1134-35-6Relevant articles and documents
Thermodynamic studies of the binding of bidentate nitrogen donors with methyltrioxorhenium (MTO) in CHCl3 solution
Nabavizadeh, S. Masoud
, p. 1644 - 1648 (2005)
Methyltrioxorhenium (MTO) adduct formation with bidentate nitrogen donors 2,2′-bipyridine (bpy), 4,4′-dimethyl-2,2′-bipyridine (Me 2bpy), 4,4′-di-tert-butyl-2,2′-bipyridine ( tBu2bpy), 1,10-phenanthroline (phen), 5-methyl-
Arenesulfonyl halides: A universal class of functional initiators for metal-catalyzed 'living' radical polymerization of styrene(s), methacrylates, and acrylates
Percec,Barboiu,Kim
, p. 305 - 316 (1998)
The complex Cu(I)Cl/4,4'-dinonyl-2,2'-bipyridine (bpy9) catalyzes via a redox process the homogeneous 'living' radical polymerization of styrene(s), methacrylates, and acrylates initiated with a variety of functional phenylsulfonyl chlorides. Polymers with narrow molecular weight distribution and molecular weights close to the theoretical ones are obtained from these three classes of monomers. Kinetics of propagation and initiation were performed with selected substituted phenylsulfonyl chlorides and with their monoadducts to monomer. Polymerizations follow first-order kinetics internally in monomer and externally in Cu(I)Cl while initiation is first order internally in initiator and in Cu(I)Cl concentrations. A catalyst concentration dependence of the optimum bpy9/Cu(I)Cl ratio which yields the largest rate constant of polymerization was observed. The apparent rate constants of propagation corrected for catalyst concentration are in the order: methacrylates > styrene > acrylates. This inversion from the classic dependence of the corresponding absolute rate constants (acrylates > methacrylates > styrene) was shown to be determined by a different steady-state concentration of propagating radicals which is in dynamic equilibrium with an extremely large excess of the corresponding dormant C-Cl species. The formation and the concentration of the radical species is determined by the C-Cl bond strength of the dormant species. Apparent rate constants of initiation corrected for catalyst concentration are in the order: styrene > methacrylates > acrylates. Within experimental error, initiation efficiency is 100% and the apparent rate constants of initiation are 4 (for styrene and methacrylates) and 3 or 2 (for acrylates) orders of magnitude higher than those of propagation. The absence of conjugation between the sulfonyl radical and its phenyl group generates a small effect of the phenyl group substituent on the rate constant of initiation. These results demonstrate that arenesulfonyl chlorides are the first class of universal functional initiators for the metal-catalyzed 'living' radical polymerization of styrene(s), methacrylates, and acrylates. This discovery provides numerous fundamental and technological opportunities in the field of controlled radical polymerization and copolymerization, of well-defined functional polymers and copolymers with complex architecture, and of self-organized supramolecular systems based on them. The experimental results demonstrate that arenesulfonyl halides, are the first class of universal functional initiators for the metal-catalyzed living radical polymerization of styrene(s), methacrylates and acrylates. This discovery provides numerous fundamental and technological opportunities in the field of controlled radical polymerization and copolymerization, of well-defined functional polymers and copolymers with complex architecture, and of self-organized supramolecular systems based on them.
Electrochemical homocoupling of 2-bromomethylpyridines catalyzed by nickel complexes
De Franca, Kelnner W. R.,Navarro, Marcelo,Leonel, Eric,Durandetti, Muriel,Nedelec, Jean-Yves
, p. 1838 - 1842 (2002)
2,2′-Bipyridine (bpy) and a series of dimethyl-2,2′-bipyridines were synthesized from 2-bromopyridine and 2-bromomethylpyridines, respectively, using an electrochemical process catalyzed by nickel complexes. The method is simple and efficient, with isolated yields between 58 and 98% according to the structure. We first studied the influence of the presence and the position of the methyl group on the yield, using N,N-dimethylformamide (DMF) or acetonitrile (AN) as the solvent, NiBr2bpy as the catalyst, and Zn as the sacrificial anode, in an undivided cell and at ambient temperature. On the basis of a better understanding of the reaction mechanism based on electroanalytical studies, we could improve the dimerization both by substituting the catalyst ligand (bpy) by the reagent itself, i.e., 2-bromomethylpyridine or 2-bromopyridine, and by using Fe instead of Zn as the sacrificial anode.
Convergent access to bis-1,2,4-triazinyl-2,2′-bipyridines (BTBPs) and 2,2′-bipyridines: Via a Pd-catalyzed Ullman-type reaction
Carrick, Jesse D.,Waters, Gabrielle D.
