Search results for "complexe"
showing 10 items of 920 documents
Photoinduced electron transfer in supramolecular complexes of a π-extended viologen with porphyrin monomer and dimer
2012
A π-extended viologen has been synthesized, forming supramolecular complexes with a freebase tetraphenylporphyrin (H2TPP) and the cofacial porphyrin dimer with an anthracene spacer [H4(DPA)] through π–π interaction in benzonitrile (PhCN). Formation of the H2TPP-BHV2+ supramolecular complex was probed by UV-vis and fluorescence spectra. The fluorescence of H2TPP was strongly quenched by electron transfer from the singlet excited state (1H2TPP*) to BHV2+ in the supramolecular complex. The transient absorption spectrum of the charge-separated (CS) state (H2TPP•+ and BHV•+) was successfully detected by the laser flash photolysis measurements of the H2TPP-BHV2+ supramolecular complex in PhCN. Th…
ChemInform Abstract: Ternary Complexes of Cimetidine and Phenobarbital with Cu(II) in Methanolic Solution.
1986
The formation constants of the binary complexes Cu(CM)2+ and Cu(CM) 2 2+ as well as those of the ternary complexes Cu(CM)L + and Cu(CM)2 L + (CM=Cimetidine=N-Cyano-N′-methyl-N″[(5-methyl-1H-imidazol-4-yl)methyltioethyl]-guanidine; HL=Phenobarbital=5-ethyl-5-phenyl-barbituric acid) have been determined in 0.1 and 1.0 mol dm−3 NaClO4 methanol solutions at 25±0.2°C. The values of logX, log βstat.., and Δ logK confirm the stability of the ternary complexes.
Electrochemical determination of the stability of complexes formed by proton-ionizable ligands of 3,5-disubstituted 1H-pyrazole with phenethylamine
1999
The application of two extreme models for diffusion in two-component systems to electrochemically determine equilibrium constants is discussed. The application of cyclic voltammetric, diferential pulse and rotating-disc electrode voltammetric data to elucidate the stoichiometry and formation constant of complex species by applying a generalization of the molar-ratio method is described. Molar-ratio experiments permit the distinction between the limiting diffusive regimes. The values of the equilibrium stability constants for complexation of phenethylamine and phenethylammonium ions by a 26-membered dioxotetraester crown of 3,5-disubstituted 1H-pyrazole as free ligand 1[L] and as dipyrazolat…
Ternary complexes of cimetidine and phenobarbital with Cu(II) in methanolic solution
1986
The formation constants of the binary complexes Cu(CM)2+ and Cu(CM) 2 2+ as well as those of the ternary complexes Cu(CM)L + and Cu(CM)2 L + (CM=Cimetidine=N-Cyano-N′-methyl-N″[(5-methyl-1H-imidazol-4-yl)methyltioethyl]-guanidine; HL=Phenobarbital=5-ethyl-5-phenyl-barbituric acid) have been determined in 0.1 and 1.0 mol dm−3 NaClO4 methanol solutions at 25±0.2°C. The values of logX, log βstat.., and Δ logK confirm the stability of the ternary complexes.
Atrane complexes chemistry as a tool for obtaining trimodal UVM-7-like porous silica
2018
[EN] The use of atrane complexes as hydrolytic precursors enables the homogeneous incorporation of manganese (25Si/Mn48) throughout the porous walls of the nanoparticles of a surfactant-templated bimodal mesoporous silica (UVM-7). The subsequent leaching of the manganese nanodomains allows adding controlled microporosity to the host silica framework. The resulting final silica material presents three pore systems structured at different length scales: interparticle textural-type macroporosity (ca. 43.2nm), ordered intraparticle mesoporosity (ca. 2.63nm; after template removal), and well-dispersed microporosity (< 2nm; as consequence of the lixiviation of the Mn-rich domains). The good dispe…
Base-assisted synthesis of 4-pyridinate gold(I) metallaligands: a study of their use in self-assembly reactions
2021
Made available in DSpace on 2021-06-25T12:16:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-06 Ministerio de Economia y Competitividad (MINECO/FEDER) of Spain Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The synthesis of di- and tritopic gold(I) metallaligands of the type [(Au4-py)(2)(mu(2)-diphosphane)] (diphosphane = bis(diphenylphosphanyl)isopropane or dppip (1), 1,2-bis(diphenylphosphanyl)ethane or dppe (2), 1,3-bis(diphenylphosphanyl)propane or dppp (3) and 1,4-bis(diphenylphosphanyl)butane or dppb (4)) and [(Au4-py)(3)(mu(3)-triphosphane)] (triphosphane = 1,1,1-tris(diphenylphosph…
Etude analytique en régime dynamique des performances thermiques des parois en blocs de terre stabilisée
2023
L’objectif visé à travers cette étude est de parvenir à dimensionner de manière optimale les épaisseurs des murs en blocs de terre stabilisée (BTS), pour obtenir un confort thermique satisfaisant à l’intérieur des constructions avec ce matériau. Pour ce faire, une méthode analytique des admittances basée sur le complexe de Fourier est utilisée. L’analyse des résultats a mis en exergue les principaux facteurs influents sur le dimensionnement idoine pour parvenir à assurer un confort thermique satisfaisant à l’intérieur de ces constructions en terre. Parmi ces facteurs, on relève les caractéristiques thermo-physiques intrinsèques des matériaux utilisés et d’autres paramètres tels que le facte…
Ferromagnetic exchange in a twisted, oxime-bridged [mniii2] dimer
2012
Journal article The dimeric complex [MnIII2(Naphth-sao)2(Naphth-saoH)2(MeOH)2][middle dot]4MeOH (1[middle dot]4MeOH), acts as a simple model complex with which to examine the magneto-structural relationship in polymetallic, oxime-bridged MnIII complexes. Dc magnetic susceptibility studies reveal that ferromagnetic exchange is mediated through the heavily twisted Mn-O-N-Mn moiety (J = +1.24 cm-1) with magnetisation measurements at low temperatures and high fields suggesting significant anisotropy. Simulations of high field, high frequency EPR data reveal a single ion anisotropy, D(MnIII) = -3.94 cm-1. Theoretical studies on simplified model complexes of 1 reveal that calculated values of the…
Iron (II) isothiocyanate complexes with substituted pyrazines: Experimental and theoretical views on their electronic structure
2015
Abstract Synthesis, structural, magnetic, Mossbauer and thermal studies of isothiocyanate iron (II) complexes with substituted pyrazines (iodo-, bromo- and amino-derivatives) are discussed here. Complexes with iodo- and bromo-derivatives were found to have the composition [Fe(Ipz)2(SCN)2(H2O)2]·2Ipz (1) and [Fe(Brpz)2(SCN)2(H2O)2]·2Brpz (2), whereas in the case of amino-functionalized pyrazine the formation of [Fe(NH2pz)4(SCN)2] (3) was observed. 3D organization of the molecular complexes is stabilized within different hydrogen, halogen and lone pair–π interactions. Spin state of iron (II) ions in 1–3 was determined as high spin by Mossbauer and magnetic measurements. DFT calculations for t…
Polyamines : études et applications
2008
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