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Aplicação de complexos de metais de transição coordenados a típicos aditivos orgânicos de banhos eletrolíticos em eletrodeposição binária de metais; Application of transition metal complexes coordinated with typical organic aditive from electrolitic bath for binary metal electrodeposition

Watanabe, Rogério Haruo
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 16/07/2008 PT
Relevância na Pesquisa
56.3%
O objetivo principal deste trabalho é aplicar complexos de cobre(II), níquel(II), zinco(II) e nióbio(V) como fontes de metais em banhos de eletrodeposição. Os íons metálicos foram coordenados aos ligantes íon oxalato, íon citrato, etilenodiamina (EDA) ou tetraetilenopentamina (TEPA), os quais são aditivos orgânicos típicos em banhos de eletrodeposição. Os complexos foram caracterizados por análise elementar, espectroscopias nas regiões do infravermelho e ultravioleta-visível e voltametria cíclica. Foram realizadas eletrólises em presença de dois complexos de coordenação em ausência de quantias adicionais de aditivos, usando aço 1010 como substrato a pH = 4.5 (H2SO4/Na2SO4), resultando em depósitos com dois elementos metálicos. Os depósitos apresentaram aspectos morfológicos com boas qualidades e sem falhas. Em adição, os depósitos foram analisados por EDX, reflectância difusa e espectroscopia de raio-X e também foram realizadas medidas de curvas de polarização. Os depósitos obtidos a partir dos complexos gerados ex-situ mostraram morfologias melhores do que depósitos obtidos de soluções preparadas com os sais dos metais na presença dos aditivos, mediante as mesmas condições de trabalho. É sugerido que os metais de partida...

Estudo de propriedades estruturais e hiperfinas em complexos metálicos; Study of structural and hyperfine properties of metal complexes

Nascimento, Rafael Rodrigues do
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 15/07/2014 PT
Relevância na Pesquisa
66.22%
O estudo computacional da interação de biomoléculas com metais de transição é bastante desafiador. Sendo assim, investigamos computacionalmente diferentes propriedades eletrônicas, estruturais e hiperfinas de complexos metálicos, a saber: a) o gradiente do campo elétrico de Crown thioethers coordenados à Ag e ao Cd e comparado com as medidas da técnica espectroscópica Time Differential Perturbed Angular Correlation durante o decaimento nuclear 111Ag -> 111Cd ; b) o acoplamento hiperfino no metal coordenado à bases de Schiff e comparado com as medidas de ressonância eletrônica paramagnética durante o equilíbrio ceto-enol; c) a interação termodinâmica entre o complexo [Cu(isaenim)]2+ e o sulco menor do DNA, por meio da dissociação do complexo supramolecular [Cu(isaenim)]2+-DNA, comparada com a energia livre experimental fornecida pela constante de equilíbrio de formação deste sistema; e d) por meio do cálculo do acoplamento hiperfino realizamos alguns passos na direção da caracterização teórica do complexo supramolecular no estado ligado. Utilizamos a teoria do funcional da densidade no esquema de Kohn-Sham para obter as propriedades hiperfinas eletrônicas e magnéticas dos complexos metálicos. No estudo do equilíbrio ceto-enol utilizamos simulações de dinâmica molecular clássica e híbrida QMMM para estimar as distancias Cu-Oágua. No caso do complexo supramolecular [Cu(isaenim)]2+-DNA...

