17322-97-3Relevant articles and documents
In situ fabricated MOF-cellulose composite as an advanced ROS deactivator-convertor: Fluoroswitchable bi-phasic tweezers for free chlorine detoxification and size-exclusive catalytic insertion of aqueous H2O2
Bankar, Balasaheb D.,Biradar, Ankush V.,Goswami, Ranadip,Neogi, Subhadip,Pillai, Renjith S.,Rajput, Sonal,Seal, Nilanjan
, p. 4316 - 4332 (2022/03/07)
Combining the merits of structural diversity, and purposeful implantation of task-specific functionalities, metal-organic frameworks (MOFs) instigate targeted reactive oxygen species (ROS) scavenging and concurrent detoxification via self-calibrated emission modulation. Then again, grafting of catalytically active sites in MOFs can benefit developing a greener protocol to convert ROS generators to technologically important building blocks, wherein tailorable MOF-composite fabrication is highly sought for practical applications, yet unexplored. The chemo-robust and hydrogen-bonded framework encompassing free -NH2 moiety affixed pores serves as an ultra-fast and highly regenerable fluoro-probe for selective detection of toxic ROS producers hypochlorite ion (ClO-) and H2O2 with record-level nanomolar sensitivity. While the bio-relevant antioxidant l-ascorbic acid (AA) imparts notable quenching to the MOF, a significant 3.5 fold emission enhancement with bi-phasic colorimetric variation ensues when it selectively scavenges ClO- from uni-directional porous channels through an unprecedented molecular tweezer approach. Apart from a battery of experimental evidence, density functional theory (DFT) results validate "on-off-on"fluoroswitching from redistribution of MOF orbital energy levels, and show guest-mediated exclusive transition from "Tight state"to "Loose state". The coordination frustrated metal site engineered pore-wall benefits the dual-functionalized MOF in converting the potential ROS generator H2O2via selective alkene epoxidation under mild-conditions. Importantly, sterically encumbered substrates exhibit poor conversion and demonstrate first-ever pore-fitting-induced size selectivity for this benign oxidation. Judiciously planned control experiments in combination with DFT-optimized intermediates provide proof-of-concept to the ionic route of ROS conversion. Considering an effective way to broaden the advanced applications of this crystalline material, reconfigurable MOF@cotton fiber (CF) is fabricated via in situ growth, which scavenges free chlorine and concomitantly squeezes it upon exposure to AA with obvious colorimetric changes over multiple real-life platforms. Furthermore, multi-cyclic alkene epoxidation by MOF@CF paves the way to futuristic continuous flow reactors that truly serves this smart composite as a bimodal ROS deactivator-convertor and explicitly denotes it as an advanced promising analogue from contemporary state-of-the-art materials.
Proton Switch in the Secondary Coordination Sphere to Control Catalytic Events at the Metal Center: Biomimetic Oxo Transfer Chemistry of Nickel Amidate Complex
Kim, Soohyung,Jeong, Ha Young,Kim, Seonghan,Kim, Hongsik,Lee, Sojeong,Cho, Jaeheung,Kim, Cheal,Lee, Dongwhan
supporting information, p. 4700 - 4708 (2021/02/12)
High-valent metal-oxo species are key intermediates for the oxygen atom transfer step in the catalytic cycles of many metalloenzymes. While the redox-active metal centers of such enzymes are typically supported by anionic amino acid side chains or porphyrin rings, peptide backbones might function as strong electron-donating ligands to stabilize high oxidation states. To test the feasibility of this idea in synthetic settings, we have prepared a nickel(II) complex of new amido multidentate ligand. The mononuclear nickel complex of this N5 ligand catalyzes epoxidation reactions of a wide range of olefins by using mCPBA as a terminal oxidant. Notably, a remarkably high catalytic efficiency and selectivity were observed for terminal olefin substrates. We found that protonation of the secondary coordination sphere serves as the entry point to the catalytic cycle, in which high-valent nickel species is subsequently formed to carry out oxo-transfer reactions. A conceptually parallel process might allow metalloenzymes to control the catalytic cycle in the primary coordination sphere by using proton switch in the secondary coordination sphere.
