13107-39-6Relevant articles and documents
Mononuclear Nonheme Iron(III)-Iodosylarene and High-Valent Iron-Oxo Complexes in Olefin Epoxidation Reactions
Wang, Bin,Lee, Yong-Min,Seo, Mi Sook,Nam, Wonwoo
, p. 11740 - 11744 (2015)
High-spin iron(III)-iodosylarene complexes are highly reactive in the epoxidation of olefins, in which epoxides are formed as the major products with high stereospecificity and enantioselectivity. The reactivity of the iron(III)-iodosylarene intermediates is much greater than that of the corresponding iron(IV)-oxo complex in these reactions. The iron(III)-iodosylarene species - not high-valent iron(IV)-oxo and iron(V)-oxo species - are also shown to be the active oxidants in catalytic olefin epoxidation reactions. The present results are discussed in light of the long-standing controversy on the one oxidant versus multiple oxidants hypothesis in oxidation reactions. On active duty: High-spin iron(III)-iodosylarene complexes epoxidize olefins with high stereospecificity and enantioselectivity. The iron(III)-iodosylarene species, not high-valent iron(IV)- and iron(V)-oxo species, are the active oxidants in catalytic olefin epoxidation reactions. The present results resolve the long-standing controversy on the one oxidant versus multiple oxidants hypothesis in oxidation reactions.
Hydrocarbon oxidation by β-halogenated dioxoruthenium(vi) porphyrin complexes: Effect of reduction potential (RuVI/V) and C-H bond-dissociation energy on rate constants
Che, Chi-Ming,Zhang, Jun-Long,Zhang, Rui,Huang, Jie-Sheng,Lai, Tat-Shing,Tsui, Wai-Man,Zhou, Xiang-Ge,Zhou, Zhong-Yuan,Zhu, Nianyong,Chang, Chi Kwong
, p. 7040 - 7053 (2005)
β-Halogenated dioxoruthenium(VI) porphyrin complexes [Ru VI-(F28-tpp)O2] [F28-tpp = 2,3,7,8,12,13, 17,18-octafluoro-5,10,15,20-tetrakis-(pentafluorophenyl)porphyrinato(2-)] and [RuVI(β-Br8-tmp)O2] [β-Br 8-tmp = 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(2,4,6-trimethylphenyl) porphyrinato(2-)] were prepared from reactions of [RuII(por)(CO)] [por = por-phyrinato(2-)] with m-chloroperoxybenzoic acid in CH 2Cl2. Reactions of [RuVI(por)O2] with excess PPh3 in CH2Cl2 gave [Ru II(F20tpp)(PPh3)2] [F 20)-tpp = 5,10,15,20-tetrakis(pentafluo-rophenyl)porphyrinato(2-)] and [RuII-(F28-tpp)(PPh3)2]. The structures of [RuII(por)(CO)(H2O)] and [Ru II(por)-(PPh3)2] (por = F20-tpp, F28-tpp) were determined by X-ray crystallography, revealing the effect of β-fluorination of the porphyrin ligand on the coordination of axial ligands to ruthenium atom. The X-ray crystal structure of [Ru VI(F20-tpp)O2] shows a Ru=O bond length of 1.718(3) A. Electrochemical reduction of [RuVI(por)O 2] (RuVI to RuV) is irreversible or quasi-reversible, with the Ep.c(RuVI/V) spanning -0.31 to -1.15V versus Cp2Fe+/0. Kinetic studies were performed for the reactions of various [RuVI(por)O2], including [RuVI-(F28-tpp)O2] and [Ru VI(β-Br8-tmp)O2], with para-substituted styrenes p-X-C6H4CH=CH2 (X = H, F, Cl, Me, MeO), cis- and trans-β-methylstyrene, cyclohexene, norbornene, ethylbenzene, cumene, 9,10-dihydroanthracene, xanthene, and fluorene. The second-order rate constants (k2) obtained for the hydrocarbon oxidations by [RuVI-(F28-tpp)O2] are up to 28-fold larger than by [RuVI(F20-tpp)O2]. Dual-parameter Hammett correlation implies that the styrene oxidation by [RuVI(F28-tpp)O2] should involve rate-limiting generation of a benzylic radical intermediate, and the spin delocalization effect is more important than the polar effect. The k2 values for the oxidation of styrene and ethylbenzene by [RuVI-(por)O 2] increase with Ep.c(RuVI/V), and there is a linear correlation between log k2 and Ep.c(Ru VI/V). The small slope (≈2 V-1) of the log k 2 versus Ep.c(RuVI/V) plot suggests that the extent of charge transfer is small in the rate-determining step of the hydrocarbon oxidations. The rate constants correlate well with the C-H bond dissociation energies, in favor of a hydrogen-atom abstraction mechanism.
