4436-22-0Relevant articles and documents
Mononuclear ruthenium compounds bearing N-donor and N-heterocyclic carbene ligands: structure and oxidative catalysis
Liu, Hai-Jie,Gil-Sepulcre, Marcos,Francàs, Laia,Nolis, Pau,Parella, Teodor,Benet-Buchholz, Jordi,Fontrodona, Xavier,García-Antón, Jordi,Romero, Nuria,Llobet, Antoni,Escriche, Lluís,Bofill, Roger,Sala, Xavier
, p. 2829 - 2843 (2017)
A new CNNC carbene-phthalazine tetradentate ligand has been synthesised, which in the reaction with [Ru(T)Cl3] (T = trpy, tpm, bpea; trpy = 2,2′;6′,2′′-terpyridine; tpm = tris(pyrazol-1-yl)methane; bpea = N,N-bis(pyridin-2-ylmethyl)ethanamine)
Photocatalytic oxidation of alkenes and alcohols in water by a manganese(v) nitrido complex
Chen, Gui,Chen, Lingjing,Ma, Li,Kwong, Hoi-Ki,Lau, Tai-Chu
, p. 9271 - 9274 (2016)
Mn(v) nitrido complex [Mn(N)(CN)4]2- is an efficient catalyst for visible-light induced oxidation of alkenes and alcohols in water using [Ru(bpy)3]2+ as a photosensitizer and [Co(NH3)5Cl]2+ as a sacrificial oxidant. Alkenes are oxidized to epoxides and alcohols to carbonyl compounds.
The reaction of dimethyldioxirane with 1,3-cyclohexadiene and 1,3-cyclooctadiene: Monoepoxidation kinetics and computational modeling
McTush-Camp, Davita,Vasquez, Pedro C.,Baumstark, Alfons L.
, p. 47 - 53 (2015)
The reaction of dimethyldioxirane (1) with excess 1,3-cyclohexadiene (2a) and 1,3-cyclooctadiene (2b) in dried acetone yielded the corresponding monoepoxides in excellent yield. Second-order rate constants for monoepoxidation were determined using UV meth
Synthesis of and Metal Complexation with a Chiral Cyclam
Higgins, Tyler F.,Lee, Seokwoo,Winkler, Jeffrey D.
, p. 5417 - 5422 (2021)
Tetraazamacrocycles, like cyclam 1, are well-studied polyamine ligands for metal ions that were first developed to model biological processes. Despite being studied for nearly 60 years, the development of chiral variants of 1 has been limited. We report t
Asymmetric Epoxidation of Olefins Catalyzed by Substituted Aminobenzimidazole Manganese Complexes Derived from L-Proline
Tian, Jing,Lin, Jin,Zhang, Jisheng,Xia, Chungu,Sun, Wei
supporting information, p. 593 - 600 (2021/11/16)
A family of manganese complexes [Mn(Rpeb)(OTf)2] (peb=1-(1-ethyl-1H-benzo[d]imidazol-2-yl)-N-((1-((1-ethyl-1H-benzo[d]imidazol-2-yl)methyl) pyrrolidin-2-yl)methyl)-N-methylmethanamine)) derived from L-proline has been synthesized and characterized, where R refers to the group at the diamine backbone. X-ray crystallographic analyses indicate that all the manganese complexes [Mn(Rpeb)(OTf)2] exhibit cis-α topology. These types of complexes are shown to catalyze the asymmetric epoxidation of olefins employing H2O2 as a terminal oxidant with up to 96% ee. Obviously, the R group of the diamine backbone can influence the catalytic activity and enantioselectivity in the asymmetric epoxidation of olefins. In particular, Mn(i-Prpeb)(OTf)2 bearing an isopropyl arm, cannot catalyze the epoxidation reaction with H2O2 as the oxidant. However, when PhI(OAc)2 is used as the oxidant instead, all the manganese complexes including Mn(i-Prpeb)(OTf)2 can promote the epoxidation reactions efficiently. Taken together, these results indicate that isopropyl substitution on the Rpeb ligand inhibits the formation of active Mn(V)-oxo species in the H2O2/carboxylic acid system via an acid-assisted pathway.
Exploration of highly electron-rich manganese complexes in enantioselective oxidation catalysis; A focus on enantioselective benzylic oxidation
Klein Gebbink, Robertus J. M.,Li, Fanshi,Lutz, Martin,Masferrer-Rius, Eduard
, p. 7751 - 7763 (2021/12/13)
The direct enantioselective hydroxylation of benzylic C-H bonds to form chiral benzylic alcohols represents a challenging transformation. Herein, we report on the exploration of new biologically inspired manganese and iron complexes bearing highly electron-rich aminopyridine ligands containing 4-pyrrolidinopyridine moieties ((S,S)-1, (R,R)-1, 2 and 5) in combination with chiral bis-pyrrolidine and N,N-cyclohexanediamine backbones in enantioselective oxidation catalysis with aqueous H2O2. The current manganese complexes outperform the analogous manganese complexes containing 4-dimethylaminopyridine moieties (3 and 4) in benzylic oxidation reactions in terms of alcohol yield while keeping similar ee values (～60% ee), which is attributed to the higher basicity of the 4-pyrrolidinopyridine group. A detailed investigation of different carboxylic acid additives in enantioselective benzylic oxidation provides new insights into how to rationally enhance enantioselectivities by means of proper tuning of the environment around the catalytic active site, and has resulted in the selection of Boc-l-Tert-leucine as the preferred additive. Using these optimized conditions, manganese complex 2 was shown to be effective in the enantioselective benzylic oxidation of a series of arylalkane substrates with up to 50% alcohol yield and 62% product ee. A final set of experiments also highlights the use of the new 4-pyrrolidinopyridine-based complexes in the asymmetric epoxidation of olefins (up to 98% epoxide yield and >99% ee).
