- Quantitative monitoring of hypoxia-induced intracellular acidification in lung tumor cells and tissues using activatable surface-enhanced raman scattering nanoprobes
-
Hypoxia is considered to contribute to pathophysiology in various cells and tissues, and a clear understanding about the relationship between hypoxia and intracellular acidification will help to elucidate the complex mechanism of glycolysis under hypoxia. However, current studies are mainly focused on overexpression of intracellular reductases accelerated by hypoxia, and the investigations focusing on the relationship between hypoxic degree and intracellular acidification remain to be explored. For this vacuity, we report herein a new activatable nanoprobe for sensing pH change under different degrees of hypoxia by surface-enhanced Raman spectroscopy (SERS). The monitoring was based on the SERS spectra changes of 4- nitrothiophenol (4-NTP)-functionalized gold nanorods (AuNR@4- NTP) resulting from the nitroreductase (NTR)-triggered reduction under hypoxic conditions while the as-generated 4-aminothiophenol (4-ATP) is a pH-sensitive molecule. This unique property can ensure the SERS monitoring of intracellular acidification in living cells and tissues under hypoxic conditions. Dynamic pH analysis indicated that the pH decreased from 7.1 to 6.5 as a function of different degrees of hypoxia (from 15 to 1%) due to excessive glycolytic activity triggered by hypoxia. Given the known advantages of SERS sensing, these findings hold promise in studies of pathophysiological pathways involving hypoxia.
- Ma, Dandan,Zheng, Jing,Tang, Pinting,Xu, Weijian,Qing, Zhihe,Yang, Sheng,Li, Jishan,Yang, Ronghua
-
-
Read Online
- Gold nanoparticle-loaded filter paper: A recyclable dip-catalyst for real-time reaction monitoring by surface enhanced Raman scattering
-
We report a robust and recyclable 'dip-catalyst' based on a gold nanoparticle (Au NP)-loaded filter paper composite, prepared by a simple dip-coating process using concentrated Au NP suspensions in toluene. While acting as catalysts, the composites display excellent surface enhanced Raman scattering (SERS) efficiency, allowing the real-time monitoring of chemical reactions. This journal is
- Zheng, Guangchao,Polavarapu, Lakshminarayana,Liz-Marzán, Luis M.,Pastoriza-Santos, Isabel,Pérez-Juste, Jorge
-
-
Read Online
- In Situ Raman Monitoring and Manipulating of Interfacial Hydrogen Spillover by Precise Fabrication of Au/TiO2/Pt Sandwich Structures
-
The spillover of hydrogen species and its role in tuning the activity and selectivity in catalytic hydrogenation have been investigated in situ using surface-enhanced Raman spectroscopy (SERS) with 10 nm spatial resolution through the precise fabrication
- Cheng, Jun,Guan, Zhiqiang,Li, Jian-Feng,Liu, Jing-Li,Qin, Si-Na,Ruan, Xiang-Yu,Tian, Zhong-Qun,Wei, Di-Ye,Wei, Jie,Xu, Hongxing,Yan, Hao,Zhang, Hua
-
-
Read Online
- pomegranate-Like Plasmonic Nanoreactors with Accessible High-Density Hotspots for in Situ SERS Monitoring of Catalytic Reactions
-
Noble metal nanoparticles (NPs) have enabled surface-enhanced Raman scattering (SERS) for in situ monitoring of NPs-catalyzed reactions. However, it still remains a great challenge to ensure that analytes without plasmonic metal surface-affinity groups (such as thiol and amino groups) can be located into hotspots and detected by SERS. Here, we report a novel sacrificial template method for the fabrication of pomegranate-like plasmonic nanoreactors (PPNs), in which high-density embedded AuNPs simultaneously generated SERS enhancement and catalytic performance. Once the analytes entering PPNs are catalyzed and meanwhile located into the hotspots, in situ SERS monitoring of catalytic reactions can be achieved. The intense hotspots of localized electric fields of PPNs were evaluated by finite-difference time-domain simulation. By using PPNs as a substrate, SERS signals of molecules without Au surface-affinity groups were obtained, such as p-naphthoquinone and 4-nitrophenol. The PPNs showed high catalytic activities in the reduction of 4-nitrothiophenol to 4-aminothiophenol and 4-nitrophenol to 4-aminophenol, respectively. Besides, the SERS spectra of both 4-nitrophenol and 4-aminophenol during the reduction reaction of 4-nitrophenol with NaBH4 were first obtained, demonstrating their utilization in the detection of catalytic reactions.
