34557-72-7Relevant articles and documents
Nitrene Photochemistry of Manganese N-Haloamides**
Bhuvanesh, Nattamai,Das, Anuvab,Figgins, Matthew T.,Hicks, Madeline H.,Ozarowski, Andrew,Powers, David C.,Reid, Kaleb A.,Telser, Joshua,Van Trieste, Gerard P.
supporting information, p. 26647 - 26655 (2021/11/18)
Manganese complexes supported by macrocyclic tetrapyrrole ligands represent an important platform for nitrene transfer catalysis and have been applied to both C?H amination and olefin aziridination catalysis. The reactivity of the transient high-valent Mn nitrenoids that mediate these processes renders characterization of these species challenging. Here we report the synthesis and nitrene transfer photochemistry of a family of MnIII N-haloamide complexes. The S=2 N-haloamide complexes are characterized by 1H NMR, UV-vis, IR, high-frequency and -field EPR (HFEPR) spectroscopies, and single-crystal X-ray diffraction. Photolysis of these complexes results in the formal transfer of a nitrene equivalent to both C?H bonds, such as the α-C?H bonds of tetrahydrofuran, and olefinic substrates, such as styrene, to afford aminated and aziridinated products, respectively. Low-temperature spectroscopy and analysis of kinetic isotope effects for C?H amination indicate halogen-dependent photoreactivity: Photolysis of N-chloroamides proceeds via initial cleavage of the Mn?N bond to generate MnII and amidyl radical intermediates; in contrast, photolysis of N-iodoamides proceeds via N?I cleavage to generate a MnIV nitrenoid (i.e., {MnNR}7 species). These results establish N-haloamide ligands as viable precursors in the photosynthesis of metal nitrenes and highlight the power of ligand design to provide access to reactive intermediates in group-transfer catalysis.
Linkage Isomers of 4-Methylimidazolate Mn(II) Porphyrinates: Hindered or Unhindered?
Zhao, Jianping,Qian, Fei,Guo, Wenping,Li, Jianfeng,Lin, Zeyuan
, p. 7465 - 7474 (2021/05/26)
Three different manganese(II) porphyrins have been exploited to react with 4-methylimidazolate (4-MeIm-), and the five-coordinate products are characterized by ultraviolet-visible, single-crystal X-ray, and electronic paramagnetic resonance spectroscopies. Interestingly, 4-MeIm- is found to bond to the metal center through either of the two N atoms (N1 or N3), which yielded two linkage isomers with either an unhindered or a hindered ligand conformation, respectively. Investigations revealed it is the large metal out-of-plane displacements (Δ24 and Δ4 ≥ 0.59 ?) that have rendered the equivalence of two isomers with a small energy difference (5.2-8.3 kJ/mol). The nonbonded intra- and intermolecular interactions thus become crucial factors in the balance of linkage isomerization. All of the products in both solution and solid states show the same characteristic resonances of high-spin Mn(II) (S = 5/2) with g⊥ ≈ 5.9 and g⊥ ≈ 2.0 at 4 K, consistent with the weak effects of the axial ligand on core conformation and metal electronic configurations. Zero-field splitting parameters obtained through simulations are also reported.
Method for synthesizing tetraaryl manganese porphyrin through synchronous aldehyde and pyrrole condensation and bivalent manganese salt oxidation insertion reaction
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Paragraph 0028-0029, (2020/09/08)
The invention discloses a method for synthesizing tetraaryl manganese porphyrin by synchronous aldehyde and pyrrole condensation and bivalent manganese salt oxidation insertion reaction. Aromatic aldehyde, pyrrole and manganese dichloride are refluxed in
Surface molecular engineering of axial-exchanged Fe(III)Cl- and Mn(III)Cl-porphyrins towards enhanced electrocatalytic ORRs and OERs
Attatsi, Isaac Kwaku,Zhu, Weihua,Liang, Xu
supporting information, (2020/03/23)
Herein, pyrene-pyridine (Pyr-Py) molecule was applied as the axial exchanged ligand to bridge Fe(III) and Mn(III)porphyrin immobilized on rGO. These axially exchanged metalloporphyrin functionalized nanocomposites revealed enhanced electrochemically catal
Spectral, Electrochemical, and ESR Characterization of Manganese Tetraarylporphyrins Containing Four β,β′-Pyrrole Fused Butano and Benzo Groups in Nonaqueous Media
Fang, Yuanyuan,Wang, Liping,Xu, Weijie,Ou, Zhongping,Chen, Mingyuan,Cong, Lei,Shan, Wenqian,Ke, Xiangyi,Kadish, Karl M.
, p. 2576 - 2587 (2019/02/19)
Two series of β,β′-pyrrole butano- A nd benzo-substituted mangenese(III) tetraarylporphyrins were synthesized and characterized with regard to their spectral and electrochemical properties. The investigated compounds have the general formula butano(Ar)su
Synthesis and photophysical properties of novel pyrene-metalloporphyrin dendritic systems
Rojas-Montoya, Sandra M.,Vonlanthen, Mireille,Porcu, Pasquale,Flores-Rojas, Gabriel,Ruiu, Andrea,Morales-Morales, David,Rivera, Ernesto
, p. 10435 - 10447 (2019/07/22)
A novel series of dendronized porphyrins bearing pyrene units in the periphery (Porph-O-Gn) and their metal complexes (M-[Porph-O-Gn]) are reported. The pyrene-containing Frechet-type dendrons up to the first generation were synthesized and further reacted with 5-phenol-10,15,20-triphenylporphyrin via an esterification reaction to afford the desired pyrene-labeled dendronized porphyrins. Later, these compounds were used as ligands to produce the corresponding complexes of Zn2+, Cu2+, Mg2+ and Mn3+. With the compounds in hand, the optical and photophysical properties of the dendritic metalloporphyrins were studied by absorption and fluorescence spectroscopy. The quantum yields, F?rster radius and efficiency of energy transfer were determined and discussed as a function of the structure and the donor-acceptor distances, finding an efficient energy transfer from the pyrene moiety to the metallated porphyrin core in each case.