A new and efficient methodology for olefin epoxidation catalyzed by supported cobalt nanoparticles
Rossi-Fernández, Lucía,Dorn, Viviana,Radivoy, Gabriel
supporting information, p. 519 - 526 (2021/03/31)
A new heterogeneous catalytic system consisting of cobalt nanoparticles (CoNPs) supported on MgO and tert-butyl hydroperoxide (TBHP) as oxidant is presented. This CoNPs@MgO/t-BuOOH catalytic combination allowed the epoxidation of a variety of olefins with good to excellent yield and high selectivity. The catalyst preparation is simple and straightforward from commercially available starting materials and it could be recovered and reused maintaining its unaltered high activity.
Rational Construction of an Artificial Binuclear Copper Monooxygenase in a Metal-Organic Framework
Feng, Xuanyu,Song, Yang,Chen, Justin S.,Xu, Ziwan,Dunn, Soren J.,Lin, Wenbin
supporting information, p. 1107 - 1118 (2021/01/25)
Artificial enzymatic systems are extensively studied to mimic the structures and functions of their natural counterparts. However, there remains a significant gap between structural modeling and catalytic activity in these artificial systems. Herein we report a novel strategy for the construction of an artificial binuclear copper monooxygenase starting from a Ti metal-organic framework (MOF). The deprotonation of the hydroxide groups on the secondary building units (SBUs) of MIL-125(Ti) (MIL = Matériaux de l'Institut Lavoisier) allows for the metalation of the SBUs with closely spaced CuI pairs, which are oxidized by molecular O2 to afford the CuII2(μ2-OH)2 cofactor in the MOF-based artificial binuclear monooxygenase Ti8-Cu2. An artificial mononuclear Cu monooxygenase Ti8-Cu1 was also prepared for comparison. The MOF-based monooxygenases were characterized by a combination of thermogravimetric analysis, inductively coupled plasma-mass spectrometry, X-ray absorption spectroscopy, Fourier-transform infrared spectroscopy, and UV-vis spectroscopy. In the presence of coreductants, Ti8-Cu2 exhibited outstanding catalytic activity toward a wide range of monooxygenation processes, including epoxidation, hydroxylation, Baeyer-Villiger oxidation, and sulfoxidation, with turnover numbers of up to 3450. Ti8-Cu2 showed a turnover frequency at least 17 times higher than that of Ti8-Cu1. Density functional theory calculations revealed O2 activation as the rate-limiting step in the monooxygenation processes. Computational studies further showed that the Cu2 sites in Ti8-Cu2 cooperatively stabilized the Cu-O2 adduct for O-O bond cleavage with 6.6 kcal/mol smaller free energy increase than that of the mononuclear Cu sites in Ti8-Cu1, accounting for the significantly higher catalytic activity of Ti8-Cu2 over Ti8-Cu1.
Activation of hydrogen peroxide by the nitrate anion in micellar media
Schmidt, Fabian,Zehner, Bastian,Kaposi, Marlene,Drees, Markus,Mink, János,Korth, Wolfgang,Jess, Andreas,Cokoja, Mirza
supporting information, p. 1965 - 1971 (2021/03/26)
We present the activation of hydrogen peroxide by micellar imidazolium nitratesviaH-bond formation in water, as shown by vibrational spectroscopy and supported by DFT calculations. Mechanistic insight into the interactions of the surfactant cation, the nitrate anion and H2O2is given. The micelles solubilise and epoxidise cyclooctene in the aqueous phase.
Aerobic epoxidation of olefins by carboxylate ligand-based cobalt (II) compound: synthesis, X-ray crystallography, and catalytic exploration
Brandao, Paula,Debnath, Rakesh,Gayen, Saikat,Ghosh, Pameli,Koner, Subratanath,Lin, Zhi,Maity, Tanmay,Mal, Dasarath,Patra, Birendra Nath,Pratihar, Jahar Lal,Sepay, Nayim
, (2022/01/04)
A new quinoline carboxylate-based cobalt (II) metal compound, [Co (HL1)2(H2O)4] (1) (H2L1 = 2-hydroxyquinoline-4-carboxylic acid) has been hydrothermally synthesized, and fully characterized by single-crystal X-ray diffraction, powder X-ray diffraction, Fourier-transform infrared (FT-IR), elemental and thermo-gravimetric analysis. Compound 1 shows high thermal stability up to ~300°C. Single-crystal X-ray diffraction study of 1 exhibited monomeric structure experiences further stabilized in solid state through different non-covalent interaction, for example, H-bonding and π···π stacking interaction and extended to 3D supramolecular H-bonded network. Compound 1 efficiently catalyzes epoxidation reactions of olefins under homogeneous conditions using molecular oxygen as an oxidizer. Another reported quinoline carboxylate-based nickel (II) monomer [Ni(L2)2(H2O)2] (2) (HL2 = thiazole-4-carboxylic acid) has been synthesized and characterized to compare it with compound 1 towards aerobic epoxidation reactions, where 1 comes as superior.
