
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supporting information
p. 5969 - 5979
(2021/05/04)
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- Reduced Amino Acid Schiff Base-Iron(III) Complexes Catalyzing Oxidation of Cyclohexane with Hydrogen Peroxide
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The reduced amino acid Schiff base ligands have been prepared and were coordinated with ferric chloride to generate the iron(III) complexes. The ligands and complexes have been characterized using FT-IR, UV-vis, elemental analysis, ICP-AES analysis, mass spectra etc. After the structural characterization, these complexes were applied for the oxidation of cyclohexane using hydrogen peroxide as the oxidant under mild conditions. The activity tests showed that the L-phenylalanine-derived reduced Schiff base iron(III) complex(Ph?FeCl) afforded the highest yield of cyclohexanol and cyclohexanone(total yield up to 23.2 %). Notably, the Ph?FeCl complex catalyzes the reaction via a heterogeneous approach, allowing the complex to be separated and recycled conveniently after the oxidation reaction. Besides, the Ph?FeCl catalyst can also be extended for the selective oxidation of other alkanes and aromatics into alcohols, ketones and phenols etc. Finally, the reaction mechanism of cyclohexane oxidation on the iron(III) complex was proposed as well by the free radical inhibitors and EPR study of active intermediates.
- Zheng, Anna,Zhou, Qingqing,Ding, Bingjie,Li, Difan,Zhang, Tong,Hou, Zhenshan
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p. 3385 - 3395
(2021/08/23)
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- Preparation method of adamantanone
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The invention discloses a preparation method of adamantanone, and relates to the technical field of adamantanone synthesis. The problems that the reaction time is long and the operation process is tedious are solved. The preparation method specifically comprises the following steps: putting raw materials including adamantane, sulfuric acid and trifluoroacetic acid into a batching kettle, and stirring and mixing at 30 DEG C; raising the temperature to 50 DEG C, and introducing nitrogen into the batching kettle; pressing the mixed materials into a reaction tube, and performing standing for 1 minute; pouring the reaction solution on 500g of ice, adding a NaOH aqueous solution which is 7 times the weight of adamantane during cooling, and adjusting the pH value to 9; and extracting by using methylbenzene of which the weight is 3 times that of adamantane. The raw materials are mixed and then heated, nitrogen is introduced, then an oxidation reaction occurs, the retention time and temperatureof reaction liquid in a reaction tube are controlled in the leading-out period, the reaction liquid is extracted through methylbenzene and the NaOH aqueous solution, the extraction liquid is subjected to reduced pressure distillation concentration, cooling, separation and drying treatment, the final product is obtained, the operation process is relatively simple, the reaction is controllable, andthe time is short.
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Paragraph 0033-0041; 0048-0060; 0067-0078; 0085-0096;
(2021/04/03)
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- Selective Aerobic Oxidation of Secondary C (sp3)-H Bonds with NHPI/CAN Catalytic System
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Abstract: The direct aerobic oxidation of secondarty C(sp3)-H bonds was achieved in the presence of N-hydroxyphthalimide (NHPI) and cerium ammonium nitrate (CAN) under mild conditions. Various benzylic methylenes could be oxidized to carbonyl compounds in satisfied selectivity while saturated cyclic alkanes could be further oxidized to the corresponding lactones with the catalytic system. Remarkably, 25% of isochroman was converted to corresponding ketone with a selectivity of 96%. The reaction was initiated by hydrogen atom abstraction from NHPI by cerium and nitrates under oxygen atmosphere to form PINO radicals. 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) addition experiments showed that the oxidation proceeded via a complex radical chain mechanism and an ion pathway. Graphic Abstract: [Figure not available: see fulltext.]
- Wang, Lingyao,Zhang, Yuanbin,Yuan, Haoran,Du, Renfeng,Yao, Jia,Li, Haoran
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p. 1663 - 1669
(2020/10/21)
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- Robust Mn(iii): N -pyridylporphyrin-based biomimetic catalysts for hydrocarbon oxidations: heterogenization on non-functionalized silica gel versus chloropropyl-functionalized silica gel
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Two classes of heterogenized biomimetic catalysts were prepared and characterized for hydrocarbon oxidations: (1) by covalent anchorage of the three Mn(iii) meso-tetrakis(2-, 3-, or 4-pyridyl)porphyrin isomers by in situ alkylation with chloropropyl-functionalized silica gel (Sil-Cl) to yield Sil-Cl/MnPY (Y = 1, 2, 3) materials, and (2) by electrostatic immobilization of the three Mn(iii) meso-tetrakis(N-methylpyridinium-2, 3, or 4-yl)porphyrin isomers (MnPY, Y = 4, 5, 6) on non-modified silica gel (SiO2) to yield SiO2/MnPY (Y = 4, 5, 6) materials. Silica gel used was of column chromatography grade and Mn porphyrin loadings were deliberately kept at a low level (0.3% w/w). These resulting materials were explored as catalysts for iodosylbenzene (PhIO) oxidation of cyclohexane, n-heptane, and adamantane to yield the corresponding alcohols and ketones; the oxidation of cyclohexanol to cyclohexanone was also investigated. The heterogenized catalysts exhibited higher efficiency and selectivity than the corresponding Mn porphyrins under homogeneous conditions. Recycling studies were consistent with low leaching/destruction of the supported Mn porphyrins. The Sil-Cl/MnPY catalysts were more efficient and more selective than SiO2/MnPY ones; alcohol selectivity may be associated with hydrophobic silica surface modification reminiscent of biological cytochrome P450 oxidations. The use of widespread, column chromatography, amorphous silica yielded Sil-Cl/MnPY or SiO2/MnPY catalysts considerably more efficient than the corresponding, previously reported materials with mesoporous Santa Barbara Amorphous No 15 (SBA-15) silica. Among the materials studied, in situ derivatization of Mn(iii) 2-N-pyridylporphyrin by covalent immobilization on Sil-Cl to yield Sil-Cl/MnP1 showed the best catalytic performance with high stability against oxidative destruction and reusability/recyclability.
- Pinto, Victor Hugo A.,Falc?o, Nathália K. S. M.,Mariz-Silva, Bárbara,Fonseca, Maria Gardennia,Rebou?as, Júlio S.
