287950-96-3Relevant articles and documents
One-step synthesis of three-dimensional graphene/multiwalled carbon nanotubes/Pd composite hydrogels: An efficient recyclable catalyst for Suzuki coupling reactions
Song, Hui-Qing,Zhu, Qian,Zheng, Xue-Jing,Chen, Xing-Guo
, p. 10368 - 10377 (2015)
In this paper, a simple one-pot hydrothermal procedure to create three-dimensional (3D) graphene/multiwalled carbon nanotubes/Pd (G/MWCNTs/Pd) composite hydrogels with a unique porous nanostructure was reported. During the formation of the G/MWCNTs/Pd composites, 2D graphene sheets and 1D MWCNTs were self-assembled to form interconnected porous microstructures and ultrafine Pd NPs were in situ grown on the 3D carbon-based skeleton simultaneously. In the as-obtained nanocomposites, MWCNTs not only prevented the close restacking of graphene sheets to increase the specific surface area but also provided an additional transport path to the catalyst surfaces which facilitated reactant transport. The G/MWCNTs/Pd composites proved to be an efficient, recyclable, and robust catalyst for the Suzuki cross-coupling reactions under mild aerobic conditions, which was attributed to the 3D macroporous framework with high specific surface area, numerous activation sites, and efficient transport pathways for improving the catalytic performance. Moreover, catalyst separation could be easily achieved by simple filtration, and the catalyst could be reused for at least six runs without significant loss in catalytic activity. Additionally, nearly no Pd species was released from the G/MWCNTs/Pd composites during the catalytic reactions, showing the heterogeneity in the present catalysis system.
A cyclobutene-1,2-Bis(imidazolium) salt as efficient precursor of palladium-catalyzed room-temperature suzuki-miyaura reactions
Rahimi, Alireza,Schmidt, Andreas
, p. 1327 - 1330 (2010)
3,3-[3,4-Bis(dichloromethylene)cyclobut-1-ene-1,2-diyl]bis(1-methyl-1H- imidazolium) bis(tetrafluoroborate), palladium(II)acetate, and sodium tert-butoxide in toluene catalyze effectively Suzuki-Miyaura cross-coupling reactions of aryl bromides, chlorides, and iodides with arylboronic acids at room temperature.
Enzymatic Esterolysis of Polymers Containing 2-Biphenylyl Ester Bonds in Side Chains
Ishikawa, Tomomichi,Otsuki, Makoto,Iwatsuki, Toshiaki
, p. 3621 - 3624 (1986)
The preparation and α-chymotrypsin-catalyzed esterolysis of polymeric substrates anchoring fungicidal biphenyl-2-ol are described.In order to obtain information regarding the influence of one type of polymeric backbone and the distance between a cleavable bond and a polymer main chain, poly(2-biphenylyl acrylate), poly(2-biphenylyl methacrylate), and poly(methacryloylamino acid 2-biphenylyl ester) were studied.The esterolysis were evaluated by means of Michaelis constant Km and the catalytic reaction rate constant kcat.Poly(2-biphenylyl methacrylate) was a more suitable substrate than poly(2-biphenylyl acrylate).Poly was the most suitable substrate in a series of polymers containing amino acid side chains with 2-biphenylyl ester terminal groups.The release rate of biphenyl-2-ol could also be controlled by using copolymers with an appropriate comonomer.