Kinetics of (porphyrin)manganese(III)-catalyzed olefin epoxidation with a soluble iodosylbenzene derivative
Collman, James P.,Zeng, Li,Wang, Hong J. H.,Lei, Aiwen,Brauman, John I.
, p. 2707 - 2714 (2006)
We examined the kinetics of a well-behaved system for homogeneous porphyrin-catalyzed olefin epoxidation with a soluble iodosylbenzene derivative 1 as the terminal oxidant and Mn(TPFPP)Cl (2) as the catalyst. The epoxidation rates were measured by using the initial rate method, and the epoxidation products were determined by gas chromatography. The epoxidation rate was found to be first order with respect to the porphyrin catalyst and zero order on the terminal oxidant. In addition, we found the rate law to be sensitive to the nature and concentration of olefin substrates. Saturation kinetics were observed with all olefin substrates at high olefin concentrations, and the kinetic data are consistent with a Michaelis-Menten kinetic model. According to the observed saturation kinetic results, we propose that there is a complexation between the active oxidant and the substrate, and the rate-determining step is thought to be the breakdown of this putative substrate-oxidant complex that generates the epoxidation products and the resting state porphyrin catalyst. Competitive epoxidations further indicate a reversible complexation of the active oxidant and the olefin substrate. The activation parameters ΔH? and ΔS? for the oxygen-transfer process (k2) in the cis-cyclooctene epoxidation were determined to be 12.3±0.9 k cal mol-1 and -15.6±3.2 cal mol-1 K-1, respectively. In addition, the Hammett constant ρ+ was measured for the epoxidation of para-substituted styrenes, and the value of -0.27±0.04 is too low to be consistent with the involvement of a discrete carbocation in the transition state. We also prepared a (porphyrin)-manganese catalyst immobilized on silica support, and found the epoxidation of cis-cyclooctene catalyzed by this heterogeneous catalyst proceeds at virtually the same turnover frequency as by the homogeneous porphyrin catalyst. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
Substituent effects on the catalytic activity of a series of manganese meso-tetra(aryl)porphyrins: (2-, 3-, 4)-Pyridyl, 4-sulfonatophenyl and 3-sulfonato-4-methoxyphenyl groups compared to phenyl and 4-methoxyphenyl ones
Zakavi, Saeed,Mojarrad, Aida Ghanbelanie,Rayati, Saeed
, p. 153 - 158,6 (2012)
Catalytic activity and oxidative stability of a series of Mn-porphyrins (Mn-pors) with pyridyl (2-, 3- or 4-), 4-sulfonatophenyl, 3-sulfonato-4- methoxyphenyl, phenyl and 4-methoxyphenyl in oxidation of olefins with tetra-n-butylammonium periodate has been investigated in a comparative study. While the complexes with pyridyl substituents, MnT(py)P(OAc) are generally more stable than those with the other aryl groups toward oxidative degradation in reaction conditions, their catalytic activity is usually lower than these Mn-pors. MnT(4-py)P(OAc) was found to be unusually more stable than MnT(2- or 3-py)P(OAc). The order of catalytic performance of the used Mn-pors and their oxidative stability are less correlated with the electronic properties of the meso substituents. On the basis of indirect evidence obtained in competition oxidation of cis- and trans-stilbene, the involvement of a six coordinate (IO4)Mn(III)(Porphyrin)(ImH) and a high valent Mn-oxo species has been proposed. However, in the case of MnT(py)P(OAc), the latter seems to be more dominant than the former.
