- Application of visible light photocatalysis with particle lithography to generate polynitrophenylene nanostructures
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Visible light photoredox catalysis was combined with immersion particle lithography to prepare polynitrophenylene organic films on Au(111) surfaces, forming a periodic arrangement of nanopores. Surfaces masked with mesospheres were immersed in solutions of p-nitrobenzenediazonium tetrafluoroborate and irradiated with blue LEDs in the presence of the photoredox catalyst Ru(bpy)3(PF6)2 to produce p-nitrophenyl radicals that graft onto gold substrates. Surface masks of silica mesospheres were used to protect small, discrete regions of the Au(111) surface from grafting. Nanopores were formed where the silica mesospheres touched the surface; the mask effectively protected nanoscopic local areas from the photocatalysis grafting reaction. Further reaction of the grafted arenes with aryl radicals resulted in polymerization to form polynitrophenylene structures with thicknesses that were dependent on both the initial concentration of diazonium salt and the duration of irradiation. Photoredox catalysis with visible light provides mild, user-friendly conditions for the reproducible generation of multilayers with thicknesses ranging from 2 to 100 nm. Images acquired with atomic force microscopy (AFM) disclose the film morphology and periodicity of the polymer nanostructures. The exposed sites of the nanopores provide a baseline to enable local measurements of film thickness with AFM. The resulting films of polynitrophenylene punctuated with nanopores provide a robust foundation for further chemical steps. Spatially selective binding of mercaptoundecanoic acid to exposed sites of Au(111) was demonstrated, producing a periodic arrangement of thiol-based nanopatterns within a matrix of polynitrophenylene.
- Verberne-Sutton, Susan D.,Quarels, Rashanique D.,Zhai, Xianglin,Garno, Jayne C.,Ragains, Justin R.
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- Chirality-Selective Functionalization of Semiconducting Carbon Nanotubes with a Reactivity-Switchable Molecule
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Chirality-selective functionalization of semiconducting single-walled carbon nanotubes (SWCNTs) has been a difficult synthetic goal for more than a decade. Here we describe an on-demand covalent chemistry to address this intriguing challenge. Our approach
- Powell, Lyndsey R.,Kim, Mijin,Wang, Yuhuang
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- Evidence for covalent bonding of aryl groups to MnO2 nanorods from diazonium-based grafting
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We show here that the surface of MnO2 nanorods can be modified with aryl groups by grafting from aqueous and non-aqueous solutions of aryldiazonium salts. X-ray photoelectron spectroscopy provides direct evidence for covalent bonding of aryl groups to MnO2 through surface oxygens.
- Bell,Brooksby,Polson,Downard
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Read Online
- Alternative method for the synthesis of triazenes from aryl diazonium salts
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An alternative mild method for access to 1-aryl-3,3-dimethyl alkyl triazenes is described. This protocol employs the dropwise addition of a methanolic solution of a carboxylate (RCO2M) or carbonate (CO32?) to a gently heated DMF solution containing an aryl diazonium salt (ArN2+), that had been previously isolated. Presumably homolysis of the weak N–O bond of diazo ether adducts formed in this operation initiates radical pathways that lead to the generation of triazene product. DMF serves as not only a one-electron donor to the diazonium salts employed in this process, but also as a source of dimethylamine radicals that act as a nucleophilic coupling partner. The reaction provides modest yields (ca. 20–40%) across an array of aryl diazonium salts that contain various substitution. Furthermore this unique approach to triazenes contrasts with traditional methods that employ dimethyl amine in reagent form which directly couples with diazonium salts. Seemingly, only one other example employing somewhat similar reaction conditions to this current investigation en route to triazenes has been reported, albeit with lower yields and for one representative example furnished as a side-product. The current work here improves upon the efficiency of this reported result, and further expands the reaction scope.
- Abrams
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supporting information
(2021/05/10)
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- Azoacetylenes for the Synthesis of Arylazotriazole Photoswitches
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We report a modular approach toward novel arylazotriazole photoswitches and their photophysical characterization. Addition of lithiated TIPS-acetylene to aryldiazonium tetrafluoroborate salts gives a wide range of azoacetylenes, constituting an underexplored class of stable intermediates.In situdesilylation transiently leads to terminal arylazoacetylenes that undergo copper-catalyzed cycloadditions (CuAAC) with a diverse collection of organoazides. These include complex molecules derived from natural products or drugs, such as colchicine, taxol, tamiflu, and arachidonic acid. The arylazotriazoles display near-quantitative photoisomerization and long thermalZ-half-lives. Using the method, we introduce for the first time the design and synthesis of a diacetylene platform. It permits implementation of consecutive and diversity-oriented approaches linking two different conjugants to independently addressable acetylenes within a common photoswitchable azotriazole. This is showcased in the synthesis of several photoswitchable conjugates, with potential applications as photoPROTACs and biotin conjugates.
- Anderl, Felix,Balkenhohl, Moritz,Carreira, Erick M.,Fink, Moritz,Pfaff, Patrick
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supporting information
p. 14495 - 14501
(2021/09/18)
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- Base-Free Cross-Couplings of Aryl Diazonium Salts in Methanol: PdII–Alkoxy as Reactivity-Controlling Intermediate
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Pd-catalyzed cross-coupling reactions of aryl diazonium salts are generally assumed to proceed via cationic PdII intermediates which in turn would be highly reactive in the subsequent transmetalation step. Contrary to this belief, we herein report our observation and rationalization of opposing reactivities of ArN2+ in Suzuki (=effective) and Stille (=ineffective) cross-couplings in MeOH. Our systematic experimental and computational studies on the roles of transmetalating agent, solvent, base and the likely involvement of in situ formed diazoether derivatives challenge the currently accepted mechanism. Our data suggest that the observed solvent dichotomy is primarily due to PdII-methoxy intermediates being formed, which are unreactive with arylstannanes, but highly reactive with arylboronic acids, complementing the Suzuki “Pd-oxy” mechanism with the direct demonstration of transmetalation of a PdII-alkoxy complex. Lewis acids were found to circumvent this reactivity divergence, promoting efficient couplings regardless of the employed conditions or coupling partners.