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supporting information
p. 16404 - 16418
(2020/12/03)
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- C–H functionalization of alkanes, bactericidal and antiproliferative studies of a gold(III)-phenanthroline complex
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This research article demonstrates the synthesis, structural characterization, C–H functionalization, bactericidal activity and anti-proliferative studies of a mononuclear Au(III) complex, [Au(phen)Cl2]NO3 (1) [phen = 1,10-phenanthroline]. X-ray structural analysis of 1 reveals that the Au(III) complex crystallises in a monoclinic system with P21/c space group and adopts a perfect square planar geometry. The Au(III) complex has been evaluated as an efficient catalytic system towards C–H activation of a series of alkane molecules in presence of TBHP. The catalyst exhibits moderate to excellent reactivity with good selectivity toward aldehyde or ketone when aryl alkanes are used, and ketone is formed when cyclic alkanes are tested. This catalytic reaction recommends the involvement of freely diffusing hydroxyl radicals rather than metal-based oxidant for this course of catalysis. The cytotoxic activity of the Au(III) complex have been investigated against the A549 human lung cancer cell line that induces apoptosis mode of cell death and loss of mitochondrial membrane potential are prominent characteristics as an anti cancer drug as well as antibacterial activity against Staphylococcus aureus.
- Al-Hunaiti, Afnan,Balakrishnan, Gowdhami,Biswas, Bhaskar,Dey, Dhananjay,Dharumadurai, Dhanasekaran,Gopal, Vinothini,Perumalsamy, Balaji,Ramasamy, Thirumurugan
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- Selective oxygenation of unactivated C-H bonds by dioxygen: Via the autocatalytic formation of oxoiron(v) species
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Selective catalytic oxygenation of unactivated C-H bonds for a series of substrates by dioxygen using iron complexes was performed without the use of a co-reductant. Mechanistic studies indicate that the reaction proceeded via the autocatalytic formation of an oxoiron(v) intermediate, which brings high regioselectivity and stereoretention.
- Chandra, Bittu,De, Puja,Sen Gupta, Sayam
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supporting information
p. 8484 - 8487
(2020/08/13)
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- Ionic liquid-stabilized vanadium oxo-clusters catalyzing alkane oxidation by regulating oligovanadates
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Alkane oxidation under mild conditions occupies an important position in the chemical industry. Herein, we have designed a novel class of ionic liquid ([TBA][Pic])-stabilized vanadium oxo-clusters (TBA = tetrabutylammonium; Pic = picolinate ions), in which the molar ratio of the IL to V atoms can be tuned facilely to obtain V-OC?IL-0.5, V-OC?IL-1 and V-OC?IL-2, respectively. The as-synthesized vanadium oxo-clusters have been characterized by elemental analysis, FT-IR, UV-vis, XRD, TGA, EPR, NMR and MS. These vanadium oxo-clusters were catalytically active for catalyzing the oxidation of cyclohexane with H2O2 as an oxidant. In particular, the oxo-cluster V-OC?IL-1 (where IL/V is 1.0) can provide an approximately 30% total yield of KA oil (cyclohexanol and cyclohexanone) without adding any co-catalyst at 50 °C within 1.0 h. Moreover, the present vanadium oxo-cluster was recyclable owing to the modification of the IL and it can also be extended to the oxidation of the sp2 hybrid aromatic ring. The further characterization results demonstrated that the oligovanadate anions were strongly dependent on the molar ratio of the IL to V atoms. The vanadium oxo-clusters with the appropriate molar ratio of IL/V could exist in the form of a trimer and a dimer due to the presence of the TBA cation and the coordination of picolinate. Notably, the oligovanadate anions are highly active species for the C-H oxidation but the mononuclear vanadate afforded a very poor activity according to the activity assessment and the identification of vanadium species from the 51V NMR spectra and MS spectra. The annihilation reaction of free radicals and EPR characterization suggested that the vanadium oxo-clusters operated via a mechanism of the HO radical in the oxidation reaction.
- Ding, Bingjie,Gong, Xueqing,Hou, Zhenshan,Li, Difan,Yao, Yefeng,Zhang, Ran,Zheng, Anna,Zhou, Qingqing
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p. 7601 - 7612
(2020/11/27)
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- Efficient alkane hydroxylation catalysis of nickel(ii) complexes with oxazoline donor containing tripodal tetradentate ligands
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Tris(oxazolynylmethyl)amine TOAR(where R denotes the substituent groups on the fourth position of the oxazoline rings) complexes of nickel(ii) have been synthesized as catalyst precursors for alkane oxidation withmeta-chloroperoxybenzoic acid (m-CPBA). The molecular structures of acetato, nitrato,meta-chlorobenzoato and chlorido complexes with TOAMe2have been determined using X-ray crystallography. The bulkiness of the substituent groups R affects the coordination environment of the nickel(ii) centers, as has been demonstrated by comparison of the molecular structures of chlorido complexes with TOAMe2and TOAtBu. The nickel(ii)-acetato complex with TOAMe2is an efficient catalyst precursor compared with the tris(pyridylmethyl)amine (TPA) analogue. Oxazolynyl donors’ strong s-electron donating ability will enhance the catalytic activity. Catalytic reaction rates and substrate oxidizing position selectivity are controlled by the structural properties of the R of TOAR. Reaction of the acetato complex with TOAMe2andm-CPBA yields the corresponding acylperoxido species, which can be detected using spectroscopy. Kinetic studies of the decay process of the acylperoxido species suggest that the acylperoxido species is a precursor of an active species for alkane oxidation.
- Hikichi, Shiro,Horii, Sena,Nakazawa, Jun,Okamura, Masaya,Terao, Ikumi
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p. 6108 - 6118
(2020/05/25)
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- Mild Deprotection of Dithioacetals by TMSCl/NaI Association in CH3CN
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A mild process using a combination of TMSCl and NaI in acetonitrile is used to regenerate carbonyl compounds from a variety of dithiane and dithiolane derivatives. This easy to handle and inexpensive protocol is also efficient to deprotect oxygenated and mixed acetals as 1,3-dioxanes, 1,3-dioxolanes and 1,3-oxathianes quantitatively. As a possible extension of this method, it was also shown that nitrogenated substrates such as hydrazones, N-tosylhydrazones, and ketimines reacted well under these conditions to give the expected ketones in high yields. The methodology proposed herein is a good alternative to the existing methods since it does not use metals, oxidants, reducing agents, acidic or basic media, and keto-products were obtained in high to excellent yields.
