- Regulating signal enhancement with coordination-coupled deprotonation of a hydrazone switch
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Proton relay plays an important role in many biocatalytic pathways. In order to mimic such processes in the context of molecular switches, we developed coordination-coupled deprotonation (CCD) driven signaling and signal enhancement sequences. This was ac
- Foy, Justin T.,Ray, Debdas,Aprahamian, Ivan
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- Ag nanoparticle immobilized on functionalized magnetic hydrotalcite (Fe3O4/HT-SH-Ag) for clean oxidation of alcohols with TBHP
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Hydrotalcite (HT) modified with magnetic nanoparticle and thiol groups for the immobilization of silver to the preparation of Fe3O4/HT-SH-Ag was used. The catalyst was completely characterized using XRD, ICP, SEM, EDS, VSM, FT-IR, and TEM analyzes. The Fe3O4/HT-SH-Ag catalyst is useful in oxidizing of primary and secondary aliphatic and benzyl alcohols to the relevant carbonyl products (aldehyde/ketone). To demonstrate the effect of Ag over the reaction, Fe3O4/HT-SH catalyst performance, and also some other control tests were studied. For this purpose, the model reaction was carried out in the presence of AgNO3, HT (I), and Fe3O4/HT (II), and low yield was obtained (20–50%). High to good efficiency were obtained for all entries, whether benzaldehyde derivatives, in short times. The catalyst can be reused for several continuous runs with a simple external magnet without losing significant reactivity.
- Salimi, Mehri,Zamanpour, Azadeh
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- A new acetal as a fluorescent probe for highly selective detection of Fe3+ and its application in bioimaging
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A simple fluorescent probe L for Fe3+ was easily synthesized based on anthracene. Among the various metal ions including Fe2+, this probe exhibited high sensitivity and good selectivity toward Fe3+ with turn-off fluorescence mode in DMSO-HEPES buffer solution (20 mM, pH = 7.0, 1:1 (v/v)). When adequate Fe3+ ion was added into the solution of probe L, its molecular structure transferred from anthraldehyde dimethyl acetal to anthraldehyde, resulting in fluorescence quenching with a low detection limit of 3.08 μM. 1H NMR spectra and TLC analysis further supported this concept. Finally, this probe was successfully applied in bioimaging.
- Wang, Min,Zhang, Yong-Ming,Zhao, Qin-Yi,Fu, Zhen-Hai,Zhang, Zhi-Hong
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- Bacteriorhodopsin analogue from anthryl chromophores
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Preparation and properties of the bacteriorhodopsin (bR) analogue having the 3,7-dimethyl-9-(9-anthryl)-2E, 4E,6E,8E-nonatetraenal (12) chromophore is described. Synthesis of the chromophore has been achieved by successive introduction of C5 units to 9-anthraldehyde (3) via the Horner reaction. The all-trans chromophore has been characterized by its ultraviolet-visible and 1H nuclear magnetic resonance spectra. Incubation of 12 with bacterioopsin suspension (prepared by photobleaching of bR isolated from Halobacterium halobium) at ambient temperature in the dark gave the new bR analogue 15, which showed an absorption band at 545 nm, and an opsin shift of 5575 cm-1. The new pigment is stable to hydroxyl amine in the dark. It showed light-dark adaptation with the light-adapted from absorbing at a slightly red-shifted value of 550 nm. All-trans-retinal did not replace the anthryl chromophore in competitive bindings. Photolysis of the bR analogue 15, followed by difference spectrophotometric analysis, indicated formation of a photoproduct with an absorption band near 400 nm. The results are discussed in terms of the steroelectronic requirements of the bR reaction centre.
- Singh,Roy
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- A new OsO4-mediated carbon-carbon bond cleavage reaction leading to the formation of anthraquinone
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A new OsO4-mediated carbon-carbon bond cleavage reaction leading to the formation of anthraquinone was observed. The reaction goes through the dihydroxylated intermediate and is aided by the presence of pyridine.
- Gao, Shouhai,Wang, Wei,Wang, Binghe
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- Nickel(II)-Catalyzed Selective (E)-Olefination of Methyl Heteroarenes Using Benzyl Alcohols via Acceptorless Dehydrogenative Coupling Reaction
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An efficient catalytic protocol for the synthesis of selective (E)-olefins by the newly synthesized nickel complexes via greener acceptorless dehydrogenative coupling methodology is presented. Two nickel(II) N, S chelating complexes were structurally characterized with the aid of spectral and single crystal X-ray diffraction methods. Olefination of 2-methylheteroarenes with benzyl alcohols via acceptorless dehydrogenative coupling is achieved by inexpensive nickel(II) catalysts. The present olefination protocol is simple and furnishes the desired 2-alkenylheteroarenes in 35 h and yields in the range of 40–93 %. The dehydrogenative coupling reaction proceeds via the generation of an aldehyde intermediate and produces water and hydrogen as sole by-products. The wide substrate scope of this catalytic reaction covered the synthesis of drug intermediates.
- Balamurugan, Gunasekaran,Ramesh, Rengan
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- A bagasse-supported magnetic manganese dioxide nanoparticle: applications in the selective aerobic oxidation of alcohols and one-pot tandem oxidative synthesis of quinazolinones
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Magnetic manganese dioxide nanoparticles (MnO2-Fe3O4) were coated on sugarcane bagasse as a sugar industrial waste and bio-support (MnO2-Fe3O4@bagasse) via an in situ reduction strategy, in which potassium permanganate was used as the precursor of MnO2 and sugarcane bagasse as a bio-support and reducing agent of KMnO4. The synthesized bio-based catalyst was characterized by X-ray diffraction, thermogravimetric analysis, inductively coupled plasma optical emission spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, Brunauer–Emmett–Teller surface area analysis, and vibrating sample magnetometer analysis. The catalyst was successfully utilized in the selective aerobic oxidation of primary and secondary benzylic alcohols to their corresponding carbonyl compounds and one-pot tandem oxidative synthesis of 2-(substituted)quinazoline-4(3H)-ones from the o-aminobenzamide and aromatic alcohols in the absence of oxidizing reagent or initiator. Graphical abstract: [Figure not available: see fulltext.]
- Farhid, Hassan,Hajishaabanha, Fatemeh,Rashidi Vahid, Adina,Shaabani, Ahmad,Shaabani, Shabnam
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- Nitrosoarene-Catalyzed HFIP-Assisted Transformation of Arylmethyl Halides to Aromatic Carbonyls under Aerobic Conditions
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A rare metal-free nucleophilic nitrosoarene catalysis accompanied by highly hydrogen-bond-donor (HBD) solvent, 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), organocatalytically converts arylmethyl halides to aromatic carbonyls. This protocol offers an effective means to access a diverse array of aromatic carbonyls with good chemoselectivity under mild reaction conditions. The activation of arylmethyl halides by HFIP to generate stable carbocation and autoxidation of in situ generated hydroxylamine to nitrosoarene in the presence of atmospheric O2 are the keys to success.