- Sanhueza, Italo A.,Klauck, Felix J. R.,Senol, Erdem,Keaveney, Sinead T.,Sperger, Theresa,Schoenebeck, Franziska
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p. 7007 - 7012
(2021/03/01)
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- Aqueous and Visible-Light-Promoted C-H (Hetero)arylation of Uracil Derivatives with Diazoniums
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Direct C5 (hetero)arylation of uracil and uridine substrates with (hetero)aryl diazonium salts under photoredox catalysis with blue light was reported. The coupling proceeds efficiently with diazonium salts and heterocycles in good functional group tolerance at room temperature in aqueous solution without transition-metal components. A plausible radical mechanism has been proposed.
- Liu, An-Di,Wang, Zhao-Li,Liu, Li,Cheng, Liang
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p. 16434 - 16447
(2021/11/16)
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- Metal-Free Visible-Light Synthesis of Arylsulfonyl Fluorides: Scope and Mechanism
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The first metal-free procedure for the synthesis of arylsulfonyl fluorides is reported. Under organo-photoredox conditions, aryl diazonium salts react with a readily available SO2 source (DABSO) to afford the desired product through simple nucleophilic fluorination. The reaction tolerates the presence of both electron-rich and -poor aryls and demonstrated a broad functional group tolerance. To shed the light on the reaction mechanism, several experimental techniques were combined, including fluorescence, NMR, and EPR spectroscopy as well as DFT calculations.
- Louvel, Dan,Chelagha, Aida,Rouillon, Jean,Payard, Pierre-Adrien,Khrouz, Lhoussain,Monnereau, Cyrille,Tlili, Anis
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supporting information
p. 8704 - 8708
(2021/05/17)
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- Gold(I)-Catalyzed Cross-Coupling Reactions of Arenediazonium Salts with Alkynoic Acids
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Abstract: The reaction of simple alkynoate salts with isolated arenediazonium tetrafluoroborate salts that had been pre-conditioned with the gold(I) catalyst AuCl(Me2S) led to the formation of cross-coupled products via a decarboxylative Sonogashira reaction process in modest yield and under mild conditions. The major by-product is a defunctionalized aryl moiety stemming from the diazonium salt, which competitively forms via hydrodediazonation. Good functional group tolerance and reaction site selectivity were attained in this limited investigation.
- Abrams, J. N.,Chi, B. K.
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p. 1236 - 1244
(2020/09/17)
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- Heterogeneous visible-light-induced Meerwein hydration reaction of alkenes in water using mpg-C3N4 as a recyclable photocatalyst
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A green and efficient visible light induced Meerwein hydration reaction of alkenes in aqueous medium using mpg-C3N4 as a recyclabe photocatalyst has been disclosed. This protocol provides a direct approach for the preparation of racemic alcohols via a free radical mechanism. Water acted as both a solvent and a reagent without any additives or co-solvents. The metal-free heterogeneous semiconductor is found to be fully recyclable at least 5 times without any significant reduction in activity. The Meerwein hydration reaction has an excellent substrate scope and gave the desired products in moderate to high yields. Furthermore, this reaction could be carried out under solar light irradiation and is applicable for large-scale reactions with satisfactory results.
- Wang, Jingjing,Xue, Linshuang,Hong, Mei,Ni, Bangqing,Niu, Tengfei
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supporting information
p. 411 - 416
(2020/02/13)
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- Discovery and structure-activity relationship studies of 1-aryl-1H-naphtho[2,3-d][1,2,3]triazole-4,9-dione derivatives as potent dual inhibitors of indoleamine 2,3-dioxygenase 1 (IDO1) and trytophan 2,3-dioxygenase (TDO)
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Indoleamine 2,3-dioxygenase 1 (IDO1) and tryptophan 2,3-dioxygenase (TDO), which mediate kynurenine pathway of tryptophan degradation, have emerged as potential new targets in immunotherapy for treatment of cancer because of their critical role in immunosuppression in the tumor microenvironment. In this investigation, we report the structural optimization and structure-activity relationship studies of 1-phenyl-1H-naphtho[2,3-d][1,2,3]triazole-4,9-dione derivatives as a new class of IDO1/TDO dual inhibitors. Among all the obtained dual inhibitors, 1-(3-chloro-4-fluorophenyl)-6-fluoro-1H-naphtho[2,3-d][1,2,3]triazole-4,9-dione (38) displayed the most potent IDO1 and TDO inhibitory activities with IC50 (half-maximal inhibitory concentration) values of 5 nM for IDO1 and 4 nM for TDO. It turned out that compound 38 was not a PAINS compound. Compound 38 could efficiently inhibit the biofunction of IDO1 and TDO in intact cells. In LL2 (Lewis lung cancer) and Hepa1-6 (hepatic carcinoma) allograft mouse models, this compound also showed considerable in vivo anti-tumor activity and no obvious toxicity was observed. Therefore, 38 could be a good lead compound for cancer immunotherapy and deserving further investigation.
