13141-42-9Relevant academic research and scientific papers
Sonogashira (Cu and amine free) and Suzuki coupling in air catalyzed: Via nanoparticles formed in situ from Pd(ii) complexes of chalcogenated Schiff bases of 1-naphthaldehyde and their reduced forms
Bhaskar, Renu,Sharma, Alpesh K.,Yadav, Manoj K.,Singh, Ajai K.
, p. 15235 - 15248 (2017)
The reaction of 1-naphthaldehyde with 2-(phenylthio/seleno)ethylamine afforded air- and moisture-insensitive Schiff bases: C10H7-1-CHN-CH2CH2EPh (L1: E = S; L2: E = Se). Then, on treatment with NaOAc and Li2PdCl4, palladacycles, [Pd(L1-H/L2-H)Cl] (1/2) were formed at room temperature, in which L1/L2 are ligated as an unsymmetric (C-, N, E) pincer. The reduction of >CN bonds of L1 and L2 with sodium borohydride gave C10H7-1-CH2NH-CH2CH2EPh (L3: E = S; L4: E = Se). The reactions of L3/L4 at room temperature, similar to those of L1/L2, resulted in the formation of complex [Pd(L3/L4)Cl2] (3/4), in which the ligand is coordinated in a bidentate (N, E) mode. The yield of all the complexes was >85%. Characterization by HR-MS, 1H, 13C{1H} and 77Se{1H} NMR spectra of L1-L4 and their complexes 1-4 were performed. The structures of L1 and 1-4 were established with single-crystal X-ray diffraction. In all the complexes, the geometry of palladium was distorted square planar. The Pd-S bond distances in 1 and 3 were 2.426(12) and 2.259(2) ?, respectively, whereas Pd-Se bond lengths (?) were 2.523(11) (2) and 2.369(10) (4) ?. The catalytic activities of 1-4 were explored for copper- and amine-free Sonogashira and Suzuki-Miyaura coupling (SMC) of aryl halides under aerobic conditions. The amount of catalyst required for achieving good conversion was 0.01 and 0.05 mol% for SMC and Sonogashira coupling, respectively. The conversion of some substrates reached a maximum in 1 and 2 h for Sonogashira coupling and SMC, respectively. The palladacycles as catalysts gave good conversion efficiency. The generation of palladium-containing nanoparticles (NPs) during both coupling reactions was observed. These were isolated and HR-TEM studies were performed on them and revealed their size as ～2-7 nm. The SEM-EDX analysis indicated the presence of organochalcogen ligands or their fragments in the samples. They independently catalyzed both reactions. Therefore, the role of 1-4 in catalysis undoubtedly exists. For Sonogashira coupling, the formation and role of such Pd-based NPs under aerobic conditions were observed for the first time. The complexes 1-4 showed the potential for reuse, as in the eighth cycle, conversion dropped by only 20%.
Silica-anchored proline-copper(I) as an efficient and recyclable catalyst for the Sonogashira reaction
Wang, Zuli,Wang, Lei,Li, Pinhua
, p. 1367 - 1372 (2008)
A novel silica-anchored proline-copper(I) organic-inorganic hybrid material as an efficient catalyst for the Sonogashira reaction was developed. Terminal alkynes were reacted with aryl iodides and bromides smoothly in the presence of a proline-functionalized silica-anchored copper(I) catalyst in DMF to afford the corresponding cross-coupling products in good to excellent yields. Furthermore, silica-anchored proline-copper(I) catalyst was recovered and recycled by a simple filtration of the reaction solution and reused for six times without significant decreases in activity. Georg Thieme Verlag Stuttgart.
A mesoionic bis(Py-tzNHC) palladium(II) complex catalyses "green" Sonogashira reaction through an unprecedented mechanism
Gazvoda, Martin,Virant, Miha,Pevec, Andrej,Urankar, Damijana,Bolje, Aljo?a,Ko?evar, Marijan,Ko?mrlj, Janez
, p. 1571 - 1574 (2016)
A novel bis(pyridyl-functionalized 1,2,3-triazol-5-ylidene)-palladium(ii) complex [Pd(Py-tzNHC)2]2+ catalyses the copper-, amine-, phosphine-, and additive-free aerobic Sonogashira alkynylation of (hetero)aryl bromides in water as the only reaction solvent. The catalysis proceeds along two connected Pd-cycles with homogeneous bis-carbene Pd0 and PdII species, as demonstrated by electrospray ionization mass spectrometry.
