37116-82-8Relevant academic research and scientific papers
All Four Atropisomers of Iron Tetra(o- N, N, N-trimethylanilinium)porphyrin in Both the Ferric and Ferrous States
Martin, Daniel J.,Mercado, Brandon Q.,Mayer, James M.
supporting information, p. 5240 - 5251 (2021/05/04)
Electrostatic effects are key to many biological and (electro)chemical transformations, especially those that involve charged species. The position and orientation of the electric field with respect to the molecules undergoing charge rearrangement are often crucial to the progress of the reaction. Recently, several molecular (electro)catalysts have been designed to contain spatially positioned charged groups that can engage in specific intramolecular electrostatic interactions. For instance, iron complexes of the tetra(o-N,N,N-trimethylanilinium)porphyrin ligand, which has four cationic groups, have been used to great effect for both CO2 and O2 reduction. Because of the ortho-substitution pattern on the porphyrin ligand, there are four possible atropisomers - such as the αβαβ isomer with trimethylanilinium groups on alternating faces of the porphyrin - and thus four unique electrostatic environments. This study details the synthesis and characterization (1H NMR spectroscopy, single crystal X-ray diffraction, and cyclic voltammetry) of these four metalloporphyrin isomers in both the ferric (FeIII) and ferrous (FeII) forms by using a synthetic route that preserves atropisomeric purity. The atropisomers are different in some respects but show remarkable similarities in others, such as their reduction potentials. This study also shows that the widely-cited literature method used previously to prepare the molecular electrocatalyst for CO2 and O2 reduction yields a mixture of atropisomers rather than a single one, as was previously assumed. These results identify the ways in which intra- and intermolecular electrostatic effects affect both solution and solid-state properties as well underscoring the challenges associated with preparing metalloporphyrins with high atropisomeric purity.
Controlling Oxygen Reduction Selectivity through Steric Effects: Electrocatalytic Two-Electron and Four-Electron Oxygen Reduction with Cobalt Porphyrin Atropisomers
Apfel, Ulf-Peter,Cao, Rui,Guo, Kai,Jin, Xiaotong,Lei, Haitao,Li, Xialiang,Long, Ran,Lv, Bin,Ma, Jun,Wang, Fang,Wang, Yanzhi,Xiong, Yujie,Zhang, Qingxin,Zhang, Wei
supporting information, p. 12742 - 12746 (2021/04/22)
Achieving a selective 2 e? or 4 e? oxygen reduction reaction (ORR) is critical but challenging. Herein, we report controlling ORR selectivity of Co porphyrins by tuning only steric effects. We designed Co porphyrin 1 with meso-phenyls each bearing a bulky ortho-amido group. Due to the resulted steric hinderance, 1 has four atropisomers with similar electronic structures but dissimilar steric effects. Isomers αβαβ and αααα catalyze ORR with n=2.10 and 3.75 (n is the electron number transferred per O2), respectively, but ααββ and αααβ show poor selectivity with n=2.89–3.10. Isomer αβαβ catalyzes 2 e? ORR by preventing a bimolecular O2 activation path, while αααα improves 4 e? ORR selectivity by improving O2 binding at its pocket, a feature confirmed by spectroscopy methods, including O K-edge near-edge X-ray absorption fine structure. This work represents an unparalleled example to improve 2 e? and 4 e? ORR by tuning only steric effects without changing molecular and electronic structures.
Iron-Catalyzed Amination of Strong Aliphatic C(sp3)-H Bonds
Das, Sandip Kumar,Roy, Satyajit,Khatua, Hillol,Chattopadhyay, Buddhadeb
supporting information, p. 16211 - 16217 (2020/10/26)
A concept for intramolecular denitrogenative C(sp3)-H amination of 1,2,3,4-tetrazoles bearing unactivated primary, secondary, and tertiary C-H bonds is discovered. This catalytic amination follows an unprecedented metalloradical activation mechanism. The utility of the method is showcased with the short synthesis of a bioactive molecule. Moreover, an initial effort has been embarked on for the enantioselective C(sp3)-H amination through the catalyst design. Collectively, this study underlines the development of C(sp3)-H bond functionalization chemistry that should find wide application in the context of drug discovery and natural product synthesis.
Selective Solvent-Free and Additive-Free Oxidation of Primary Benzylic C–H Bonds with O2 Catalyzed by the Combination of Metalloporphyrin with N-Hydroxyphthalimide
Shen, Hai-Min,Qi, Bei,Hu, Meng-Yun,Liu, Lei,Ye, Hong-Liang,She, Yuan-Bin
, p. 3096 - 3111 (2020/04/29)
Abstract: A protocol for solvent-free and additive-free oxidation of primary benzylic C–H bonds with O2 was presented through adjusting the combination of metalloporphyrins and NHPI as binary catalysts to overcome the deficiencies encountered in current oxidation systems. The effects of reaction temperature, porphyrin structure, central metal, catalyst loading and O2 pressure were investigated systematically. For the optimized combination of T(2-OCH3)PPCo and NHPI, all the primary benzylic C–H bonds could be functionalized efficiently and selectively at 120 °C and 1.0?MPa O2 with aromatic acids as the primary products. The selectivity towards aromatic acids could reach up to 70–95% in the conversion of more than 30% for most of the substrates possessing primary benzylic C–H bonds in the metalloporphyrin loading of 0.012% (mol/mol). And the superior performance of T(2-OCH3)PPCo among the metalloporphyrins investigated was mainly attributed to its high efficiency in charge transfer and fewer positive charges around central metal Co (II) which favored the adduction of O2 to cobalt (II) forming the high-valence metal-oxo complex followed by the production of phthalimide N-oxyl radical (PINO) and the initiation of the catalytic oxidation cycle. This work would provide not only an efficient protocol in utilization of hydrocarbons containing primary benzylic C–H bonds, but also a significant reference in the construction of more efficient C–H bonds oxidation systems. Graphic Abstract: The solvent-free and additive-free oxidation of primary benzylic C–H bonds with O2 was presented through adjusting the combination of metalloporphyrins and NHPI as binary catalysts, and the highest selectivity towards aromatic acid reached up to 95.1% with the conversion of 88.5% in the optimized combination of T(2-OCH3)PPCo and NHPI.[Figure not available: see fulltext.].