- Pan, Shulei,Zhou, Yangli,Wang, Qiusheng,Wang, Yanlin,Tian, Chenyu,Wang, Tianqi,Huang, Luyi,Nan, Jinshan,Li, Linli,Yang, Shengyong
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- σ-Bond initiated generation of aryl radicals from aryl diazonium salts
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σ-Bond nucleophiles and molecular oxygen transform aryl diazonium salts into aryl radicals. Experimental and computational studies show that Hantzsch esters transfer hydride to aryl diazonium species, and that oxygen initiates radical fragmentation of the diazene intermediate to produce aryl radicals. The operational simplicity of this addition-fragmentation process for the generation of aryl radicals, by a polar-radical crossover mechanism, has been illustrated in a variety of bond-forming reactions.
- Chan, Bun,McErlean, Christopher S. P.,Nashar, Philippe E.,Tatunashvili, Elene
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supporting information
p. 1812 - 1819
(2020/03/17)
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- Heterogeneous Carbon Nitrides Photocatalysis Multicomponent Hydrosulfonylation of Alkynes to Access β-Keto Sulfones with the Insertion of Sulfur Dioxide in Aerobic Aqueous Medium
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Although hydrosulfonylation of alkynes is an ideal process to generate β-keto sulfones, such an approach is rarely implemented. Here we reported a facile and efficient graphitic carbon nitride (p-g-C3N4) photocatalyzed hydrosulfonylation of alkynes with the insertion of sulfur dioxide in aerobic conditions. Controlled experiments and ESR results indicated both the superoxide radicals and valence band holes played an important role in the reaction. Further isotope experiments confirmed the oxygen atom of the products comes from H2O, while the O2 plays an important role in the reaction by quenching the DABCO radical cation. The metal-free heterogeneous semiconductor is fully recyclable at least 6 times without significant reducing activity. Furthermore, this reaction could be carried out under solar light irradiation and was applicable for a large-scale reaction with conserved results.
- Ni, Bangqing,Zhang, Binbin,Han, Jine,Peng, Bohan,Shan, Yuling,Niu, Tengfei
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supporting information
p. 670 - 674
(2020/01/31)
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- RhIII-Catalyzed Synthesis of Highly Substituted 2-Pyridones using Fluorinated Diazomalonate
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A RhIII-catalyzed strategy was developed for the rapid construction of highly substituted 2-pyridone scaffolds using α,β-unsaturated oximes and fluorinated diazomalonate. The reaction proceeds through direct, site-selective alkylation based on migratory insertion and subsequent cyclocondensation. A wide substrate scope with different functional groups was explored. The requirement of fluorinated diazomalonate was explored for this transformation. The developed methodology was further extended with the synthesis of the bioactive compound.
- Das, Debapratim,Sahoo, Gopal,Biswas, Aniruddha,Samanta, Rajarshi
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supporting information
p. 360 - 364
(2020/01/25)
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- Dual palladium-photoredox catalyzed chemoselective C-H arylation of phenylureas
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A highly chemoselective C-H arylation of phenylureas has been accomplished using dual palladium-photoredox catalysis at room temperature without any additives, base or external oxidants. Regioselective C-H arylation ofN,N'-diaryl substituted unsymmetrical phenylureas has also been accomplished by a careful choice of aryl groups.
- Babu, Sakamuri Sarath,Shahid,Gopinath, Purushothaman
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supporting information
p. 5985 - 5988
(2020/06/04)
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- Visible-Light-Mediated Ru-Catalyzed Synthesis of 3-(Arylsulfonyl)but-3-enals via Coupling of α-Allenols with Diazonium Salts and Sulfur Dioxide
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The first coupling of α-allenols, sulfur dioxide, and arenediazonium salts is presented. The three-component reaction which is promoted by visible light can be easily accomplished using DABSO as a sulfur dioxide surrogate in the presence of a photoredox catalyst. In this manner, a broad range of electron-rich and electron-deficient aryl substituents are well accommodated in the sulfonylation-rearrangement cascade to afford the 2,2-disubstituted 3-(arylsulfonyl)but-3-enals in reasonable yields. Based on control experiments, a radical mechanism which does imply 1,2-aryl migration has been proposed.
- Herrera, Fernando,Luna, Amparo,Almendros, Pedro
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supporting information
p. 9490 - 9494
(2020/12/21)
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- Comparison of the Thermal Stabilities of Diazonium Salts and Their Corresponding Triazenes
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A range of diazonium salts and their corresponding triazenes have been prepared in order to directly compare their relative thermal stabilities (via initial decomposition temperature) from differential scanning calorimetry (DSC) data. A structure-stability relationship has been explored to investigate trends in stability, depending on the aromatic substituent and the structure of the secondary amine component of the diazonium salts and triazenes. All of the triazenes investigated show significantly greater stability (many are stable above 200 °C) compared with the corresponding diazonium salts, which show varying stabilities.
- Schotten, Christiane,Leprevost, Samy K.,Yong, Low Ming,Hughes, Colan E.,Harris, Kenneth D. M.,Browne, Duncan L.
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supporting information
p. 2336 - 2341
(2020/06/05)
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- Copper-mediated tandem ring-opening/cyclization reactions of cyclopropanols with aryldiazonium salts: Synthesis of: N -arylpyrazoles
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A general method for the synthesis of structurally diverse N-arylpyrazoles from readily available cyclopropanols and aryldiazonium salts is disclosed. The reaction was conducted at room temperature within minutes with a broad substrate scope and excellent regioselectivity.