Synthesis and characterization of a polymer-anchored palladium(II) Schiff base complex and its catalytic efficiency in phosphine-free Sonogashira coupling reactions
Islam,Mondal, Sanchita,Roy, Anupam Singha,Mondal, Paramita,Mobarak, Manir,Hossain, Dildar,Pandit, Palash
, p. 305 - 313 (2010)
A polymer-anchored Pd(II) Schiff base complex has been synthesized by reacting a polymeric amine with 2-pyridinecarboxaldehyde to get the polymer-anchored Schiff base, which was then reacted with palladium acetate. The catalyst was characterized by physicochemical and spectroscopic methods. It shows excellent catalytic activity in the Sonogashira coupling of phenylacetylene with aryl halides using triethylamine as a base and copper iodide as a co-catalyst in water under open air at 70 °C. We have also studied the effects of base and solvent on the coupling reaction. Sonogashira reactions of phenylacetylene with a variety of functionalized aryl halides were performed under the optimized reaction conditions. This catalyst gives excellent yields without the use of phosphine ligands. Further experiments showed that the catalyst can be used five times without much loss in the catalytic activity. Springer Science+Business Media B.V. 2010.
Synthesis and characterization of nickel inverse 9-metallacrown-3, palladium-silver, and dinuclear platinum complexes containing pyrazole-functionalized NHC ligands
Chen, Chao,Qiu, Huayu,Chen, Wanzhi
, p. 8671 - 8678 (2011)
Three metallacrown nickel complexes [Ni3(μ-OH)(L1) 3](PF6)2 (1, L1 = 3-((N-methylimidazolylidenyl) methyl)-5-methylpyrazolate), [Ni3(μ-OH)(L2)3](PF 6)2 (2, L2 = 3-((N-mesitylimidazolylidenyl)methyl)-5- methylpyrazolate), and [Ni3(μ-OH)(L3)3](PF 6)2 (3, L3 = 3-((N-pyrimidin-2-ylimidazolylidenyl)methyl)- 5-methylpyrazolate) were obtained by the reactions of corresponding silver-NHC complexes with Raney nickel powder at 45 °C. The same reaction at 80 °C afforded [Ni3(L2)4](PF6)2 (4). The carbene-transfer reaction of the silver-carbene complex with [(η3-C3H5)PdCl]2 yielded the heterotrimetallic complex [AgPd2(η3-C 3H5)2(L2)2](PF6) (5), whereas the carbene-transfer reaction with Pt(cod)Cl2 gave [Pt 2(L3)2](PF6)2 (6). All of these complexes have been fully characterized by ESI-MS, NMR spectroscopy, and elemental analysis. The molecular structures of 1-6 were also studied by X-ray diffraction analysis. In 1-3, three nickel centers are bridged together by three pyrazole-NHC ligands and a hydroxide group, forming a 9-metallacrown-3 topology. Complex 4 is paramagnetic, consisting of two square-planar nickel(II) ions and one tetrahedral nickel ion in which three Ni ions are bridged by four pyrazolate units. In the mixed Pd-Ag complex 5, two palladium and one silver centers are bridged by two pyrazole-NHC ligands. Complex 5 showed good catalytic activity in the Sonogashira coupling reaction of aryl bromides and phenylacetylene under mild conditions typically catalyzed by Pd-Cu systems.
Cyclization of Diaryl(hetaryl)alkynes under Selenobromination Conditions: Regioselectivity and Mechanistic Studies
Paegle, Edgars,Belyakov, Sergey,Petrova, Marina,Liepinsh, Edvards,Arsenyan, Pavel
, p. 4389 - 4399 (2015)
The cyclization of substituted diaryl(hetaryl)alkynes with in-situ-prepared SeBr4 has been achieved. The use of an alkene additive as a bromine scavenger gives simple access to functionalized benzo[b]selenophene and selenophenothiophene derivatives from commercially available or easily accessible starting materials. The reactions can be performed in air without the use of moisture-sensitive reagents, dry solvents, or an inert atmosphere. Mechanistic studies confirmed a regioselective anti 1,2-addition in the selenobromination step, and a subsequent electrophilic substitution in the aromatic ring to complete the cyclization. The cyclization of substituted diaryl(hetaryl)alkynes with in-situ-prepared SeBr4 has been achieved. The use of an alkene additive as a bromine scavenger gives simple access to functionalized benzo[b]selenophene and selenophenothiophene derivatives from commercially available or easily accessible starting materials.