Síntese, caracterização e estudo das atividades antibacterianas de complexos de Au(I), Ag(I) e Pd(II) com rimantadina; Syinthesis, characterization and study of antibacterial activities of metal complexes of Au(I), Ag(I) and Pd(II) with rimantadine

Suelen Ferreira Sucena
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 19/08/2013 PT
Relevância na Pesquisa
66.2%
A rimantadina (C12H21N - rtd) ´e um agente antiviral, que inibe especificamente a replicacão do vírus influenza tipo A. A presença do grupo -NH2 confere a ela uma habilidade em se coordenar a diferentes íons metálicos. Neste trabalho foram sintetizado 3 novos complexos metálicos de Au(I), Ag(I) e Pd(II) com rimantadina. Os complexos foram preparados pela reacão de solucões aquosas ou alcoólicas da rimantadina com os respectivos sais de Au(I), Ag(I) e Pd(II). Os compostos foram caracterizados por um conjunto de análises químicas e espectroscópicas, bem como através de cálculos de Density Functional Theory (DFT). Os espectros no infravermelho (IV) e de ressonância magnética nuclear (RMN) da rtd livre e dos complexos indicaram a coordenação da rtd aos íons metálicos através do átomo de nitrogênio do grupo NH2. Os compostos foram analisados quanto as suas atividades biológicas antibacteriana sobre cepas de bactérias Gram-positivas e Gram-negativas. Os resultados mostraram que os complexos de Au(I) e Ag(I) são ativos sobre cepas de Staphylococcus aureus, Pseudomonas aeruginosa e Escherichia coli.; Rimantadine (C12H21N - rtd) is a antiviral agent which inhibit specifically the replication of the virus influenza A. The presence of group -NH2 confers the ability to coordinate with different metal ions. In this work 3 novel metal complexes of Au(I)...

Síntese e caracterização estrutural de complexos metálicos com ligantes bioativos N,O-doadores e estudo de suas atividades biológicas in vitro; Synthesis and structural characterization of metal complexes with N,O-donor bioactive ligands, and biological study in vitro

Marcos Alberto de Carvalho
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 25/02/2015 PT
Relevância na Pesquisa
66.26%
O uso de metais em medicina, no tratamento de doenças, data desde a antiguidade. Sais de prata são utilizados há séculos como agentes antimicrobianos, enquanto que, mais recentemente, complexos de Au(I) e Pt(II) tem sido pesquisados e utilizados como agentes antiartríticos e antitumorais, respectivamente. Nesta Tese, são apresentados estudos de síntese, caracterização estrutural e ensaios biológicos in vitro de novos complexos metálicos de Pt(II), Pd(II), Ag(I) e Au(III) com diferentes ligantes bioativos: triptofano (Trp), triptamina (tra), ácido mefenâmico (mef) e carnosina (car). Os complexos foram preparados a partir da reação em solução aquosa ou alcoólica dos ligantes e dos respectivos sais metálicos. As composições dos complexos foram determinadas por análise elementar, espectrometria de massas e por análise termogravimétrica. Estudos espectroscópicos e de modelagem molecular permitiram propor os modos de coordenação dos ligantes aos íons metálicos. Os complexos de Ag(I) e Pd(II) com Trp mostraram atividade sobre cepas bacterianas Gram-negativas e Gram-positivas. O complexo de Pd(II) com triptamina não apresentou atividade frente as cepas de Escherichia coli, Pseudomonas aeruginosa e Staphylococcus aureus. O complexo de Pd(II) com ácido mefenâmico e bipiridina mostrou atividade inibitória frente a cepas de S. aureus e não foi ativo sobre E. coli e P. aeruginosa. Estudos de citotoxicidade dos complexos de Ag(I)...

Study of the antimicrobial activity of metal complexes and their ligands through bioassays applied to plant extracts