- Liu, Jidan,Xu, Erjie,Jiang, Jinyuan,Huang, Zeng,Zheng, Liyao,Liu, Zhao-Qing
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supporting information
p. 2202 - 2205
(2020/02/26)
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- Pentafluoroethylation of Arenediazonium Tetrafluoroborates Using On-Site Generated Tetrafluoroethylene
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Copper-mediated pentafluoroethylation of arenediazonium tetrafluoroborates with tetrafluoroethylene (TFE) on-site generated from TMSCF3 has been developed as a new method to prepare pentafluoroethyl arenes. The active pentafluoroethylation reagent “CuC2F5” is pre-generated from CuSCN, TFE and CsF, and its generation and further reaction are strongly solvent-dependent. This pentafluoroethylation reaction represents the first example of Sandmeyer-type pentafluoroethylation, which exhibits good functional group tolerance and potential applications for the synthesis of complicated bioactive compounds.
- Xing, Bo,Li, Lingchun,Ni, Chuanfa,Hu, Jinbo
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supporting information
p. 1131 - 1136
(2019/10/22)
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- Light-Induced Mechanistic Divergence in Gold(I) Catalysis: Revisiting the Reactivity of Diazonium Salts
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In a systematic study of the Au-catalyzed reaction of o-alkynylphenols with aryldiazonium salts, we find that essentially the same reaction conditions lead to a change in mechanism when a light source is applied. If the reaction is carried out at room temperature using a AuI catalyst, the diazonium salt undergoes electrophilic deauration of a vinyl AuI intermediate and provides access to substituted azobenzofurans. If the reaction mixture is irradiated with blue LED light, C?C bond formation due to N2-extrusion from the diazonium salt is realized selectively, using the same starting materials without the need for an additional photo(redox) catalyst under aerobic conditions. We report a series of experiments demonstrating that the same vinyl AuI intermediate is capable of producing the observed products under photolytic and thermal conditions. The finding that a vinyl AuI complex can directly, without the need for an additional photo(redox) catalyst, result in C?C bond formation under photolytic conditions is contrary to the proposed mechanistic pathways suggested in the literature till date and highlights that the role of oxidation state changes in photoredox catalysis involving Au is thus far only poorly understood and may hold surprises for the future. Computational results indicate that photochemical activation can occur directly from a donor–acceptor complex formed between the vinyl AuI intermediate and the diazonium salt.
- Taschinski, Svenja,D?pp, René,Ackermann, Martin,Rominger, Frank,de Vries, Folkert,Menger, Maximilian F. S. J.,Rudolph, Matthias,Hashmi, A. Stephen K.,Klein, Johannes E. M. N.
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supporting information
p. 16988 - 16993
(2019/11/13)
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- Copper(I)-promoted trifluoromethylthiolation of arenediazonium salts with AgSCF3
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An efficient method for trifluoromethylthiolation of arenediazonium salts has been developed in mild conditions with a stable and convenient AgSCF3. It provides a straightforward and convenient way for the synthesis of trifluoromethylthiolated compound from diazonium salts in moderate to good yields.
- Zheng, Changge,Liu, Yang,Hong, Jianquan,Huang, Shuai,Zhang, Wei,Yang, Yupeng,Fang, Ge
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supporting information
p. 1404 - 1407
(2019/05/01)
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- Olefin Bifunctionalization: A Visible-light Photoredox-catalyzed Aryl Alkoxylation of Olefins
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Olefin bifunctionalization is a facile route to obtain complex molecules from abundant and commercially available olefin feedstocks. Visible light together with a catalytic amount of tris(bipyridine)ruthenium salt catalyzes the aryl alkoxylation of styrenes with aryl diazonium salts in alcohol solvents via a photoredox process. The scope of this proposed reaction with respect to various aryl diazonium salts and styrenes has been investigated.
- Yamaguchi, Eiji,Tanaka, Wakako,Itoh, Akichika
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supporting information
p. 121 - 124
(2018/12/13)
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- Phenalenyl Based Aluminum Compound for Catalytic C-H Arylation of Arene and Heteroarenes at Room Temperature
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Main group metal based catalysis has been considered to be a cost-effective alternative way to the transition metal based catalysis, due to the high abundance of main group metals in the Earth's crust. Among the main group metals, aluminum is the most abundant (7-8%) in the Earth's crust, making the development of aluminum based catalysts very attractive. So far, aluminum based compounds have been popularly used as Lewis acids in a variety of organic reactions, but chemical transformation demanding a redox based process has never utilized an Al(III) complex as a catalyst. Herein, we tuned the redox noninnocence behavior of a phenalenyl ligand by coupling with Al(III) ion, which subsequently can store the electron upon reduction with K to carry out direct C-H arylation of heteroarenes/mesitylene at ambient temperature. A mechanistic investigation revealed that a three-electron reduced phenalenyl based triradical aluminum(III) complex plays the key role in such catalysis. The electronic structure of the catalytically active triradical species has been probed using EPR spectroscopy, magnetic susceptibility measurements, and electronic structure calculations using a DFT method.
- Vardhanapu, Pavan K.,Ahmed, Jasimuddin,Jose, Anex,Shaw, Bikash Kumar,Sen, Tamal K.,Mathews, Amita A.,Mandal, Swadhin K.