- Pradhan, Suman,Sharma, Vishali,Chatterjee, Indranil
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supporting information
p. 6148 - 6152
(2021/08/03)
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- Catalytic study of the copper-based magnetic nanocatalyst on the aerobic oxidation of alcohols in water
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A copper-based magnetic nanocatalyst has been prepared by co-precipitation method and characterized by FESEM, EDS, TEM, XRD, XRF, ICP–OES, FTIR, and BET analysis. This new nanocatalyst displays a good activity toward the aerobic oxidation of a wide range of alcohols in water. Moreover, it is recyclable up to five following runs by simple filtration without any significant loss of its catalytic activity.
- Dehkordi, S. Saeid Saei,Albadi, Jalal,Jafari, Abbas Ali,Samimi, Heshmat Allah
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p. 2527 - 2538
(2021/03/24)
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- Magnetic spent coffee ground as an efficient and green catalyst for aerobic oxidation of alcohols and tandem oxidative Groebke–Blackburn–Bienaymé reaction
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Abstract: In this work, magnetic spent coffee ground as a green, inexpensive, and abundant material was synthesized and characterized by a variety of techniques, including X-ray diffraction pattern, thermal gravimetric analysis, scanning electron microscopy, energy-dispersive spectroscopy, inductively coupled plasma optical emission spectrometry, and Fourier transform infrared spectroscopy. The magnetic spent coffee ground was successfully utilized as a catalyst in aerobic oxidation of primary and secondary benzylic alcohols and tandem oxidative Groebke–Blackburn–Bienaymé reaction. Graphic abstract: [Figure not available: see fulltext.].
- Farhid, Hassan,Shaabani, Ahmad
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p. 1199 - 1209
(2020/11/09)
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- New Low-Dimensional Perovskites Based on Lead Bromide
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Abstract: The reactions of lead bromide with 7,7,8,8-tetracyanoquinodimethane and anthracen-9-ylmethanamine hydrobromide in dimethylformamide (DMF) afford the known low-dimensional perovskite {PbBr2(DMF)}n (I) with an impurity of a new hybrid 1D perovskite {Ca(DMF)6[PbBr3]2}n (II), which is isolated in the individual form and characterized by X-ray diffraction analysis. In the crystal of compound II, lead bromide forms infinite chains of PbBr5 octahedra with one vacant vertex between which calcium cations coordinated by the DMF molecules are arranged. The calcium cations presumably have got into the reaction mixture from water used for the washing of the reaction vessel for crystallization after the previous attempt of the synthesis. An attempt of the purposeful preparation of this hybrid 1D perovskite from various calcium salts as sources of this metal ion gives one more new low-dimensional perovskite {Ca(DMF)6[PbBr2.3Cl0.7]2}n (III) in which halide anions (bromide and chloride anions from lead bromide and calcium chloride, respectively) build up the coordination sphere of the lead ion to an octahedral one inducing no noticeable changes in the crystal packing compared to that of compound II. The X-ray diffraction results are deposited with the Cambridge Crystallographic Data Centre (CIF files CCDC nos. 2045586 (I), 2047219 (II), and 2047220 (III)).
- Isakovskaya,Nikovskii,Nelyubina, Yu. V.
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p. 365 - 375
(2021/07/16)
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- Substituted 9-Anthraldehydes from Dibenzocycloheptanol Epoxides via Acid-Catalyzed Epoxide Opening/Semipinacol Rearrangement
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Starting from benzaldehyde derivatives, the corresponding dibenzocycloheptenol could be prepared in five steps. Under both substrate (secondary vs tertiary alcohol and the substituents on the aromatic ring(s)) and condition control, the subsequent epoxidation and acid-catalyzed epoxide opening/semipinacol rearrangement/aromatization afforded the corresponding 9-anthraldehydes in good yields, up to 88% over two steps. The presence of the electron-withdrawing group(s) on the aromatic ring(s) suppressed the rate of the epoxidation while the subsequent semipinacol rearrangement step required heating; the presence of the electron-donating group(s), on the other hand, frequently led to the decomposition during the epoxidation. From the mechanistic studies, the semipinacol rearrangement of the epoxide could precede the ionization at the bisbenzylic position, yielding the aldehyde intermediate. The ensuing dehydrative aromatization led to the formation of 9-anthraldehyde. Conversely, nucleophilic addition to the aldehyde and dehydrative aromatization with concomitant loss of formic acid led to anthracene.
- Phumjan, Tanawat,Songthammawat, Poramate,Jongcharoenkamol, Jira,Batsomboon, Paratchata,Ruchirawat, Somsak,Ploypradith, Poonsakdi
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p. 13322 - 13349
(2021/09/13)
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- Photo-on-Demand Synthesis of Vilsmeier Reagents with Chloroform and Their Applications to One-Pot Organic Syntheses
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The Vilsmeier reagent (VR), first reported a century ago, is a versatile reagent in a variety of organic reactions. It is used extensively in formylation reactions. However, the synthesis of VR generally requires highly toxic and corrosive reagents such as POCl3, SOCl2, or COCl2. In this study, we found that VR is readily obtained from a CHCl3 solution containing N,N-dimethylformamide or N,N-dimethylacetamide upon photo-irradiation under O2 bubbling. The corresponding Vilsmeier reagents were obtained in high yields with the generation of gaseous HCl and CO2 as byproducts to allow their isolations as crystalline solid products amenable to analysis by X-ray crystallography. With the advantage of using CHCl3, which bifunctionally serves as a reactant and a solvent, this photo-on-demand VR synthesis is available for one-pot syntheses of aldehydes, acid chlorides, formates, ketones, esters, and amides.
- Liang, Fengying,Eda, Kazuo,Okazoe, Takashi,Wada, Akihiro,Mori, Nobuaki,Konishi, Katsuhiko,Tsuda, Akihiko
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p. 6504 - 6517
(2021/05/06)
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- Ionic liquid [Bmim][AuCl4] encapsulated in ZIF-8 as precursors to synthesize N-decorated Au catalysts for selective aerobic oxidation of alcohols
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Here we report a novel approach to synthesize Au NPs immobilized on N-doped carbon materials. In this strategy, an ionic liquid (IL) [Bmim][AuCl4] was selected as the precursor for Au NPs and porous framework of ZIF-8 as the host for the IL. Raman spectroscopy, transmission electron microscopy, N2 physical absorption and Fourier infrared spectra confirmed that the IL was successfully incorporated in the ZIF-8 pores. Followed by a thermal treatment under inert atmosphere, highly dispersed Au NPs were obtained and stabilized by nitrogen species from the carbonization of organic ligand in the metal-organic frameworks (MOFs). The [Bmim][AuCl4]@ZIF-8-6.25percent-T materials exhibited high catalytic activity for the selective aerobic oxidation of alcohols, affording excellent yields (up to >99percent) under atmospheric air and base-free conditions. Catalytic reaction along with catalyst characterization results revealed a strong interaction between Au NPs and N species. TEM, XRD and XPS characterization results further suggested that the N species could not only prevent the Au NPs from aggregation, but also further enhance the reaction activity.