Intramolecular arene hydroxylation versus intermolecular olefin epoxidation by (μ-η2:η2-peroxo)dicopper(II) complex supported by dinucleating ligand
Matsumoto, Takahiro,Furutachi, Hideki,Kobino, Masashi,Tomii, Masato,Nagatomo, Shigenori,Tosha, Takehiko,Osako, Takao,Fujinami, Shuhei,Itoh, Shinobu,Kitagawa, Teizo,Suzuki, Masatatsu
, p. 3874 - 3875 (2006)
A discrete (μ-η2:η2-peroxo)Cu(II)2 complex, [Cu2(O2)(H-L)]2+, is capable of performing not only intramolecular hydroxylation of a m-xylyl linker of a dinucleating ligand but also intermolec
Epoxidation of olefins catalyzed by a molybdenum-Schiff base complex anchored in the pores of SBA-15
Bagherzadeh, Mojtaba,Zare, Maryam,Amini, Mojtaba,Salemnoush, Taghi,Akbayrak, Serdar,?zkar, Saim
, p. 470 - 480 (2014)
Novel mesostructured hybrid materials containing a molybdenum Schiff base complex grafted on the internal surface of SBA-15 pores were prepared by introducing MoO2(acac)2 into a mesoporous silica functionalized with Schiff base ligan
Novel chiral sulphonato-salen-manganese(III)-pillared hydrotalcite catalysts for the asymmetric epoxidation of styrenes and cyclic alkenes
Bhattacharjee, Samiran,Anderson, James A.
, p. 151 - 158 (2006)
A novel chiral sulphonato-salen-manganese (III) complex has been prepared and intercalated into a Zn-Al layered-double hydroxide (LDH) structure. The resulting catalyst was found to be highly active and enantioselective in the epoxidation of various styre
Chemoenzymatic enantioconvergent hydrolysis of p-nitrostyrene oxide into (R)-p-nitrophenyl glycol by a newly cloned epoxide hydrolase VrEH2 from Vigna radiata
Wu, Yan-Wen,Kong, Xu-Dong,Zhu, Qing-Qing,Fan, Li-Qiang,Xu, Jian-He
, p. 16 - 20 (2014)
An epoxide hydrolase from Vigna radiata, VrEH2, was successfully cloned and overexpressed in Escherichia coli. Its temperature and pH optima were 30 °C and 6.5, respectively. VrEH2 showed an opposite regioselectivity towards (S)- and (R)-para-nitrostyrene oxide (pNSO), which enables it to catalyze the enantioconvergent hydrolysis of rac-pNSO affording (R)-p-nitrophenyl glycol (pNPG). Preparative synthesis of (R)-pNPG from rac-pNSO by a chemoenzymatic enantioconvergent hydrolysis route with one quarter time as using VrEH2 alone, gave (R)-pNPG in 99.0% ee and 71.5% overall yield after recrystallization, indicating the potential of VrEH2 as a promising biocatalyst for the preparation of enantiopure diols in organic synthesis.
Length tunable porphyrinoid porous coordination polymer rods and their heterogeneous catalytic study on olefin oxidation
Kim, Sundol,Lee, Young Sun,Lee, Da Hee,Hyun, Min Young,Hong, Jin-Yeon,Huh, Seong,Kim, Cheal,Lee, Suk Joong
, p. 29 - 32 (2013)
We developed a series of micro-size hexagon-faced plate and rods from Mn(III)-porphyrin and In(III) whose lengths were modulated by water. Regardless of a wide range of length distribution, they are isostructural. In addition, the heterogeneous olefin oxidation was performed.