Epoxidation of Cyclooctene Using Water as the Oxygen Atom Source at Manganese Oxide Electrocatalysts
Jin, Kyoungsuk,Maalouf, Joseph H.,Lazouski, Nikifar,Corbin, Nathan,Yang, Dengtao,Manthiram, Karthish
supporting information, p. 6413 - 6418 (2019/05/02)
Epoxides are useful intermediates for the manufacture of a diverse set of chemical products. Current routes of olefin epoxidation either involve hazardous reagents or generate stoichiometric side products, leading to challenges in separation and significant waste streams. Here, we demonstrate a sustainable and safe route to epoxidize olefin substrates using water as the oxygen atom source at room temperature and ambient pressure. Manganese oxide nanoparticles (NPs) are shown to catalyze cyclooctene epoxidation with Faradaic efficiencies above 30%. Isotopic studies and detailed product analysis reveal an overall reaction in which water and cyclooctene are converted to cyclooctene oxide and hydrogen. Electrokinetic studies provide insights into the mechanism of olefin epoxidation, including an approximate first-order dependence on the substrate and water and a rate-determining step which involves the first electron transfer. We demonstrate that this new route can also achieve a cyclooctene conversion of ～50% over 4 h.
Dinuclear Iron(III) and Nickel(II) Complexes Containing N-(2-Pyridylmethyl)-N′-(2-hydroxyethyl)ethylenediamine: Catalytic Oxidation and Magnetic Properties
Jeong, Ah Rim,Shin, Jong Won,Jeong, Jong Hwa,Bok, Kwon Hee,Kim, Cheal,Jeong, Donghyun,Cho, Jaeheung,Hayami, Shinya,Min, Kil Sik
, p. 3023 - 3033 (2017/03/13)
Dinuclear FeIII and NiII complexes, [(phenO)Fe(N3)]2(NO3)2 (1) and [(phenOH)Ni(N3)2]2 (2), were prepared by treating Fe(NO3)3?9 H2O and Ni(NO3)2?6 H2O in methanol, respectively, with phenOH (=N-(2-pyridylmethyl)-N′-(2-hydroxyethyl)ethylenediamine) and NaN3; both 1 and 2 were characterized by elemental analysis, IR spectroscopy, X-ray diffraction, and magnetic susceptibility measurements. Two ethoxo-bridged FeIII and two azido-bridged NiII were observed in 1 and 2, respectively; corresponding antiferromagnetic interaction via the bridged ethoxo groups and strong ferromagnetic coupling via the bridged end-on azido ligands within the dimeric unit were observed. Complex 1 did not exhibit any catalytic activity, while 2 exhibited excellent catalytic activities for the epoxidation of aliphatic, aromatic, and terminal olefins.
Regiocontrolled syntheses of FAHFAs and LC-MS/MS differentiation of regioisomers
Balas, Laurence,Bertrand-Michel, Justine,Viars, Fanny,Faugere, Julien,Lefort, Corinne,Caspar-Bauguil, Sylvie,Langin, Dominique,Durand, Thierry
supporting information, p. 9012 - 9020 (2016/10/07)
An efficient regiospecific total synthesis of several branched fatty acyl hydroxyl-fatty acids (FAHFA) has been achieved from available terminal alkenes and alkynes. The key steps feature a boron trifluoride mediated epoxide ring opening with acetylide carbanions, followed by hydrogenation of the alkyne function. The carboxylic acid of the hydroxylated chains is introduced at the last step of the synthesis to allow the esterification of the branched hydroxyl group by fatty acids beforehand. The chemical syntheses of a "linear" FAHFA and a branched FAHFA analog containing a Z-olefin in the hydroxyl-fatty acid chain are also reported. A LC-MS/MS method has been developed. Several reversed phase columns were compared. Regioisomers were separated.