- Chen, Miao,Chen, Xiaoqing,Hao, Naiying,Li, Ruili,Liu, Qi,Peng, Mei,Wang, Lumin,Xiang, Juan,Yang, Hua,Zhu, Yuqiu
-
-
Read Online
- Site-specific growth of Au-Pd alloy horns on Au nanorods: A platform for highly sensitive monitoring of catalytic reactions by surface enhancement raman spectroscopy
-
Surface-enhanced Raman scattering (SERS) is a highly sensitive probe for molecular detection. The aim of this study was to develop an efficient platform for investigating the kinetics of catalytic reactions with SERS. To achieve this, we synthesized a novel Au-Pd bimetallic nanostructure (HIF-AuNR@AuPd) through site-specific epitaxial growth of Au-Pd alloy horns as catalytic sites at the ends of Au nanorods. Using high-resolution electron microscopy and tomography, we successfully reconstructed the complex three-dimensional morphology of HIF-AuNR@AuPd and identified that the horns are bound with high-index {11l} (0.25 a strong SERS effect at the rod ends, making HIF-AuNR@AuPd an excellent bifunctional platform for in situ monitoring of surface catalytic reactions. Using the hydrogenation of 4-nitrothiophenol as a model reaction, we demonstrated that its first-order reaction kinetics could be accurately determined from this platform. Moreover, we clearly identified the superior catalytic activity of the rod ends relative to that of the rod bodies, owing to the different SERS activities at the two positions. In comparison with other reported Au-Pd bimetallic nanostructures, HIF-AuNR@AuPd offered both higher catalytic activity and greater detection sensitivity.
- Huang, Jianfeng,Zhu, Yihan,Lin, Ming,Wang, Qingxiao,Zhao, Lan,Yang, Yang,Yao, Ke Xin,Han, Yu
-
-
Read Online
- Plasmon-free SERS self-monitoring of catalysis reaction on Au nanoclusters/TiO2 photonic microarray
-
Here, using the (Au/TiO2)-catalyzed reduction of 4-nitrothiophenol as a probe reaction, a catalysis/SERS bifunctional composite fabricated by uniformly dispersing catalysis-active Au nanoclusters (~2 nm) on a SERS-active TiO2 photonic microarray was successfully applied to the non-plasmonic SERS self-monitoring of a catalytic reaction for the first time, which is superiorly sensitive and interference-free.
- Qi, Dianyu,Yan, Xuefeng,Wang, Lingzhi,Zhang, Jinlong
-
-
Read Online
- Fabrication of a Flowerlike Ag Microsphere Film with Applications in Catalysis and as a SERS Substrate
-
Three-dimensional flowerlike Ag microstructures were assembled in situ on a substrate to fabricate Ag microflower (Ag MF) films. The morphology and size of the Ag MFs can be easily controlled by varying the reaction time. The mechanism of growth of Ag MFs was investigated by SEM. The shape evolution revealed that the Ag MFs are assembled from thin nanosheets composed of Ag nanoparticles (NPs), and the elemental composition of the NPs was evidenced by energy-dispersive X-ray spectroscopic analysis. The potential of the film as a catalyst in the reduction of nitrophenols was investigated. The reusability of the catalyst was estimated by recycling catalysis of 4-nitrophenol. Moreover, the Ag MF film could be used as a versatile substrate for surface-enhanced Raman scattering (SERS) for detection of Rhodamine 6G with a detection limit as low as 1 × 10–7 m. The results demonstrated that the Ag MF film exhibits excellent SERS enhancement ability and catalytic activity.
- Dai, Qijun,Li, Lu,Wang, Chungang,Lv, Changli,Su, Zhongmin,Chai, Fang
-
-
Read Online
- Single Ag Nanowire Electrodes and Single Pt@Ag Nanowire Electrodes: Fabrication, Electrocatalysis, and Surface-Enhanced Raman Scattering Applications
-
Silver nanowires (AgNWs) have received much attention due to their excellent optical, electrical, and conductive properties. In this work, we provided a new perspective for investigating the property of AgNWs from a single nanowire level. Single Ag nanowire electrodes and single Pt@Ag nanowire electrodes were fabricated by a laser-assisted pulling technique and galvanic replacement reaction (GRR). The radius, length, and metal ratio of the nanowires are tunable as needed. The prepared nanowire exhibited excellent electrocatalytic activity toward the methanol electro-oxidation and high sensitivity for monitoring the reduction of 4-nitrothiophenol by recording SERS spectra. This work will help us deeply understand the catalytic performance at the single nanowire level and open a new perspective for nanomaterials research.
- Wang, Dongmei,Hua, Hongmei,Liu, Yong,Tang, Haoran,Li, Yongxin
-
-
Read Online
- Insight into the mechanism of gold-catalyzed reduction of nitroarenes based on the substituent effect and: In situ IR
-
A study is presented here on the mechanistic pathway of catalytic reduction of nitroarenes with diverse substituent groups in the presence of ultra-small gold nanoparticles and NaBH4. The kinetic data based on the substituent effect and the Hammett plot, together with analyses of intermediates, revealed that this reaction followed a direct route and that all of the reaction steps were rapid without accumulation of intermediates. In particular, in situ IR was found to be an effective method for the real-time monitoring of this model reduction in our catalytic system and confirmed the presence of a hydroxylamine intermediate. These results will provide a new insight into the mechanism of gold-catalyzed reduction of nitroarenes and offer a reference for future mechanism tests of heterogeneous nanocatalysis.