Unusual Acetonitrile Adduct Formed via Photolysis of 4′-Chloro-2-Hydroxybiphenyl in Aqueous Solution
Zhang, Xiting,Guo, Yan,Dallin, Erin,Ma, Jiani,Dai, Mingdong,Phillips, David Lee
, p. 11635 - 11640 (2020)
In this work, 2,4′-dichlorobiphenyl (1) yielded 4′-chloro-2-hydroxybiphenyl (2) after photolysis in neutral acetonitrile aqueous (ACN-H2O) solutions. Ultrafast spectroscopic measurements and density functional theory (DFT) computations were performed for 2 in ACN and ACN-H2O (v/v, 1:1). These results were compared with previously published results for 2-hydroxybiphenyl (3). The counterparts 2 and 3 went through a singlet excited state intramolecular proton transfer (ESIPT) in ACN but behaved differently in ACN-H2O with a dehydrochlorination process occurring for 2 and an ESIPT taking place for 3. Computational results indicate that the phenol O-H bond elongates after photoexcitation to induce a concerted asynchronous process with the C-Cl bond increasing first followed by HCl elimination. A biradical intermediate (IM1) is then formed with some spin located at the phenyl 4′-C radical that appears to favor a hydrogen atom transfer (HAT) process and some spin located on phenoxyl that appears to prefer a subsequent a CH2CN radical rebound. The hydrogen bond promotes HCl elimination, while this is disfavored for ESIPT, making 4′-Cl extrusion the predominant process in ACN-H2O solutions. The mechanistic investigations have fundamental and significant implications for the understanding of polychlorinated biphenyl photolysis in an aqueous environment and hence the photodegradation of these kinds of pollutants in the natural environment.
Tailored synthesis of various nanomaterials by using a graphene-oxide-based gel as a nanoreactor and nanohybrid-catalyzed C-C bond formation
Biswas, Abhijit,Banerjee, Arindam
, p. 3451 - 3456 (2014)
New graphene oxide (GO)- based hydrogels that contain vitamin B2/B12 and vitamin C (ascorbic acid) have been synthesized in water (at neutral pH value). These gel-based soft materials have been used to synthesize various metal nanoparticles, including Au, Ag, and Pd nanoparticles, as well as nanoparticle-containing reduced graphene oxide (RGO)-based nanohybrid systems. This result indicates that GO-based gels can be used as versatile reactors for the synthesis of different nanomaterials and hybrid systems on the nanoscale. Moreover, the RGO-based nanohybrid hydrogel with Pd nanoparticles was used as an efficient catalyst for C-C bond-formation reactions with good yields and showed high recyclability in Suzuki-Miyaura coupling reactions.
Palladium nanoparticles supported on SiO2 by chemical vapor deposition (CVD) technique as efficient catalyst for Suzuki-Miyaura coupling of aryl bromides and iodides: Selective coupling of halophenols
Iranpoor, Nasser,Firouzabadi, Habib,Safavi, Afsaneh,Motevalli, Somayeh,Doroodmand, Mohammad M.
, p. 417 - 424 (2012)
Nanoparticles of palladium were supported on SiO2 by chemical vapor deposition technique. The obtained Pd nanocatalyst was characterized by various techniques. This catalyst was found to be very efficient for the selective cross-coupling of hydroxyl-substituted aryl iodides and bromide with arylboronic acids in water at room temperature to produce the corresponding hydroxyl-substituted biaryls. Coupling of phenylboronic acid with aryl iodides and bromides carrying substituents other than hydroxy group was also performed efficiently in refluxing ethanol. Copyright 2012 John Wiley & Sons, Ltd. Palladium nanoparticles supported on SiO2 as an efficient heterogeneous catalyst was prepared by CVD technique and applied in Suzuki coupling reaction mild conditions. The Suzuki reaction of halophenols was conducted at room temperature in the presence of this catalyst. Copyright
Synthesis and characterization of poly(biphenyl-2-yl p-styrenesulphonate) as profungicide in controlled release technique
Khazaei, Ardeshir,Soudbar, Davood,Sadri, Minoo,Hosseini, Hassan
, p. 763 - 766 (2007)
A new fungicide controlled release formulation was prepared by the reaction of p-styrenesulphonyl chloride with biphenyl-2-ol (Dowicide A) as fungicide. The resulting monomer containing the fungicide was polymerized with benzoyl peroxide as initiator. The monomer and the polymer were identified by spectroscopic methods, and molecular weight of the polymer was determined by GPC. Also mp, Tg and Td of the polymer were identified by DSC. The release characteristic of the polymer was studied in neutral, alkaline, and acidic media. Also, the effect of the temperature on the release of bioactive agent (Dowicide A) was investigated. The hydrolysis data showed that the release rates are strongly dependent upon the pH of the medium and the temperature.