- Yao, Yunxin,Zhao, Guangkuan,Hamze, Abdallah,Alami, Mouad,Provot, Olivier
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p. 5775 - 5779
(2020/08/17)
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- Stable group 8 metal porphyrin mono- And bis(dialkylcarbene) complexes: Synthesis, characterization, and catalytic activity
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Alkyl-substituted carbene (CHR or CR2, R = alkyl) complexes have been extensively studied for alkylcarbene (CHR) ligands coordinated with high-valent early transition metal ions (a.k.a. Schrock carbenes or alkylidenes), yet dialkylcarbene (CR2) complexes remain less developed with bis(dialkylcarbene) species being little (if at all) explored. Herein, several group 8 metal porphyrin dialkylcarbene complexes, including Fe- and Ru-mono(dialkylcarbene) complexes [M(Por)(Ad)] (1a,b, M = Fe, Por = porphyrinato dianion, Ad = 2-adamantylidene; 2a,b, M = Ru) and Os-bis(dialkylcarbene) complexes [Os(Por)(Ad)2] (3a-c), are synthesized and crystallographically characterized. Detailed investigations into their electronic structures reveal that these complexes are formally low-valent M(ii)-carbene in nature. These complexes display remarkable thermal stability and chemical inertness, which are rationalized by a synergistic effect of strong metal-carbene covalency, hyperconjugation, and a rigid diamondoid carbene skeleton. Various spectroscopic techniques and DFT calculations suggest that the dialkylcarbene Ad ligand is unique compared to other common carbene ligands as it acts as both a potent σ-donor and π-acceptor; its unique electronic and structural features, together with the steric effect of the porphyrin macrocycle, make its Fe porphyrin complex 1a an active and robust catalyst for intermolecular diarylcarbene transfer reactions including cyclopropanation (up to 90% yield) and X-H (X = S, N, O, C) insertion (up to 99% yield) reactions.
- Che, Chi-Ming,Huang, Jie-Sheng,Low, Kam-Hung,Wan, Qingyun,Wang, Hai-Xu,Zhang, Jun-Long,Zhou, Cong-Ying
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p. 2243 - 2259
(2020/03/11)
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- A tunable synthesis of either benzaldehyde or benzoic acid through blue-violet LED irradiation using TBATB
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In this paper, a highly efficient, metal-free, and homogeneous method for the selective aerobic photooxidation of alcohols and photooxidative-desilylation of tert-butyldimethylsilyl ethers (TBDMS) in the presence of tetrabutylammonium tribromide (TBATB) under irradiation of visible light was reported. The light source: blue (460 nm) and violet (400 nm) LED, can control selective oxidation to aldehyde or carboxylic acid.
- Mardani, Atefeh,Heshami, Marouf,Shariati, Yadollah,Kazemi, Foad,Abdollahi Kakroudi, Mazaher,Kaboudin, Babak
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- A rapid screening method for thermal conductivity properties of thermal insulation materials by a thermochemiluminescence probe
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Acridine-based 1,2-dioxetane as a thermochemiluminescence (TCL) probe for temperature sensing exhibited an excellent response for temperature in the range of 85-130 °C with favorable sensitivity and good resolution. The proposed TCL probe could be applied to screen thermal conductivity properties of different thermal insulation materials. This journal is
- Teng, Xu,Jin, Mingzhe,Ding, Caifeng,Lu, Chao
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supporting information
p. 12781 - 12784
(2020/11/02)
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- Thiourea-Mediated Halogenation of Alcohols
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The halogenation of alcohols under mild conditions expedited by the presence of substoichiometric amounts of thiourea additives is presented. The amount of thiourea added dictates the pathway of the reaction, which may diverge from the desired halogenation reaction toward oxidation of the alcohol, in the absence of thiourea, or toward starting material recovery when excess thiourea is used. Both bromination and chlorination were highly efficient for primary, secondary, tertiary, and benzyl alcohols and tolerate a broad range of functional groups. Detailed electron paramagnetic resonance (EPR) studies, isotopic labeling, and other control experiments suggest a radical-based mechanism. The fact that the reaction is carried out at ambient conditions, uses ubiquitous and inexpensive reagents, boasts a wide scope, and can be made highly atom economic, makes this new methodology a very appealing option for this archetypical organic reaction.
- Mohite, Amar R.,Phatake, Ravindra S.,Dubey, Pooja,Agbaria, Mohamed,Shames, Alexander I.,Lemcoff, N. Gabriel,Reany, Ofer
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supporting information
p. 12901 - 12911
(2020/11/26)
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- Synthesis, crystal structure and immobilization of a new cobalt(ii) complex with a 2,4,6-tris(2-pyridyl)-1,3,5-triazine ligand on modified magnetic nanoparticles as a catalyst for the oxidation of alkanes
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A new Co(ii) complex with formula [Co(tptz)Cl2]·2H2O (tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine) has been synthesized and characterized by X-ray crystallography, elemental analyses and spectroscopic methods. It was then supported on modified Fe3O4 nanoparticles using tetraethylorthosilicate (TEOS) and (3-aminopropyl)trimethoxysilane (APTMS) and designated as a Fe3O4@SiO2@APTMS@complex nanocatalyst. The prepared nanocatalyst was characterized by means of FT-IR, Raman, XPS, EDX, XRD, VSM, SEM and TEM studies. The catalytic activity of the [Co(tptz)Cl2]·2H2O complex and Fe3O4@SiO2@APTMS@complex designated as catalysts A and B was used for oxidation of activated secondary alkanes such as fluorene, diphenyl methane, ethylbenzene, cyclooctane and adamantane. Observation of 39-99% conversions and 27-100% selectivities toward the corresponding ketones as well as the heterogeneity and reusability of the catalyst B seem promising.
- Azarkamanzad, Zahra,Farzaneh, Faezeh,Maghami, Mahboobeh,Simpson, Jim
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p. 12020 - 12031
(2019/08/07)
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- Iron-catalyzed oxidative functionalization of C(sp3)-H bonds under bromide-synergized mild conditions
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An efficient oxidation and functionalization of C-H bonds with an inorganic-ligand supported iron catalyst and hydrogen peroxide to prepare the corresponding ketones was achieved using the bromide ion as a promoter. Preliminary mechanistic investigations indicated that the bromide ion can bind to FeMo6 to form a supramolecular species (FeMo6·2Br), which can effectively catalyze the reaction.