- Wang, Cui,Zou, Wei,Wang, Jiasheng,Ge, Yuzhen,Lu, Rongwen,Zhang, Shufen
-
-
Read Online
- Tip-enhanced Raman imaging of photocatalytic reactions on thermally-reshaped gold and gold-palladium microplates
-
Tip-enhanced Raman spectroscopy (TERS) is used to investigate plasmonic and photocatalytic properties of walled gold-palladium microplates (WAu@PdMPs), an alloy bimetallic nanostructures with unique chemical selectivity, and high sensitivity. We found tha
- Li, Zhandong,El-Khoury, Patrick Z.,Kurouski, Dmitry
-
-
Read Online
- Synthesis of highly-branched Au@AgPd core/shell nanoflowers for in situ SERS monitoring of catalytic reactions
-
Alloy and small size nanostructures are favorable to catalytical performance, but not to surface-enhanced Raman spectroscopy (SERS) applications. Integrating SERS and catalytic activity into the nanocrystals with both alloy and small size structures is of great interest in fabrication of SERS platform to in situ monitor catalytical reaction. Herein, we report a facile method to synthesize Au@AgPd trimetallic nanoflowers (Au@AgPd NFs) with both SERS and catalytic activities, through simultaneous selective growth of Ag and Pd on Au core to form highly-branched alloy shell. These nanocrystals have the properties of small sizes, defects abundance, and highly-dispersed alloy shell which offer superior catalytic activity, while the merits of monodisperse, excellent stability, and highly-branched shell and core/alloy-shell structure promise the enhanced SERS activity. We further studied their growth mechanisms, and found that the ratio of Ag to Pd, sizes of Au core, and surfactant cetyltrimethylammonium bromide together determine this special structure. Using this as-synthesized nanocrystals, a monolayer bifunctional platform with both SERS and catalytical activity was fabricated through self-assembly at air/water interface, and applied to in situ SERS monitoring the reaction process of Pd-catalyzed hydrogenation of 4-nitrothiophenol to 4-aminothiophenol.
- Lai, Yujian,Dong, Lijie,Liu, Rui,Lu, Shaoyu,He, Zuoliang,Shan, Wanyu,Geng, Fanglan,Cai, Yaqi,Liu, Jingfu
-
-
Read Online
- Promotion of SERS and catalytic activities with bimetallic and ternary concave nanolayers
-
A seed growth process accompanied by a galvanic replacement reaction (etching and alloying) using CTAB/HAuCl4/AgNO3/ascorbic acid was developed to fabricate silver nanocubes with concave AuAg nanolayers. The solid nanostructure consisted of a concave face of the inner Ag solid counterpart with a hole surrounded by an AuAg nanowall. We found that the CTA+ ions played a vital role in the adsorption of Au(i)/CTA+ micelles selectively at the {100} facets to trigger galvanic replacement etching. Meanwhile, the reaction involving AgNO3 helped to switch the co-reduction of metal atoms from the [110] sites to the [100] vector and favored AuAg co-reduction of atoms along the {100} vector for concave AuAg nanolayer formation. Such AuAg atoms at the concave layer induced strong charge transfer-based surface-enhanced Raman scattering (SERS) when thiol molecules were bound to the active atoms and enabled the detection of the toxin malachite green at the fM level via physisorption. These highly active atoms at the concave facets aided superior electron-transfer catalysis. After etching with H2O2 to produce pure-Ag-removed and concave AuAg nanowalls, the efficiencies of the SERS and catalytic performances were degraded due to the decrease in the active atom density. This reaction strategy of simultaneous etching and co-reduction could be further extended to the trimetallic AuAg:Pd concave nanocomposite synthesis to improve the hydrogenation reaction thus obtaining a very high kinetic constant.