Immobilization of dioxomolybdenum(VI) complex bearing salicylidene 2-picoloyl hydrazone on chloropropyl functionalized SBA-15: A highly active, selective and reusable catalyst in olefin epoxidation
Bagherzadeh, Mojtaba,Zare, Maryam,Salemnoush, Taghi,?zkar, Saim,Akbayrak, Serdar
, p. 55 - 62 (2014)
A novel organic-inorganic hybrid heterogeneous catalyst system was obtained from the reaction of the molybdenum(VI) complex of salicylidene 2-picoloyl hydrazone with mesoporous silica containing 3-chloropropyl groups prepared by a direct synthetic approach involving hydrolysis and co-condensation of tetraethylorthosilicate (TEOS) and 3-chloropropyltrimethoxysilane in the presence of the triblock copolymer P123 as template under acidic conditions. Characterization of the functionalized materials by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), N2 adsorption/desorption, FT-IR and UV-Vis spectroscopy, and thermogravimetric analysis (TGA) reveals that the molybdenum complex is successfully grafted into the pores of the host silica structure. Furthermore, the resulting hybrid material was found to be highly active catalyst in the liquid-phase epoxidation of olefins with t-BuOOH as the oxygen source. Leaching tests and metal analysis of reaction solutions show that the catalytic activity stemmed from the immobilized species, not from the leaching of active species into solution.
Synthesis and characterization of SBA-polyperoxyacid: An efficient heterogeneous solid peroxyacid catalyst for epoxidation of alkenes
Davarpanah, Jamal,Kiasat, Ali Reza
, p. 75 - 80 (2014)
SBA-propy-3-allyl-imidazolium chloride (SBA-Im-Allyl) was easily prepared by nucleophilic substitution of SBA-propylchloride (SBA-Cl) with imidazole and then quaternization with allyl chloride. Then, a novel solid polyperoxyacid was synthesized by anchori
Synthesis, characterization, and X-ray structure of n′-(2-hydroxy- 5-methylbenzylidene)-4-trifluoromethylbenzohydrazide and its dioxidomolybdenum(vi) complex with catalytic property
Liang, Peng,Hong, Zhe
, p. 950 - 955 (2017)
A new hydrazone compound N′-(2-hydroxy-5-methylbenzylidene)-4-trifluoromethylbenzohydrazide (H2L) was prepared. Based on H2L, a new dioxidomolybdenum(VI) complex [cis-MoO2L(MeOH)], was obtained. Single crystals of H2
Ultrasound promoted preparation of Mn(III)-porphyrin nanoparticles: An efficient heterogeneous catalyst for oxidation of alkenes, alkanes and sulfides
Rayati, Saeed,Nejabat, Fatemeh,Naghashian, Nasireh
, p. 1232 - 1237 (2015)
In the present research meso-tetrakis(4-carboxyphenyl)porphyrinatomanganese(III) acetate (Mn(TCPP)OAc) nanoparticles have been prepared for the first time without any stabilizing agent or supporting matrix under ultrasonic irradiation. Scanning electron microscopy (SEM) was used to characterize and investigate the nanocatalyst. Rapid, efficient, facile and highly selective oxidation of a wide range of olefins by tetra-n-butylammonium hydrogen monopersulfate over the prepared manganese nanocatalyst was investigated. Also oxidation of sulfides and alkanes in the presence of the (Mn(TCPP)OAc) nanoparticles were studied. The catalyst is recovered by filtration and reused at least five times.
