90-41-5Relevant academic research and scientific papers
Novel iota carrageenan-based RhCl3 as an efficient and recyclable catalyst in Suzuki cross coupling
Leviev, Sivan,Levy-Ontman, Oshrat,Wolfson, Adi
, (2020)
RhCl3 was heterogenized into renewable polysaccharide supports, and the effect of polysaccharide type on the new catalyst performances in a Suzuki cross-coupling reaction was studied. The conversion of the fresh iota carrageenan heterogeneous system (?-RhCl3), was found to be the highest, whereas it was lower than the conversion of its homogeneous analogue. In addition, the ?-RhCl3 (catalyst loading of 6.5 % wt) was proven to be efficient heterogeneous catalyst that was easily recycled, whereas the conversion was increased in the first and second cycles. Scanning electronic microscopy (SEM) combining Energy dispersive X-ray spectrometry and Surface analysis by X-ray photoelectron spectroscopy were performed, confirming that RhCl3 was embedded within the ?-carrageenan. The Fourier-transform infrared spectrometry of the heterogeneous ?-RhCl3 catalyst was compared to that of the native polysaccharide, and no new bands were detected. Nonetheless, a comparison of SEM image of ?-carrageenan with and without RhCl3, as well as rheological measurements of the aqueous solution of ? with and without RhCl3, indicated the incorporation of the polysaccharide with the RhCl3.
Biosynthesis of poly(ethylene glycol)-supported palladium nanoparticles using Colocasia esculenta leaf extract and their catalytic activity for Suzuki-Miyaura cross-coupling reactions
Borah, Raju Kumar,Saikia, Hirak Jyoti,Mahanta, Abhijit,Das, Vijay Kumar,Bora, Utpal,Thakur, Ashim Jyoti
, p. 72453 - 72457 (2015)
A simple and green protocol for the synthesis of poly(ethylene glycol) stabilized palladium nanoparticles under ambient conditions from the aqueous extracts of Colocasia esculenta leaves has been reported. The nanoparticles are characterized using UV-visible spectroscopy, FTIR spectroscopy, XRD and SEM analysis. The prepared Pd NPs showed excellent catalytic activity towards Suzuki-Miyaura cross coupling reactions for a wide variety of aryl halides and phenyl boronic acid substrates. The catalytic system was found to be recyclable and could be reused in subsequent catalytic runs without significant loss of activity.
Pd nanoparticles in hollow magnetic mesoporous spheres: High activity, and magnetic recyclability
Sun, Jian,Dong, Zhengping,Sun, Xun,Li, Ping,Zhang, Fengwei,Hu, Wuquan,Yang, Haidong,Wang, Haibo,Li, Rong
, p. 46 - 51 (2013)
The nanoreactor of hollow magnetic mesoporous silica spheres (Pd/HMMS), with Pd and Fe3O4 nanoparticles embedded in the mesoporous silica shell, were successfully prepared by using the colloidal carbon spheres of glucose, Pd and Fe3O4 heteroaggregates as the hard template together with a coating of tetraethoxysilane (TEOS) and cetyltrimethylammonium bromide (CTAB) mixture. The synthesized Pd/HMMS shows excellent catalytic activity in the Suzuki cross-coupling reaction of iodobenzene with phenylboronic acid with over 99% yield in 3 min and can be recycled multiple times without any significant loss in catalytic activity.
Pd-Cu alloy nanoparticle supported on amine-terminated ionic liquid functional 3D graphene and its application on Suzuki cross-coupling reaction
Ru, Yu,Huang, Yanli,Wang, Yuanyuan,Dai, Liyi
, (2019)
Well distributed Pd-Cu bimetallic alloy nanoparticles supported on amine-terminated ionic liquid functional three-dimensional graphene (3D IL-rGO/Pd-Cu) as an efficient catalyst for Suzuki cross-coupling reaction has been prepared via a facile synthetic method. The introduction of IL-NH2 cations on the surface of graphene sheets can effectively avoid the re-deposition of graphene sheets, allowing the catalyst to be reused up to 10?cycles. The addition of Cu not only saves cost but also ensures high catalytic efficiency. It is worthy to note that the catalyst 3D IL-rGO/Pd2.5Cu2.5 can efficiently catalyze the Suzuki cross-coupling reaction with the yield up to 100% in 0.25?h, almost one-fold higher than that by the pristine IL-rGO/Pd2.5 catalyst (52%). The Powder X-Ray Diffraction (XRD), combining energy dispersive X-ray spectroscopy (EDS) mapping results confirm the existence and distribution of Pd and Cu in the bimetallic nanoparticles. The transmission electron microscopy (TEM) reveals the nanoparticle size with an average diameter of 3.0?±?0.5?nm. X-ray photoelectron spectroscopy (XPS) analysis proved the presence of electron transfer from Cu to Pd upon alloying. Such alloying-induced electronic modification of Pd-Cu alloy and 3D ionic liquid functional graphene with large specific surface area both accounted for the catalytic enhancement.
A selective luminescent probe for the direct time-gated detection of adenosine triphosphate
Weitz, Evan A.,Chang, Jennifer Y.,Rosenfield, Adam H.,Pierre, Valerie C.
, p. 16099 - 16102,4 (2012)
A molecular probe for the luminescent detection of adenosine nucleotides is presented. The probe, Tb-DOTAm-Phen, readily distinguishes among the three adenosine nucleotides in buffered aqueous conditions at neutral pH, a requirement for the direct monitoring of enzymatic reactions converting adenosine triphosphate (ATP) to adenosine diphosphate or adenosine monophosphate. The probe is most efficient under millimolar concentrations of ATP which are relevant to intracellular conditions. Moreover, the long luminescence lifetime of the probe readily enables time-gating experiments.