- Huang, Wei-Shan,Sun, I-Wen,Huang, Chih-Chia
-
-
Read Online
- Fabrication of monodispersed Au@Ag bimetallic nanorod-loaded nanofibrous membrane with fast thermo-responsiveness and its use as a smart free-standing SERS substrate
-
A novel type of metal nanoparticle-loaded smart nanofibrous membrane with fast thermo-responsiveness was fabricated by electrospinning an aqueous solution containing poly(N-isopropylacrylamide-co-N-hydroxymethylacrylamide) and monodispersed Au@Ag bimetallic nanorods with a core-shell structure, followed by heat treatment. The results obtained by electron microscopy show that the anisotropic nanoparticles are oriented along the axes of its constituent nanofibers. The membrane produced has high stability in aqueous media and remarkable thermo-responsiveness. It takes less than 10 seconds to reach its deswelling or swelling equilibrium state with the temperature alternating between 25 °C and 50 °C. The smart nanofibrous membrane with macroscopic mechanical strength can be used as a free-standing surface-enhanced Raman scattering (SERS) substrate with high Raman signal reproducibility for quantitative analysis, and its SERS efficiency can be readily elevated by raising the detection temperature across its phase transition temperature due to its fast thermo-response rate. Particularly, since the composite nanofibrous membrane possesses catalytic properties toward the reduction of 4-nitrothiophenol to 4-aminothiophenol by NaBH4, it has the ability to act as an in situ SERS monitor for the reaction, and it was deduced from the detected intermediate that the reaction proceeds via a condensation reaction route.
- Chen, Siyuan,Wang, Liying,Dong, Xu,Liu, Xiaoyun,Zhou, Jianfeng,Yang, Jianmao,Zha, Liusheng
-
-
Read Online
- Probing Single-Atom Catalysts and Catalytic Reaction Processes by Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy
-
Developing advanced characterization techniques for single-atom catalysts (SACs) is of great significance to identify their structural and catalytic properties. Raman spectroscopy can provide molecular structure information, and thus, the technique is a promising tool for catalysis. However, its application in SACs remains a great challenge because of its low sensitivity. We develop a highly sensitive strategy that achieves the characterization of the structure of SACs and in situ monitoring of the catalytic reaction processes on them by shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) for the first time. Using the strategy, Pd SACs on different supports were identified by Raman spectroscopy and the nucleation process of Pd species from single atoms to nanoparticles was revealed. Moreover, the catalytic reaction processes of the hydrogenation of nitro compounds on Pd SACs were monitored in situ, and molecular insights were obtained to uncover the unique catalytic properties of SACs. This work provides a new spectroscopic tool for the in situ study of SACs, especially at solid–liquid interfaces.
- Wei, Jie,Qin, Si-Na,Yang, Ji,Ya, Han-Long,Huang, Wei-Hsiang,Zhang, Hua,Hwang, Bing Joe,Tian, Zhong-Qun,Li, Jian-Feng
-
-
Read Online
- In-situ SHINERS Study of the Size and Composition Effect of Pt-based Nanocatalysts in Catalytic Hydrogenation
-
Understanding the structure-activity relationship of catalytic reactions at a molecular level still remains a great challenge. Herein, shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) is employed to in-situ study the catalytic hydrogenation of para-nitrothiophenol (pNTP) on Pt-based nanocatalysts with different size and composition. The nanocatalysts are assembled on pinhole-free shell-isolate nanoparticles (SHINs), which work as Raman amplifiers to enhance the Raman signals of species on the catalysts, allowing the in-situ monitoring of catalytic reactions carried out on the catalysts. Using this strategy, we find that the catalytic activity of the Pt nanocatalysts shows a volcanic trend with the Pt size, and that PtM (M=Ni or Cu) bimetallic nanocatalysts display much higher performance compared with Pt due to better activation of the nitro group. This work demonstrates that SHINERS is a promising technique for in-situ study of nanocatalysis thus can deepen the understanding of the behaviors of different catalysts.
- Wang, Chen,Chen, Xing,Chen, Tian-Ming,Wei, Jie,Qin,Zheng, Ju-Fang,Zhang, Hua,Tian, Zhong-Qun,Li, Jian-Feng
-
-
Read Online
- Palladium-rich plasmonic nanorattles with enhanced LSPRsviasuccessive galvanic replacement mediated by co-reduction
-
Catalytic transformations under light irradiation have been extensively demonstrated by the excitation of the localized surface plasmon resonances (LSPRs) in noble metal-based nanoparticles. To fully harness the potential of noble metal-based nanocatalysts, it is fundamentally imperative to explore hybrid nano-systems with the most desirable enhanced LSPRs and intrinsic catalytic activities. Pd-containing hollow multimetallic nanostructures transformed from the sacrificial template of Agviagalvanic replacement reaction (GRR) offer such ideal platforms to gain quantitative insights into nanoparticle-catalyzed reactions. In this work, we successfully fabricated Pd-rich plasmonic nanorattles by means of co-reduction mediated GRR using CTAC-stabilized Au@Ag nanocuboids as templates and H2PdCl4as a Pd precursor in the presence of ascorbic acid (AA) acting as a mild reducing agent. Successive titration of Au@Ag nanocuboids with the Pd precursor in the presence of AA modulates the rate of the galvanic replacement reaction as well as effective diffusion of Pd into the Ag matrix, resulting in increased dimensions and enlarged cavity sizes. Reduction of oxidized Ag+back to Ag0by AA, along with the deposition of Pd to form homogeneously mixed bimetallic layers not only prevents LSPRs peak from damping with increasing Pd content but also ensures the enhanced catalytic activities. Through precise control of added H2PdCl4titrant, an unconventional steep increase in extinction intensity accompanied by tunable plasmon resonances shifted towards the NIR spectral region was experimentally observed due to the increasing physical cross-sections and plasmon hybridization in hollow nanorattles. Four colloids of Pd-rich nanorattles obtained by addition of different amounts of the H2PdCl4titrant were used as catalysts for reduction of 4-nitrothiophenol in the presence of NaBH4monitored by SERS.