Chiral electron deficient ruthenium helical coordination polymer as a catalyst for the epoxidation of substituted styrenes
Jahromi, Bahareh Tamaddoni,Kharat, Ali Nemati,Zamanian, Sara
, p. 137 - 140 (2015)
An air and moisture stable ruthenium(III) formate complex [Ru(HCO2)Cl2]n has been synthesized and examined in the epoxidation of substituted styrenes. X-ray crystallographic data of this complex were determined and showed that the formate ligand coordinates to the ruthenium centers in a μ2-η2 fashion (syn, syn). Its asymmetric unit contains one Ru(III) ion together with the half of a formate ligand and one chloride anion, which are bridged between the metal centers, forming a 1-D chain coordination polymer. This electron deficient helical coordination polymer was employed in the epoxidation of para-fluorostyrene, affording the epoxide product in 92% yield. Natural chirality of this coordination polymer is applicable in asymmetric epoxidation reactions.
Structure-Guided Regulation in the Enantioselectivity of an Epoxide Hydrolase to Produce Enantiomeric Monosubstituted Epoxides and Vicinal Diols via Kinetic Resolution
Hou, Xiao-Dong,Hu, Bo-Chun,Hu, Die,Lei, Yu-Qing,Rao, Yi-Jian,Wu, Min-Chen,Zhang, Dong
supporting information, p. 1757 - 1761 (2022/03/16)
Structure-guided microtuning of an Aspergillus usamii epoxide hydrolase was executed. One mutant, A214C/A250I, displayed a 12.6-fold enhanced enantiomeric ratio (E = 202) toward rac-styrene oxide, achieving its nearly perfect kinetic resolution at 0.8 M in pure water or 1.6 M in n-hexanol/water. Several other beneficial mutants also displayed significantly improved E values, offering promising biocatalysts to access 19 structurally diverse chiral monosubstituted epoxides (97.1 - ≥ 99% ees) and vicinal diols (56.2-98.0% eep) with high yields.
Enantiomer Separation of Nitriles and Epoxides by Crystallization with Chiral Organic Salts: Chirality Switching Modulated by Achiral Acids
Hirose, Takuji,Kodama, Koichi,Shimomura, Yuki
, p. 6552 - 6557 (2021/11/16)
Enantiomer separation of nitriles and epoxides by inclusion crystal formation with organic-salt type chiral hosts was achieved. The stereochemistry of the preferentially included nitrile could be switched only by changing the achiral carboxylic acid component. Crystallographic analysis of the inclusion crystals reveals that the hydrogen-bonding networks are controlled by the acidity of the phenol group of the acids, which results in chirality switching.
Effect of the Ligand Backbone on the Reactivity and Mechanistic Paradigm of Non-Heme Iron(IV)-Oxo during Olefin Epoxidation
Biswas, Jyoti Prasad,Ansari, Mursaleem,Paik, Aniruddha,Sasmal, Sheuli,Paul, Sabarni,Rana, Sujoy,Rajaraman, Gopalan,Maiti, Debabrata
supporting information, p. 14030 - 14039 (2021/05/11)
The oxygen atom transfer (OAT) reactivity of the non-heme [FeIV(2PyN2Q)(O)]2+ (2) containing the sterically bulky quinoline-pyridine pentadentate ligand (2PyN2Q) has been thoroughly studied with different olefins. The ferryl-oxo complex 2 shows excellent OAT reactivity during epoxidations. The steric encumbrance and electronic effect of the ligand influence the mechanistic shuttle between OAT pathway I and isomerization pathway II (during the reaction stereo pure olefins), resulting in a mixture of cis-trans epoxide products. In contrast, the sterically less hindered and electronically different [FeIV(N4Py)(O)]2+ (1) provides only cis-stilbene epoxide. A Hammett study suggests the role of dominant inductive electronic along with minor resonance effect during electron transfer from olefin to 2 in the rate-limiting step. Additionally, a computational study supports the involvement of stepwise pathways during olefin epoxidation. The ferryl bend due to the bulkier ligand incorporation leads to destabilization of both (Formula presented.) and (Formula presented.) orbitals, leading to a very small quintet–triplet gap and enhanced reactivity for 2 compared to 1. Thus, the present study unveils the role of steric and electronic effects of the ligand towards mechanistic modification during olefin epoxidation.