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p. 289 - 299
(2019/01/10)
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- Mild-Base-Promoted Arylation of (Hetero)Arenes with Anilines
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Transition metal-free radical arylation of heteroarenes is achieved at room temperature by simply adding aqueous sodium carbonate to a solution of the corresponding heteroarene and arenediazonium salt, which can even be formed in situ. Such an easy, inexpensive and mild methodology has been optimized and applied to the expeditious modification of interesting molecular cores like naphthylimide or bisthienylcyclopentenes.
- Monzón, Diego M.,Santos, Tanausú,Pinacho-Crisóstomo,Martín, Víctor S.,Carrillo, Romen
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p. 325 - 333
(2018/01/15)
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- An Iron-Based Long-Lived Catalyst for Direct C?H Arylation of Arenes and Heteroarenes
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Direct C?H arylation of arenes and heteroarenes to biaryls at ambient temperature has been accomplished using a phenalenyl-supported iron(III) catalyst. The present catalyst requires a chemical reductant such as potassium and functions without any light stimulation. C?H arylation of various heteroarenes including pyridine as well as unactivated arene such as benzene delivered good to excellent yield (28 examples, up to 92 %) at room temperature. A combined effort based on experiments and theoretical calculations established that a phenalenyl-based radical species (generated by chemical reduction of the iron(III) coordinated phenalenyl complex) plays key role during the catalysis. Furthermore, this catalyst displayed remarkable stability during the catalysis, as evident from the fact that it was still usable over ten consecutive catalytic runs without losing its catalytic efficiency.
- Chakraborty, Soumi,Ahmed, Jasimuddin,Shaw, Bikash Kumar,Jose, Anex,Mandal, Swadhin K.
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supporting information
p. 17651 - 17655
(2018/11/10)
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- Palladium catalyzed stereocontrolled synthesis of C-aryl glycosides using glycals and arenediazonium salts at room temperature
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A stereocontrolled synthesis of aryl-C-glycosides was achieved using glycals and aryldiazonium salts in the presence of palladium acetate. A wide range of glycals including d-glucal, d-galactal, l-rhamnal, d-xylal and d-ribal underwent C-arylation at the anomeric carbon in the presence of different aryldiazonium tetrafluoroborates and gave synthetically useful 2,3-deoxy-3-keto-α-aryl-C-glycosides in good to excellent yields. Broad substrate scope, simple operation and room temperature reactions make this protocol very attractive in organic synthesis.
- Singh, Adesh Kumar,Kandasamy, Jeyakumar
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supporting information
p. 5107 - 5112
(2018/07/29)
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- Synthesis of Chiral Sulfonyl Lactones via Copper-Catalyzed Asymmetric Radical Reaction of DABCO?(SO2)
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In the present work, an asymmetric copper-catalyzed radical multi-component cascade reaction of an unsaturated carboxylic acid, aryldiazonium tetrafluoroborate, and DABCO?(SO2)2 (DABSO) has been developed for the enantioselective synthesis of sulfonyl lactones. In this reaction, this SO2 surrogate, DABSO was applied for the first time in the construction of chiral compounds. This multiple-step asymmetric radical reaction was carried out under mild conditions and tolerated a wide range of substrates, resulting in the corresponding sulfonyl lactones with up to 95% chemical yields and 88% ee. The current reaction enriches the research contents of DABSO, and provides a new and efficient strategy to chiral functionalized lactones bearing quarternary stereogenic center. (Figure presented.).
- Wang, Yang,Deng, Lingling,Zhou, Jie,Wang, Xiaochen,Mei, Haibo,Han, Jianlin,Pan, Yi
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supporting information
p. 1060 - 1065
(2018/01/22)
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- Erythrosine B Catalyzed Visible-Light Photoredox Arylation–Cyclization of N-Alkyl-N-aryl-2-(trifluoromethyl)acrylamides to 3-(Trifluoromethyl)indolin-2-one Derivatives
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3-Trifluoromethylindoline-2-one derivatives were prepared in a visible-light photocatalytic transformation of acrylamides. The arylation–cyclization sequence was initiated by light-induced aryl radical generation from aryldiazonium salts with the utilization of erythrosine B as an organic photocatalyst.
- Gonda, Zsombor,Béke, Ferenc,Tischler, Orsolya,Petró, Milán,Novák, Zoltán,Tóth, Balázs L.
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supporting information
p. 2112 - 2117
(2017/04/24)
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- Efficient copper-catalyzed N-arylation of NH-containing heterocycles and sulfonamides with arenediazonium tetrafluoroborates
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A practical copper-catalyzed N-arylation of NH-containing heterocycles with arenediazonium tetrafluoroborates has been developed using CuCl as catalyst and K2CO3 as additive under ligand-free conditions. This reaction system has wide substrate scope including imides, 1H-pyrazole, 1H-tetrazoles, 1,2-benzisothiazol-3(2H)-one, and related sulfonamides and gives moderate to excellent yields (up to 95%) of the desired products. This strategy is very general, simple, environmentally friendly, and tolerant of oxygen.
- Ouyang, Yu-Qing,Yang, Zhen-Hua,Chen, Zhong-Hui,Zhao, Sheng-Yin
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supporting information
p. 771 - 778
(2017/04/06)
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- MONOAZO DYES WITH CYCLIC AMINE AS FLUORESCENCE QUENCHERS
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The present disclosure provides reactive quencher dyes that can be used in the detection and/or quantification of desirable target molecules, such as proteins, nucleic acids and various cellular organelles. These dyes are essentially non-fluorescent but are efficient quenchers of various fluorescent dyes. Also, provided are methods of using the dyes, bio-probes incorporating dyes and methods of using the bio-probes. The quencher dyes described herein are modified to provide beneficial properties.