- Evangelista, Andrew J.,Ivanchenko, Mariia,Jing, Hao
-
p. 40112 - 40119
(2021/12/31)
-
- A Common, Facile and Eco-Friendly Method for the Reduction of Nitroarenes, Selective Reduction of Poly-Nitroarenes and Deoxygenation of N-Oxide Containing Heteroarenes Using Elemental Sulfur
-
A transition metal-free, environment-friendly and practical protocol was developed either for the reduction of nitroarenes or for the deoxygenation of N-oxide containing heteroarenes. The reaction proceeded with the use of a non-toxic and cheap feedstock as elemental sulfur in aqueous methanol under relatively mild conditions. Green chemistry credentials were widely favorable compared to traditional and industrial protocols with good E-factors and a low production of waste. The strategy allowed the efficient reduction of a large variety of substituted-nitroarenes including various o-nitroanilines as well as selective reduction of various poly-nitroarenes in excellent yields with a broad substrate scope. The protocol was successfully extended to the deoxygenation of some N-oxide containing heteroarenes, like benzofuroxans, phenazine N,N'-dioxides, pyridine N-oxides, 2H-indazole N1-oxides, quinoxaline N1,N4-dioxides and benzo[d]imidazole N1,N3-dioxides. A gram-scale example for the synthesis of luminol, in green conditions, was reported. A solid mechanism of reaction was proposed from experimental evidences.
- Cerecetto, Hugo,Romero, Angel H.
-
supporting information
(2020/03/23)
-
- Copper(ii)-catalyzed c-n coupling of aryl halides and n-nucleophiles promoted by quebrachitol or diethylene glycol
-
Herein, we report the natural ligand quebrachitol (QCT) as a promoter for a Cu(II) catalyst, which is highly effective for N-Arylation of various amines and related aryl halides. A series of diarylamine derivatives were obtained in high yields by using diethylene glycol (DEG) as both ligand and solvent. The C-N coupling reactions proceed under mild conditions and exhibit good functional group tolerance.
- Chen, Guoliang,Chen, Yuanguang,Du, Fangyu,Fu, Yang,Wu, Ying,Zhou, Qifan
-
supporting information
p. 2161 - 2168
(2019/11/25)
-
- Copper-Catalyzed Direct Synthesis of Aryl Thiols from Aryl Iodides Using Sodium Sulfide Aided by Catalytic 1,2-Ethanedithiol
-
A copper-catalyzed direct and effective synthesis of aryl thiols from aryl iodides using readily available Na 2 S·9H 2 O and 1,2-ethanedithiol was described. A variety of aryl thiols were readily obtained in yields of 76-99%. In this protocol, Na 2 S·9H 2 O was used as ultimate sulfur source, and 1,2-ethanedithiol functioned as an indispensable catalytic reagent.
- Xue, Hongyu,Jing, Bing,Liu, Shasha,Chae, Junghyun,Liu, Yajun
-
p. 2272 - 2276
(2017/10/06)
-
- SINGLE-STEP SYNTHESIS METHOD OF ARYL THIOL AND APPLICATION THEREOF
-
The present invention relates to a single-step synthesis method of aryl thiol, and more specifically, to a method of synthesizing aryl thiol in a single-step by making aryl halide react with alkane dithiol in the presence of a transition metal catalyst. According to the present invention, a single-step synthesis method using the transition metal catalyst, the synthesis method which is capable of synthesizing aryl thiol from aryl halide at a high yield, can be provided. Various aryl halides may be applied to the synthesis method. Further, the synthesis method has advantages that an easily usable reagent may be used, operations are simple, and reactions can be performed under mild conditions. In addition, the synthesized aryl thiol may be used in the synthesis of advanced molecules such as diaryl sulfides and benzothiophenes.COPYRIGHT KIPO 2017
- -
-
Paragraph 0032; 0033; 0063; 0067; 0068; 0070
(2017/09/02)
-
- Copper(II)-Catalyzed Single-Step Synthesis of Aryl Thiols from Aryl Halides and 1,2-Ethanedithiol
-
A highly efficient transition metal-catalyzed single-step synthesis of aryl thiols from aryl halides has been developed employing copper(II) catalyst and 1,2-ethanedithiol. The key features are use of readily available reagents, a simple operation, and relatively mild reaction conditions. This new protocol shows a broad substrate scope with excellent functional group compatibility. A variety of aryl thiols are directly prepared from aryl halides in high yields. Furthermore, the aryl thiols are used in situ for the synthesis of more advanced molecules such as diaryl sulfides and benzothiophenes.
