366-18-7Relevant articles and documents
INVESTIGATION OF THE INTERACTION OF PYRIDINE WITH THE SURFACE OF LAMINAR SILICATES BY THE METHOD OF OPTICAL ELECTRONIC SPECTROSCOPY.
Sivalov,Tarasevich
, p. 214 - 218 (1981)
A study of the nature of the active sites on the surface of laminar silicates and an attempt to identify those that are responsible for the observed conversion of sorbed pyridine on the surface of laminar silicate to more complex formations characterized by a rather developed system of conjugated pi -bonds are discussed.
General Method for Synthesis of Bipyridines: Palladium Catalyzed Cross-coupling Reaction of Trimethylstannylpyridines with Bromopyridines
Yamamoto, Yutaka,Azuma, Yutaka,Mitoh, Hiroyuki
, p. 564 - 565 (1986)
Trimethylstannylpyridines 1 were treated with bromopyridines 2 in the presence of catalytic amount of tetrakis(triphenylphosphine)palladium to give the corresponding bipyridines 3 in moderate to good yields.Nicotelline (6) was similarly synthesized from 2,4-bis(trimethylstannyl)pyridine (5) and 3-bromopyridine (2b).
Mild and efficient formation of symmetric biaryls via Pd(II) catalysts and Cu(II) oxidants
Parrish, Jay P.,Flanders, Vincent L.,Floyd, Ryan J.,Jung, Kyung Woon
, p. 7729 - 7731 (2001)
Described herein is a mild and efficient palladium-catalyzed synthesis of symmetric biaryls from organostannanes. This methodology offers products rapidly in very high yields.
Cation-Assisted Ligand Photosubstitution in Transition-Metal Complexes. Photoreactions of Ru(bpy)32+ with Ag+ in Acetonitrile
Foreman, T. K.,Bonilha, J. B. S.,Whitten, D. G.
, p. 3436 - 3439 (1982)
Irradiation of Ru(bpy)32+ in the presence of Ag+ in acetonitrile leads to the photosubstitution product Ru(bpy)2(CH3CN)22+.The reaction does not occur in the absence of Ag+ or acetonitrile; although Ag+ quenches the luminescent MLCT state of Ru(bpy)32+, a kinetic analysis indicates the photosubstitution does not originate from this excited state.The most reasonable mechanism for the process involves decay of the MLCT state via a d-d excited state to a ligand-labilized intermediate which is interpreted by Ag+ in a process which assists the substitution by removal of a bpy ligand.This mechanism is thus parallel to anion-induced substitution reactions which evidently proceed via competitive anion-ligand capture of the same or similar intermediates.
Photoactivatable RuII Complex Bearing 2,9-Diphenyl-1,10-phenanthroline: Unusual Photochemistry and Significant Potency on Cisplatin-Resistant Cell Lines
Mansour, Najwa,Mehanna, Stephanie,Mroueh, Mohamad A.,Audi, Hassib,Bodman-Smith, Kikki,Daher, Costantine F.,Taleb, Robin I.,El-Sibai, Mirvat,Khnayzer, Rony S.
, p. 2524 - 2532 (2018)
The current study investigates [Ru(bipy)2(dpphen)]Cl2 [where bipy = 2,2′-bipyridine and dpphen = 2,9-diphenyl-1,10-phenanthroline] (complex 1) for photoactivatable chemotherapy (PACT) application on five cancer cell lines. [Ru(bipy)2(phen)]Cl2 [where phen = 1,10-phenanthroline] (complex 2) was included as an unstrained control. Upon excitation with visible light, complex 2 proved to be photostable while complex 1 underwent a quantitative dissociation of the bipy ligand and formation of a RuII polypyridyl aqua complex in water. Complex 1 demonstrated only marginal activity in the dark; its cytotoxicity increased significantly upon photoactivation with a high phototoxicity index (PI = [IC50 dark]/[IC50 light]) ranging from 39.2-fold in A549 to over 100-fold in MDA-MB-231. Complex 2, on the other hand, did not show much difference in anticancer activity between dark and light conditions. Importantly, the IC50 of the photoproduct of complex 1 was several folds lower than that of cisplatin in all tested cell lines. Furthermore, the dissociating ligand (bipy) was biologically inert in almost all cell lines investigated confirming that phototoxicity was mediated primarily by the Ru aqua complex that is released upon irradiation. In conclusion, the Ru-centered complex 1 could represent a potential photoactivatable chemotherapeutic drug that increases selectivity to tumors and offers alternative treatment in the light of increasing cisplatin resistance.