- Yu, Han,Zhao, Qixin,Wei, Zheyu,Wu, Zhikang,Li, Qi,Han, Sheng,Wei, Yongge
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supporting information
p. 7840 - 7843
(2019/07/12)
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- The Role of Iodanyl Radicals as Critical Chain Carriers in Aerobic Hypervalent Iodine Chemistry
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Selective O2 utilization remains a substantial challenge in synthetic chemistry. Biological small-molecule oxidation reactions often utilize aerobically generated high-valent catalyst intermediates to effect substrate oxidation. Available synthetic methods for aerobic oxidation catalysis are largely limited to substrate functionalization chemistry by low-valent catalyst intermediates (i.e., aerobically generated Pd(II) intermediates). Motivated by the need for new chemical platforms for aerobic oxidation catalysis, we recently developed aerobic hypervalent iodine chemistry. Here, we report that in contrast to the canonical two-electron oxidation mechanisms for the oxidation of organoiodides, the developed aerobic hypervalent iodine chemistry proceeds via a radical chain mechanism initiated by the addition of aerobically generated acetoxy radicals to aryl iodides. Despite the radical chain mechanism, aerobic hypervalent iodine chemistry displays substrate tolerance similar to that observed with traditional terminal oxidants, such as peracids. We anticipate that these insights will enable new sustainable oxidation chemistry via hypervalent iodine intermediates. O2 is routinely utilized in biological catalysis to generate high-valent catalyst intermediates that engage in substrate oxidation chemistry. Analogous synthetic chemistry via aerobically generated high-valent intermediates would enable new sustainable synthetic methods but is largely unknown because of the challenges in selective O2 utilization. We have developed aerobic hypervalent iodine chemistry as a platform for coupling O2 reduction with a diverse set of substrate functionalization mechanisms. Many of the synthetic applications of hypervalent iodine reagents rely on selective two-electron oxidation-reduction chemistry. Here, we report that one-electron oxidation reactions pathways via iodanyl radical intermediates are critical in aerobic hypervalent iodine chemistry. The new appreciation for the critical role that iodanyl radicals can play in the synthesis of hypervalent iodine compounds will provide new opportunities in sustainable oxidation catalysis. Aerobic hypervalent iodine chemistry provides a strategy for coupling the one-electron chemistry of O2 with two-electron processes typical of organic synthesis. We show that in contrast to the canonical two-electron oxidation of aryl iodides, aerobic synthesis proceeds by a radical chain process initiated by the addition of aerobically generated acetoxy radicals to aryliodides to generate iodanyl radicals. Robustness analysis reveals that the developed aerobic oxidation chemistry displays substrate tolerance similar to that observed in peracid-based methods and thus holds promise as a sustainable synthetic method.
- Hyun, Sung-Min,Yuan, Mingbin,Maity, Asim,Gutierrez, Osvaldo,Powers, David C.
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supporting information
p. 2388 - 2404
(2019/09/12)
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- Direct Oxidation of Csp3?H bonds using in Situ Generated Trifluoromethylated Dioxirane in Flow
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A fast, scalable, and safer Csp3?H oxidation of activated and un-activated aliphatic chains can be enabled by methyl(trifluoromethyl)dioxirane (TFDO). The continuous flow platform allows the in situ generation of TFDO gas and its rapid reactivity toward tertiary and benzylic Csp3?H bonds. The process exhibits a broad scope and good functional group compatibility (28 examples, 8–99 %). The scalability of this methodology is demonstrated on 2.5 g scale oxidation of adamantane.
- Lesieur, Mathieu,Battilocchio, Claudio,Labes, Ricardo,Jacq, Jér?me,Genicot, Christophe,Ley, Steven V.,Pasau, Patrick
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supporting information
p. 1203 - 1207
(2019/01/04)
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- Photoelimination of nitrogen from adamantane and pentacycloundecane (PCU) diazirines: A spectroscopic study and supramolecular control
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Photochemical reactivity of pentacycloundecane (PCU) and adamantane diazirines was investigated by preparative irradiation in different solvents, laser flash photolysis (LFP) and quantum chemical computations. In addition, formation of inclusion complexes for diazirines with cucurbit[7]uril, β- and γ-cyclodextrin (β- and γ-CD) was investigated by 1H NMR spectroscopy, isothermal microcalorimetry and circular dichroism spectroscopy, followed by the investigation of photochemical reactivity of the formed complexes. Diazirines undergo efficient photochemical elimination of nitrogen (ΦR > 0.5) and deliver the corresponding singlet carbenes. Singlet carbenes react in intra- and intermolecular reactions and we found a rare singlet carbene pathway in CH3OH involving protonation and formation of a carbocation, detected due to the specific rearrangement of the pentacycloundecane skeleton. Singlet diazirines undergo intersystem crossing and deliver triplet carbenes that react with oxygen to form ketones which were isolated after irradiation. Our main finding is that the formation of diazirine inclusion complexes with β-CD and γ-CD changes the relative ratio of singlet vs. triplet pathways, with singlet carbene products being dominant from the chemistry of the irradiated complexes. Our combined theoretical and experimental studies provide new insights into the supramolecular control of carbene reactivity which has possible applications for the control of product distribution by solvent effects and the choice of constrained media.
- ?umanovac, Tatjana,Ale?kovi?, Marija,?ekutor, Marina,Matkovi?, Marija,Baron, Thibaut,Mlinari?-Majerski, Kata,Bohne, Cornelia,Basari?, Nikola
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p. 1806 - 1822
(2019/07/16)
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- Oxidation of Adamantane with H2O2–CF3COCF3 · 1.5 H2O in the Presence of VO(acac)2
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The system hydrogen peroxide–hexafluoroacetone sesquihydrate effectively oxidizes adamantane in the presence of VO(acac)2 to afford 64% of adamantan-1-ol in tert-butyl alcohol or 76% of adamantan-2-one in a mixture of acetic acid with pyridine.