Santos,Antonio F.; Brotto,Débora F.; Favarin,Lis R.V.; Cabeza,Natália A.; Andrade,Geziel R.; Batistote,Margareth; Cavalheiro,Alberto A.; Neves,Ademir; Rodrigues,Daniela C.M.; Anjos,Ademir dos
Fonte: Sociedade Brasileira de Farmacognosia Publicador: Sociedade Brasileira de Farmacognosia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2014 EN
Relevância na Pesquisa
56.16%
The appearance of resistant bacteria was found to reduce the efficiency of antimicrobial therapies with the current antibiotics, thereby increasing the need for more efficient drugs for the treatment of infections. Several studies have demonstrated an increase in antimicrobial activity following the interaction of several compounds with metal ions. The present study used a methodology adapted for antimicrobial bioassays using plant extracts, in compliance with the standards of the Clinical and Laboratory Standards Institute against Gram-positive and Gram-negative bacteria. The results obtained were considered appropriate for determining MIC, MBC as for performing antimicrobial sensitivity testing with good efficiency and reproducibility. The bacteria Pseudomonas fluorescens exhibited high sensitivity to the tested compounds, being efficient to evaluate the antibacterial activity. The bioassays with the metal complexes of flavonoid quercetin and Ga(III) ions, and synthetic ligand H2bbppd and Cu(II) ions showed a greater inhibitory effect than their individual ligands, thus, the addition indicated an increase in the antimicrobial activity after the coordination. Both metal complexes exhibit good antimicrobial performances, such as low minimum inhibitory concentration (MIC ≤ 250 µg/ml)...

Antimicrobial and toxicological studies of some metal complexes of 4-methylpiperazine-1-carbodithioate and phenanthroline mixed ligands

Kalia,S.B.; Kaushal,G.; Kumar,M.; Cameotra,S.S.; Sharma,A.; Verma,M.L.; Kanwar,S.S.
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2009 EN
Relevância na Pesquisa
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A few mixed ligand transition metal carbodithioate complexes of the general formula [M(4-MPipzcdt)x(phen)y]Y (M = Mn(II), Co(II), Zn(II); 4-MPipzcdt = 4-methylpiperazine-1-carbodithioate; phen = 1,10-phenanthroline; x = 1 and y = 2 when Y = Cl; x = 2 and y = 1 when Y = nil) were synthesized and screened for their antimicrobial activity against Candida albicans, Escherichia coli, Pseudomonas aeruginosa,Staphylococcus aureus andEnterococcusfaecalis by disk diffusion method. All the complexes exhibited prominent antimicrobial activity against tested pathogenic strains with the MIC values in the range <8-512 μgmL-1. The complexes [Mn(4-MPipzcdt)2(phen)] and [Co(4-MPipzcdt)(phen)2]Cl inhibited the growth of Candida albicans at a concentration as low as 8 µgmL-1.The complexes were also evaluated for their toxicity towards human transformed rhabdomyosarcoma cells (RD cells). Moderate cell viability of the RD cells was exhibited against the metal complexes.

Molecular wires : syntheses, electrochemistry and properties of metal complexes containing carbon chains / by Mark Edward Smith.

Smith, Mark Edward, 1975-
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado Formato: 113274 bytes; application/pdf
Publicado em //2002 EN
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66.13%
Describes the synthesis, properties and reactions of transition metal complexes containing poly-ynyl ligands; Thesis (Ph.D.)--University of Adelaide, Dept. of Chemistry, 2002; "September 2002"; Includes as appendix: a list of publications by the author arising from this work; and, copies of some published journal articles; Includes bibliographical references.; [12], 209 leaves, [35] pages : ill. ; 30 cm.; Title page, contents and abstract only. The complete thesis in print form is available from the University Library.

Dinuclear polypyridylruthenium(II) complexes: Flow cytometry studies of their accumulation in bacteria and the effect on the bacterial membrane

Li, F.; Feterl, M.; Warner, J.; Keene, F.; Collins, J.
Fonte: Oxford Univ Press Publicador: Oxford Univ Press
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
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Objectives To determine the energy dependency of and the contribution of the membrane potential to the cellular accumulation of the dinuclear complexes [{Ru(phen)₂}₂{μ-bbn}]⁵+ (Rubbn) and the mononuclear complexes [Ru(Me₄phen)₃]²+ and [Ru(phen)₂(bb₇)]²+ in Staphylococcus aureus and Escherichia coli, and to examine their effect on the bacterial membrane. Methods The accumulation of the ruthenium complexes in bacteria was determined using flow cytometry at a range of temperatures. The cellular accumulation of the ruthenium complexes was also determined in cells that had been incubated with the metal complexes in the presence or absence of metabolic stimulators or inhibitors and/or commercial dyes to determine the membrane potential or membrane permeability. Results The accumulation of ruthenium complexes in the two bacterial strains was shown to increase with increasing incubation temperature, with the relative increase in accumulation greater with E. coli, particularly for Rubb₁₂ and Rubb₁₆. No decrease in accumulation was observed for Rubb₁₂ in ATP-inhibited cells. While carbonyl cyanide m-chlorophenyl hydrazone (CCCP) did depolarize the cell membrane, no reduction in the accumulation of Rubb₁₂ was observed; however...