Homolytic versus Heterolytic Hydrogen Evolution Reaction Steered by a Steric Effect
Apfel, Ulf-Peter,Cao, Rui,Ding, Shuping,Guo, Xiaojun,Li, Jianfeng,Li, Xialiang,Ren, Wanjie,Wang, Ni,Xu, Gelun,Zhang, Wei,Zhang, Zongyao,Zhao, Jianping
supporting information, p. 8941 - 8946 (2020/04/22)
Several H?H bond forming pathways have been proposed for the hydrogen evolution reaction (HER). Revealing these HER mechanisms is of fundamental importance for the rational design of catalysts and is also extremely challenging. Now, an unparalleled example of switching between homolytic and heterolytic HER mechanisms is reported. Three nickel(II) porphyrins were designed and synthesized with distinct steric effects by introducing bulky amido moieties to ortho- or para-positions of the meso-phenyl groups. These porphyrins exhibited different catalytic HER behaviors. For these Ni porphyrins, although their 1e-reduced forms are active to reduce trifluoroacetic acid, the resulting Ni hydrides (depending on the steric effects of porphyrin rings) have different pathways to make H2. Understanding HER processes, especially controllable switching between homolytic and heterolytic H?H bond formation pathways through molecular engineering, is unprecedented in electrocatalysis.
Tuning Gold Nanoparticles with Chelating Ligands for Highly Efficient Electrocatalytic CO2 Reduction
Cao, Zhi,Zacate, Samson B.,Sun, Xiaodong,Liu, Jinjia,Hale, Elizabeth M.,Carson, William P.,Tyndall, Sam B.,Xu, Jun,Liu, Xingwu,Liu, Xingchen,Song, Chang,Luo, Jheng-hua,Cheng, Mu-Jeng,Wen, Xiaodong,Liu, Wei
supporting information, p. 12675 - 12679 (2018/09/11)
Capped chelating organic molecules are presented as a design principle for tuning heterogeneous nanoparticles for electrochemical catalysis. Gold nanoparticles (AuNPs) functionalized with a chelating tetradentate porphyrin ligand show a 110-fold enhanceme
SELECTIVE PORPHYRIN-CATALYZED ELECTROCHEMICAL REDUCTION OF CO2 INTO CO, IN PARTICULAR IN WATER
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Page/Page column 24, (2018/03/26)
The present invention relates to the use of complexes of water soluble porphyrins of formula (I). The present invention relates to water soluble porphyrins of formula (I), wherein R1 to R11 and R1' to R8' are as
Through-Space Charge Interaction Substituent Effects in Molecular Catalysis Leading to the Design of the Most Efficient Catalyst of CO2-to-CO Electrochemical Conversion
Azcarate, Iban,Costentin, Cyrille,Robert, Marc,Savéant, Jean-Michel
supporting information, p. 16639 - 16644 (2017/01/10)
The starting point of this study of through-space substituent effects on the catalysis of the electrochemical CO2-to-CO conversion by iron(0) tetraphenylporphyrins is the linear free energy correlation between through-structure electronic effec
Synthesis, characterization and spectral properties of substituted tetraphenylporphyrin iron chloride complexes
Sun, Zhi-Cheng,She, Yuan-Bin,Zhou, Yang,Song, Xu-Feng,Li, Kai
scheme or table, p. 2960 - 2970 (2011/06/21)
A series of substituted tetraphenylporphyrin iron chloride complexes [RTPPFe(III)Cl, R=o/p-NO2, o/p-Cl, H, o/p-CH3, o/p-OCH3] were synthesized by a novel universal mixed-solvent method and the spectral properties of free b
Controlled porphyrinogen oxidation for the selective synthesis of meso-tetraarylchlorins
Serra, Arménio C.,Rocha Gonsalves, António M.D'A.
supporting information; experimental part, p. 4192 - 4194 (2010/09/12)
Chlorins have been synthesized through the reduction of the corresponding porphyrins although theoretically they can be obtained from reduced macrocycle forms as porphyrinogens. A new method for the oxidation of meso- tetraarylporphyrinogens was developed generating a substantial amount of chlorin relatively to porphyrin. The structure of the porphyrinogen, particularly the presence of substituents on the meso-phenyl groups, is decisive for the final yield of chlorin. In the case of meso-tetrakis(2,6-dichlorophenyl)porphyrinogen, 92% of the corresponding chlorin is obtained.
