Search results for "Pyridine"
showing 10 items of 2516 documents
Crystal structure and magnetic properties of the flexible self-assembled two-dimensional square network complex [Cu2(mal)2(H2O)2(4,4′-bpy)] (H2mal=ma…
2001
Abstract The copper(II) complex [Cu 2 (mal) 2 (H 2 O) 2 (4,4′-bpy)] ( 1 ) (H 2 mal=malonic acid and 4,4′-bpy=4,4′-bipyridine) has been prepared and its structure determined by single crystal X-diffraction methods. Compound 1 has a two-dimensional square grid network structure. The square grids are stacked parallel but in a staggered manner on each other along the c -axis, with an interlayer separation of 3.850(1) A. Each layer contains a large cavity of 15.784(1)×15.784(1) A with each edge shared by one malonate group and one 4,4′-bpy ligand and a small planar square of 4.644(1)×4.644(1) A with Cu(II) ions and malonate groups at each corner and side, respectively. Each copper atom is in a d…
Magneto-structural study on a series of rhenium(IV) complexes containing biimH2, pyim and bipy ligands
2008
Abstract Three rhenium(IV) mononuclear compounds of formulae [ReCl4(biimH2)] · 2DMF (1), [ReCl4(pyim)] · DMF (2) and [ReCl4(bipy)] (3) (biimH2 = 2,2′-biimidazole, pyim = 2-(2′-pyridyl)imidazole, bipy = 2,2′-bipyridine and DMF = N,N-dimethylformamide) have been prepared and characterized. The crystal structure of 2 was determined by single crystal X-ray diffraction. Compound 2 crystallizes in the monoclinic system with P21/c as space group. The rhenium atom is six-coordinated by four Cl atoms and two nitrogen atoms from a bidentate pyim ligand [average values of Re–Cl and Re–N bonds lengths being 2.330(2) and 2.117(4) A, respectively]. The magnetic properties were investigated from susceptib…
Construction of Coordination Polymers from Semirigid Ditopic 2,2′-Biimidazole Derivatives: Synthesis, Crystal Structures, and Characterization
2017
Eight coordination polymers (CPs), {[Ag(L1)]ClO4}n (1), {[Ag(L2)1.5]ClO4·C2H3N}n (2a), {[Ag(L2)]ClO4}n (2b), [Zn(L1)Cl2]n (3), {[Zn(L2)Cl2]·CHCl3}n (4), {[Cu(L1)2Cl]Cl·H2O}n (5), [Cu2(L2)(μ-Cl)2]n (6), and [Cu4(L2)(μ-Cl)4]n (7) were synthesized via self-assembly of corresponding metal ions and biimidazole based ditopic ligands, 1,1′-bis(pyridin-3-ylmethyl)-2,2′-biimidazole L1 and 1,1′-bis(pyridin-4-ylmethyl)-2,2′-biimidazole L2. These ligands possess conformational flexibility and two pairs of coordination sites: pyridine nitrogen (NPy) atoms and imidazole nitrogen (NIm) atoms. Depending on the metal center in CPs, the biimidazole compounds act as tetra- (1, 7), tri- (2a), or bidentate (2a,…
Mononuclear Perfluoroalkyl-Heterocyclic Complexes of Pd(II): Synthesis, Structural Characterization and Antimicrobial Activity
2020
Two mononuclear Pd(II) complexes [PdCl2(pfptp)] (1) and [PdCl2(pfhtp)] (2), with ligands 2-(3-perfluoropropyl-1-methyl-1,2,4-triazole-5yl)-pyridine (pfptp) and 2-(3-perfluoroheptyl-1-methyl-1,2,4-triazole-5yl)-pyridine (pfhtp), were synthesized and structurally characterized. The two complexes showed a bidentate coordination of the ligand occurring through N atom of pyridine ring and N4 atom of 1,2,4-triazole. Both complexes showed antimicrobial activity when tested against both Gram-negative and Gram-positive bacterial strains.
[1,2,3]Triazolo[1,5-a]pyridines. A theoretical (DFT) study of the ring-chain isomerization
2008
The ring opening isomerization of [1,2,3]triazolo[1,5-a]pyridines to the corresponding 2-pyridyl derivatives has been studied by means of DFT calculations at the B3LYP/6-31+G(d,p) computational level. The effect of the substitution as well as those of protonation, deprotonation, and lithiation on different positions has been studied. The electronic characteristics of the optimized structures have been analyzed by means of the Atoms In Molecules (AIM), Electron Localization Function (ELF), Molecular Electrostatic Potential (MEP), and Natural Bond Orbital (NBO) methodologies. © 2008 Elsevier Ltd. All rights reserved.
Synaptic release of zinc from brain slices: factors governing release, imaging, and accurate calculation of concentration.
2006
Cerebrocortical neurons that store and release zinc synaptically are widely recognized as critical in maintenance of cortical excitability and in certain forms of brain injury and disease. Through the last 20 years, this synaptic release has been observed directly or indirectly and reported in more than a score of publications from over a dozen laboratories in eight countries. However, the concentration of zinc released synaptically has not been established with final certainty. In the present work we have considered six aspects of the methods for studying release that can affect the magnitude of zinc release, the imaging of the release, and the calculated concentration of released zinc. We…
CCDC 890481: Experimental Crystal Structure Determination
2013
Related Article: C.R.de Arellano, E.Escriva, C.J.Gomez-Garcia, G.M.Espallargas, R.Ballesteros, B.Abarca|2013|CrystEngComm|15|1836|doi:10.1039/c2ce26654g
Understanding the participation of 3-nitropyridine in polar Diels–Alder reactions. A DFT study
2015
The reactivity of 3-nitropyridine acting as an electrophilic dienophile in polar Diels-Alder (P-DA) reactions toward three different dienes of increased nucleophilicity has been theoretically studied using DFT methods at the MPWB1K/6-31G(d) level. It has been observed that this aromatic heterocyclic system suffers cycloaddition reactions yielding isoquinoline derivatives. The present DFT study establishes that while the P-DA reactions with isoprene and 1-methoxy-1,3-butadiene take place through a two-stage one-step mechanism, the use of the strong nucleophilic Danishefsky's diene changes the mechanism to a two-step one with formation of a zwitterionic intermediate. These P-DA reactions are …
CCDC 770750: Experimental Crystal Structure Determination
2011
Related Article: E.Nauha, A.Ojala, M.Nissinen, H.Saxell|2011|CrystEngComm|13|4956|doi:10.1039/c1ce05077j
Achieving branched polyethylene waxes by aryliminocycloocta[b]pyridylnickel precatalysts: Synthesis, characterization, and ethylene polymerization
2017
Cycloocta[b]pyridin-10-one was prepared to form the corresponding imino derivatives, which then reacted with (DME)NiBr2 to form 10-aryliminocycloocta[b]pyridylnickel bromides (Ni1–Ni5). The new compounds were characterized by means of FT-IR spectroscopy as well as elemental analysis and the organic ligands were also analyzed by the NMR measurements. Furthermore, the molecular structure of a representative complex Ni3 was determined by the single crystal X-ray diffraction, indicating the distorted tetrahedral geometry around the nickel atom. Upon the activation with either methylaluminoxane (MAO) or diethylaluminium chloride (Et2AlCl), the title nickel complexes exhibited high activity in et…