- Liu, Yajun,Kim, Jihye,Seo, Heesun,Park, Sunghyouk,Chae, Junghyun
-
supporting information
p. 2205 - 2212
(2015/07/27)
-
- Catalytic hydrogenation of sulfur-containing nitrobenzene over Pd/C catalysts: In situ sulfidation of Pd/C for the preparation of PdxSy catalysts
-
The preparation of supported palladium sulfides catalysts has attracted much attention due to their good sulfur-resistant properties in the hydrogenation of sulfur-containing compounds. In this work, we unambiguously demonstrated that Pd/C catalyst could be in situ sulfided by organic sulfur-containing reactant molecules and the sulfidation was highly dependent on temperature. The in situ sulfidation of Pd/C catalyst was composed of a reaction of Pd with the sulfur derived from the cleavage of C-S bond of sulfur-containing reactant molecules, followed by a transformation to PdxSy at high temperatures (around 120 °C). The sulfided Pd/C catalyst could be used for at least 18 recycles without a significant loss in its activity during the hydrogenation of sulfur-containing nitrobenzene at 180 °C with 3 MPa H2, which could be attributed to the stable presence of Pd4S and Pd16S7.
- Zhang, Qunfeng,Xu, Wei,Li, Xiaonian,Jiang, Dahao,Xiang, Yizhi,Wang, Jianguo,Cen, Jie,Romano, Stephen,Ni, Jun
-
-
- Indium(III)-Catalyzed Reduction of Nitrobenzenes to Anilines: Scope and Limitations
-
We have demonstrated that a combination of indium(III) iodide and 1,1,3,3-tetramethyldisiloxane (TMDS) effectively catalyzes the chemoselective reduction of nitrobenzenes with a variety of functional groups (halogens, alkyl, alkoxy, hydroxy, ester, amino, amide, cyanide, thiol, and an alkene moiety), producing the corresponding aniline derivatives.
- Sakai, Norio,Asama, Shun,Konakahara, Takeo,Ogiwara, Yohei
-
p. 3179 - 3185
(2015/10/19)
-
- CuI-nanoparticles-catalyzed selective synthesis of phenols, anilines, and thiophenols from aryl halides in aqueous solution
-
CuI-nanoparticles-catalyzed selective synthesis of phenols, anilines, and thiophenols from aryl halides was developed in the absence of both ligands and organic solvents. Anilines were formed selectively with ammonia competing with hydroxylation and thiophenols were generated selectively with sulfur powder after subsequent reduction competing with hydroxylation and amination.
- Xu, Hua-Jian,Liang, Yu-Feng,Cai, Zhen-Ya,Qi, Hong-Xia,Yang, Chun-Yan,Feng, Yi-Si
-
p. 2296 - 2300
(2011/06/17)
-
- Copper-catalyzed coupling of thiourea with aryl iodides: The direct synthesis of aryl thiols
-
A general, economical and efficient protocol for the direct copper-catalyzed coupling of thiourea with aryl iodides is developed and it will be potentially applied in large-scale industry as a preferred process.
- Qiao, Shu,Xie, Kun,Qi, Junsheng
-
scheme or table
p. 1441 - 1443
(2011/01/04)
-
- Dichroic dye and microencapsulated liquid crystal composition thereof
-
Dichroic dyes, compositions thereof, and liquid crystal compositions, microencapsulated liquid crystal compositions and liquid-crystal display elements employing the same. The dichroic dyes have high photostability in addition to excellent solubility. Furthermore, the liquid crystal composition employing the above dichroic dyes can have an orientational order parameter more than 0.7.
- -
-
-
- The unexpected desulfurization of 4-aminothiophenols
-
Thermolysis of 4-aminophenyl benzyl sulfide at 523 K in the hydrogen donor solvent (HDS), 9,10-dihydroanthracene (AnH2), gave 4-aminothiophenol and toluene as the predominant products of the homolytic S-C bond cleavage. Under these conditions, a portion of the 4-aminothiophenol was desulfurized to aniline with first-order kinetics and with a rate constant estimated by kinetic modeling to be 7.0 × 10-6 s-1. Starting with 4-NH2C6H4SH at 523 K, it was found that sulfur loss was more efficient in the non-HDSs, anthracene and hexadecane, than in AnH2. Under similar (competitive) reaction conditions, YC 6H4SHs with Y = H, 4-CN, and 3-CF3 were completely inert; with Y = 4-CH3O, there was some very minor desulfurization, whereas with Y = 4-N(CH3)2 and 4-N(CH3)(H), the sulfur extrusions were as fast as that for Y = 4-NH2. We tentatively suggest that this apparently novel reaction is a chain process initiated by the bimolecular formation of diatomic sulfur, S2, followed by a reversible addition of ground state, triplet 3S2 to the thiol sulfur atom, 4-NH2C 6H4S↑(SS↑)H, and insertion into the S-H bond, 4-NH2C6H4SSSH. In a cascade of reactions, aniline and S8 are formed with the chains being terminated by reaction of 4-NH2C6H4S↑(SS↑)H with 4-NH2C6H4SH. Such a reaction mechanism is consistent with the first-order kinetics. That this reaction is primarily observed with 4-YC6H4SH having Y = N(CH3) 2, N(CH3)(H), and NH2 is attributed to the fact that these compounds can exist as zwitterions.