- Chen, Fengfeng,Lu, Qingwen,Fan, Ting,Fang, Ruiqi,Li, Yingwei
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- Visible-light assisted of nano Ni/g-C3N4 with efficient photocatalytic activity and stability for selective aerobic C?H activation and epoxidation
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A selective, economical, and ecological protocol has been described for the oxidation of methyl arenes and their analogs to the corresponding carbonyl compounds and epoxidation reactions of alkenes with molecular oxygen (O2) or air as a green oxygen source, under mild reaction conditions. The nano Ni/g-C3N4 exhibited high photocatalytic activity, stability, and selectivity in the C?H activation of methyl arenes, methylene arenes, and epoxidation of various alkenes under visible- light irradiation without the use of an oxidizing agent and under base free conditions.
- Akrami, Zahra,Hosseini-Sarvari, Mona
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supporting information
(2020/10/13)
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- Supramolecular Catalysis of the oxa-Pictet–Spengler Reaction with an Endohedrally Functionalized Self-Assembled Cage Complex
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An endohedrally functionalized self-assembled Fe4L6 cage complex can catalyze oxa-Pictet—Spengler cyclizations of tryptophols and various aldehyde derivatives, showing strong rate accelerations and size-selectivity. Selective molecular recognition of substrates controls the reactivity, and the cage is capable of binding and activating multiple different species along the multistep reaction pathway. The combination of a functionalized active site, size-selective reactivity, and multistep activation, all from a single host molecule, illustrates the biomimetic nature of the catalysis.
- Harman, W. Hill,Hooley, Richard J.,Ngai, Courtney,Sanchez-Marsetti, Colomba M.
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supporting information
p. 23505 - 23509
(2020/10/21)
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- Visible-light mediated facile dithiane deprotection under metal free conditions
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Visible light mediated facile and selective dithiane deprotection under metal free conditions is developed. Eosin Y (1 mol%) proved to be an effective catalyst for the dithiane deprotection under the ambient photoredox conditions. The standard household compact fluorescent light source (CFL bulb) proved to be effective under open-air conditions in aqueous acetonitrile at room temperature. The protocol that exhibits a broad substrate scope and functional group tolerance has been shown to expand to a range of transformations for the electron-rich and -deficient thioacetals and thioketals. The synthetic utility of this protocol has also been demonstrated by gram-scale application.
- Dharpure, Pankaj D.,Bhowmick, Anindita,Warghude, Prakash K.,Bhat, Ramakrishna G.
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- Amino-Induced 2D Cu-Based Metal–Organic Framework as an Efficient Heterogeneous Catalyst for Aerobic Oxidation of Olefins
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With the assistance of hydrogen bonds of the o-amino group, we have successfully tuned a coordination structure from a metal–organic polyhedron (MOP) to a two-dimensional (2D) metal–organic framework (MOF). The amino group forms hydrogen bonds with the two vicinal carboxylic groups, and induces the ligand to coordinate with copper ions to form the 2D structure. The obtained 2D Cu-based MOF (Cu-AIA) has been applied as an efficient heterogeneous catalyst in the aerobic epoxidation of olefins by using air as oxygen source. Without the aggregation problem of active sites in MOPs, Cu-AIA possesses much higher reactivity than MOP-1. Furthermore, the amino group of the framework has been used as a modifiable site through post-synthetic metalation (PSMet) to prepare a 2D MOF-supported Pd single-site heterogeneous catalyst, which shows excellent catalytic performance for the Suzuki reaction. It indicates that Cu-AIA can also work as a good 2D MOF carrier for the derivation of other heterogeneous catalysts.
- Bao, Shixiong,Cai, Mengke,Ding, Shujiang,Li, Guangqin,Tang, Jia,Tao, Jinzhang,Wang, Xiaoxia,Xie, Guanqun
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supporting information
(2020/03/13)
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- Metal-ligand cooperativity in a ruthenium(II) complex of bis-azoaromatic ligand for catalytic dehydrogenation of alcohols
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Herein a new Ru-phosphine complex (1) with molecular formula [RuL(PPh3)Cl2] is reported where L is a redox active pincer ligand 2,6-bis(phenylazo)pyridine. The isolated complex has been characterized by usual spectroscopic techniques including single crystal X-ray crystallographic analysis. Complex 1 efficiently catalyzes aerobic oxidation of a wide range of primary and secondary benzylic, allylic, heterocyclic, alicyclic alcohols under mild conditions and is found to be superior over several other Ru (0, +2 and +3), Ru-H and Ru-PPh3 catalysts. Mechanistic studies indicate that a transient Ru-H intermediate is formed in the catalytic cycle which gets switched into a Ru-hydrazo intermediate via hydrogen-walking mechanism. The catalyst is regenerated by aerial oxidation producing H2O2 as a by-product.
- Saha, Tanushri,Pramanick, Rajib,Sengupta, Debabrata,Goswami, Sreebrata
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p. 160 - 166
(2018/09/29)
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- A Laccase Heterogeneous Magnetic Fibrous Silica-Based Biocatalyst for Green and One-Pot Cascade Synthesis of Chromene Derivatives
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Green cascade approaches, which utilize sustainable and recyclable heterogeneous biocatalysts, can be used in the catalysis of multicomponent organic reactions to synthesize biologically important substances. Three magnetic nanoparticles, iron (II, III) oxide, cobalt ferrite, and nickel ferrite, were prepared by co-precipitation and functionalized with fibrous silica (KCC-1), and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM). Laccase immobilized on CoFe2O4-KCC-1 was used as a heterogeneous biocatalyst for green and one-pot cascade synthesis of 2-amino-5-oxo-4-aryl-4H,5H-pyrano[3,2-c]chromene-3-carbonitriles. The reaction was performed in the presence of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) as a synthetic redox mediator. The optimum reaction conditions were found to be as immobilized laccase (100 mg, 95 U) and TEMPO (2 mol-%) in a 100 mm sodium citrate buffer (pH 4.5), 40 °C, and incubation time 17 h. About 80 % of initial activity of the immobilized laccase was retained after 15 independent runs.