, p. 10807 - 10815 (2020)
Multidentate, soft-Lewis basic, complexant scaffolds have displayed significant potential in the discrete speciation of the minor actinides from the neutron-absorbing lanthanides resident in spent nuclear fuel. Efforts to devise convergent synthetic strategies to targets of interest to improve liquid-liquid separation outcomes continue, but significant challenges to improve solubility in process-relevant diluents to effectively define meaningful structure-activity relationships remain. In the current work, a synthetic method to achieve the challenging 2,2′-bipyridine bond of the bis-1,2,4-triazinyl-2,2′-bipyridine (BTBP) complexant class leveraging a Pd-catalyzed Ullman-type coupling is reported. This convergent strategy improves upon earlier work focused on linear synthetic access to the BTBP complexant moiety. Method optimization, relevant substrate scope and application, as well as a preliminary mechanistic interrogation are reported herein.
Characterization of alumina-supported palladium oxide catalysts used in the oxidative coupling of 4-methylpyridine
Neal, Luke M.,Jones, Samuel D.,Everett, Michael L.,Hoflund, Gar B.,Hagelin-Weaver, Helena E.
, p. 25 - 35 (2010)
A number of PdO/Al2O3 catalysts were characterized using XPS, TEM and XRD. The results reveal that the most active catalysts (palladium oxide supported on nanoparticle alumina; PdO/n-Al2O 3(+)) have both PdOx (x > 1) and Pd0 species, in addition to PdO, on the surface. Small nm-sized structures in the support are also important for a high catalytic activity.
Mixed effect of the supporting electrolyte and the zinc anode in the electrochemical homocoupling of 2-bromopyridines catalyzed by nickel complexes in an undivided cell
De Franca, Kelnner W. R.,De Lira Oliveira, Jadson,Florencio, Tupolevck,Da Silva, Aderivaldo P.,Navarro, Marcelo,Leonel, Eric,Nedelec, Jean-Yves
, p. 10778 - 10781 (2005)
Nickel-catalyzed electroreductive homocoupling of 2-bromomethylpyridines and 2-bromopyridine has been investigated in an undivided cell in the presence of a zinc sacrificial anode. A series of reactions were performed with various types and concentrations of supporting electrolyte. It was observed that a key step in this process is the formation of an arylzinc through a nickel-zinc transmetalation. This intermediate can be transformed back to the reactive arylnickel species to afford the homocoupling as the final product. The back process from the arylzinc intermediate is, however, suppressed in the presence of high concentration (0.2 M) of tetraalkylammonium salts. On the contrary, with NaI, the formation of the dimer is not prevented, whatever the NaI concentration.
Synthesis, structural characterization, and initial electroluminescent properties of bis-cycloiridiated complexes of 2-(3,5-bis(trifluoromethyl)phenyl)-4-methylpyridine
Ionkin, Alex S.,Wang, Ying,Marshall, William J.,Petrov, Viacheslav A.
, p. 4809 - 4827 (2007)
A series of bis-cyclometalated Ir(III) complexes (8-10, 12, 15, 17, 19, 21, 23, 25, 28, 29 and 33) bearing two chromophoric N∧C cyclometalated ligands derived from 2-(3,5-bis(trifluoromethyl)phenyl)-4-methylpyridine (1) and a third nonchromophoric ligand has been synthesized. A palladium-catalyzed cross-coupling reaction between 2-chloro-4-methylpyridine (2) and 3,5-bis(trifluoromethyl)phenylboronic acid (3) was used to prepare 2-(3,5-bis(trifluoromethyl)phenyl)-4-methylpyridine (1). Cyclometalation of (1) by IrCl3 was carried out in (MeO)3P{double bond, long}O, with the formation of chloro-bridged dimer [N∧C]2Ir(μ-Cl)2Ir[C∧N]2 (8). Reaction of (8) with lithium 2,4-pentanedionate, lithium 2,2,6,6-tetramethyl-heptane-3,5-dionate (13), dipivaloyltrimethylsilylphosphine (14), 2,2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-octadione (16), 1,1,1,3,3,3-hexafluoro-2-pyridin-2-yl-propan-2-ol (18), 1,1,1,3,3,3-hexafluoro-2-pyrazol-1-ylmethyl-propan-2-ol (20), 2-diphenylphosphanylethanol (22), and 1-diphenylphosphanylpropan-2-ol (24), afforded octahedral iridium complexes 9, 12, 15, 17, 19, 21, 23 and 25, respectively. Complex 10, which contains three different ligands (L1 = N∧C of 1; L2 = N∧C of 4,4′-dimethyl-[2,2′]bipyridinyl 4; L3 = O∧O of 2,4-pentanedione), and complex 11, which contains no cyclometalated ligands (L1 = 4; L2 = L3 = Cl; L4 = O∧O of 2,4-pentanedione) were also isolated as minor products in a one-pot reaction between a 94:5 mixture of 1 and 4, IrCl3 and lithium 2,4-pentanedionate. Reaction of 8 with diphenylphosphanylmethanol (27) in 1,2-dichloroethane unexpectedly led to complexes 28 and 29. The reactions of 8 with benzoylformic acid resulted in the formation of hydroxyl-bridged dimer [N∧C]2Ir(μ-OH)2Ir[C∧N]2 (33). According to X-ray analyses, Ir-to-Ir distances in the crystal cell increase from 6.86 A? for 10 to 13.31 A? for 33. The angle theta, which represents the twisting of two cyclometalated C-Ir-N planes relative to each other, varies from 97.5° for 21 to 90.76 for complex 28. OLED devices were fabricated from several Ir complexes and preliminary results are discussed.