- Mulder, Peter,Mozenson, Olga,Lin, Shuqiong,Ingold
-
p. 2379 - 2386
(2007/10/03)
-
- PROCESS FOR PREPARATION OF THIOPHENOL DERIVATIVES
-
Provided is a process for preparing thiophenol derivatives, using aromatic disulfide as a starting material, and inexpensive sodium bisulfite (NaHSO3) as a reducing agent. The process can be carried out on an industrial scale at low production costs, secures advantageous reaction conditions by using a small amount of water- soluble alcohol solvent. Further, the process can maximize the purity of the products by inhibiting reverse oxidation of the final product by the action of sulfur dioxide (SO2) produced during the preparation process, after solvent extraction of the starting materials present as impurities of the thiophenol derivatives.
- -
-
Page/Page column 8-9
(2008/06/13)
-
- A rapid and efficient cleavage of organic disulfides to mercaptans using ZrCl4/NaBH4
-
A practical and cheaper reagent system ZrCl/NaBH4 is used for the reductive cleavage of organic disulfides to mercaptans under mild conditions, in excellent yields.
- Purushothama Chayr,Rajaram,Iyengar
-
p. 3905 - 3911
(2007/10/03)
-
- Compounds having antidiabetic, hypolipidemic, antihypertensive properties, process for their preparation and pharmaceutical compositions containing them
-
Thiazolidinediones of formula (I) their tautomeric forms, their derivatives, their stereoisomers, their polymorphs, their pharmaceutically acceptable salts, their pharmaceutically acceptable solvates and pharmaceutical compositions containing them having antidiabetic, hypolipidemic, and antihypertensive properties have been prepared. STR1
- -
-
-
- Thiazolidinedione derivatives having antidiabetic, hypolipidaemic antihypertensive properties, process for their preparation and pharmaceutical compositions containing them
-
A compound of the general formula (I), where A represents, substituted or unsunstituted unsaturated aliphatic, alicyclic, aromatic, heterocyclic groups, B represents a substituted or unsubstituted divalent alkylene or alkenyl group having 1 to 10 carbon atoms, wherein substituents may be present in one or more of the divalent alkylene or alkenyl groups, D represents a substituted or insubstituted divalent alkenyl, alkynyl, aralkyl alkoxycarbonyl or aryloxycarbonyl groups, X represents CH2, C=O, CH-OH, sulphur, oxygen, N-Y, where Y represents hydrogen, substituted or unsubstituted alkyl, aryl, aralkyl or acyl, Ar represents a divalent aromatic, single or fused ring system, with or without substituents, the ring may contain one or more hetero atoms selected from nitrogen, sulphur, or oxygen; R1and R2each represents hydrogen or together represent a bond either or both may be substituents or both together form a part of a ring. Methods for preparing the compound and pharmaceutical compositions containing a compound of formula (I).
- -
-
-
- Fiber reactive anthraquinone dyes
-
Fiber reactive dyes of the anthraquinone type which provide brilliant violet colors without metal complexing. These dyes may be represented by the formula: STR1 wherein W is selected from NR2 and oxygen; R is independently selected from hydrogen, C1 -C6 alkyl; C1 -C6 alkoxy, sulfo and carboxy; R1 is selected from hydrogen, C1 -C6 alkyl and phenyl; R2 is selected from hydrogen and C1 -C6 alkyl; R3 is selected from hydrogen, and C1 -C4 alkyl; n is an integer of 1 or 2; and Y is CH=CH2, or CH2 CH2 Z wherein Z is a group capable of being split off by the action of an alkali reagent.
