2142-63-4Relevant academic research and scientific papers
Trinuclear ruthenium carbonyl complexes with salicylaldimine ligands as efficient catalysts for the oxidation of secondary alcohols
Han, Zhangang,Hao, Zhiqiang,Li, Ying,Lin, Jin,Lu, Guo-Liang,Ma, Zhihong
, (2021)
A series of novel trinuclear ruthenium carbonyl complexes [μ-?2-2-OC6H4-CH=N-Ar)]2Ru3(CO)8 [Ar = Ph (8), C6H4-4-Me (9), C6H4-4-CF3 (10), C6H4-4-Cl (11), C6H3-2,6-Me2 (12), C6H3-2,6-Et2 (13)] and [μ-?2-2-OC6H4-CH=N-C6H3-2,6-iPr2]Ru3(CO)9 (14) were designed and synthesized. All the seven novel complexes were fully characterized by elemental analysis, IR and NMR spectroscopy. Molecular structures of 8, 11, 13 and 14 were further confirmed by single-crystal X-ray diffraction. The catalytic performance of these complexes in the oxidation of secondary alcohols was explored and it was found the combination of such complexes and N-methylmorpholine-N-oxide (NMO) exhibits high catalytic activities for the oxidation of secondary alcohols, giving the corresponding carbonyl compounds in excellent yields.
Efficient aerobic oxidation of alcohols to aldehydes and ketones using a ruthenium carbonyl complex of a tert-butyl-substituted tetramethylcyclopentadienyl ligand as catalyst
Hao, Zhiqiang,Yan, Xinlong,Li, Zhanwei,Wu, Ruitao,Ma, Zhihong,Li, Suzhen,Han, Zhangang,Zheng, Xuezhong,Lin, Jin
, p. 635 - 640 (2018)
Tert-butyl-substituted tetramethylcyclopentadiene [C5HMe4tBu] was reacted with Ru3(CO)12 to prepare [(η5-C5Me4tBu)Ru(CO)(μ-CO)]2. The complex was characterized by IR, 1H NMR, 13C NMR, elemental analysis, and single-crystal X-ray diffraction. The complex was investigated as a catalyst in the aerobic oxidation of alcohols to the corresponding aldehydes and ketones in the presence of 2,2’,6,6’-tetramethylpiperidine N-oxide (TEMPO) as co-oxidant. The combination of [(η5-C5Me4tBu)Ru(CO)(μ-CO)]2 and TEMPO afforded an efficient catalytic system for the aerobic oxidation of a variety of primary and secondary alcohols, giving the corresponding carbonyl compounds in good-to-excellent yields.
Ruthenium carbonyl complexes supported by pyridine-alkoxide ligands: Synthesis, structure and catalytic oxidation of secondary alcohols
Zong, Siqi,Liu, Kang,Yue, Xiaohui,Hao, Zhiqiang,Ma, Zhihong,Han, Zhangang,Lu, Guo-Liang,Lin, Jin
, p. 13947 - 13953 (2019)
Five novel trinuclear ruthenium complexes [[PyCHC(RC6H4)O]2Ru3(CO)8] [R = 4-OMe (6), 4-Br (7), 4-CF3 (8)] and [[PyCH2CH(RC6H4)O]2Ru3(CO)8] [R = 2-Br (9), 2-CF3 (10)], were synthesized by treating Ru3(CO)12 with two equivalents of the corresponding pyridine-alcohols PyCH2CH(RC6H4)OH [1-5, R = 4-OMe, 4-Br, 4-CF3, 2-Br and 2-CF3] in refluxing toluene. The structures of 6-10 were fully characterized by IR and NMR spectroscopy, elemental analysis and single-crystal X-ray diffraction. They were found to be efficient catalysts for the oxidation of secondary alcohols by NMO, giving the corresponding ketones in good to excellent yields within 15 min, of which [PyCHC(4-OCH3C6H4)O]2Ru3(CO)8 (6) is the best.