- Mogharabi-Manzari, Mehdi,Ghahremani, Mohammad Hossein,Sedaghat, Tabassom,Shayan, Fatemeh,Faramarzi, Mohammad Ali
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p. 1741 - 1747
(2019/02/20)
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- A Fluorescent Silver(I) Carbene Complex with Anticancer Properties: Synthesis, Characterization, and Biological Studies
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The silver(I) N-heterocyclic carbene (NHC) complex bis(1-(anthracen-9-ylmethyl)-3-ethylimidazol-2-ylidene) silver chloride ([Ag(EIA)2]Cl), bearing two anthracenyl fluorescent probes, has been synthesized and characterized. [Ag(EIA)2]Cl is stable in organic solvents and under physiological conditions, and shows potent cytotoxic effects in vitro toward human SH-SY5Y neuroblastoma cells. The interactions of [Ag(EIA)2]Cl with a few model biological targets have been studied as well as its ability to be internalized in cells. The in vitro anticancer activity is apparently related to the level of drug internalization. Notably, [Ag(EIA)2]Cl does not react with a few model proteins, but is capable of binding the C-terminal dodecapeptide of thioredoxin reductase hTrxR(488–499) and to strongly inhibit the activity of this enzyme. Binding occurs through an unconventional process leading to covalent binding of one or two carbene ligands to the C-terminal dodecapeptide with concomitant release of the silver cation. To the best of our knowledge, this mode of interaction is reported here for the first time for Ag(NHC)2 complexes.
- Fabbrini, Maria Giulia,Cirri, Damiano,Pratesi, Alessandro,Ciofi, Lorenzo,Marzo, Tiziano,Guerri, Annalisa,Nistri, Silvia,Dell'Accio, Alfonso,Gamberi, Tania,Severi, Mirko,Bencini, Andrea,Messori, Luigi
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supporting information
p. 182 - 188
(2019/01/04)
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- 9-benzyl naphthylamine and synthesis method thereof
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The invention discloses 9-benzyl naphthylamine with mild reaction conditions, good atom economy and high yield and a synthesis method of the 9-benzyl naphthylamine. The synthesis method comprises thefollowing steps: dissolving anthracene in dichloromethane, cooling to the temperature of 0 DEG C, adding 1, 1-dichloromethyl ether and titanium tetrachloride, heating to the room temperature, stirring, adding saturated sodium bicarbonate, extracting with dichloromethane to obtain an organic phase, drying, evaporating a solvent under reduced pressure, dissolving tert-butyl carbamate in a mixed solvent of acetonitrile and the dichloromethane, stirring, adding triethylsilane and trifluoroacetic acid, and reacting at room temperature; adding saturated sodium bicarbonate, extracting with dichloromethane to obtain an organic phase, drying, evaporating the solvent under reduced pressure, dissolving in the dichloromethane, adding trifluoroacetic acid, stirring, evaporating the solvent until a solid is obtained, adding the solid in sodium hydroxide, stirring, adding dichloromethane for extraction, drying the obtained organic phase, evaporating the solvent until a solid is obtained so as to obtain the target product.
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Paragraph 0227; 0028
(2019/06/27)
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- On/Off O2 Switchable Photocatalytic Oxidative and Protodecarboxylation of Carboxylic Acids
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Photoredox catalysis in recent years has manifested a powerful branch of science in organic synthesis. Although merging photoredox and metal catalysts has been a widely used method, switchable heterogeneous photoredox catalysis has rarely been considered. Herein, we open a new window to use a switchable heterogeneous photoredox catalyst which could be turned on/off by changing a simple stimulus (O2) for two opponent reactions, namely, oxidative and protodecarboxylation. Using this strategy, we demonstrate that Au@ZnO core-shell nanoparticles could be used as a switchable photocatalyst which has good catalytic activity to absorb visible light due to the localized surface plasmon resonance effect of gold, can decarboxylate a wide range of aromatic and aliphatic carboxylic acids, have multiple reusability, and are a reasonable candidate for synthesizing both aldehydes/ketones and alkane/arenes in a large-scale set up. Some biologically active molecules are also shown via examples of the direct oxidative and protodecarboxylation which widely provided pharmaceutical agents.
- Bazyar, Zahra,Hosseini-Sarvari, Mona
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p. 13503 - 13515
(2019/10/11)
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- Construction of a fluorescent probe for selectively detecting singlet oxygen with a high sensitivity and large concentration range based on a two-step cascade sensing reaction
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A novel fluorescent probe XQ-1 for selectively detecting 1O2 on the basis of a two-step cascade reaction has been rationally constructed. The probe responded to 1O2 not only showing a high sensitivity, but also displaying a large concentration range, which means that the probe can be used as a powerful tool to monitor the efficacy of PDT toward cancer and concurrently track the adverse effects on healthy cells.
- Long, Lingliang,Yuan, Xiangqi,Cao, Siyu,Han, Yuanyuan,Liu, Weiguo,Chen, Qian,Gong, Aihua,Wang, Kun
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supporting information
p. 8462 - 8465
(2019/07/22)
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- Copper based coordination polymers based on metalloligands: Utilization as heterogeneous oxidation catalysts
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This work presents the synthesis and characterization of two Cu(ii)-based coordination polymers prepared by utilizing two different Co(iii)-based metalloligands offering appended arylcarboxylic acid groups. Both coordination polymers are three-dimensional in nature and present pores and channels filled with water molecules. Both coordination polymers function as heterogeneous catalysts for the epoxidation of various olefins using O2 while employing isobutyraldehyde as the coreductor and for peroxide-mediated oxidation of assorted benzyl alcohols. The catalytic results illustrate efficient oxidation reactions, whereas the hot-fltration test and leaching experiments indicate the true heterogeneous nature of the catalysis.
- Kumar, Gulshan,Hussain, Firasat,Gupta, Rajeev
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p. 16985 - 16994
(2019/01/03)
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- An efficient and sustainable protocol for oxidation of alcohols to carbonyl compounds
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A simple and extremely efficient protocol is developed for oxidation of alcohols to carbonyl compounds at room temperature by using green solvent lactic acid and green oxidant H2O2. This protocol provides high conversion under catalyst free conditions. The easy work up procedure allows high selectivity and good to excellent yields of carbonyl compounds with purity. We have performed wide range of substrates in present study with primary focus on reusability of lactic acid.
- Wagh, Ravindra B.,Nagarkar, Jayashree M.
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supporting information
p. 3443 - 3447
(2018/08/20)
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- Effects of Ancillary Ligands on Redox and Chemical Properties of Ruthenium Coordinated Azoaromatic Pincer
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In this work, the effect of the electronically different ancillary ligands on the overall properties of the RuIIL moiety (L = 2,6-bis(phenylazo)pyridine) in heteroleptic complexes of general formula [RuLQCl]0/+ was investigated. Four different ancillary ligands (Q) with different electronic effects were used to prepare the heteroleptic compounds from the precursor complex, [RuL(CH3CN)Cl2] (1); Q = pcp: 2-(4-chloro-phenylazo)pyridine (strong π-acceptor), [2]+ bpy: 2,2′-bipyridyl (moderate π-acceptor), [3]+ acac-: acetylacetonate (strong σ-donor), 4; and DTBCat2-: 3,5-di-tert-butyl catecholate (strong π-donor), 5. The complexes [2]+, [3]+, 4, and 5 were fully characterized and structurally identified. The electronic structures of these complexes along with their redox partners were elucidated by using a host of physical measurements: nuclear magnetic resonance, cyclic voltammetry, electronic paramagnetic resonance, UV-vis-NIR spectroscopy, and density functional theory. The studies revealed significant effects of the coligands on azo bond lengths of the RuL moiety and their redox behavior. Aerobic alcohol oxidation reactions using these Ru complexes as catalysts were scrutinized. It was found that the catalytic efficiency is primarily controlled by the electronic effect of the coligand. Accordingly, the complex [2]+ (containing a strong π-acceptor coligand, pcp) brings about oxidation efficiently, producing 86% of benzaldehyde. In comparison, however, the complexes 4 and 5 (containing electron donating coligand) furnished only 15-20% of benzaldehyde under identical reaction conditions. Investigations of the reaction mechanism suggest that an unstable Ru-H species is formed, which is transformed to a Ru-hydrazo intermediate by H-walking as reported by Hall et al. (J. Am. Chem. Soc., 2015, 137, 12330). Aerial O2 regenerates the catalyst via oxidation of the hydrazo intermediate.
