41882-47-7Relevant academic research and scientific papers
Cyclometalated Half-Sandwich Iridium(III) Complexes: Synthesis, Structure, and Diverse Catalytic Activity in Imine Synthesis Using Air as the Oxidant
Li, Rong-Jian,Ling, Chun,Lv, Wen-Rui,Deng, Wei,Yao, Zi-Jian
, p. 5153 - 5162 (2021/05/04)
Four air-stable cyclometalated half-sandwich iridium complexes 1-4 with C,N-donor Schiff base ligands were prepared through C-H activation in moderate-to-good yields. These complexes have been well characterized, and their exact structure was elaborated on by single-crystal X-ray analysis. The iridium(III) complexes 1-4 showed good catalytic activity in the imine synthesis under open-flask conditions (air as the oxidant) from primary amine oxidative homocoupling, secondary amine dehydrogenation, and the cross-coupling reaction of amine and alcohol. Substituents bonded on the ligands of the iridium complexes displayed little effect on the catalytic efficiency. The stability and good catalytic efficiency of the iridium catalysts, mild reaction conditions, and substrate universality showed their potential application in industrial production.
Redox-Neutral Imination of Alcohol with Azide: A Sustainable Alternative to the Staudinger/Aza-Wittig Reaction
Li, Huaifeng,Lupp, Daniel,Das, Pradip K.,Yang, Li,Gon?alves, Théo P.,Huang, Mei-Hui,El Hajoui, Marwa,Liang, Lan-Chang,Huang, Kuo-Wei
, p. 4071 - 4076 (2021/04/12)
The traditional Staudinger/aza-Wittig reaction represents one of the most powerful tools for imine formation. However, for this multistep procedure, the sacrificial phosphine has to be used, resulting in difficulties in the purification process and waste disposal at the same time. Here, we report a redox-neutral azide-alcohol imination methodology enabled by a base-metal nickel PN3 pincer catalyst. The one-step, waste-free, and high atom-economical features highlight its advantages further. Moreover, mechanistic insight suggests a non-metal-ligand cooperation pathway based on the observation of an intermediate and density functional theory calculations.
FeCl2-PPh3 as an efficient catalytic system for the acceptorless dehydrogenation of amines into imines
Nazarahari, Maryam,Azizian, Javad
, p. 5705 - 5710 (2021/07/06)
In this work, a novel and simple catalytic system including FeCl2, PPh3 and potassium tert-butoxide has been employed for the synthesis of imines from amines. In order to prove the catalytic acceptorless dehydrogenation pathway for this transformation, the liberated H2 gas is detected by NMR spectroscopy. By utilizing this protocol, a variety of arylamines were used successfully for the preparation of corresponding imines in good to excellent yields (on a 1?mmol scale, 73–91% yield for homocoupling, 71 and 91% for heterocoupling).
Nickel Complexes Bearing N,N,O-Tridentate Salicylaldiminato Ligand: Efficient Catalysts for Imines Formation via Dehydrogenative Coupling of Primary Alcohols with Amines
Han, Zhangang,Hao, Zhiqiang,Lin, Jin,Lu, Guo-Liang,Zhang, Junhua,Zhang, Xiaoying
, p. 3843 - 3853 (2021/11/18)
Treatment of salicylaldiminato ligand L1H-L2H (L1H = 2,4-di-tert-butyl-6-((quinolin-8-ylimino)methyl)phenol; L2H = 2,4-di-tert-butyl-6-(((2-(diethylamino)ethyl)imino)methyl)phenol) with Ni(OAc)2·4H2O in refluxing ethanol afforded nickel complexes [(L1)Ni(OAc)] (1) and [(L2)Ni(OAc)] (2), respectively. Reaction of L3H (L3H = (2,4-di-tert-butyl-6-(((2-(pyridin-2-yl)ethyl)imino)methyl)phenol)) with Ni(OAc)2·4H2O in the presence of excess triethylanmine gave the dual ligands coordinated nickel complex [(L2)2Ni] (3). Complexes 1-3 were well characterized by high-resolution mass spectrometry, infrared spectroscopy, elemental analysis, and X-ray diffraction analysis. All the three Ni(II) complexes exhibited efficient activity and good selectivity in the acceptorless dehydrogenative coupling of alcohols and amines to produce imines and diimines. The present protocol provides an atom-economical and sustainable route for the synthesis of various imine derivatives by employing an earth-abundant nickel salt and easily prepared salicylaldiminato ligands.
Air-Stable Half-Sandwich Iridium Complexes as Aerobic Oxidation Catalysts for Imine Synthesis
Deng, Wei,Fan, Xiao-Nan,Ou, Hui-Dan,Yao, Zi-Jian
supporting information, (2020/04/02)
Several N,O-coordinate half-sandwich iridium complexes, 1-5, containing constrained bulky β-enaminoketonato ligands were prepared and clearly characterized. Single-crystal X-ray diffraction characterization of these complexes indicates that the iridium center adopts a distorted octahedral geometry. Complexes 1-5 showed good catalytic efficiency in the oxidative homocoupling of primary amines, dehydrogenation of secondary amines, and the oxidative cross-coupling of amines and alcohols, which furnished various types of imines in good yields and high selectivities using O2 as an oxidant under mild conditions. No distinctive substituent effects of the iridium catalysts were observed in these reactions. The diverse catalytic activity, broad substrate scope, mild reaction conditions, and high yields of the products made this catalytic system attractive in industrial processes.