- Kislitsina,Shchadneva,Khusnutdinov
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p. 992 - 995
(2018/09/12)
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- "ship in a bottle" Porph@MOMs as highly efficient catalysts for selective controllable oxidation and insights into different mechanisms in heterogeneous and homogeneous environments
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In the present work, three "ship in a bottle" Porph@MOMs are reported as biomimetic oxidation catalysts for different reactions. These frameworks are constructed from trimesic acid and metal ions (M = Fe, Co and Mn) in which tetra(N-methyl-4-pyridyl)porphyrin (MTMPyP) is encapsulated within the cavities. Additionally, the catalytic activities of the corresponding homogeneous compounds, FeTMPyP, CoTMPyP and MnTMPyP, and the frameworks without porphyrins within the cavities were investigated in the foregoing oxidation reactions. The prepared 3D porous structures have the ability to control selectivity toward the desired product. Furthermore, they are capable of acting as effective peroxidase mimics, which successfully catalyze the oxidation of diverse olefins as well as hydrocarbons using TBHP as an oxidant. The heterogeneous catalysts significantly enhance conversion in contrast to their corresponding homogeneous systems. Remarkably, an insight into the catalyst behavior was gained from the proposed mechanism based on the reversal of selectivity. Investigation of the stability and reusability of the catalysts revealed the heterogeneity character of the catalyst with no desorption during the course of oxidation reactions. The high yields, clean reactions, high thermal stability and reusability of the catalysts make them good candidates for heterogeneous catalysts in various oxidation reactions.
- Saghian,Dehghanpour,Sharbatdaran
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p. 12872 - 12881
(2018/08/01)
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- Liquid-phase oxidation of alkanes with molecular oxygen catalyzed by high valent iron-based perovskite
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Hexagonal BaFeO3-δ containing high valent iron species acted as an efficient heterogeneous catalyst for the aerobic oxidation of alkanes without the need for additives. The activity of BaFeO3-δ was much higher than that of typical Fe3+/Fe2+-containing iron oxide-based catalysts, and the recovered catalyst could be reused without significant loss of catalytic performance.
- Shibata, Satomi,Sugahara, Kosei,Kamata, Keigo,Hara, Michikazu
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supporting information
p. 6772 - 6775
(2018/06/26)
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- A chemiluminescent probe for cellular peroxynitrite using a self-immolative oxidative decarbonylation reaction
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Peroxynitrite (ONOO-) is a highly reactive oxygen species which has been recognized as an endogenous mediator of physiological activities like the immune response as well as a damaging agent of oxidative stress under pathological conditions. While its biological importance is becoming clearer, many of the details of its production and mechanism of action remain elusive due to the lack of available selective and sensitive detection methods. Herein, we report the development, characterization, and biological applications of a reaction-based chemiluminescent probe for ONOO- detection, termed as PNCL. PNCL reacts with ONOO-via an isatin moiety through an oxidative decarbonylation reaction to initiate light emission that can be observed instantly with high selectivity against other reactive sulphur, oxygen, and nitrogen species. Detailed studies were performed to study the reaction between isatin and ONOO-, which confirm selectivity for ONOO- over NO2. PNCL has been applied for ONOO- detection in aqueous solution and live cells. Moreover, PNCL can be employed to detect cellular ONOO- generated in macrophages stimulated to mount an immune response with lipopolysaccharide (LPS). The sensitivity granted by chemiluminescent detection together with the specificity of the oxidative decarbonylation reaction provides a useful tool to explore ONOO- chemistry and biology.
- Cao, Jian,An, Weiwei,Reeves, Audrey G.,Lippert, Alexander R.
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p. 2552 - 2558
(2018/03/08)
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- Synthesis, molecular structure, conformation and biological activity of Ad-substituted N-aryl-tetraoxaspiroalkanes
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An efficient method has been developed for the synthesis of 7′-arylspiro{adamantane-[2,3′]-(1′,2′,4′,5′,7′-tetraoxazocanes)} by the ring transformation reaction of spiro{adamantane-[2,3’]-(1′,2′,4′,5′,7′-pentaoxacane)} with arylamines in the presence of S
- Tyumkina, Tatyana V.,Makhmudiyarova, Nataliya N.,Kiyamutdinova, Guzeliya M.,Meshcheryakova, Ekaterina S.,Bikmukhametov, Kamil Sh.,Abdullin, Marat F.,Khalilov, Leonard M.,Ibragimov, Askhat G.,Dzhemilev, Usein M.
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p. 1749 - 1758
(2018/03/07)
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- Stereospecific sp3 C–H oxidation with m-CPBA: A CoIII Schiff base complex as pre-catalyst vs. its CoIIICdII heterometallic derivative
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The mono- and binuclear Schiff base complexes [CoL3]·DMF (1) and [CoCdL3Cl2]·0.5H2O (2) were facilely synthesized using zerovalent cobalt and cadmium chloride (for 2) as starting materials and the pre-formed pro-ligand HL (2-methoxy-6-[(methylimino)methyl]phenol, the product of condensation of o-vanillin and methylamine) in air. The compounds were characterized by single crystal X-ray diffraction analysis and spectroscopic methods in solution and in the solid state. Both complexes demonstrate a profound catalytic activity in the stereoselective oxidation of cis-1,2-dimethylcyclohexane (model substrate) with m-CPBA (m-chloroperbenzoic acid) under mild conditions in the presence of promoters of various acidity (HNO3, TFA and HOAc). The heterometallic binuclear CoIIICdII pre-catalyst (2) was more active than the mononuclear CoIII one (1), exhibiting higher products yields up to 51% and excellent stereospecificity (up to 99.2% retention of stereoconfiguration). This result could be associated with a synergistic effect of two different metals in 2. Based on the large obtained kinetic isotope effect and H218O labeling studies, the overall reaction mechanism was proposed to proceed without the participation of free alkyl radicals. The acidity of the promoter was shown to influence catalytic parameters for both 1 and 2 so that the better parameters are achieved with the acid possessing lower pKa values (a stronger acid). The comparison of the catalytic behaviours of 1 and 2 is discussed in detail considering relevant examples from the literature.
- Nesterova, Oksana V.,Kasyanova, Katerina V.,Makhankova, Valeriya G.,Kokozay, Vladimir N.,Vassilyeva, Olga Yu.,Skelton, Brian W.,Nesterov, Dmytro S.,Pombeiro, Armando J.L.
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p. 171 - 184
(2018/05/28)
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- Metal-free hypervalent iodine/TEMPO mediated oxidation of amines and mechanistic insight into the reaction pathways
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A highly efficient metal free approach for the oxidation of primary and secondary amines to their corresponding aldehydes and ketones using PhI(OAc)2 in combination with a catalytic amount of TEMPO as an oxidizing agent is described. This protocol is rapid and provides diverse products under milder reaction conditions in excellent yields. In addition, the mechanistic study is well demonstrated by spectroscopic methods.