- Rath, Santi Prasad,Sengupta, Debabrata,Ghosh, Pradip,Bhattacharjee, Rameswar,Chakraborty, Mou,Samanta, Subhas,Datta, Ayan,Goswami, Sreebrata
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p. 11995 - 12009
(2018/09/25)
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- Highly Efficient Supramolecular Catalysis by Endowing the Reaction Intermediate with Adaptive Reactivity
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A new strategy of highly efficient supramolecular catalysis is developed by endowing the reaction intermediate with adaptive reactivity. The supramolecular catalyst, prepared by host–guest complexation between 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) and cucurbit[7]uril (CB[7]), was used for biphasic oxidation of alcohols. Cationic TEMPO+, the key intermediate, was stabilized by the electrostatic effect of CB[7] in aqueous phase, thus promoting the formation of TEMPO+ and inhibiting side reactions. Moreover, through the migration into the organic phase, TEMPO+ was separated from CB[7] and recovered the high reactivity to drive a fast oxidation of substrates. The adaptive reactivity of TEMPO+ induced an integral optimization of the catalytic cycle and greatly improved the conversion of the reaction. This work highlights the unique advantages of dynamic noncovalent interactions on modulating the activity of reaction intermediates, which may open new horizons for supramolecular catalysis.
- Jiao, Yang,Tang, Bohan,Zhang, Yucheng,Xu, Jiang-Fei,Wang, Zhiqiang,Zhang, Xi
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supporting information
p. 6077 - 6081
(2018/04/30)
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- An Azoaromatic Ligand as Four Electron Four Proton Reservoir: Catalytic Dehydrogenation of Alcohols by Its Zinc(II) Complex
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Electroprotic storage materials, though invaluable in energy-related research, are scanty among non-natural compounds. Herein, we report a zinc(II) complex of the ligand 2,6-bis(phenylazo)pyridine (L), which acts as a multiple electron and proton reservoir during catalytic dehydrogenation of alcohols to aldehydes/ketones. The redox-inactive metal ion Zn(II) serves as an oxophilic Lewis acid, while the ligand behaves as efficient storage of electron and proton. Synthesis, X-ray structure, and spectral characterizations of the catalyst, ZnLCl2 (1a) along with the two hydrogenated complexes of 1a, ZnH2LCl2 (1b), and ZnH4LCl2 (1c) are reported. It has been argued that the reversible azo-hydrazo redox couple of 1a controls aerobic dehydrogenation of alcohols. Hydrogenated complexes are hyper-reactive and quantitatively reduce O2 and para-benzoquinone to H2O2 and para-hydroquinone, respectively. Plausible mechanistic pathways for alcohol oxidation are discussed based on controlled experiments, isotope labeling, and spectral analysis of intermediates.
- Pramanick, Rajib,Bhattacharjee, Rameswar,Sengupta, Debabrata,Datta, Ayan,Goswami, Sreebrata
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p. 6816 - 6824
(2018/06/26)
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- Vitamin B12 supported on graphene oxide: As a bio-based catalyst for selective aerobic oxidation of alcohols
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The environmental impact of chemical processes has now opened new windows of opportunity for bio-based catalysts. In this paper a highly active bio-based catalyst of vitamin B12 supported on graphene oxide nanosheets is reported for the selective aerobic oxidation of alcohols to the corresponding carbonyl compounds. Operational simplicity, mild reaction conditions, high yield and selectivity, non-hazardous nature, commercial availability and affordability are the main advantages of this novel catalytic system.
- Shaabani, Ahmad,Rashidi Vahid, Adina,Shaabani, Shabnam,Mohammadian, Reza,Nazeri, Mohammad Taghi,Keramati Nejad, Mina
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- Dual Fluorophore Containing Efficient Photoinduced Electron Transfer Based Molecular Probe for Selective Detection of Cr3+ and PO43- Ions through Fluorescence " Turn-On-Off" Response in Partial Aqueous and Biological Medium: Live Cell Imaging and Logic Application
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The present work describes a new photoinduced electron transfer (PET) based molecular probe in which naphthalimide (NPI) and anthracene (AN) chromophores are linked through a molecular bridge of piperazine and triazole units by the Click reaction. A typical meaningful structural variation has made the present probe highly selective for Cr3+ ion (limit of detection (LOD), 5.567 × 10-8 M) that displayed enhanced, "turn-On" emission (due to the PET-Off photophysical mechanism) and naked-eye sensitive bright green color fluorescence in the environment of interfering and competitive ions, in Tris-HCl buffer. The minimum energy structure obtained through theoretical calculations (density functional theory (DFT) and time-dependent (TD)-DFT) revealed a "tub" shape structure for probe 10. Upon complexation, the conformation of piperazine fragment changes from chair to boat in which the triazole and piperazine units create a cavity to tether Cr3+. Moreover, the probe showed excellent biocompatibility and cell permeability to sense Cr3+ sensitively in live cells and, thus, holds great promise for application in biological and environmental sciences. Additionally, the sensitive "Off-On-Off" sensing behavior of probe 10 providing two chemical inputs (Cr3+ and PO43-) helps to construct an INHIBIT logic gate. Also the probe has been utilized as printing material to decode secret information through the Cr3+ ion containing "marker ink" under UV light.