Übergangsmetallkomplexe von Kohlenhydratderivaten; Transition Metal Complexes of Carbohydrate Derivatives

Heber, Ulrich
Fonte: Universität Tübingen Publicador: Universität Tübingen
Tipo: Dissertation; info:eu-repo/semantics/doctoralThesis
DE_DE
Relevância na Pesquisa
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Kohlenhydratderivate sind als Vertreter des sog. ''chiral pools'' nicht nur Ausgangsstoffe für die Synthese chiraler Verbindungen, sondern finden in den letzten Jahren gehäuft Anwendung als chirale Liganden in der Chemie der Übergangsmetalle. Seit ihrer Entdeckung durch Fischer und Öfele in den 1950er Jahren haben Aren-Chromtricarbonylkomplexe eine breite Anwendung in der organischen Synthese gefunden. Die Komplexierung mit einem Chromtricarbonylfragment erlaubt Reaktionen, wie beispielsweise die nucleophile aromatische Substitution oder die Deprotonierung in benzylischer Position, die ohne die Komplexierung nicht oder nur sehr schwer möglich wären. Ausgenutzt wurde dies zur Synthese von diversen Naturstoffen, insbesondere solchen mit einem hochsubstituierten Benzol- oder Cyclohexangrundgerüst. Ziel dieser Arbeit war die Synthese neuartiger kohlenhydratsubstituierter Übergangsmetallkomplexe. Dabei wurden drei verschiedene Systeme als Liganden für Übergangsmetalle verwendet: Zur spezifischen Komplexierung mit Cr(CO)3 wurden verschiedene Phenylglycoside zu den entsprechenden kohlenhydratsubstituierten Aren-Chromtricarbonyl-Komplexen umgesetzt, welche meist kristalline Verbindungen darstellen, die sich zur Einkristallröntgenstrukturanalyse eigneten. In diesen Kristallstrukturen wurden zahlreiche sog. nicht-klassische Wasserstoffbrückenbindungen zwischen den Sauerstoffatomen der Carbonyleinheiten am Chrom und Wasserstoffatomen sowohl von benachbarten Molekülen als auch innerhalb desselben Moleküls gefunden. Auch konnte in einer Kristallstruktur eine Wasserstoffbrücke zwischen einem Ringsauerstoffatom eines Kohlenhydratrestes und einem Wasserstoffatom eines benachbarten komplexierten Aromaten nachgewiesen werden. Ausgehend vom Glucosamin wurden zweizähnige Liganden synthetisiert...

Synthesis and characterisation of nickel Schiff base complexes containing the meso-1,2-diphenylethylenediamine moiety: selective interactions with a tetramolecular DNA quadruplex

