128924-07-2Relevant articles and documents
Palladium nanoparticles supported on carbon nanotubes from solventless preparations: Versatile catalysts for ligand-free Suzuki cross coupling reactions
Siamaki, Ali R.,Lin, Yi,Woodberry, Kendra,Connell, John W.,Gupton, B. Frank
, p. 12909 - 12918 (2013/10/22)
Palladium nanoparticles supported on single- or multi-walled carbon nanotubes (Pd/SWCNT and Pd/MWCNT) were prepared by a rapid, solventless method that does not require reducing agents or electric current. The method involves a straightforward process using dry mixing of a precursor Pd salt (e.g., palladium acetate) with carbon nanotubes at ambient temperature by ball-milling (mechanochemical route) or with subsequent annealing at 300°C (thermal route) in an inert atmosphere. The Pd/MWCNT sample with Pd nanoparticle size of 1-3 nm and uniform dispersion prepared by mechanochemical ball-milling at room temperature [designated as (Pd/MWCNT)M] displayed remarkable catalytic activity towards Suzuki cross coupling reactions with a high turn over number (TON) of 7250 and turn over frequency (TOF) of 217-500 h-1. These nanoparticles were characterized by a variety of techniques including transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Additionally, the (Pd/MWCNT)M sample was successfully employed in Suzuki cross coupling reactions with a wide variety of functionalized substrates.
Controlling molecular crystal polymorphism with self-assembled monolayer templates
Hiremath, Rupa,Basile, Joseph A.,Varney, Stephen W.,Swift, Jennifer A.
, p. 18321 - 18327 (2007/10/03)
The control of crystal polymorphism is a long-standing issue in solid-state chemistry, which has many practical implications for a variety of commercial applications. At least four different crystalline forms of 1,3-bis(m- nitrophenyl) urea (MNPU), a clas
Nucleophilic Substitution of Nitrite in Nitrobenzenes, Nitrobiphenyls and Nitronaphthalenes
Effenberger, Franz,Koch, Markus,Streicher, Willi
, p. 163 - 173 (2007/10/02)
Aromatic compounds, accessible only by multistep procedures, can be synthesized easily by nucleophilic substitution of nitrite in nitrobenzenes, nitrobiphenyls, and nitronaphthalines.Thus, meta-substituted phenols 3, 4, and 7 are obtained from 1,3-dinitrobenzene (1) and meta-substituted nitrobenzenes 6, as well as 3,5-disubstituted phenols 10 and 5-substituted resorcinol derivatives 11 from 3,5-disubstituted nitrobenzenes 9.The unsymmetrically substituted nitrobiphenyls 13, 15, 17, 19, 23, 24, and 26 are also available by nitrite exchange from the corresponding easily accessible dinitrobiphenyls 16, 18, 20, 22, and 25.A nitrite exchange with nucleophiles is easily possible in the 1,5-disubstituted naphthalenes 29, 34, while in the case of the 1,8-disubstituted naphthalenes 31, 36 only the chloro derivative 36 undergoes this exchange under much stronger conditions in low yield.
Efficient palladium-catalyzed synthesis of unsymmetrical donor-acceptor biaryls and polyaryls
Amatore, Christian,Jutand, Anny,Negri, Serge,Fauvarque, Jean-Francois
, p. 389 - 398 (2007/10/02)
4,4'-Unsymmetrically substituted biphenyls can be synthesized by cross-coupling reactions of substituted aromatic organometallic reagents and aromatic halides catalyzed by palladium complexes.This two-step method from commercially available aromatic halides has been used for the synthesis of a series of donor/acceptor para-substituted biphenyls, D-C6H4-C6H4-A, where D is an electron donor group and A an electron acceptor group, which are of interst as liquid crystal precursors and as having potential in non-linear optics.Biaryls in which the donor-phenyl moiety is replaced by a 2-furyl or 2-thienyl can be synthesized similarly.The method can also be used for the convergent synthesis of previously unreported unsymmetrically substituted polyparaphenylenes D-(C6H4)n-A (n = 3, 4).