- Dwivedi, Sushil K.,Gupta, Ramesh C.,Srivastava, Priyanka,Singh, Priya,Koch, Biplob,Maiti, Biswajit,Misra, Arvind
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p. 10974 - 10981
(2018/09/06)
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- Redox Noninnocent Azo-Aromatic Pincers and Their Iron Complexes. Isolation, Characterization, and Catalytic Alcohol Oxidation
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The new redox-noninnocent azoaromatic pincers 2-(arylazo)-1,10-phenanthroline (L1) and 2,9-bis(phenyldiazo)-1,10-phenanthroline (L2) are reported. The ligand L1 is a tridentate pincer having NNN donor atoms, whereas L2 is tetradentate having two azo-N donors and two N-donor atoms from the 1,10-phenanthroline moiety. Reaction of FeCl2 with L1 or L2 produced the pentacoordinated mixed-ligand Fe(II) complexes FeL1Cl2 (1) and FeL2Cl2 (2), respectively. Homoleptic octahedral Fe(II) complexes, mer-[Fe(L1)2](ClO4)2 [3](ClO4)2 and mer-[Fe(L2)2](ClO4)2 [4](ClO4)2, have been synthesized from the reaction of hydrated Fe(ClO4)2 and L1 or L2. The ligand L2, although having four donor sites available for coordination, binds the iron center in a tridentate fashion with one uncoordinated pendant azo function. Molecular and electronic structures of the isolated complexes have been scrutinized thoroughly by various spectroscopic techniques, single-crystal X-ray crystallography, and density functional theory. Beyond mere characterization, complexes 1 and 2 were successfully used as catalysts for the aerobic oxidation of primary and secondary benzylic alcohols. A wide variety of substituted benzyl alcohols were found to be converted to the corresponding carbonyl compounds in high yields, catalyzed by complex 1. Several control reactions were carried out to understand the mechanism of this alcohol oxidation reactions.
- Sinha, Suman,Das, Siuli,Sikari, Rina,Parua, Seuli,Branda?, Paula,Demeshko, Serhiy,Meyer, Franc,Paul, Nanda D.
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p. 14084 - 14100
(2017/11/27)
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- One-Pot Cascade Synthesis of Quinazolin-4(3H)-ones via Nickel-Catalyzed Dehydrogenative Coupling of o-Aminobenzamides with Alcohols
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In this paper, we report a general, efficient, and environmentally benign method for the one-pot cascade synthesis of quinazolin-4(3H)-ones via acceptorless dehydrogenative coupling of o-aminobenzamide with alcohols catalyzed by a simple Ni(II) catalyst, [Ni(MeTAA)], featuring a tetraaza macrocyclic ligand (tetramethyltetraaza[14]annulene (MeTAA)). A wide variety of substituted quinazolin-4(3H)-ones were synthesized in high yields starting from readily available benzyl alcohols and o-aminobenzamides. Several controlled reactions along with deuterium labeling studies were carried out to establish the acceptorless dehydrogenative nature of the reactions.
- Parua, Seuli,Das, Siuli,Sikari, Rina,Sinha, Suman,Paul, Nanda D.
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p. 7165 - 7175
(2017/07/26)
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- NaBrO3/bmim[HSO4]: a versatile system for the selective oxidation of 1,2-diols, α-hydroxyketones, and alcohols
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Abstract: Sodium bromate with bmim[HSO4] has been found to be an excellent oxidizing agent in aqueous medium. NaBrO3:bmim[HSO4] oxidized 1,2-diols, α-hydroxyketones, and alcohols to the corresponding carbonyl compounds in excellent yields. This method offers advantages such as low cost reagents, aqueous reaction conditions, moderate temperatures and short reaction times and hence environmentally benign reaction. Moreover, the ionic liquid bmim[HSO4] could be recycled for at least three times without loss of significant activity. Graphical abstract: [Figure not available: see fulltext.]
- Khurana, Jitender M.,Lumb, Anshika,Chaudhary, Ankita
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p. 381 - 386
(2017/02/10)
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- Preparation method of 9-anthraldehyde-1, 1-diphenylhydrazone
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The invention relates to a preparation method of 9-anthraldehyde-1, 1-diphenylhydrazone. The preparation method comprises that anthracene, phosphorous oxychloride and N, N-dimethyl formamide are added into a reaction container, the materials undergo a reaction at a temperature of 60-120 DEG C for 6-48h to produce 9-anthraldehyde, N-nitrosodiphenylamine, zinc, acetate acid gracial and an alcohol solvent are added into the reaction container, the mixture undergoes a reaction at a temperature of 0-40 DEG C for 1-9h to produce 1, 1-diphenylhydrazine, 9-anthraldehyde and 1, 1-diphenylhydrazine are added into the reaction container, the mixture undergoes a reaction, the reaction product is cooled and precipitated, and the crystals are filtered and then are recrystallized in benzene so that 9-anthraldehyde-1, 1-diphenylhydrazone is obtained. Through simple recrystallization of the desired compound, a product with purity greater than 99.5% is obtained. The preparation method has the advantages of low raw material cost, mild reaction conditions and high desired product yield. The preparation method provides possibility for use of the hydrazone compound as a semi-conducting material in research on organic electroluminescent devices and organic light conductors.
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Paragraph 0029; 0034; 0035; 0037; 0040; 0044; 0048; 0052
(2017/02/24)
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- Fused ring compound and application thereof, electroluminescent device and preparation method thereof
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The invention discloses a fused ring compound and an application thereof, an electroluminescent device and a preparation method thereof. The fused ring compound has the following general formula as shown in the description, wherein -R1, -R2 and -CHO are connected to any unsaturated carbon atom of a naphthalene nucleus; and -R1 and -R2 are each any one of hydrogen, an alkane group or a polycyclic aromatic hydrocarbon group. In such a manner, according to the embodiment, an aggregation-induced quenching phenomenon of the fused ring compound in an aggregated state or a solid state can be reduced.
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Paragraph 0047; 0048; 0049
(2017/08/31)
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- Simple and Efficient Ruthenium-Catalyzed Oxidation of Primary Alcohols with Molecular Oxygen
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Oxidative transformations utilizing molecular oxygen (O2) as the stoichiometric oxidant are of paramount importance in organic synthesis from ecological and economical perspectives. Alcohol oxidation reactions that employ O2are scarce in homogeneous catalysis and the efficacy of such systems has been constrained by limited substrate scope (most involve secondary alcohol oxidation) or practical factors, such as the need for an excess of base or an additive. Catalytic systems employing O2as the “primary” oxidant, in the absence of any additive, are rare. A solution to this longstanding issue is offered by the development of an efficient ruthenium-catalyzed oxidation protocol, which enables smooth oxidation of a wide variety of primary, as well as secondary benzylic, allylic, heterocyclic, and aliphatic, alcohols with molecular oxygen as the primary oxidant and without any base or hydrogen- or electron-transfer agents. Most importantly, a high degree of selectivity during alcohol oxidation has been predicted for complex settings. Preliminary mechanistic studies including18O labeling established the in situ formation of an oxo–ruthenium intermediate as the active catalytic species in the cycle and involvement of a two-electron hydride transfer in the rate-limiting step.