A Convenient and Stable Heterogeneous Nickel Catalyst for Hydrodehalogenation of Aryl Halides Using Molecular Hydrogen
Leonard, David K.,Ryabchuk, Pavel,Anwar, Muhammad,Dastgir, Sarim,Junge, Kathrin,Beller, Matthias
, (2022/02/03)
Hydrodehalogenation is an effective strategy for transforming persistent and potentially toxic organohalides into their more benign congeners. Common methods utilize Pd/C or Raney-nickel as catalysts, which are either expensive or have safety concerns. In this study, a nickel-based catalyst supported on titania (Ni-phen@TiO2-800) is used as a safe alternative to pyrophoric Raney-nickel. The catalyst is prepared in a straightforward fashion by deposition of nickel(II)/1,10-phenanthroline on titania, followed by pyrolysis. The catalytic material, which was characterized by SEM, TEM, XRD, and XPS, consists of nickel nanoparticles covered with N-doped carbon layers. By using design of experiments (DoE), this nanostructured catalyst is found to be proficient for the facile and selective hydrodehalogenation of a diverse range of substrates bearing C?I, C?Br, or C?Cl bonds (>30 examples). The practicality of this catalyst system is demonstrated by the dehalogenation of environmentally hazardous and polyhalogenated substrates atrazine, tetrabromobisphenol A, tetrachlorobenzene, and a polybrominated diphenyl ether (PBDE).
Triptycene ring metal palladium compound and application thereof
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Paragraph 0085-0092, (2021/02/24)
The invention discloses a triptycene cyclometalated palladium compound and an application thereof. The triptycene cyclometalated palladium compound has the following general formula, wherein three RAscan be the same or different and are respectively and independently expressed as R1-(Z1-A1-Z2)x-,wherein the three RBs can be the same or different and are respectively and independently expressed asR2-(Z3-A2-Z4)y-, the two RCs may be the same or different, each independently expressed as R3-(Z5-A3-Z6)z-. The triptycene cyclometalated palladium compound provided by the invention has a triptycenelarge-steric-hindrance group, and can stabilize a zero-valent palladium intermediate in a catalytic cycle, so that the catalytic efficiency is improved, the use amount of a catalyst can be reduced tobe less than ten thousandth, and the compound is simple in synthesis step, high in yield, relatively low in cost and suitable for various substrates, and the method has an important application valuefor researching the progress and application of the coupling reaction.
NaI/PPh3-Mediated Photochemical Reduction and Amination of Nitroarenes
Qu, Zhonghua,Chen, Xing,Zhong, Shuai,Deng, Guo-Jun,Huang, Huawen
supporting information, p. 5349 - 5353 (2021/07/21)
A mild transition-metal- and photosensitizer-free photoredox system based on the combination of NaI and PPh3 was found to enable highly selective reduction of nitroarenes. This protocol tolerates a broad range of reducible functional groups such as halogen (Cl, Br, and even I), aldehyde, ketone, carboxyl, and cyano. Moreover, the photoredox catalysis with NaI and stoichiometric PPh3 provides also an alternative entry to Cadogan-type reductive amination when o-nitrobiarenes were used.
Cyclic (Alkyl)(amino)carbene Ligand-Promoted Nitro Deoxygenative Hydroboration with Chromium Catalysis: Scope, Mechanism, and Applications
Zhao, Lixing,Hu, Chenyang,Cong, Xuefeng,Deng, Gongda,Liu, Liu Leo,Luo, Meiming,Zeng, Xiaoming
supporting information, p. 1618 - 1629 (2021/01/25)
Transition metal catalysis that utilizes N-heterocyclic carbenes as noninnocent ligands in promoting transformations has not been well studied. We report here a cyclic (alkyl)(amino)carbene (CAAC) ligand-promoted nitro deoxygenative hydroboration with cost-effective chromium catalysis. Using 1 mol % of CAAC-Cr precatalyst, the addition of HBpin to nitro scaffolds leads to deoxygenation, allowing for the retention of various reducible functionalities and the compatibility of sensitive groups toward hydroboration, thereby providing a mild, chemoselective, and facile strategy to form anilines, as well as heteroaryl and aliphatic amine derivatives, with broad scope and particularly high turnover numbers (up to 1.8 × 106). Mechanistic studies, based on theoretical calculations, indicate that the CAAC ligand plays an important role in promoting polarity reversal of hydride of HBpin; it serves as an H-shuttle to facilitate deoxygenative hydroboration. The preparation of several commercially available pharmaceuticals by means of this strategy highlights its potential application in medicinal chemistry.
Synthesis of Stannylated Aryl Imines and Amines via Aryne Insertion Reactions into Sn?N Bonds
Kran, Eva,Mück-Lichtenfeld, Christian,Daniliuc, Constantin G.,Studer, Armido
supporting information, p. 9281 - 9285 (2021/05/31)
The reaction of in situ generated arynes with stannylated imines to provide ortho-stannyl-aniline derivatives is reported. The readily prepared trimethylstannyl benzophenone imine is introduced as an efficient reagent to realize the aryne σ-insertion reaction. The imine functionality is an established N-protecting group and insertions proceed with good yields and good to excellent regioselectivities. The product anilines are valuable starting materials for follow-up chemistry thanks to the rich chemistry offered by the trimethylstannyl moiety.