Structural and Synthetic Insights into Pyridine Homocouplings Mediated by a β-Diketiminato Magnesium Amide Complex
Davin, Laia,Clegg, William,Kennedy, Alan R.,Probert, Michael R.,McLellan, Ross,Hevia, Eva
, p. 14830 - 14835 (2018)
The reaction of [(DippNacnac)Mg(TMP)] (1) with 4-subtituted pyridines proceeds via sequential regioselective metallation and 1,2-addition to furnish a range of symmetric 4,4′-R2-2,2′-bipyridines in good yield, representing a new entry into bipyridine synthesis. Interestingly, the reaction of 1 with 2-OMe-pyridine led to formation of asymmetric bipyridine 6, resulting from the C6-magnesiation of the heterocycle followed by a C?C coupling step by addition to the C2 position of a second, non-metallated molecule, and subsequent elimination of [DippNacnacMgOMe]2 (7). Synthesis combined with spectroscopic and structural analysis help rationalise the underlying processes resulting in the observed reactivity, and elucidate the key role that the sterically encumbered β-diketiminate ligand plays in determining regioselectivity.
High-intensity ultrasound and microwave, alone or combined, promote Pd/C-catalyzed aryl-aryl couplings
Cravotto, Giancarlo,Beggiato, Marina,Penoni, Andrea,Palmisano, Giovanni,Tollari, Stefano,Lévêque, Jean-Marc,Bonrath, Werner
, p. 2267 - 2271 (2005)
Pd-catalyzed homo- and cross-couplings of boronic acids and aryl halides were successfully carried out both in aqueous media under high-intensity ultrasound (US) and in DME under microwave (MW). Heterogeneous catalysis with Pd/C was employed, avoiding phosphine ligands and phase-transfer catalysts. In a trial series involving 15 different iodo- and bromoaryls and 7 boronic acids, both energy sources drastically reduced reaction times affording biaryls in acceptable to good yields. With palladium(II) acetate as catalyst, electron-deficient aryl chlorides also reacted, affording a few biaryls in acceptable yields. Ullmann-type zinc-mediated homocoupling of iodo- and bromoaryls in the presence of Pd/C under CO2 atmosphere was achieved in aqueous media under US, though not under MW. Suzuki homo- and cross-couplings were also carried out in a new reactor developed in our laboratory, featuring combined US and MW irradiation, further improving a green synthetic method.
Stille-type cross-coupling - An efficient way to various symmetrically and unsymmetrically substituted methyl-bipyridines: Toward new ATRP catalysts
Schubert, Ulrich S.,Eschbaumer, Christian,Heller, Marcel
, p. 3373 - 3376 (2000)
(matrix presented) Various mono- and disubstituted 2,2′-bipyridines were synthesized in high yields and multigram scales utilizing Stille-type coupling procedures. The corresponding bromo-picoline and tributyltin-picoline building blocks were prepared from commercially available amino-picoline compounds. As first examples of metal complexes, 4,5′-dimethyl-2,2′-bipyridine was reacted with copper(II) and iron(II) ions and investigated as catalyst in ATRP.
METHOD FOR COUPLING HALOGENATED PYRIDINE COMPOUND WITH HALOGENATED AROMATIC COMPOUND
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Paragraph 0066, (2020/10/20)
There is a demand for the development of a technique according to which a reaction for coupling a halogenated pyridine compound with a halogenated aromatic compound can be performed in a simple manner through a small number of steps without using expensive agents such as a palladium catalyst. A method for coupling a halogenated pyridine compound with a halogenated aromatic compound includes a step of coupling a halogenated pyridine compound with a halogenated aromatic compound to obtain a pyridine compound by reacting, in a reaction solvent, the halogenated pyridine compound and the halogenated aromatic compound with a solution containing an alkali metal.
Dehydrogenative Synthesis of 2,2′-Bipyridyls through Regioselective Pyridine Dimerization
Yamada, Shuya,Kaneda, Takeshi,Steib, Philip,Murakami, Kei,Itami, Kenichiro
supporting information, p. 8341 - 8345 (2019/04/30)
2,2′-Bipyridyls have been utilized as indispensable ligands in metal-catalyzed reactions. The most streamlined approach for the synthesis of 2,2′-bipyridyls is the dehydrogenative dimerization of unfunctionalized pyridine. Herein, we report on the palladium-catalyzed dehydrogenative synthesis of 2,2′-bipyridyl derivatives. The Pd catalysis effectively works with an AgI salt as the oxidant in the presence of pivalic acid. A variety of pyridines regioselectively react at the C2-positions. This dimerization method is applicable for challenging substrates such as sterically hindered 3-substituted pyridines, where the pyridines regioselectively react at the C2-position. This reaction enables the concise synthesis of twisted 3,3′-disubstituted-2,2′-bipyridyls as an underdeveloped class of ligands.