Stepwise benzylic oxygenation via uranyl-photocatalysis
Hu, Deqing,Jiang, Xuefeng
supporting information, p. 124 - 129 (2022/01/19)
Stepwise oxygenation at the benzylic position (1°, 2°, 3°) of aromatic molecules was comprehensively established under ambient conditions via uranyl photocatalysis to produce carboxylic acids, ketones, and alcohols, respectively. The accuracy of the stepwise oxygenation was ensured by the tunability of catalytic activity in uranyl photocatalysis, which was adjusted by solvents and additives demonstrated through Stern–Volmer analysis. Hydrogen atom transfer between the benzylic position and the uranyl catalyst facilitated oxygenation, further confirmed by kinetic studies. Considerably improved efficiency of flow operation demonstrated the potential for industrial synthetic application.
Visible light-mediated, high-efficiency oxidation of benzyl to acetophenone catalyzed by fluorescein
Geng, Haoxing,Liu, Xin,Zhu, Qing
supporting information, (2021/12/20)
An environmentally friendly aerobic oxidation of benzyl C(sp3)-H bonds to ketones via selective oxidation catalysis was developed. Fluorescein is an efficient photocatalyst with excellent chemical selectivity. The reaction has a wide substrate scope, and a successful gram-scale experiment demonstrated its potential industrial utility.
Visible-light photocatalytic selective oxidation of C(sp3)-H bonds by anion-cation dual-metal-site nanoscale localized carbon nitride
Duan, Limei,Li, Peihe,Li, Wanfei,Liu, Jinghai,Liu, Ying,Liu, Zhifei,Lu, Ye,Sarina, Sarina,Wang, Jinghui,Wang, Yin,Wang, Yingying,Zhu, Huaiyong
, p. 4429 - 4438 (2021/07/12)
Selective oxidation of C(sp3)-H bonds to carbonyl groups by abstracting H with a photoinduced highly active oxygen radical is an effective method used to give high value products. Here, we report a heterogeneous photocatalytic alkanes C-H bonds oxidation method under the irradiation of visible light (λ= 425 nm) at ambient temperature using an anion-cation dual-metal-site modulated carbon nitride. The optimized cation (C) of Fe3+or Ni2+, with an anion (A) of phosphotungstate (PW123?) constitutes the nanoscale dual-metal-site (DMS). With a Fe-PW12dual-metal-site as a model (FePW), we demonstrate a A-C DMS nanoscale localized carbon nitride (A-C/g-C3N4) exhibiting a highly enhanced photocatalytic activity with a high product yield (86% conversion), selectivity (up to 99%), and a wide functional group tolerance (52 examples). The carbon nitride performs the roles of both the visible light response, and improves the selectivity for the oxidation of C(sp3)-H bonds to carbonyl groups, along with the function of A-C DMS in promoting product yield. Mechanistic studies indicate that this reaction follows a radical pathway catalyzed by a photogenerated electron and hole on A-C/g-C3N4that is mediated by thetBuO˙ andtBuOO˙ radicals. Notably, a 10 g scale reaction was successfully achieved for alkane photocatalytic oxidation to the corresponding product with a good yield (80% conversion), and high selectivity (95%) under natural sunlight at ambient temperature. In addition, this A-C/g-C3N4photocatalyst is highly robust and can be reused at least six times and the activity is maintained.
Flexible on-site halogenation paired with hydrogenation using halide electrolysis
Shang, Xiao,Liu, Xuan,Sun, Yujie
supporting information, p. 2037 - 2043 (2021/03/26)
Direct electrochemical halogenation has appeared as an appealing approach in synthesizing organic halides in which inexpensive inorganic halide sources are employed and electrical power is the sole driving force. However, the intrinsic characteristics of direct electrochemical halogenation limit its reaction scope. Herein, we report an on-site halogenation strategy utilizing halogen gas produced from halide electrolysis while the halogenation reaction takes place in a reactor spatially isolated from the electrochemical cell. Such a flexible approach is able to successfully halogenate substrates bearing oxidatively labile functionalities, which are challenging for direct electrochemical halogenation. In addition, low-polar organic solvents, redox-active metal catalysts, and variable temperature conditions, inconvenient for direct electrochemical reactions, could be readily employed for our on-site halogenation. Hence, a wide range of substrates including arenes, heteroarenes, alkenes, alkynes, and ketones all exhibit excellent halogenation yields. Moreover, the simultaneously generated H2at the cathode during halide electrolysis can also be utilized for on-site hydrogenation. Such a strategy of paired halogenation/hydrogenation maximizes the atom economy and energy efficiency of halide electrolysis. Taking advantage of the on-site production of halogen and H2gases using portable halide electrolysis but not being suffered from electrolyte separation and restricted reaction conditions, our approach of flexible halogenation coupled with hydrogenation enables green and scalable synthesis of organic halides and value-added products.