- Bansode, Ajay H.,Suryavanshi, Gurunath
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p. 32055 - 32062
(2018/09/29)
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- Nucleofugal behavior of a β-shielded α-cyanovinyl carbanion
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Sterically well-shielded against unsolicited Michael addition and polymerization reactions, α-metalated α-(1,1,3,3-tetramethyl-indan-2-ylidene)acetonitriles added reversibly to three small aldehydes and two bulky ketones at room temperature. Experimental conditions were determined for transfer of the nucleofugal title carbanion unit between different carbonyl compounds. These readily occurring retro-additions via C-C(O) bond fission may also be used to generate different metal derivatives of the nucleofugal anions as equilibrium components. Fluoride-catalyzed, metal-free desilylation admitted carbonyl addition but blocked the retro-addition.
- Knorr, Rudolf,Schmidt, Barbara
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p. 3018 - 3024
(2019/01/05)
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- Oxidation of aliphatic and aromatic C[sbnd]H bonds by t-BuOOH catalyzed by μ-nitrido diiron phthalocyanine
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Low temperature selective transformation of alkanes to useful products continues to be an important challenge in chemistry and industry. μ-Nitrido diiron phthalocyanines in combination with H2O2 have been recently identified as powerful oxidation catalysts for these challenging reactions due to the formation of ultra-high valent diiron oxo species PcFe(IV)μNFe(IV)[dbnd]O(Pc+[rad]). This very strong two-electron oxidizing species is generated from peroxo complex PcFe(IV)μNFe(III)[sbnd]O[sbnd]O[sbnd]R(Pc) (R[dbnd]H in the case of H2O2) via heterolytic O[sbnd]O bond cleavage. Therein we show that the evolution of the peroxo diiron complex depends on the peroxide structure. Using tBuOOH we have demonstrated the formation of an one-electron oxidizing PcFe(IV)μNFe(IV)[dbnd]O(Pc) and tBuO[rad] radical via homolytic O[sbnd]O cleavage of the peroxocomplex. The reactivity of the μ-nitrido diiron tetra-t-butylphthalocyanine ? tBuOOH catalytic system was investigated in the oxidation of different C[sbnd]H bonds in alkanes, olefins, aromatic and alkylaromatic compounds. The main products of cyclohexane oxidation were cyclohexanone and cyclohexanol whereas bicyclohexyl was formed in minor amounts even in the presence of O2 and tBuOOH. Under optimal conditions, the turnover numbers of almost 5300 have been achieved.
- Kudrik, Evgeny V.,Sorokin, Alexander B.
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p. 499 - 505
(2016/12/16)
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- Dioxetane formation and chemiluminescent emission upon the combination of a vinylphenol derivative with naphthalene endoperoxide
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We designed a chemiluminescent system using nanoparticles. We prepared mesoporous nanoparticles bearing naphthalene endoperoxide as a singlet oxygen generator in the pore and vinyl phenol derivative as an emission unit. The combination of these functional molecules gave highly efficient and bright chemiluminescence through the formation of a 1,2-dioxetane intermediate.
- Umehara, Yui,Son, Aoi,Kondo, Teruyuki,Tanabe, Kazuhito
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p. 9472 - 9475
(2017/02/15)
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- Inhibition and Stabilization: Cucurbituril Induced Distinct Effects on the Schiff Base Reaction
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The different effects of cucurbit[7]uril (CB[7]) on the Schiff base reactions in aqueous solution were explored by 1H NMR spectroscopy and single X-ray crystallography. With CB[7], the condensation reaction of aldehyde and primary amine is dramatically inhibited. In contrast, the presence of CB[7] does tremendously stabilize iminium cation in water through ion-dipole interactions. A single crystal structure of the complex of iminium ion 7 with CB[7] grown in water is reported.
- Gong, Wanjun,Ma, Jun,Zhao, Zhiyong,Gao, Fang,Liang, Feng,Zhang, Haijun,Liu, Simin
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p. 3298 - 3301
(2017/03/23)
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- Synthesis, characterization, DFT studies, and immobilization of cobalt(II) complex with N,N′,N″-tris(2-pyrimidinyl)dimethylentriamine on modified iron oxide as oxidation catalyst
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[Co3(PDMT)Cl6] complex, in which PDMT is N,N′,N″-tris(2-pyrimidinyl)dimethylentriamine was prepared in cyclohexanol under hydrothermal condition. At first, the crystal structure of PDMT was solved based on the Rietveld method by using laboratory X-ray powder diffraction data. The molecular geometry of the ligand and complex were optimized by B3LYP method. In order to heterogenize the prepared complex, it was immobilized on the modified Fe3O4 nanoparticles with (3-aminopropyl)trimethoxysilane (APTMS). The prepared compound designated as Fe3O4SiO2-2APTMS[Co3(PDMT)Cl6] was found to successfully catalyze the epoxidation of cyclooctene, styrene, cyclohexene, trans-stilbene as well as oxidation of fluorene, diphenylmethane, ethylbenzene, adamantane, cyclohexane, cyclooctane and norbornene with TBHP as oxidant with 25-100% conversions and 18-100% selectivities. Ligand, complex and Fe3O4SiO2-2APTMS[Co3(PDMT)Cl6] were characterized by FT-IR, TEM, XRD, Mass, UV-Vis, DSC-TGA, NMR, GC and GC-Mass techniques.
- Sharbatdaran, Masoomeh,Farzaneh, Faezeh,Larijani, Majid Mojtahedzadeh,Salimi, Alireza,Ghiasi, Mina,Ghandi, Mehdi
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p. 264 - 275
(2016/06/09)
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- A cobalt Schiff base complex on TiO2 nanoparticles as an effective synergistic nanocatalyst for aerobic C-H oxidation
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A novel visible light active TiO2 nanoparticle was produced by functionalization with a cobalt Schiff base complex under ultrasonic agitation. It was characterized by different techniques such as FT-IR, EDX, XPS, ICP-AES and TGA. The particle size of the synthesized nanocomposite was found to be in the range of 22-32 nm according to TEM images. A red-shift of the band-edge and a significant reduction of the band-gap (2.9 eV) were revealed by UV-DRS. The as-prepared nanocomposite demonstrated high oxidation activity and desired selectivity in the aerobic benzylic C-H oxidation of a structurally diverse set of alcohols and benzylic hydrocarbons. A synergistic effect of the cobalt Schiff base complex and TiO2 nanoparticles on the visible-light photocatalytic activity was explored. Spectral results and leaching experiments revealed that the heterogeneous catalyst preserved its structure after many reuses.