Highly efficient microwave assisted synthesis of magnetically separable GO-CoFe2O4 nanocomposite for visible light induced oxidative coupling of benzyl amines
Jain, Suman L.,Khatri, Praveen K.,Sadanandan, Aathira M.
, (2020/06/26)
The present paper describes an efficient microwave-assisted synthesis of magnetic CoFe2O4 and its nanocomposite with graphene oxide (GO-CoFe2O4) for photocatalytic oxidative coupling of benzylamines to the corresponding imines using molecular oxygen. The surface morphologies and structures of both CoFe2O4 and GO-CoFe2O4 nanocomposites were investigated by various spectroscopic techniques including powder X-ray diffraction (XRD), Transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption–desorption isotherms, X-ray photoelectron spectroscopy (XPS) and Raman Spectroscopy. Photocatalytic oxidative coupling experiments demonstrated that GO-CoFe2O4 exhibited significantly higher efficiency than CoFe2O4 nanoparticles, suggesting that GO played an important role in the reaction. Moreover, the magnetic nature of the synthesized nanocomposite provided facile recovery of the material by the influence of an external magnet.
Polyoxometalate-Supported Aminocatalyst for the Photocatalytic Direct Synthesis of Imines from Alkenes and Amines
Shi, Zhuolin,Li, Jie,Han, Qiuxia,Shi, Xiaoyun,Si, Chen,Niu, Guiqin,Ma, Pengtao,Li, Mingxue
supporting information, (2019/10/08)
Developing efficient photocatalysts for direct oxidative coupling of alkenes and amines with O2 under mild conditions is very significant. Herein, ZnW-PYI is well-designed by assembling a [PZnW11O39(H2O)]5- photooxidation catalyst and chiral aminocatalyst pyrrolidine-2-ylimidazole (PYI) via a coordination model. ZnW-PYI efficiently catalyzed the synthesis of imines from alkenes and amines using O2 as the oxidant through nucleophilic catalysis by employing pyrrolidine as an organocatalyst. Combining a polyoxometalate and PYI within one single framework is an effective approach not only for stabilization and heterogenization of the redox-active catalyst and aminocatalyst but also for realization of compatibility between the reaction intermediates and synergy of multiple catalytic cycles.
Mesoporous cobalt/manganese oxide: A highly selective bifunctional catalyst for amine-imine transformations
Dutta, Biswanath,March, Seth,Achola, Laura,Sahoo, Sanjubala,He, Junkai,Shirazi Amin, Alireza,Wu, Yang,Poges, Shannon,Pamir Alpay,Suib, Steven L.
, p. 3180 - 3185 (2018/07/29)
Herein, we discuss a heterogeneous catalytic protocol using cobalt doped mesoporous manganese oxide for amine-alcohol cross-coupling to selectively produce symmetric or asymmetric imines. Thorough investigations on the surface chemistry and physical properties of the material revealed its outstanding oxidation-reduction properties and reaction mechanism which was supported by quantum mechanical calculations done by using density functional theory (DFT).
Hydrogenated Cu2OAu@CeO2 Z-scheme catalyst for photocatalytic oxidation of amines to imines
Liu, Yingying,Chen, Yajie,Zhou, Wei,Jiang, Baojiang,Zhang, Xin,Tian, Guohui
, p. 5535 - 5543 (2018/11/20)
The design and fabrication of highly active visible light photocatalysts for organic synthesis reactions are particularly challenging for solar energy utilization and conversion. Herein, hydrogenated Z-scheme yolk-shell Cu2OAu@CeO2 (H-Cu2OAu@CeO2) photocatalysts were synthesized using cubic Cu2O as the starting core material via surface Au deposition and oxidation etching process, followed by hydrogenation treatment. When compared with CeO2, Cu2O@CeO2, and Cu2O@CeO2Au nanocomposites, optimized H-Cu2OAu@CeO2 showed remarkably higher visible light oxidation activity for the synthesis of imines from amines at ambient pressure and room temperature. The remarkably enhanced photoactivity of the H-Cu2OAu@CeO2 composite mainly derives from the enhanced photoinduced charge separation efficiency, porous yolk-shell structure, proper surface defects, and well-maintained strong oxidation/reduction capabilities. The Z-scheme charge transfer process and photocatalytic reaction mechanism of the H-Cu2OAu@CeO2 composites were also provided through spectral and photoelectrochemical analyses together with the investigation of structure and photocatalytic oxidation reactions. This study provides a probable approach for designing unique Z-scheme catalysts.
Direct access to: N -alkylated amines and imines via acceptorless dehydrogenative coupling catalyzed by a cobalt(ii)-NNN pincer complex
Midya, Siba P.,Pitchaimani, Jayaraman,Landge, Vinod G.,Madhu, Vedichi,Balaraman, Ekambaram
, p. 3469 - 3473 (2018/07/29)
A simple, phosphine-free Co(ii)-NNN pincer complex catalyzed direct N-alkylation of anilines with alcohols via hydrogen auto-transfer (HA) and selective acceptorless dehydrogenative coupling (ADC) of benzylamines with alcohols affording imines with the liberation of molecular hydrogen and water is reported.