Directing Effects of Phenyl Substitution in the Reaction of OH Radical with Aromatics: The Radiolytic Hydroxylation of Biphenyl
Chen, Xiaofeng,Schuler, Robert H.
, p. 421 - 425 (1993)
The initial yields for formation of 2-, 3-, and 4-hydroxybiphenyl following the radiolytic oxidation of biphenyl in the presence of ferricyanide are respectively, 1.19, 1.13, and 1.55 molecules/100 eV.These yields reflect relative rates of 0.71:0.37:1 for *OH radical attack on each of the ortho, meta, and para positions of biphenyl.Comparison of the corresponiding partial rate constants to that of benzene shows that the phenyl substitution has a significant effect in directing *OH addition to the ortho and para positions of aromatic systems.Comparison with phenol shows that a phenyl substituent has only a slightly smaller effect than does OH in increasing the partial rate constant at the ortho and para positions but is substantially less effective in decreasing the rate of *OH reaction at the meta position.
Improvement of desulfurization activity in Rhodococcus erythropolis KA2-5-1 by genetic engineering.
Hirasawa,Ishii,Kobayashi,Koizumi,Maruhashi
, p. 239 - 246 (2001)
Rhodococcus erythropolis KA2-5-1 can desulfurize dibenzothiophene (DBT) into 2-hydroxybiphenyl. A cryptic plasmid, pRC4, which was derived from R. rhodochrous IFO3338, was combined with an Escherichia coli vector to construct an E. coli-Rhodococcus shuttle vector. The complete nucleotide sequence of 2582-bp pRC4 was analyzed. Based on the characteristics of its putative replication genes, pRC4 was assigned to the family of pAL5000-related replicons. The desulfurization gene cluster, dszABC, and the related reductase gene, dszD, cloned from KA2-5-1, were reintroduced into KA2-5-1 and efficiently expressed. The DBT desulfurization ability of the transformant carrying two dszABC clusters and one dszD on the vector was about 4-fold higher than that of the parent strain, and the transformant also showed improved desulfurization activity for light gas oil (LGO). Sulfur components in LGO before and after the reaction were analyzed with gas chromatography-atomic emission detection.
Catalytic activity and facile recovery of a cyclometalated N-heterocyclic carbene palladium(II) complex immobilized by non-covalent interactions on reduced graphene oxide
Karami, Kazem,Ramezanpour, Azar,Zakariazadeh, Mostafa,Silvestru, Cristian
, (2019)
The growing concern about the potentially adverse effects of the production of chemical compounds on the sustainable development of the environment has led to a great deal of efforts to search for low-cost and environmentally friendly catalytic systems. A pyrene-tagged N-heterocyclic carbene palladacycle complex ([Pd{(C,N)C6H4CH2NH(Et)}(Imd-P)Br]) was prepared by reacting imidazolium salt with dimer ([Pd2{(C,N)C6H4CH2NH(Et)}2(μ-OAc)2]). Then, it was immobilized onto the surface of reduced graphene oxide (rGO) via π–π stacking forces. The hybrid compound ((NHC)Pd-rGO) was made in a one-step process. Various techniques were employed to characterize the compound. In addition, computational studies were used to verify the interaction between the Pd complex and rGO. The catalytic activity of the molecular complex and hybrid material was evaluated in both Suzuki–Miyaura cross-coupling reactions and reduction of p-nitrophenol to p-aminophenol. The catalytic activity of the hybrid material was enhanced in comparison with the corresponding homogeneous analogue. Thus, rGO seems to play a significant role in catalytic activity. Hot filtration experiments show the heterogeneous nature of the catalyst resulting from the strong interaction between pyrene and graphene. The hybrid (NHC)Pd-rGO material could be recycled up to six times with no decrease in catalytic activity.