Trinuclear nickel and cobalt complexes containing unsymmetrical tripodal tetradentate ligands: Syntheses, structural, magnetic, and catalytic properties
Shin, Jong Won,Jeong, Ah Rim,Lee, Sun Young,Kim, Cheal,Hayami, Shinya,Min, Kil Sik
, p. 14089 - 14100 (2016/11/06)
The coordination chemistries of the tetradentate N2O2-type ligands N-(2-pyridylmethyl)iminodiethanol (H2pmide) and N-(2-pyridylmethyl)iminodiisopropanol (H2pmidip) have been investigated with nickel(ii) and cobalt(ii/iii) ions. Three novel complexes prepared and characterized are [(Hpmide)2Ni3(CH3COO)4] (1), [(Hpmide)2Co3(CH3COO)4] (2), and [(pmidip)2Co3(CH3COO)4] (3). In 1 and 2, two terminal nickel(ii)/cobalt(ii) units are coordinated to one Hpmide- and two CH3CO2-. The terminal units are each connected to a central nickel(ii)/cobalt(ii) cation through one oxygen atom of Hpmide- and two oxygen atoms of acetate ions, giving rise to nickel(ii) and cobalt(ii) trinuclear complexes, respectively. Trinuclear complexes 1 and 2 are isomorphous. In 3, two terminal cobalt(iii) units are coordinated to pmidip2- and two CH3CO2-. The terminal units are each linked to a central cobalt(ii) cation through two oxygen atoms of pmidip2- and one oxygen atom of a bidentate acetate ion, resulting in a linear trinuclear mixed-valence cobalt complex. 1 shows a weak ferromagnetic interaction with the ethoxo and acetato groups between the nickel(ii) ions (g = 2.24, J = 2.35 cm-1). However, 2 indicates a weak antiferromagnetic coupling with the ethoxo and acetato groups between the cobalt(ii) ions (g = 2.37, J = -0.5 cm-1). Additionally, 3 behaves as a paramagnetic cobalt(ii) monomer, due to the diamagnetic cobalt(iii) ions in the terminal units (g = 2.53, =D= = 36.0 cm-1). No catalytic activity was observed in 1. However, 2 and 3 showed significant catalytic activities toward various olefins with modest to good yields. 3 was slightly less efficient toward olefin epoxidation reaction than 2. Also 2 was used for terminal olefin oxidation reaction and was oxidised to the corresponding epoxides in moderate yields (34-75%) with conversions ranging from 47-100%. The cobalt complexes 2 and 3 promoted the O-O bond cleavage to ～75% heterolysis and ～25% homolysis.
A discrete {Co4(μ3-OH)4}4+ cluster with an oxygen-rich coordination environment as a catalyst for the epoxidation of various olefins
Lee, Sun Young,Kim, Namseok,Lee, Myoung Mi,Jo, Young Dan,Bae, Jeong Mi,Hyun, Min Young,Yoon, Sungho,Kim, Cheal
, p. 1727 - 1736 (2016/01/30)
Using the sterically hindered terphenyl-based carboxylate, the tetrameric Co(ii) complex [Co4(μ3-OH)4(μ-O2CAr4F-Ph)2(μ-OTf)2(Py)4] (1) with an asymmetric cubane-type core has been synthesized and fully characterized by X-ray diffraction, UV-vis spectroscopy, and electron paramagnetic resonance spectroscopy. Interestingly, the cubane-type cobalt cluster 1 with 3-chloroperoxybenzoic acid as the oxidant was found to be very effective in the epoxidation of a variety of olefins, including terminal olefins which are more challenging targeting substrates. Moreover, this catalytic system showed a fast reaction rate and high epoxide yields under mild conditions. Based on product analysis and Hammett studies, the use of peroxyphenylacetic acid as a mechanistic probe, H218O-exchange experiments, and EPR studies, it has been proposed that multiple reactive cobalt-oxo species CoVO and CoIVO were involved in the olefin epoxidation.
