15980-22-0Relevant articles and documents
Cyclodextrin modified microgels as "nanoreactor" for the generation of Au nanoparticles with enhanced catalytic activity
Jia, He,Schmitz, Dominik,Ott, Andreas,Pich, Andrij,Lu, Yan
, p. 6187 - 6195 (2015)
We report a facile and green method for the fabrication of hybrid microgels by the immobilization of catalytically active Au nanoparticles in α-cyclodextrin (α-CD) modified poly(N-vinylcaprolactam) (PVCL) microgels without addition of reducing agent and surfactant. It has been shown that only in the case of α-CD modified microgels metal particles were immobilized inside the colloidal gels, which is due to a coordination of the cyclodextrin molecules to the surface of Au nanoparticles. The PVCL-α-CD-Au composite particles can work efficiently as catalyst for the reduction of aromatic nitro-compounds by using the reduction of 4-nitrophenol (Nip) and 2,6-dimethyl-4-nitrophenol (DMNip) as model reactions. Most importantly, due to the selective binding ability of α-CDs to certain reagents, the synthesized hybrid microgels show different catalytic activity for the target compounds during the catalytic reactions: a significant enhancement in the catalytic activity has been observed for the reduction of Nip, while no obvious effect has been found for the reduction of DMNip.
Stabilization of the Pentazolate Anion in a Zeolitic Architecture with Na20N60 and Na24N60 Nanocages
Zhang, Wenquan,Wang, Kangcai,Li, Juecheng,Lin, Zhien,Song, Siwei,Huang, Shiliang,Liu, Yu,Nie, Fude,Zhang, Qinghua
, p. 2592 - 2595 (2018)
The experimental detection and synthesis of pentazole (HN5) and its anion (cyclo-N5?) have been actively pursued for the past hundred years. The synthesis of an aesthetic three-dimensional metal–pentazolate framework (denoted as MPF-1) is presented. It consists of sodium ions and cyclo-N5? anions in which the isolated cyclo-N5? anions are preternaturally stabilized in this inorganic open framework featuring two types of nanocages (Na20N60 and Na24N60) through strong metal coordination bonds. The compound MPF-1 is indefinitely stable at room temperature and exhibits high thermal stability relative to the reported cyclo-N5? salts. This finding offers a new approach to create metal–pentazolate frameworks (MPFs) and enables the future exploration of interesting pentazole chemistry and also related functional materials.
Structural Analysis and Controllable Fabrication of Two Pentazolate-Based 3D Topological Networks
Cao, Yuteng,Xia, Honglei,Wang, Kangcai,Zhang, Qinghua,Zhang, Wenquan
, p. 8409 - 8413 (2021)
Two novel sodium-pentazolate frameworks (namely, MPF-3 and MPF-4) were achieved by adding simple additives. MPF-3 exhibits an aesthetic three-dimensional (3D) framework with the zeolitic MTN topology, featuring Na28N80 and Na20N60 nanocages. In MPF-4, two left-handed helical chains construct enclosed homochiral channels filled with dimethyl sulfone molecules, which constitute a zeolite-like UNJ topology. Importantly, the preparation of these two compounds provides an effective experimental means to explore the unique symmetrical structure and multiple coordination modes of pentazolium anion and demonstrates that it is possible to regulate the crystal structure through appropriate additives.
Catalytic Deoxygenation of Nitroarenes Mediated by High-Valent Molybdenum(VI)-NHC Complexes
Liu, Shenyu,Amaro-Estrada, Jorge Ivan,Baltrun, Marc,Douair, Iskander,Schoch, Roland,Maron, Laurent,Hohloch, Stephan
supporting information, p. 107 - 118 (2021/02/05)
The high-valent molybdenum(VI) N-heterocyclic carbene complexes, (NHC)MoO2 (1) and (NHC)MoO(NtBu) (2) (NHC = 1,3-bis(3,5-di-tert-butyl-2-phenolato)-benzimidazol-2-ylidene), are investigated toward their catalytic potential in the deoxygenation of nitroarenes. Using pinacol as the sacrificial and green reductant, both complexes are shown to be very active (pre)catalysts for this transformation allowing a reduction of the catalyst loading down to 0.25 mol %. Mechanistic investigations show μ-oxo bridged molybdenum(V) complexes [(NHC)MoO]2O (4) and [(NHC)Mo(NtBu)]2O (5) as well as zwitterionic pinacolate benzimidazolium complex 6, with a doubly protonated NHC ligand, to be potentially active species in the catalytic cycle. Both 4 and 5 can be prepared independently by the deoxygenation of 1 and 2 using triethyl phosphine (PEt3) or triphenyl phosphine (PPh3) and were shown to exhibit an unusual multireferenced ground state with a very small singlet-triplet gap at room temperature. Computational studies show that the spin state plays an unneglectable role in the catalytic process, efficiently lowering the reaction barrier of the deoxygenation step. Mechanistic details, putting special emphasis on the fate of the catalyst will be presented and potential routes how nitroarene reduction is facilitated are evaluated.