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Paragraph 0063
(2016/10/27)
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- An unprecedentedly simple method of synthesis of aryl azides and 3-hydroxytriazenes
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Fischer's approach towards the synthesis of aryl azides and triazinoles from diazonium salts and hydroxylammonium chloride (phenylhydraxylamine) was reinvestigated and optimized. The new methodology enables the preparation of aryl azides and triazinoles in high yields in water at room temperature. The procedure is very simple, robust, easily scalable, reproducible, and "green".
- Gribanov, Pavel S.,Topchiy, Maxim A.,Golenko, Yulia D.,Lichtenstein, Yana I.,Eshtukov, Artur V.,Terekhov, Vladimir E.,Asachenko, Andrey F.,Nechaev, Mikhail S.
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supporting information
p. 5984 - 5988
(2018/06/06)
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- Direct and Versatile Synthesis of Red-Shifted Azobenzenes
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A straightforward synthesis of azobenzenes with bathochromically-shifted absorption bands is presented. It employs an ortho-lithiation of aromatic substrates, followed by a coupling reaction with aryldiazonium salts. The products are obtained with good to excellent yields after simple purification. Moreover, with the presented methodology, a structurally diverse panel of different azobenzenes, including unsymmetric tetra-ortho-substituted ones, can be readily obtained, which paves the way for future development of red-light-addressable azobenzene derivatives for in vivo application.
- Hansen, Mickel J.,Lerch, Michael M.,Szymanski, Wiktor,Feringa, Ben L.
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supporting information
p. 13514 - 13518
(2016/10/21)
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- Ferrocene catalysed C–H arylation of arenes and reaction mechanism study using cyclic voltammetry
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Ferrocene catalysed C–H arylation of benzene using aryldiazonium salt is studied. Yield of biphenyl in this reaction was found to be better than some of the known methods. Aryldiazonium salts with electron withdrawing groups produced excellent yields (upto 85%) in C–H arylation. Applicability of this reaction was studied on several arenes and heteroarene such as benzene, naphthalene, anthracene, pyrene and pyridine. Catalytic role of ferrocene in aryl radical formation was studied by cyclic voltammetry of phenyldiazonium tetrafluoroborate. In presence of ferrocene more radical formation was observed. This reaction model works at ambient temperature and features the use of inexpensive catalyst for the synthesis of biaryl derivatives.
- Dixit, Swati,Siddiqui, Qamar Tabrez,Muneer, Mohammad,Agarwal, Neeraj
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p. 4228 - 4231
(2016/08/25)
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- Synthesis of 2-aryl-2H-tetrazoles via a regioselective [3+2] cycloaddition reaction
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A regioselective cycloaddition reaction of arenediazonium salts with trimethylsilyldiazomethane is reported. A series of 2-aryltetrazoles were obtained in good to moderate yields with wide functional group compatibility. Furthermore, this cycloaddition reaction opens the way to build up the versatile intermediate 2-aryl-5-bromotetrazole.
- Patouret, Remi,Kamenecka, Theodore M.
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supporting information
p. 1597 - 1599
(2018/03/28)
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- Gold-catalysed cross-coupling between aryldiazonium salts and arylboronic acids: Probing the usefulness of photoredox conditions
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The synthesis of biaryl compounds from aryldiazonium salts and arylboronic acids was achieved using PPh3AuCl as catalyst, CsF as base and acetonitrile as solvent. Combined to photosensitizers, irradiation by blue LEDs allowed accelerating the reaction and expanding its scope. Various functional groups were compatible including bromoaryls, iodoaryls, aldehydes and alcohols. A 2-iodobenzyl alcohol moiety was smoothly introduced by this method, enabling its consecutive isotopic labelling by a Pd-catalysed alkoxycarbonylation.
- Cornilleau, Thomas,Hermange, Philippe,Fouquet, Eric
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supporting information
p. 10040 - 10043
(2016/08/15)
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- The promoting effect of pyridine ligands in the Pd-catalysed Heck-Matsuda reaction
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An efficient Pd-catalyzed arylation reaction of challenging acyclic olefins, in the presence of an organic ligand, has been disclosed. Commercially available cheap pyridine-based ligands are able to promote good to excellent yields for poorly efficient Heck-Matsuda arylation reactions of several allylic alcohols. A wide range of electronically different arenediazonium salts bearing either electron-releasing or withdrawing groups have been used allowing the synthesis of a range of β-aryl-methoxy-lactols. The catalytic system has been optimised, along with the reaction conditions, in order to achieve remarkable yields in less than 1 h.
- Khodja, Walid,Leclair, Alexandre,Rull-Barrull, Jordi,Zammattio, Fran?oise,Kutonova, Ksenia V.,Trusova, Marina E.,Felpin, Fran?ois-Xavier,Rodriguez-Zubiri, Mireia
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p. 8855 - 8862
(2016/10/11)
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- A family of low molecular-weight, organic catalysts for reductive C-C bond formation
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Hydrazines form a new family of low molecular-weight reducing agents for diazonium salts. Using only small amounts of hydrazine catalyst, the coupling of diazonium salts to a variety of reactive partners has been achieved, without the requirement for either metal adjuvants or irradiation with visible or ultraviolet light. The generality of the concept proposed herein as well as its advantages in the preparative scale is outlined and discussed.