Ruthenium(II) Complexes Bearing Schiff Base Ligands for Efficient Acceptorless Dehydrogenation of Secondary Alcohols?
Dong, Qing,Feng, Qi,Han, Zhangang,Hao, Zhiqiang,Lin, Jin,Liu, Kang,Lu, Guo-Liang,Ma, Dongzhu
, p. 121 - 128 (2020/12/25)
Four ruthenium(II) complexes 1—4 [RN=CH-(2,4-(tBu)2C6H2O)]RuH(PPh3)2(CO) (R = C6H5, 1; R = 4-MeC6H4, 2; R = 4-ClC6H4, 3; R = 4-BrC6H4, 4) bearing Schiff base ligands were prepared by treating RuHClCO(PPh3)3 with RN=CH-(2,4-(tBu)2C6H2OH (L1—L4) in the presence of triethylamine. Their structures were fully characterized by elemental analysis, IR, NMR spectroscopy and X-ray crystallography. These Ru(II) complexes exhibit high catalytic performance and good functional-group compatibility in the acceptorless dehydrogenation of secondary alcohols, affording the corresponding ketones in 82%—94% yields.
Preparation of trinuclear ruthenium clusters based on piconol ligands and their application in Oppenauer-type oxidation of secondary alcohols
Dong, Qing,Ma, Zongwen,Hao, Zhiqiang,Han, Zhangang,Lin, Jin,Lu, Guo-Liang
, (2021/06/18)
Treatment of Ru3(CO)12 with one equivalent of 2-indolyl-6-pyridinyl-alcohol ligands 2-(C8H6N)-6-(CR1R2OH)C5H3N (R1 = R2 = Me (L1H); R1 = R2 = C2H5 (L2H); R1, R2 = ?(CH2)4- (L3H);& R1, R2 = ?(CH2)5- (L4H)) in refluxing THF afforded the corresponding trinuclear ruthenium clusters L(μ2-H)Ru3(CO)9 (1a–1d), respectively. All the novel Ru complexes were well characterized by NMR, elemental analyses and IR spectra. Structures of complexes 1a, 1c, and 1d were further determined by X-ray crystallographic studies. Complexes 1a–1d were applied to catalytic Oppenauer-type oxidation of secondary alcohols with acetone as oxidant, and complex 1a was found to be the most efficient catalyst.
Hydration of Alkynes to Ketones with an Efficient and Practical Polyoxomolybdate-based Cobalt Catalyst
Xie, Ya,Wang, Jingjing,Wang, Yunyun,Han, Sheng,Yu, Han
, p. 4985 - 4989 (2021/10/12)
Hydration of alkynes to ketones is one of the most atom economical and universal methods for the synthesis of carbonyl compounds. However, the basic reaction usually requires organic ligand catalysts or harsh reaction conditions to insert oxygen into the C≡C bond. Here, we report an inorganic ligand supported cobalt (III) catalyst, (NH4)3[CoMo6O18(OH)6], which is supported by a central cobalt (III) mononucleus and a ring-shaped pure inorganic ligand composed of six MoVIO6 octahedrons to avoid the disadvantages of expensive and unrecyclable organic ligand catalysts or noble metal catalysts. Under mild conditions, the cobalt (III) catalyst can be used for the hydration of alkynes to ketones. The catalyst is non-toxic, green, and environment friendly. The catalyst can be recycled at least six times with high activity. According to control experiments, a reasonable mechanism is provided.