- Jafarpour, Maasoumeh,Kargar, Hossein,Rezaeifard, Abdolreza
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p. 25034 - 25046
(2016/03/22)
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- Aerobic benzylic C-H oxidation catalyzed by a titania-based organic-inorganic nanohybrid
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The incorporation of Co(OAc)2 into ascorbic acid-coated TiO2 nanoparticles easily provided a new heterogeneous visible-light active titania-based photocatalyst (TiO2/AA/Co) which was characterized by different techniques such as FT-IR, XPS, ICP-AES, TGA and TEM. A red-shift of the band-edge and a significant reduction of the band-gap (2.8 eV) were demonstrated by UV-DRS. The as-prepared TiO2/AA/Co nanoparticles possess excellent photocatalytic properties under visible light for the aerobic benzylic C-H oxidation of a structurally diverse set of benzylic alcohols and benzylic hydrocarbons in ethyl acetate as a safe solvent. The spectral results and leaching experiments revealed that the structural integrity of the solid catalyst is well preserved after being reused many times.
- Jafarpour, Maasoumeh,Feizpour, Fahimeh,Rezaeifard, Abdolreza
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p. 54649 - 54660
(2016/07/06)
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- Synthesis, characterization and immobilization of a new cobalt(II) complex on modified magnetic nanoparticles as catalyst for epoxidation of alkenes and oxidation of activated alkanes
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The [Co(2-hydroxy-1-naphthaldehyde)2(DMF)2] complex 1 was prepared and characterized by X-ray crystallography, successfully supported on modified Fe3O4 nanoparticles using tetraethylorthosilicate (TEOS) and (3-aminopropyl)trimethoxysilane (APTMS) and designated as Fe3O4@SiO2@APTMS@complex nanocatalyst. FT-IR, elemental analysis, XRD, VSM and TEM studies have been used to characterize the nanocatalyst. The catalytic activity of Fe3O4@SiO2@APTMS@complex was evaluated by the epoxidation of norbornene, cyclooctene, styrene, α-methyl styrene, trans-stilbene and limonene, with 50-100% conversions and 83-100% selectivities. Furthermore, it was found that Fe3O4@SiO2@APTMS@complex successfully catalyzes the oxidation of activated secondary alkanes such as fluorene, adamantane, diphenyl methane, and ethylbenzene with 40-100% conversions and 80-100% selectivities toward the corresponding products. Based on the obtained results, the heterogeneity and reusability of the catalyst seems promising.
- Asgharpour, Zeinab,Farzaneh, Faezeh,Abbasi, Alireza
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p. 95729 - 95739
(2016/10/25)
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- Reactions of 2-methyleneadamantane and 2-benzylideneadamantane with acetyl nitrate
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The reactions of 2-methylene- and 2-benzylideneadamantane with acetyl nitrate have been studied. In the case of 2-methyleneadamantane, the reaction proceeds via addition of nitronium cation at the double bond followed by stabilization of 2-nitromethyl-2-adamantyl carbocation. In the case of 2-benzylidenadamantane, ortho-substitution at the benzene ring occurred predominantly.
- Krasnikov,Osyanin,Osipov,Klimochkin
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p. 262 - 266
(2016/04/20)
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- An alkoxyamine compound, alkoxy alcohol oxidation catalyst and method of using the alcohol oxidation
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PROBLEM TO BE SOLVED: To provide a novel alkoxyamine compound which can be easily manufactured and applied suitably as an alcohol oxidation catalyst capable of exerting sufficiently high catalytic activity in oxidation of primary and secondary alcohols.SOLUTION: There is provided an alkoxyamine compound with a homoadamantane skeleton represented by the general formula (1) in the figure. [In the formula (1), Rand Rare each independently any one selected from the group consisting of a hydrogen atom and alkyl groups that may be substituted.
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Paragraph 0096; 0099-0100
(2017/02/02)
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- Olefin cis-Dihydroxylation and Aliphatic C-H Bond Oxygenation by a Dioxygen-Derived Electrophilic Iron-Oxygen Oxidant
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Many iron-containing enzymes involve metal-oxygen oxidants to carry out O2-dependent transformation reactions. However, the selective oxidation of C-H and C-C bonds by biomimetic complexes using O2 remains a major challenge in bioinspired catalysis. The reactivity of iron-oxygen oxidants generated from an FeII-benzilate complex of a facial N3 ligand were thus investigated. The complex reacted with O2 to form a nucleophilic oxidant, whereas an electrophilic oxidant, intercepted by external substrates, was generated in the presence of a Lewis acid. Based on the mechanistic studies, a nucleophilic FeII-hydroperoxo species is proposed to form from the benzilate complex, which undergoes heterolytic O-O bond cleavage in the presence of a Lewis acid to generate an FeIV-oxo-hydroxo oxidant. The electrophilic iron-oxygen oxidant selectively oxidizes sulfides to sulfoxides, alkenes to cis-diols, and it hydroxylates the C-H bonds of alkanes, including that of cyclohexane. Lewis acid mediated O-O bond cleavage: A nucleophilic iron(II)-hydroperoxo oxidant, formed upon oxidative decarboxylation of an iron(II)-α-hydroxy acid complex, undergoes heterolytic O-O bond cleavage in the presence of a Lewis acid to generate an electrophilic iron(IV)-oxo-hydroxo oxidant. The electrophilic oxidant oxidizes sulfides to sulfoxides and alkenes to cis-diols, and it hydroxylates the strong C-H bonds of aliphatic substrates.
- Chatterjee, Sayanti,Paine, Tapan Kanti
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supporting information
p. 9338 - 9342
(2015/08/06)
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- Fabrication of CuCr2O4 spinel nanoparticles: A potential catalyst for the selective oxidation of cycloalkanes via activation of Csp3-H bond
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We report here preparation of CuCr2O4 spinel nanoparticle catalyst, mediated by cationic surfactant CTAB in hydrothermal route. XRD revealed the formation of CuCr2O4 spinel phase and TEM showed the particle size of 30-60 nm. The catalyst was speculated to be highly active for selective oxidation of cyclohexane to cyclohexanone with H2O2. A cyclohexane conversion of 70% with 85% cyclohexanone selectivity was achieved over this catalyst at 50 °C temperature. Moreover, the catalyst did not show any significant activity loss even after 8 reuses and proved its efficacy in the oxidation of other cycloalkanes also.
