60430-21-9Relevant academic research and scientific papers
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.].
Cobalt single-atoms anchored on porphyrinic triazine-based frameworks as bifunctional electrocatalysts for oxygen reduction and hydrogen evolution reactions
Yi, Jun-Dong,Xu, Rui,Chai, Guo-Liang,Zhang, Teng,Zang, Ketao,Nan, Bing,Lin, Hua,Liang, Yu-Lin,Lv, Jiangquan,Luo, Jun,Si, Rui,Huang, Yuan-Biao,Cao, Rong
, p. 1252 - 1259 (2019/01/23)
Designing and fabrication of highly active single-atom catalysts (SACs) with maximized atomic efficiency is highly desirable but still remains a great challenge. Herein, highly active and stable cobalt single-atoms with a Co-N4 moiety were uniformly anchored on a porous porphyrinic triazine-based framework (CoSAs/PTF) by a simple ionothermal method. Due to the abundant single-atom Co-N4 species, the hierarchical porous structure and the good conductivity, the resultant catalyst is highly active for the electrocatalytic oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). For the ORR, a more positive half-wave potential of 0.808 V (vs. RHE) was achieved, compared with commercial benchmark Pt/C (0.806 V). Furthermore, a small onset potential of 21 mV and a low Tafel slope of 50 mV per decade were obtained for the HER. The porphyrin-like structure was found to stabilize the CoSAs effectively, thus leading to long-term durability and a remarkable methanol-tolerant behavior. This bifunctional single-atom catalyst might be a promising candidate to replace Pt-based electrocatalysts in electrolysers and fuel cells.
Synthesis, characterization, singlet-oxygen photogeneration, DNA photocleavage and two-photon-absorption properties of some (4-cyanophenyl) porphyrins
Wang, Kai,Poon, Chun-Ting,Wong, Wai-Kwok,Wong, Wai-Yeung,Choi, Chun Y.,Kwong, Daniel W.J.,Zhang, Heng,Li, Zao-Ying
, p. 922 - 928 (2009/06/06)
A series of (4-cyanophenyl)porphyrins have been prepared and structurally characterized by 1H NMR, IR and UV/Vis spectroscopy, mass spectrometry, and elemental analysis. The relative singlet-oxygen quantum yields, two-photon absorption cross-se
Femtosecond dynamics of metalloporphyrins: Electron transfer and energy redistribution
Yu,Baskin,Steiger,Wan,Anson,Zewail
, p. 1 - 8 (2008/10/08)
Femtosecond-resolved, real-time dynamics of the low-lying excited state 2Q(π,π *) of cobalt(II) tetraphenylporphyrin are reported in different solvents of varying polarity and structure. The dependence of the dynamics on the probing wavelength and on the metal and porphyrin substitution was also investigated. The decay in the π system of the porphyrin occurs with a lifetime of 220 fs in benzene, while a second process with a lifetime of 1.8 ps is consistent with a proposed model for intramolecular charge separation: porphyrin a2u(π)→Co(dz2). The dynamics of the charge transfer state is influenced by the solvents' polarity and coordination ability.