Acid directed in situ oxidation and decarboxylation of 4,4′,6, 6′-tetra-methyl-2,2′-bipyridine: Synthesis and structural characterisation of 4,4′,6-tri-carboxy-2,2′-bipyridine and its copper(II) coordination polymer
Kelly, Niamh R.,Goetz, Sandrine,Hawes, Chris S.,Kruger, Paul E.
, p. 102 - 109 (2013)
The reaction of either 4,4′,6,6′-tetramethyl-2,2′- bipyridine, L, or 4,4′,6,6′-tetracarboxy-2,2′-bipyridine, H4L, with Cu(OAc)2·H2O under acidic hydrothermal conditions (50:1 H2O/HNO3; 160 °C) led to the formation of crystalline {[Cu(HL′)(H2O)]·H 2O}, 1, which was structurally characterised to identify H 3L′ as 4,4′,6-tricarboxy-2,2′-bipyridine. Clearly, in situ mono-decarboxylation of a tetracarboxylic acid ligand gave the tricarboxy-analogue, H3L′. The structure of 1 consists of a 1D coordination polymer that cross-links through hydrogen-bonding between adjacent carboxylic acid and carboxylate groups, as well as through an aqua ligand and lattice water molecule, to form a densely interconnected 3D network. Regioselective mono-decarboxylation of L or H4L at the 6′-carboxylic acid position may also be affected by heating L or H 4L in acidic solution under hydrothermal conditions (2:1 H 2O/HNO3; 160°C) to yield crystalline 4,4′,6-tricarboxy-2,2′-bipyridinium nitrate hydrate {[H 4L′][NO3]·H2O}, 2, which was also structural characterised. The structure of 2 features an array of hydrogen-bonding interactions that generate a 3D network. More forceful heating of the acidic solution at 180°C led to double decarboxylation and the formation of 4,4′-dicarboxy-2,2′-bipyridine, whereas heating at 200°C led to total decarboxylation and the formation of 2,2′- bipyridine. Details of the structures of 1 and 2 along with their synthesis are discussed.
Excited state dynamics of organo-lanthanide electroluminescent phosphors: The properties of Tb(tb-pmp)3 and Gd(tb-pmp)3
Thorne,Rey,Denning,Watkins,Etchells,Green,Christou
, p. 4014 - 4021 (2002)
The excitation energy transfer rates between the excited states of a Tb(III) complex containing the ligand 1-phenyl-3-methyl-4-(trimethylacetyl)pyrazol-4-one, are described. Energy transfer rate constants are derived from time-gated and time-correlated single photon counting measurements. Comparison with the analogous Gd(III) complex shows that there is efficient intramolecular energy transfer from a singlet state of the ligand to excited terbium f-electron states. There is no evidence of bi-exciton annihilation in these materials, even at very high exciton densities. The use of this complex as the active medium for electroluminescent device applications is addressed. We note the particular properties of the ligand which make it suitable for this application and suggest possible improvements.
DIMER FORMATION IN THE REACTION OF ARYL HALIDES CATALYZED BY NICKEL COMPLEXES
Budnikova, Yu. G.,Kargin, Yu. M.,Yanilkin, V. V.
, p. 1299 - 1300 (1992)
The synthesis of diaryls catalyzed by electrochemically generated zero-valent nickel with 2,2'-dipyridyl as the ligand was carried out from aryl halides in high yield.Feasibility was demonstrated for synthesizing the catalyst itself by the anodic dissolution of nickel in the presence of 2-bromopyridine in a diaphragmless cell.Keywords: synthesis, diaryls, aryl halides.
The use of Ni(CO)2(PPh3)2 in aryl and pyridyl coupling reactions
Leadbeater, Nicholas E.,Resouly, Sarah M.
, p. 4243 - 4246 (1999)
The zerovalent nickel complex Ni(CO)2(PPh3)2 has been used for the coupling of aryl halides to form biaryls and for the coupling of bromopyridines to form polypyridines. The effects of solvent, halide and substituents have also been investigated.
Phototoxicity of strained Ru(II) complexes: Is it the metal complex or the dissociating ligand?
Azar, Daniel F.,Audi, Hassib,Farhat, Stephanie,El-Sibai, Mirvat,Abi-Habib, Ralph J.,Khnayzer, Rony S.
, p. 11529 - 11532 (2017)
A photochemically dissociating ligand in Ru(bpy)2(dmphen)Cl2 [bpy = 2,2′-bipyridine; dmphen = 2,9-dimethyl-1,10-phenanthroline] was found to be more cytotoxic on the ML-2 Acute Myeloid Leukemia cell line than Ru(bpy)2(H2O)22+ and prototypical cisplatin. Our findings illustrate the potential potency of diimine ligands in photoactivatable Ru(ii) complexes.