A pentazolate-based bowl-shaped molecular container
Cao, Yuteng,Huang, Shiliang,Zhang, Qinghua,Zhang, Wenquan
supporting information, p. 17542 - 17546 (2020/12/30)
A three-dimensional bowl-shaped molecular container based on pentazole was first synthesized. These containers are sealed and linked by the assembled molecular plane . Each container has an ovoid cavity occupied by one DMSO guest molecule. The self-assembly of this molecular container will provide opportunities for the use of pentazole in supramolecular chemistry. This journal is
Iodine(III)-Catalyzed Electrophilic Nitration of Phenols via Non-Br?nsted Acidic NO2+ Generation
Juárez-Ornelas, Kevin A.,Jiménez-Halla, J. Oscar C.,Kato, Terumasa,Solorio-Alvarado, César R.,Maruoka, Keiji
, p. 1315 - 1319 (2019/03/07)
The first catalytic procedure for the electrophilic nitration of phenols was developed using iodosylbenzene as an organocatalyst based on iodine(III) and aluminum nitrate as a nitro group source. This atom-economic protocol occurs under mild, non-Br?nsted acidic and open-flask reaction conditions with a broad functional-group tolerance including several heterocycles. Density functional theory (DFT) calculations at the (SMD:MeCN)Mo8-HX/(LANLo8+f,6-311+G) level indicated that the reaction proceeds through a cationic pathway that efficiently generates the NO2+ ion, which is the nitrating species under neutral conditions.
Synthesis of anionic chemodosimeters based on silylated pyridinium N-phenolate betaine dyes
Guerra, Jo?o P.T.A.,Lindner, Alexandra,Nicoleti, Celso R.,Marini, Vanderléia G.,Silva, Marcelo,Machado, Vanderlei G.
supporting information, p. 4733 - 4736 (2015/07/20)
Three novel silylated pyridinium N-phenolate betaine dyes were synthesized and characterized. These compounds were used in acetonitrile as anionic chemodosimeters for the colorimetric detection of F- and CN-. In addition, the system was made highly selective to CN- in relation to other anions in acetonitrile/water mixtures. The nucleophilic attack of the anion on the silicon center of the chemodosimeters, through a nucleophilic substitution at silicon (SN2@Si), immediately breaks the Si-O bond, with the formation of their corresponding colored pyridinium N-phenolate betaine dyes as the leaving groups. Thus, this process is effective for the detection of F- and CN-, which are strongly nucleophilic analytes in anhydrous acetonitrile. Fluoride is strongly hydrated when water is present in the medium, this being the reason for the pronounced reduction in the selectivity of this anion in comparison with CN-.
The Diels-Alder reactions of para-benzoquinone nitrogen-derivatives: An experimental and theoretical study
Uliana, Marciana P.,Servilha, Bruno M.,Alexopoulos, Olga,De Oliveira, Kleber T.,Tormena, Cláudio F.,Ferreira, Marco A.B.,Brocksom, Timothy J.
, p. 6963 - 6973 (2015/11/09)
An experimental and theoretical study of the comparative reactivity and selectivity of the Diels-Alder reactions of para-benzoquinones and three nitrogen derivatives have been performed. The mono-oximes derivatives do not react under the tested reaction conditions, whereas the tosylated mono-oximes react slowly. However, the mono N-tosyl imines show excellent reactivity, and superior to the parent parabenzoquinones. DFT calculations support these experimental results.
Super-hydrophobic yolk-shell nanostructure with enhanced catalytic performance in the reduction of hydrophobic nitroaromatic compounds
Shi, Song,Wang, Min,Chen, Chen,Gao, Jin,Ma, Hong,Ma, Jiping,Xu, Jie
supporting information, p. 9591 - 9593 (2013/10/08)
A self-templating method to fabricate a super-hydrophobic yolk-shell nano-reactor was reported. Metal nanoparticles were encapsulated in the porous super-hydrophobic shell. This super-hydrophobic catalyst showed excellent performance in the reduction of nitroaromatic compounds in aqueous phase and a positive correlation was found between the reaction rate and the hydrophobicity of the substrate. The Royal Society of Chemistry 2013.
DPPH radical scavenging activity of paracetamol analogues
Alisi, Maria Alessandra,Brufani, Mario,Cazzolla, Nicola,Ceccacci, Francesca,Dragone, Patrizia,Felici, Marco,Furlotti, Guido,Garofalo, Barbara,La Bella, Angela,Lanzalunga, Osvaldo,Leonelli, Francesca,Marini Bettolo, Rinaldo,Maugeri, Caterina,Migneco, Luisa Maria,Russo, Vincenzo
, p. 10180 - 10187 (2013/01/15)
Biochemical studies suggest a direct relationship between the radical scavenging activity of paracetamol (I) and its antipyretic and analgesic action. To evaluate the effect of chemical modifications on the radical scavenging activity of compounds of type I, analogues 1-14 were prepared and submitted to a stable free radical (DPPH; 1,1-diphenyl-2-picryl-hydrazyl) assay. All paracetamol derivatives showed a significant higher efficiency than the parent compound. This study showed that radical scavenging activity can be increased by decreasing the phenolic ortho substituents steric hindrance or by introducing substituents on the acyl moiety like an indazole ring or the ionic N-methyl morpholinium group. A significant activating effect was also observed by replacing the 1,4-acylamidophenol with a 1,4-acylamidonaphthol system.