Crystallographic identification of a series of manganese porphyrin complexes with nitrogenous bases
Lahanas, Nicole,Kucheryavy, Pavel,Lalancette, Roger A.,Lockard, Jenny V.
, p. 304 - 312 (2019/02/20)
Studying the axial ligation behavior of metalloporphyrins with nitrogenous bases helps to better understand not only the biological function of heme-based protein systems, but also the catalytic properties of porphyrin-based reaction sites in other biomim
Axial base-controlled catalytic activity, oxidative stability and product selectivity of water-insoluble manganese and iron porphyrins for oxidation of styrenes in water under green conditions
Zakavi, Saeed,Hashemi-Amiri, Akbar,Asadi, Fatemeh
, (2017/11/30)
A series of water-insoluble iron(III) and manganese(III) porphyrins, FeT(2-CH3)PPCl, FeT(4-OCH3)PPCl, FeT(2-Cl)PPCl, FeTPPCl, MnT(2-CH3)PPOAc, MnT(4-OCH3)PPOAc, MnT(2-Cl)PPOAc and MnTPPOAc, in the presence of imidazole (ImH), F?, Cl?, Br? and acetate were used as catalysts for the aqueous-phase heterogeneous oxidation of styrenes to the corresponding epoxides and aldehydes with sodium periodate. Also, the effect of various reaction parameters such as reaction time, molar ratio of catalyst to axial base, type of axial base, molar ratio of olefin to oxidant and nature of metal centre on the activity and oxidative stability of the catalysts and the product selectivity was investigated. Higher catalytic activities were found for the iron complexes. Interestingly, the selectivity towards the formation of epoxide and aldehyde (or acetophenone) was significantly influenced by the type of axial base. Furthermore, Br? and ImH were found to be the most efficient co-catalysts for the oxidation of olefins performed in the presence of the manganese and iron porphyrins, respectively. The optimized molar ratio of catalyst to axial base was different for various axial bases. Also, the order of co-catalyst activity of the axial bases obtained in aqueous medium was different from that reported for organic solvents. The use of a convenient axial base under optimum reaction catalyst to co-catalyst molar ratio in the presence of the manganese porphyrin gave the oxidative products with a conversion of ca 100% in a reaction time of less than 3?h. However, the catalytic activity of the iron porphyrins could not be effectively improved by increasing the catalyst to co-catalyst molar ratio.
Biomimetic Cleavage of Aryl–Nitrogen Bonds in N-Arylazoles Catalyzed by Metalloporphyrins
Yu, Zongjiang,Zhai, Guoqing,Xian, Mo,Lu, Ming,Wang, Pengcheng,Jiang, Tao,Xu, Chao,Sun, Weizhi
, p. 2636 - 2642 (2018/06/20)
The cleavage of C–N single bonds of N-containing compounds provides either an excellent nitrogen source or an excellent carbon source. In this study, an efficient metalloporphyrins/H2O2 cleavage of C–N bonds of arylpyrazoles was investigated. The effects of different factors, including different catalysts, catalyst dosages, H2O2 dosages, reaction temperature and reaction time were studied. The experimental results showed that the optimal catalyst was FeTPPCl, and the yield of pyrazole derivatives could reach up to 12.3%, which was fourfold higher than hemin catalyzed reaction and closed to ceric ammonium nitrate catalyzed reaction, respectively. Compared with transition-metal-catalyzed and strong-oxidization cleavage of C–N bonds, this protocol is characterized by environmentally-friendly, stable, mild reaction conditions and simplified operation procedures. Graphical Abstract: [Figure not available: see fulltext.].
Bromo-substituted Mn(II) and Mn(III)-tetraarylporphyrins: synthesis and properties
Chizhova, Natalya Vasil’evna,Maltceva, Olga Valentinovna,Zvezdina, Svetlana Veniaminovna,Mamardashvili, Nugzar Zhoraevich,Koifman, Oscar Iosifovich
, p. 3222 - 3232 (2018/12/04)
Mono-, tetra-, and octa-bromo substituted Mn(II)- and Mn(III)-tetraarylporphyrins were synthesized by reactions of manganese(II) chloride with corresponding porphyrin ligands or their Cd(II)-complexes in DMF. With the use of the metal exchange reaction, the time of the Mn-porphyrins formation is significantly reduced with increase in yield of final products in comparison with the complexation reaction. Mn(III)-tetraarylporphyrins reduce to the Mn(II)-porphyrins in DMF in the presence of NaOH and in pure DMF. The obtained compounds were identified using UV–vis and 1H NMR spectroscopy, mass-spectrometry, and elemental analysis.