- Acharyya, Shankha S.,Ghosh, Shilpi,Adak, Shubhadeep,Tripathi, Deependra,Bal, Rajaram
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p. 145 - 150
(2015/01/09)
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- Ruthenium Trichloride Catalyzed Highly Efficient Deoximation of Oximes to the Carbonyl Compounds and Nitriles without Acceptors
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An acceptor-free catalysis protocol for the deoximation of ketoximes and aldoximes using RuCl3 as the catalyst has been developed. Under the optimized conditions, various oximes were converted to ketones and nitriles with excellent isolated yields. An acceptor-free catalysis protocol for the deoximation of ketoximes and aldoximes using RuCl3 as the catalyst has been developed. Under the optimized conditions, various oximes were converted to ketones and nitriles with excellent isolated yields.
- Liu, Yuxiao,Yang, Na,Chu, Changhu,Liu, Renhua
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supporting information
p. 1011 - 1014
(2015/09/28)
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- Reaction of nitroso chlorides of the adamantane series with nucleophiles
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Reactions of nitroso chlorides of 2-alkylydene adamantanes with O- and N-nucleophiles resulted in α-substituted oximes of the adamantane series. Reaction involved 1,4-nucleophilic addition of the nucleophiles to the generated in situ nitroso alkenes actin
- Krasnikov,Osyanin,Osipov,Klimochkin, Yu. N.
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p. 2454 - 2458
(2016/09/28)
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- Evidence that steric factors modulate reactivity of tautomeric iron-oxo species in stereospecific alkane C-H hydroxylation
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A new iron complex mediates stereospecific hydroxylation of alkyl C-H bonds with hydrogen peroxide, exhibiting excellent efficiency. Isotope labelling studies provide evidence that the relative reactivity of tautomerically related oxo-iron species responsible for the C-H hydroxylation reaction is dominated by steric factors. This journal is The Royal Society of Chemistry.
- Mitra, Mainak,Lloret-Fillol, Julio,Haukka, Matti,Costas, Miquel,Nordlander, Ebbe
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supporting information
p. 1408 - 1410
(2014/02/14)
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- Oxidation of hydrocarbons with tetra-n-butylammonium peroxy monosulfate catalyzed by β-tetrabromo-meso-tetrakis(4-methoxyphenyl)-and β-tetrabromo-meso-tetraphenylporphyrinatomanganese(III)
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β-Tetrabromo-meso-tetrakis(4-methoxyphenyl)porphyrin, H2 T(4-OCH3 P)PBr4, was synthesized and characterized by UV-Vis and 1H NMR spectroscopy. Oxidation of alkanes and olefins with tetra-n-butylammonium peroxymonosulfate (n-Bu4NHSO5) was studied in the presence of MnT(4-OCH3 P)PBr4 (OAc) and MnTPPPBr4 (OAc) (TPP = meso-tetraphenylporphyrin). While significance differences were observed between the catalytic activities of the title complexes in the oxidation of alkanes, the 2 manganese porphyrins showed comparable activities in oxidation of most of the olefins used. However, the latter showed greater catalytic performance in the oxidation of the hydrocarbons. Moreover, the oxidative degradation of the former (60%) was greater than that of the latter (45%) in the oxidation of cyclooctene. TUeBITAK.
- Rayati, Saeed,Zakavi, Saeed,Valinejad, Hossein
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p. 611 - 616
(2014/07/07)
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- Binuclear iron(III) octakis(perfluorophenyl)tetraazaporphyrin μ-oxodimer: A highly efficient catalyst for biomimetic oxygenation reactions
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Binuclear iron(III) octakis(perfluorophenyl)tetraazaporphyrin μ-oxodimer complex was prepared by the reaction of bis(perfluorophenyl)maleonitrile and Fe(CO)5and tested in catalytic oxygenation reactions of several hydrocarbons in comparison with the analogous non-fluorinated phthalocyanine complexes. Results of the study demonstrate that this complex is a highly efficient catalyst for the oxygenation of anthracene, 2-tert-butylanthracene, naphthalene, 2-methylnaphthalene, phenanthrene, adamantane, and toluene using iodosylbenzene, oligomeric iodosylbenzene sulfate, or Oxone as stoichiometric oxidants.
- Yusubov, Mekhman S.,Celik, Cumali,Geraskina, Margarita R.,Yoshimura, Akira,Zhdankin, Viktor V.,Nemykin, Victor N.
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supporting information
p. 5687 - 5690
(2014/12/11)
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- Synthesis, characterization, photophysics and photochemistry of pyrylogen electron transfer sensitizers
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A series of new dicationic sensitizers that are hybrids of pyrylium salts and viologens has been synthesized. The electrochemical and photophysical properties of these "pyrylogen" sensitizers are reported in sufficient detail to allow rationale design of new photoinduced electron transfer reactions. The range of their reduction potentials (+0.37-+0.05 V vs SCE) coupled with their range of singlet (48-63 kcal mol-1) and triplet (48-57 kcal mol-1) energies demonstrate that they are potent oxidizing agents in both their singlet and triplet excited states, thermodynamically capable of oxidizing substrates with oxidation potentials as high as 3.1 eV. The pyrylogens are synthesized in three steps from readily available starting materials in modest overall 11.4-22.3% yields. These sensitizers have the added advantages that: (1) their radical cations do not react on the CV timescale with oxygen bypassing the need to run reactions under nitrogen or argon and (2) have long wavelength absorptions between 413 and 523 nm well out of the range where competitive absorbance by most substrates would cause a problem. These new sensitizers do react with water requiring special precautions to operate in a dry reaction environment. Hybrids of pyrylium salts and viologens photochemically generate radical-cation/radical-cation pairs with substantial intra-ion repulsion that increases the rate constant of separation, kSEP, and competitively inhibits energy wasting return electron transfer. These first representatives of dicationic charge-shift sensitizers generate radical cations that do not react with oxygen on the CV timescale and absorb between 413 and 523 nm well outside the range where competitive absorbance by most substrates would cause a problem.
- Clennan, Edward L.,Liao, Chen
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p. 344 - 357
(2014/04/03)
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