- Ray, Ritwika,Chandra, Shubhadeep,Maiti, Debabrata,Lahiri, Goutam Kumar
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supporting information
p. 8814 - 8822
(2016/07/06)
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- Electronic Structure and Multicatalytic Features of Redox-Active Bis(arylimino)acenaphthene (BIAN)-Derived Ruthenium Complexes
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The article examines the newly designed and structurally characterized redox-active BIAN-derived [Ru(trpy)(R-BIAN)Cl]ClO4 ([1a]ClO4-[1c]ClO4), [Ru(trpy)(R-BIAN)(H2O)](ClO4)2 ([3a](ClO4)2-[3c](ClO4)2), and BIAO-derived [Ru(trpy)(BIAO)Cl]ClO4 ([2a]ClO4) (trpy = 2,2′:6′,2′′-terpyridine, R-BIAN = bis(arylimino)acenaphthene (R = H (1a+, 3a2+), 4-OMe (1b+, 3b2+), 4-NO2 (1c+, 3c2+), BIAO = [N-(phenyl)imino]acenapthenone). The experimental (X-ray, 1H NMR, spectroelectrochemistry, EPR) and DFT/TD-DFT calculations of 1an-1cn or 2an collectively establish {RuII-BIAN0} or {RuII-BIAO0} configuration in the native state, metal-based oxidation to {RuIII-BIAN0} or {RuIII-BIAO0}, and successive electron uptake processes by the α-diimine fragment, followed by trpy and naphthalene π-system of BIAN or BIAO, respectively. The impact of the electron-withdrawing NO2 function in the BIAN moiety in 1c+ has been reflected in the five nearby reduction steps within the accessible potential limit of -2 V versus SCE, leading to a fully reduced BIAN4- state in [1c]4-. The aqua derivatives ({RuII-OH2}, 3a2+-3c2+) undergo simultaneous 2e-/2H+ transfer to the corresponding {RuIV-O} state and the catalytic current associated with the RuIV/RuV response probably implies its involvement in the electrocatalytic water oxidation. The aqua derivatives (3a2+-3c2+) are efficient and selective precatalysts in transforming a wide variety of alkenes to corresponding epoxides in the presence of PhI(OAc)2 as an oxidant in CH2Cl2 at 298 K as well as oxidation of primary, secondary, and heterocyclic alcohols with a large substrate scope with H2O2 as the stoichiometric oxidant in CH3CN at 343 K. The involvement of the {RuIV-O} intermediate as the active catalyst in both the oxidation processes has been ascertained via a sequence of experimental evidence.
- Singha Hazari, Arijit,Ray, Ritwika,Hoque, Md Asmaul,Lahiri, Goutam Kumar
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p. 8160 - 8173
(2016/08/24)
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- Linker Installation: Engineering Pore Environment with Precisely Placed Functionalities in Zirconium MOFs
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Precise placement of multiple functional groups in a highly ordered metal-organic framework (MOF) platform allows the tailoring of the pore environment, which is required for advanced applications. To realize this, we present a comprehensive study on the linker installation method, in which a stable MOF with coordinatively unsaturated Zr6 clusters was employed and linkers bearing different functional groups were postsynthetically installed. A Zr-MOF with inherent missing linker sites, namely, PCN-700, was initially constructed under kinetic control. Twelve linkers with different substituents were then designed to study their effect on MOF formation kinetics and therefore resulting MOF structures. Guided by the geometrical analysis, linkers with different lengths were installed into a parent PCN-700, giving rise to 11 new MOFs and each bearing up to three different functional groups in predefined positions. Systematic variation of the pore volume and decoration of pore environment were realized by linker installation, which resulted in synergistic effects including an enhancement of H2 adsorption capacities of up to 57%. In addition, a size-selective catalytic system for aerobic alcohol oxidation reaction is built in PCN-700 through linker installation, which shows high activity and tunable size selectivity. Altogether, these results exemplify the capability of the linker installation method in the pore environment engineering of stable MOFs with multiple functional groups, giving an unparalleled level of control.
- Yuan, Shuai,Chen, Ying-Pin,Qin, Jun-Sheng,Lu, Weigang,Zou, Lanfang,Zhang, Qiang,Wang, Xuan,Sun, Xing,Zhou, Hong-Cai
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supporting information
p. 8912 - 8919
(2016/07/30)
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- A straightforward and versatile protocol for the direct conversion of benzylic azides to ketones and aldehydes
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The synthesis of carbonyl compounds from benzylic azides through benzylideneamides is described for the first time. NaH-mediated activation of benzyl azides allows a rapid water-promoted oxidation under a facile protocol with good yields.
- González-Calderón, Davir,Morales-Reza, Marco A.,Díaz-Torres, Eduardo,Fuentes-Benítes, Aydeé,González-Romero, Carlos
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p. 83547 - 83550
(2016/10/12)
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- Method for preparing of hydroxy compound
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The present invention relates to a method for preparing a hydroxy polycyclic aromatic compound and, more specifically, to a method which can moderately and simply prepare a hydroxy compound with high purity without a complex and dangerous process, wherein the hydroxy compound represented by chemical formula 1 is a monomer for preparing a hard mask polymer composition having anti-reflective properties useful in a lithography process of semiconductor preparation processes.COPYRIGHT KIPO 2016
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Paragraph 0082; 0083
(2018/02/14)
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- An Unprecedented Photochemical Reaction for Anthracene-Containing Derivatives
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A series of anthracene-containing derivatives have been synthesised and characterised. The photochemical behaviour of these derivatives have been investigated by 1H NMR spectroscopy. An unprecedented photolysis reaction for anthracene-containing derivatives was observed in the case of anthracenes directly armed with a -CH2O-R group upon UV irradiation. The photolysis reaction process has been demonstrated to occur in three steps. Firstly, the anthracene-containing derivatives are converted into the corresponding endoperoxide intermediate upon UV irradiation in the presence of air; then, the endoperoxide intermediate is decomposed to the corresponding starting compound and 9-anthraldehyde; finally, 9-anthraldehyde is further oxidised to anthraquinone. Additionally, the photolysis reaction of anthracene-containing derivatives is significantly promoted in the presence of a thiacalix[4]arene platform.
- Zhao, Jiang-Lin,Jiang, Xue-Kai,Wu, Chong,Wang, Chuan-Zeng,Zeng, Xi,Redshaw, Carl,Yamato, Takehiko
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p. 3217 - 3222
(2016/10/25)
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- "Click" post-functionalization of a metal-organic framework for engineering active single-site heterogeneous Ru(III) catalysts
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We present a general strategy for incorporating π-conjugated NNN-chelators (e.g., terpyridyl moiety) into a porous metal-organic framework (MOF) MIL-101(Cr) by using the "click" post-functionalization. The functionalized MOF could be used as a platform for metalation to yield highly active and stable single-site heterogeneous metal (e.g., Ru(iii)) catalysts.
- Wu, Suntao,Chen, Liyu,Yin, Biaolin,Li, Yingwei
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supporting information
p. 9884 - 9887
(2015/06/16)
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- Metal free visible light driven oxidation of alcohols to carbonyl derivatives using 3,6-di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz) as catalyst
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3,6-Di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz) catalyzed oxidation of alcohols to the corresponding carbonyl compounds under visible light irradiation is described. This reaction occurs smoothly at room temperature and shows good tolerance of functional groups. It provides an alternative approach for the synthesis of alkyl and aryl aldehydes and ketones.
