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-
Reactions of tris(2-pyridyl)phosphine oxides with electrophiles: Formation of 5-substituted 2, 2′-bipyridyls
Uchida, Yuzuru,Matsumoto, Masami,Kawamura, Haruyasu
, p. 72 - 81 (2003)
The reaction of tris (2-pyridyl)phosphine oxides with benzeneselenenyl chloride in methanol gave the corresponding 5-phenylseleno-2, 2′-bipyridyls together with a small amount of 2, 2′-bipyridyls. Similarly, the reaction with arenesulfenyl chlorides in aqueous acetonitrile afforded two kinds of coupling products, 5-phenylthio-2, 2′-bipyridyls and 2, 2′-bipyridyls. While in the reaction with arenesulfinyl chlorides in aqueous acetonitrile, four corresponding bipyridyl derivatives, 2, 2′-bipyridyls, 5-aryhhio-2, 2′-bipyridyls, 5-arylsulfinyl-2, 2′-bipyridyls, and 5-arylsulfonyl-2, 2′-bipyridyls, were formed.
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.
Synthesis of dimethylbipyridines by the reductive coupling of 2-halomethylpyridines with nickel catalyst
Rajalakshmanan,Alexander
, p. 891 - 895 (2005)
The one-pot synthesis of 4,4′-dimethyl-2,2′-bipyridine and 6,6′-dimethyl-2,2′-bipyridine by the reductive coupling of 2-bromo-4-methylpyridine and 2-bromo-6-methylpyridine, respectively, with nickel catalyst, generated in situ by the reduction of Ni(PPh3) 2Cl2 with zinc in the presence of Et4NI, is described.
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.
Electrochemical and Spectral investigations of Ring-Substituted Bipyridine Complexes of Ruthenium
Elliott, C. Michael,Hershenhart, Elise J.
, p. 7519 - 7526 (1982)
A spectroelectrochemical study of a series of Ru complexes has been carried out by using an optically transparent thin-layer electrode (OTTLE).The visible spectra of the reduced complexes Ru(Bp5COOEt)3n (Bp5COOEt = 5,5'-bis(ethoxycarbonyl)-2,2'-bipyridine) and Ru(bpy)3n (bpy = bipyridine) appear to resemble the spectra of the corresponding ligand radical anion whereas the spectrum of Ru(Bp4COOEt)3n (Bp4COOEt = 4,4'-bis(ethoxycarbonyl)-2,2'-bipyridine) does not.In the near-IR two types of spectral behavior are observed once the complexes are reduced beyong the 2+ oxidation state: Type A complexes (e.g., Ru(bpy)3, Ru(Bp4Me)3 (Bp4Me = 4,4'-dimethyl-2,2'-bipyridine)) exhibit low-intensity (ε n, Ru(Bp4CONEt)3n (Bp4CONEt = 4,4'-bis(diethylcarbamyl)-2,2'-bipyridine)) exhibit broad bands of greater intensity (1000 ε 15000).Possible origins for type B behavior are discussed.Examination of electrochemical results reveals an almost perfect linear correlation when ligand reduction potentials are plotted against the 2+/1+ couple of the corresponding ruthenium complex (correlation coefficient = 0.9993).The thermodynamic applications of this observation are considered.Both the spectral and electrochemical data support a model of the reduced metal complex having electrons localized in ligand orbitals.
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 palladium oxide catalysts supported on nanoparticle metal oxides for the oxidative coupling of 4-methylpyridine
Neal, Luke M.,Everett, Michael L.,Hoflund, Gar B.,Hagelin-Weaver, Helena E.
, p. 210 - 221 (2011)
Palladium catalysts supported on various metal oxides were characterized using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and transmission electron microscopy (TEM) to investigate why these catalysts do not show any correlation between the measured Pd surface area and the catalytic activity for the oxidative coupling of 4-methylpyridine to 4,4′-dimethyl- 2,2′-bipyridine. The XPS data confirm the classification of n-Al 2O3(+), n-MgO and p-SiO2 as non-interacting supports, since the Pd 3d5/2 binding energy (BE) of palladium on these supports is 336.1 eV, consistent with bulk PdO. In contrast, catalysts supported on p-TiO2, n-ZnO, n-ZrO2, n-ZrO 2(CeO2), and n-CeO2 have Pd 3d5/2 BEs ranging from 336.3 to 337.4 eV, which reveal varying degrees of metal-support interactions. Metal support interactions leading to electron deficient Pd2+ species are likely beneficial for the reaction due to a facilitated C-H insertion step. While both the PdO/p-TiO2 and PdO/n-TiO2 catalysts have a Pd 3d BE of 336.3 eV, their differences in activity can be attributed to (1) the PdO/n-TiO2 catalyst as prepared having a significantly higher number of hydroxyl groups on the surface compared with the PdO/p-TiO2 catalyst, and (2) the p-TiO2 support being crystalline with an anatase phase, while the n-TiO2 support is nearly amorphous. The presence of surface hydroxyl groups before reaction could hinder the first C-H activation step, and an anatase phase of the support can result in more favorable palladium-support interactions compared with an amorphous TiO2. The XPS data also indicates that while Pd-support interactions are beneficial, very strong interactions, such as in the case of CeO2, can lead to migration of the support over Pd, which reduces the Pd surface area and explains the lower than expected activity of the PdO/n-CeO2 catalyst. On some supports in this study leaching may occur during the reaction, but the characterization data indicate that other factors of catalyst deactivation are more important. XRD reveals that the complete reduction of the PdO particles on the surface is very fast compared to the reaction time. This observation explains why reducible supports with mobile oxygen are beneficial in this reaction. These supports can facilitate the reoxidation of palladium due to strong metal-support interactions. Migration of the support over the active palladium species is another deactivation pathway that appears to be more severe than leaching on these catalysts.
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.
Side-chain retention during lithiation of 4-picoline and 3,4-lutidine: Easy access to molecular diversity in pyridine series
Kaminski, Thomas,Gros, Philippe,Fort, Yves
, p. 3855 - 3860 (2003)
The first direct ring-selective lithiation of 4-picoline and 3,4-lutidine has been achieved through the use of BuLi/LiDMAE aggregates to prevent the usual side-chain metallation. Several functionalities have been introduced at the C-2, C-6 and C-5 positions by ring-selective sequential lithiation, opening a simple and fast route to polysubstituted pyridine building blocks. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