- -
-
-
- Kinetic and Equilibrium Studies of ?-Adduct Formation and Nucleophilic Substitution in the Reactions of Hydroxide Ions with 2,4,6-Trinitrophenyl Sulfides and Ethers
-
Kinetic and equlibrium data are reported for reaction of hydroxide ions in 20/80 DMSO/water (v/v) with a series of 4'-substituted phenyl 2,4,6-trinitrophenyl sulfides, 1, and with ethyl thiopicrate, 2, ethyl picrate, 3, phenyl picrate, 4, and 1,3,5-trinitrobenzene, 5.In each case a rapid reaction is observed involving reversible hydroxide addition at an unsubstituted ring-position.In the case of 1-4 this is followed by slower, irreversible attack at the 1-position leading to the formation of picric acid.The Hammett ρ value for equilibrium addition of hydroxide to the 3-position of 1 is 0.98, and the ρ value for rate constants for attack at the 1-position is 0.62.The results are discussed in terms of the electronic and steric effects of the 1-substituents.Comparison of 1-5 indicates that changing from an OR to SR group introduces additional steric crowding.However for the reactions studied changing from R = Et to R = Ph has little steric consequence.
- Chamberlin, Rachel,Crampton, Michael R.,Knight, Roland L.
-
p. 2986 - 2998
(2007/10/02)
-
- Pantothenic acid derivatives
-
Compounds represented by general formula (I) below STR1 wherein R1 and R2, which are the same or different, each represent a hydrogen atom or a protective group for a hydroxyl group; R3 represents a saturated or unsaturated, linear, branched or cyclic, monovalent C5 ?C25 -aliphatic hydrocarbon group which may be substituted with an aromatic group, or a group of formula STR2 where R4 represents a saturated or unsaturated, linear, branched or cyclic, monovalent C5 ?C25 -aliphatic hydrocarbon group which may be substituted with an aromatic group, and R5 represents a hydrogen atom, or a saturated or unsaturated, linear, branched or cyclic, monovalent hydrovarbon group which may be substituted with an aromatic group; Q represents (a) a group of formula --X1 --A--Y1 --, where A represents a saturated or unsaturated, linear, branched or cyclic divalent C2 ?C16 -aliphatic hydrocarbon group which may be substituted with an aromativ group, a divalent aromatic hydrocarbon group or a divalent aromatic heterocyclic group; one of X1 and Y1 represents STR3 and the other represents --O--, --S-- or STR4 in which R6 and R7 each represent a hydrogen atom or a lower alkyl group; (b) a group of formula --X2 --(CH2)l --Y2 --, where one of X2 and Y2 represents a group of formula STR5 and the other represents --O--, --S-- or STR6 in which STR7 represents a 4?7-membered, divalent nitrogen-containing aromatic heterocyclic group, and R6 has the same meaning as defined above, and l is 0, 1 or 2; or (c) a group of formula STR8 where m is 2 or 3; n is an integer of from 1 to 4. The compounds have excellent inhibitory activity against acyl Co A-cholesterol-acyltransferase.
- -
-
-
- Thiocarbamates and their derivatives
-
A process is provided for preparing N-acyl-aminothiophenols, e.g., N-acetyl-para-aminothiophenol, or aminothiophenols, e.g., para-aminothiophenol, by reacting a hydroxy aromatic ketone, e.g., 4-hydroxyacetophenone (4-HAP), with hydroxylamine or a hydroxylamine salt, to form the oxime of the ketone, subjecting the oxime to a Beckmann rearrangement in the presence of a catalyst to form the N-acyl-hydroxy aromatic amine, e.g., N-acetyl-para-aminophenol (APAP), reacting the N-acyl-hydroxy aromatic amine with an N,N-di (organo) thiocarbamoyl halide, e.g., N,N-dimethylthiocarbamoyl chloride, to form an O-(N-acyl-aminoaryl)-N,N-di (organo) thiocarbamate, e.g., O-(N-acetyl-para-aminophenyl)-N,N-dimethylthiocarbamate, pyrolytically rearranging the O-(N-acyl-aminoaryl)-N,N-di (organo) thiocarbamate to form an S-(N-acyl-aminoaryl)-N,N-di (organo) thiocarbamate, e.g., S-(N-acetyl-para-aminophenyl)-N,N-dimethylthiocarbamate, and hydrolyzing the latter compound to obtain the N-acyl aminothiophenol or aminothiophenol. The N-acyl aminothiophenol may be reacted with an acylating agent to form the N,S-diacyl-aminothiophenol, e.g., N,S-diacetyl-p-aminothiophenol, or may be further hydrolyzed to the aminothiophenol, e.g., p-aminothiophenol.
- -
-
-
- SYNTHESIS OF AROMATIC THIOLS FROM ARYL IODIDES AND THIOUREA BY MEANS OF NICKEL CATALYST
-
Nickel(0) complex, generated in situ from bis(triethylphosphine)nickel(II) chloride and sodium cyanoborohydride, catalyzed the nucleophilic displacement of aryl iodides with thiourea.S-Aryl-isothiuronium salts or aromatic thiols were obtained in good yields after simple work-up procedures.
- Takagi, Kentaro
-
p. 1307 - 1308
(2007/10/02)
-