- Samanta, Suvendu,Biswas, Papu
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p. 84328 - 84333
(2015/10/28)
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- A novel and active catalyst Ag/ZnO for oxidant-free dehydrogenation of alcohols
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Nano Ag/ZnO catalysts were prepared by varying load of Ag on ZnO supports using a new and very simple method. The structure of nano Ag/ZnO has been confirmed by various techniques. The Ag/ZnO with 7.4 × 10-5 mol% of Ag has pore size distribution about 2.74 nm and this nano Ag/ZnO is found to be the best catalyst for oxidation of primary and secondary benzyl alcohols into corresponding aldehydes and ketones in oxidant-free at the atmospheric pressure. The influence of various parameters such as: solvent, base, temperature, time of reaction, etc. has been systematically studied on nano Ag/ZnO catalyst.
- Hosseini-Sarvari, Mona,Ataee-Kachouei, Tahereh,Moeini, Fatemeh
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- Nanoscaled copper metal-organic framework (MOF) based on carboxylate ligands as an efficient heterogeneous catalyst for aerobic epoxidation of olefins and oxidation of benzylic and allylic alcohols
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Aerobic epoxidation of olefins at a mild reaction temperature has been carried out by using nanomorphology of [Cu3(BTC)2 ] (BTC = 1,3,5-benzenetricarboxylate) as a high-performance catalyst through a simple synthetic strategy. An aromatic carboxylate ligand was employed to furnish a heterogeneous copper catalyst and also serves as the ligand for enhanced catalytic activities in the catalytic reaction. The utilization of a copper metal-organic framework catalyst was further extended to the aerobic oxidation of aromatic alcohols. The shape and size selectivity of the catalyst in olefin epoxidation and alcohol oxidation was investigated. Furthermore, the as-synthesized copper catalyst can be easily recovered and reused several times without leaching of active species or significant loss of activity.
- Qi, Yue,Luan, Yi,Yu, Jie,Peng, Xiong,Wang, Ge
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p. 1589 - 1597
(2015/01/30)
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- Palladium-catalyzed synthesis of aldehydes from aryl halides and tert-butyl isocyanide using formate salts as hydride donors
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An efficient one-pot palladium-catalyzed hydroformylation of aryl halides to produce aromatic aldehydes has been achieved, employing tert-butyl isocyanide as a C1 resource and formate salt as a hydride donor without any additional bases. Characterized by its mild reaction conditions, easy operation and lower toxicity, this reaction can tolerate a wide array of functional groups with moderate to excellent yields.
- Zhang, Ying,Jiang, Xiao,Wang, Jin-Mei,Chen, Jing-Lei,Zhu, Yong-Ming
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p. 17060 - 17063
(2015/03/30)
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- Solvent effects in the reaction between (anthracen-9-yl)methyl sulfides and electron-deficient acetylenes
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Solvent-dependent diverse reactivity of (anthracen-9-yl)methyl sulfides with a few electron-deficient acetylenes is described. Diversity in reactivity is attributed to competition between one electron transfer, two electron transfer and Diels-Alder reaction of these sulfides with electron-deficient acetylenes. We have proposed plausible mechanisms to account for various reactions observed by us.
- Gopalakrishnan, Reshma,Jacob, Jomon P.,Mallia, Rekha R.,Unnikrishnan, Perupparampil A.,Prathapan, Sreedharan
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p. 472 - 479
(2015/06/30)
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- Mononuclear complexes of amide-based ligands containing appended functional groups: Role of secondary coordination spheres on catalysis
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Amide-based ligands H2L1, H2L2 and H2L3 containing thiazole, thiazoline and benzothiazole appended groups have been used to synthesize Zn2+ (1 and 3), Cd2+ complexes (2 and 4), and a Mn2+ complex (5). In all cases, potentially multidentate ligands create a meridional N3 coordination environment around the M(ii) ion whereas additional sites are occupied by labile nitrate ions in 1-4 and MeOH in 5. Interestingly, metal complexation caused the migration of protons from amidic N-H sites to the appended heterocyclic rings in complexes 1-4. Structural studies show that the protonated heterocyclic rings in these complexes create a hydrogen bond based cavity adjacent to the metal ion. Importantly, binding studies confirm that the substrates are bound within the complex cavity closer to the Lewis acidic metal in all complexes including the oxidation-sensitive Mn ion in complex 5. All complexes have been utilized as the reusable and heterogeneous catalysts for ring-opening reactions of assorted epoxides, cyanation reactions of various aldehydes, and epoxidation reactions of several olefins. This journal is
- Bansal, Deepak,Kumar, Gulshan,Hundal, Geeta,Gupta, Rajeev
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p. 14865 - 14875
(2015/02/19)
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- Metal-free, visible-light photoredox catalysis: Transformation of arylmethyl bromides to alcohols and aldehydes
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A mild, simple, and controllable metal-free photocatalytic system for the transformation of arylmethyl bromides to corresponding alcohols and aldehydes in high yields with visible-light irradiation has been achieved. Eosin Y was found to be an efficient promoter for this oxidative dehalogenation reaction under photo irradiation conditions.
- Li, Jian,Wang, Hongni,Liu, Li,Sun, Jiangtao
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p. 49974 - 49978
(2014/12/10)
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- Palladium supported on magnetic core-shell nanoparticles: An efficient and reusable catalyst for the oxidation of alcohols into aldehydes and ketones by molecular oxygen
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In continuing our efforts to develop economical and ecofriendly synthetic protocols, we present a proline-palladium catalyst supported on magnetic nanoparticles (0.5 mol %) for oxidation by molecular oxygen. The supported Pd catalyst shows high activity in the oxidation of alcohols into the corresponding carbonyl compounds where easy catalyst recovery and excellent recycling efficiency are observed. It is possible to recover and reuse the grafted palladium catalysts at least eight times without significant loss of its catalytic activity. Copyright
- Zhang, Lei,Li, Pinhua,Yang, Jin,Wang, Min,Wang, Lei
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p. 217 - 222
(2014/03/21)
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- 2-Iodoxybenzenesulfonic acid-catalysed oxidation of primary and secondary alcohols with oxone in cetyl trimethylammonium bromide micelles at room temperature
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A mild and green protocol for alcohol oxidation using 2-iodoxybenzene sulfonic acid/oxone at room temperature in CTAB micelles has been developed. Typically, secondary benzyl alcohols were oxidised to ketones and primary benzyl alcohols to aldehydes in good yields in 2 h. Under harsher conditions (100 °C/24 h), aliphatic alcohols were oxidised to ketones or organic acids in moderate to high yields.
- Liu, Yangyang,Wang, Boliang
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p. 427 - 431
(2014/08/05)
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