A surfactant-like ionic liquid with permanganate dissolved as a highly selective epoxidation system
Lu, Yu-Jing,Wong, Wing-Leung,Chow, Cheuk-Fai
, p. 25 - 28 (2015/06/08)
A ligand-free catalytic epoxidation system using permanganate in a surfactant-like ionic liquid (IL) medium was developed. The results indicate that the IL takes crucial effects in the epoxide selectivity. The loading of permanganate is also found critical in preventing over-oxidation of epoxides. The system with 0.3 mol% permanganate and 3.5-equivalent CH3CO3H is able to achieve excellent yields and selectivity of epoxides. The study of epoxidation with KMnO4 in IL medium reveals an unusual oxidation behavior of permanganate not found in traditional solvents.
Epoxidation of alkenes efficiently catalyzed by Mo salen supported on surface-modified halloysite nanotubes
Long, Yu,Yuan, Bing,Ma, Jiantai
, p. 348 - 354 (2015/09/28)
Halloysite-nanotube-supported Mo salen (HNTs-Mo-SL) catalysts were successfully prepared using a facile chemical surface modification and self-assembly method. The morphologies, sizes, structure, and dispersion of the as-prepared catalysts were investigated by transmission electron microscopy, X-ray diffraction, and Fourier-transform infrared, inductively coupled plasma, and X-ray photoelectron spectroscopy, which confirmed the existence of the Mo salen structure and successful synthesis of the HNTs-Mo-SL catalyst. The immobilized catalyst was found to be highly reactive in the epoxidation of a wide range of alkenes, including linear, cyclic, and aromatic alkenes. The immobilized catalyst exhibited a higher catalytic activity for alkene epoxidation than homogeneous Mo. In contrast experiments, it was determined that the salen structure played an important role in immobilizing MoO(O2)2(DMF)2 and improving the conversion and efficiency of alkene epoxidation, which could not be obtained using other ligands, such as the N atom as a single ligand. Furthermore, the bonding between Mo and the salen ligands and the possible mechanism of alkene epoxidation catalyzed by the catalyst were determined. The catalyst could be reused several times without significant loss of catalytic activity. Given that halloysite nanotubes are cheap and easy to obtain, this catalyst offers a novel alternative for the rational design of catalysts with desired features.
A new halide-free efficient reaction-controlled phase-transfer catalyst based on silicotungstate of [(C18H37)2(CH 3)2N]3[SiO4H(WO5) 3] for olefin epoxidation, oxidation of sulfides and alcohols with hydrogen peroxide
Ma, Baochun,Zhao, Wei,Zhang, Fuming,Zhang, Yingshuai,Wu, Songyun,Ding, Yong
, p. 32054 - 32062 (2014/08/18)
A new reaction-controlled phase-transfer catalyst based on silicotungstate of [(C18H37)2(CH3) 2N]3[SiO4H(WO5)3] for oxidation of hydrocarbons is developed. The catalyst is a new heteropoly compound with silicon as heteroatom, which is different to the previously reported reaction-controlled phase transfer catalysts that were composed of quaternary ammonium heteropolyoxotungstates of [π-C5H 5N(CH2)15CH3]3[PW 4O16] and [π-C5H5N(CH 2)15CH3]3[PW4O 32] with phosphorus as heteroatom. The oxidation of various alkenes (such as linear terminal olefins, internal olefins, cyclic olefins and unactivated alkenes) to epoxides, sulfides to sulfoxides and sulfones, alcohols to carbonyl compounds, are successfully catalyzed by this recyclable and environmentally benign catalyst using H2O2 as oxidant and ethyl acetate as solvent. This catalyst is not only capable of catalyzing homogeneous oxidation of organic substrates with unique reaction-controlled phase-transfer character, but also avoids the use of toxic solvents. The catalyst could be easily recovered and reused after reaction, and the epoxidation of cyclohexene was performed twenty times without obvious loss in activity. The fresh catalyst and the used one were characterized by ICP, IR, UV-vis, 29Si MAS NMR and 183W NMR in detail. the Partner Organisations 2014.