- Shaaban, Saad,Jolit, Ana?s,Petkova, Desislava,Maulide, Nuno
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supporting information
p. 13902 - 13905
(2015/09/15)
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- Synthesis of difluoromethyl thioethers from difluoromethyl trimethylsilane and organothiocyanates generated in situ
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A copper-CF2H complex generated in situ from copper thiocyanate and TMS-CF2H smoothly converts organothiocyanates into valuable difluoromethyl thioethers. This reaction step can be combined with several thiocyanation methods to one-pot protocols, allowing late-stage difluoromethylthiolations of widely available alkyl halides and arenediazonium salts. This strategy enables the introduction of difluoromethylthio groups - a largely unexplored substituent with highly promising properties - into drug-like molecules. A copper-CF2H complex generated in situ from copper thiocyanate and TMS-CF2H smoothly converts organothiocyanates into valuable difluoromethyl thioethers. This reaction step can be combined with several thiocyanation methods to one-pot protocols, allowing late-stage difluoromethylthiolations of widely available alkyl halides and arenediazonium salts.
- Bayarmagnai, Bilguun,Matheis, Christian,Jouvin, Kvin,Goossen, Lukas J.
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supporting information
p. 5753 - 5756
(2015/06/10)
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- An easy route to (hetero)arylboronic acids
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An unprecedented spontaneous reactivity between diazonium salts and diboronic acid has been unveiled, leading to a versatile arylboronic acid synthesis directly from (hetero)arylamines. This fast reaction (35 min overall) tolerates a wide range of functional groups and is carried out under very mild conditions. The radical nature of the reaction mechanism has been investigated.
- Erb, William,Hellal, Akila,Albini, Mathieu,Rouden, Jacques,Blanchet, Jerome
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supporting information
p. 6608 - 6612
(2014/06/09)
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- The photoredox-catalyzed meerwein addition reaction: Intermolecular amino-arylation of alkenes
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A variety of amides are efficiently accessible under mild conditions by intermolecular amino-arylation using a photo Meerwein addition with visible light. The reaction has a broad substrate scope, tolerates a large range of functional groups, and was applied to the synthesis of a 3-aryl-3,4- dihydroisoquinoline. From elimination to addition: A variety of amides are efficiently accessible under mild conditions by intermolecular amino-arylation using a photo Meerwein addition with visible light. The reaction has a broad substrate scope, tolerates a large range of functional groups, and was applied to the synthesis of 3-aryl-3,4-dihydroisoquinoline. Copyright
- Prasad Hari, Durga,Hering, Thea,K?nig, Burkhard
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supporting information
p. 725 - 728
(2014/01/23)
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- A simple catalytic system based on PdCl2(CH3CN) 2 in water for cross-coupling reactions using diazonium salts
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Aryl-heteroaryl and heteroaryl-heteroaryl compounds are obtained through the Suzuki-Miyaura cross-coupling reactions between diazonium salts and potassium trifluoroborates using PdCl2(CH3CN)2 as the catalyst in water and in the absence of any additive, ligand or base. In addition, the same mild catalytic system is effective for the Matsuda-Heck reaction between several monoolefins with aryldiazonium salts.
- El Bakouri, Ouissam,Fernández, Martí,Brun, Sandra,Pla-Quintana, Anna,Roglans, Anna
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p. 9761 - 9765
(2013/10/22)
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- A simple, enaminone-based approach to some bicyclic pyridazinium tetrafluoroborates
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Easily obtainable cyclic enaminones (piperidin-2-ylidenealkanones) can be transformed into substituted bicyclic pyridazinium tetrafluoroborates upon treatment with corresponding diazonium salts. The transformation can be performed either in a one-pot way or in a two-step process with the isolation of single azo-coupled enaminone as the intermediate. The former method is superior. Under the optimized conditions, a number of pyridazinium salts substituted with both electron-donating and electron-withdrawing substituents was easily synthesized. A mechanism of the formation of the pyridazinium salts is suggested. A partial drawback is the possibility of the formation of a mixture of products when using a different diazonium salt in each step due to a reversibility of the azo coupling. This can be suppressed by using a more reactive diazonium salt before a less reactive one.
- Josefik, Frantisek,Svobodova, Marketa,Bertolasi, Valerio,Simunek, Petr
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supporting information
p. 1463 - 1471
(2013/08/23)
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- A transition-metal-free synthesis of arylcarboxyamides from aryl diazonium salts and isocyanides
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A transition-metal-free carboxyamidation process, using aryl diazonium tetrafluoroborates and isocyanides under mild conditions, has been developed. This novel conversion was initiated by a base and solvent induced aryl radical, followed by radical addition to isocyanide and single electron transfer (SET) oxidation, affording the corresponding arylcarboxyamide upon hydration of the nitrilium intermediate.
- Xia, Zhonghua,Zhu, Qiang
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supporting information
p. 4110 - 4113
(2013/09/12)
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- Comparative studies on the redox reaction of Fe(CN)6 4-/3- at modified glassy carbon electrodes Via diazonium salts electroreduction
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In this paper, the electrochemical properties of glassy carbon (GC) electrodes modified with different functional groups have been investigated. A diazonium salt coupling procedure was used to covalently bind the various p-substituted aryl groups to GC surface. In order to establish suitable grafting conditions enforceable to all kinds of diazonium derivatives, the selection of the molecules to be grafted was done for the contrasted electronegativity of the substituents. We obtained that grafting density could be controlled by varying the concentration of the diazonium, the duration and the value of the applied potential. The surface modification was checked by the blocking action of GC modified electrodes for Fe(CN)63-/4- redox probe in cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements.