Recyclable and reusable NiCl2(PPh3)2/CuI/PEG-400/H2O system for the sonogashira coupling reaction of aryl iodides with alkynes
Wei, Ting,Zhang, Tingli,Huang, Bin,Tuo, Yuxin,Cai, Mingzhong
, p. 846 - 849 (2015)
A stable and highly efficient NiCl2(PPh3)2/CuI/PEG-400/H2O catalytic system for the Sonogashira reaction has been developed. In the presence of NiCl2(PPh3)2 and CuI, the coupling reaction of aryl iodides with terminal alkynes was carried out smoothly in a mixture of poly(ethylene glycol) (PEG-400) and water at 100C with K2CO3 as base to afford a variety of arylacetylenes in good to excellent yields. The isolation of the products was readily performed by extraction with petroleum ether, and the NiCl2(PPh3)2/CuI/PEG-400/H2O system could be easily recycled and reused six times without significant loss of catalytic activity. Our system not only avoids the use of easily volatile organic solvents but also solves the basic problem of catalyst reuse.
N-heterocyclic carbene adducts of cyclopalladated ferrocenylchloropyrimidine: Synthesis, structural characterization and application in the Sonogashira reaction
Xu, Chen,Lou, Xin-Hua,Wang, Zhi-Qiang,Fu, Wei-Jun
, p. 519 - 523 (2012)
Three N-heterocyclic carbene (NHC) adducts of cyclopalladated ferrocenylchloropyrimidine, 2-4 [PdCl{[(n5-C5H 5)]Fe[(n5-C5H3)-N2C 4H2-Cl]}(NHCs)] have been prepared by reaction of the chloride-bridged palladacyclic dimer 1 [PdCl{[(n5-C5H 5)]Fe[(n5-C5H3)-N2C 4H2-Cl]}]2 with the corresponding imidazolium salts. These complexes were characterized by elemental analysis, IR, ESI-MS and NMR. The use of these complexes as catalysts for the Sonogashira reaction was examined. Complex 4 proved to be an efficient catalyst for the Sonogashira reaction of aryl bromides and some activated aryl chlorides under copperand amine-free conditions. Typically, using 0.1-2 mol % of catalyst in the presence of 1.5 equivalents of CsOAc as base in dimethylacetamide at 120 °C provided coupling products in good yields. Springer Science+Business Media B.V. 2012.
Blue fluorescent 4a-aza-4b-boraphenanthrenes
Bosdet, Michael J. D.,Jaska, Cory A.,Piers, Warren E.,Sorensen, Ted S.,Parvez, Masood
, p. 1395 - 1398 (2007)
Figure presented Phenanthrene analogues with internalized B-N moieties were found to afford blue light emission with good quantum efficiencies, whereas the isomeric species with peripheral B-N moieties displayed only UV emission behavior, like the all-carbon framework.
Palladium particles from oxime-derived palladacycle supported on Fe3O4/oleic acid as a catalyst for the copper-free Sonogashira cross-coupling reaction
Karami, Kazem,Najvani, Samaneh Dehghani,Naeini, Nasrin Haghighat,Hervés, Pablo
, p. 1047 - 1053 (2015)
An oxime-derived palladacycle was synthesized using 4-bromobenzoxime and pyridine in CHCl3, and characterized by FT-IR and 1H NMR spectroscopy. This Pd complex was supported on Fe3O4/oleic acid and shown to be an efficient catalyst for the copper-free Sonogashira cross-coupling reaction of various aryl halides with phenylacetylene in air and in ethanol or mixed aqueous medium. The oxime-derived palladacycle gave highly active palladium nanoparticles for the organic synthesis. The coupling products were obtained in high yields with low Pd loading and the heterogeneous catalyst can be separated by an external magnet and reused six times without loss of its activity. The characterization of the catalyst was carried out by XRD, SEM and TEM. Both TEM and XRD revealed that the palladium nanoparticles were well dispersed with diameters from 5 to 10 nm and average size 9.97 nm.