- Raicopol, Matei,Branzoi, Viorel,Necula, Luiza,Ionita, Mariana,Pilan, Luisa
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p. 807 - 814
(2013/05/09)
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- Triphenyl moieties as building blocks for obtaining molecular glasses with nonlinear optical activity
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The incorporation of trityl and triphenylsilyl groups into low molecular weight molecules allows the formation of stable molecular glasses. A series of materials based on the N-phenyldiethanolamine core was synthesized bearing different azobenzenes and benzylydene-1,3-indandione as active chromophores. Molecular hyperpolarizability of the synthesized compounds was calculated by a restricted Hartree-Fock method with basis 6-31G(d,p) and measured in solutions by hyper-Rayleigh scattering. Non-linear optical (NLO) activity of the thin glassy films was confirmed after a corona poling procedure. Thermal sustainability of the NLO response of up to 85 °C was achieved. Quantum chemical calculations of the compounds revealed increased steric bulk and conformational freedom of the triphenylsilyl moiety. While the presence of the triphenylsilyl group results in more stable glasses and increased material nonlinearity, in the case of trityl groups, measured glass transition temperatures are higher.
- Traskovskis, Kaspars,Mihailovs, Igors,Tokmakovs, Andrejs,Jurgis, Andrejs,Kokars, Valdis,Rutkis, Martins
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experimental part
p. 11268 - 11276
(2012/08/14)
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- Electrochemical study on carbon nanotubes functionalization by diazonium salts electroreduction
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In this paper, the functionalization of single walled carbon nanotubes (SWCNTs) via electrochemical reduction of aryl diazonium salts in a manner that is similar to the one employed for glassy carbon surfaces is reported. 1-3 The functionalization processes with diazonium salts can lead to further modifications of the nanotubes in order to facilitate their incorporation into polymer composite materials or use in sensors applications. The molecules used for SWCNTs functionalization were chosen for the opposite electronic effects of the aryl substituents and we observed that grafting behaviour depended on the electronic nature of the substituent. The functionalization of SWCNTs was evidenced using voltammetric methods by electrochemical signals related to the immobilized groups in their characteristic potential domain. For electrochemically inactive groups, where it was not possible to evidence the SWCNTs modification by direct electrochemistry methods, the functionalization of SWCNTs was probed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) using [Fe(CN)6] 3-/4- as redox marker.
- Pilan, Luisa,Raicopol, Matei,Ionita, Mariana,Branzoi, Viorel
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p. 815 - 822
(2013/05/22)
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- Rhodium(I)-catalyzed synthesis of aryltriethoxysilanes from arenediazonium tosylate salts with triethoxysilane
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An efficient method for the preparation of aryltriethoxy-silanes from arenediazonium tosylate salts has been developed, which expands the substrates of rhodium-catalyzed silylation from iodides, bromides, and triflates to diazonium salts. A new method for hydrodediazoniation has also been explored.
- Tang, Zhi Yong,Zhang, Yuan,Wang, Tao,Wang, Wei
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supporting information; experimental part
p. 804 - 808
(2010/06/14)
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- Base free aryl coupling of diazonium compounds and boronic esters: Self-activation allowing an overall highly practical process
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Boronic esters have long been considered as poor partners in cross-coupling reactions with arene diazoniums. Here is reported an unprecedented application of self-activated boronic esters in a base-free cross-coupling reaction with diazonium salts under mild and user friendly conditions.
- Bonin, Helene,Delbrayelle, Dominique,Demonchaux, Patrice,Gras, Emmanuel
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supporting information; experimental part
p. 2677 - 2679
(2010/07/08)
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- POLYMERIZABLE COMPOSITIONS
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The invention relates to the use of triazenes of formula (I) wherein Q is a direct bond or a bivalent radical -(CR8R9)-, Z1 is -O-, -NR10-, -CH2-,-(CR11R12)- or -C(=O)- and R1 to R12 are optionally substituted hydrocarbon residues, as precursors for radicals useful in reactions triggered by free radicals, such as polymerization of unsaturated monomers and degradation of polyolefins. Most of the triazenes of formula (I) are novel and claimed, too, as well as the preparation of triazenes of formula (I) and polymerisable compositions comprising them.
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Page/Page column 22-23
(2010/11/03)
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- Evidence of reversibility in azo-coupling reactions between 1,3,5-tris(N,N-dialkylamino)benzenes and arenediazonium salts
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(Chemical Equation Presented) The reactions between strongly electron-rich aromatic substrates (1,3,5-tris(N,N-dialkylamino)benzenes, neutral carbon super nucleophiles) and diazonium salts produce moderately stable σ complexes (Wheland complexes). The reactivity of Wheland complexes with electrophiles (other diazonium salts, or 4,7-dinitrobenzofuroxan) produces exchange reactions in the electrophilic part: the better electrophile replaces the less powerful electrophile. In the same way, in Wheland complexes with the 1,3,5-tris(morpholinyl)-benzene, the 1,3,5-tris(piperidinyl)benzene replaces the less powerful nucleophile 1,3,5-tris(morpholinyl)-benzene. Evidence is reported here indicating that for the title system the reaction of the attack of the electrophilic reagent producing Wheland complexes is a reversible process. The final products of the diazo-coupling reactions undergo a further attack of some diazonium salts. From the final products of the double diazo-coupling reactions (diazo compounds), we collected evidence that is a clear instance of complete reversibility of the diazo-coupling reaction.
- Boga, Carla,Del Vecchio, Erminia,Forlani, Luciano,Tozzi, Silvia
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p. 8741 - 8747
(2008/03/13)
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