Davis, Kimberley J; Richardson, Christopher; Beck, Jennifer L; Knowles, Brett M; Guédin, Aurore; Mergny, Jean-Louis; Willis, Anthony C; Ralph, Stephen F
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Artigo de Revista Científica Formato: 15 pages
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As part of a program of preparing metal complexes which exhibit unique affinities towards different DNA structures, we have synthesised the novel Schiff base complex N,N'-bis-4-(hydroxysalicylidine)meso-diphenylethylenediaminenickel(ii) (), via the reaction of meso-1,2-diphenylethylenediamine and 2,4-dihydroxybenzaldehyde. This compound was subsequently reacted with 1-(2-chloroethyl)piperidine or 1-(2-chloropropyl)piperidine, to afford the alkylated complexes N,N'-bis-(4-((1-(2-ethyl)piperidine)oxy)salicylidine)meso-1,2-diphenylethylenediaminenickel(ii) () and N,N'-bis-(4-((1-(3-propyl)piperidine)oxy)-salicylidine)meso-1,2-diphenylethylenediaminenickel(ii) (), respectively. These complexes were characterised by microanalysis and X-ray crystallography in the solid state, and in solution by (1)H and (13)C NMR spectroscopy. Electrospray ionisation mass spectrometry (ESI-MS) was used to confirm the identity of () and (). The affinities of () and () towards a discrete 16 mer duplex DNA molecule, and examples of both tetramolecular and unimolecular DNA quadruplexes, was explored using a variety of techniques. In addition, the affinity of two other complexes () and (), towards the same DNA molecules was examined. Complexes () and () were prepared by methods analogous to those which afforded () and ()...

LUMINESCENT TRANSITION METAL COMPLEXES BASED ON N-HETEROCYCLIC AND N^C-CHELATE 4-COORDINATE ORGANOBORYL LIGANDS

Wang, NAN
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
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The objective of this thesis is to examine the photophysical and structural properties of Ru(II)/Re(I) based bimetallic complexes based on p-[N-2-(2’-pyridyl)benzimidazolyl]-[N-2-(2’-pyridyl)indolyl]-benzene (L1) ligand, as well as the photophysical and photochemical properties of N^C-chelate 4-coordinate organoboron compounds that contain a metal acetylide group. Ligand L1 was synthesized and fully characterized. Due to the incorporation of two distinct chelating sites, an N^N-chelate site and an N^C-chelate site, L1 has been found to be very effective in selective binding to two different metal ions. Two new heterobimetallic complexes Ru(II)-Pt(II) and Ru(II)-Pd(II) using L1 as the bridging ligand were prepared and fully characterized. All Ru(II)-containing complexes have been found to be luminescent. The Pt(II) unit appears to enhance phosphorescent efficiency of the Ru(II) unit while the Pd(II) unit has little influence. Using L1 as the bridging unit, two new Re(I) based heterobimetallic complexes Re(I)-Pt(II) and Re(I)-Pd(II) were also successfully synthesized. Results indicate that there is communication between the two different metal centers. The preliminary results indicated that the mononuclear Re(I) complex based on L1 is a promising candidate for the electrocatalytic CO2 reduction. Pd(II) and Pt(II) complexes were synthesized with an atropisomeric bis-pyridyl chelate ligand bis{3...

Synthesis and properties of d6 metal complexes of bidentate and tridentate ‘super donor’ ligands

Pal, Amlan Kumar
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
EN
Relevância na Pesquisa
56.37%
La polyvalence de la réaction de couplage-croisé C-N a été explorée pour la synthèse de deux nouvelles classes de ligands: (i) des ligands bidentates neutres de type N^N et (ii) des ligands tridentates neutres de type N^N^N. Ces classes de ligands contiennent des N-hétérocycles aromatiques saturés qui sont couplés avec hexahydropyrimidopyrimidine (hpp). Les ligands forment de cycles à six chaînons sur la coordination du centre Ru(II). Ce fait est avantageux pour améliorer les propriétés photophysiques des complexes de polypyridyl de Ru(II). Les complexes de Ru(II) avec des ligands bidentés ont des émissions qui dépendent de la basicité relative des N-hétérocycles. Bien que ces complexes sont électrochimiquement et photophysiquement attrayant, le problème de la stereopurité ne peut être évité. Une conception soigneuse du type de ligand nous permet de synthétiser un ligand bis-bidentate qui est utile pour surmonter le problème de stereopurité. En raison de la spécialité du ligand bis-bidentate, son complexe diruthénium(II,II) présente une grande diastéréosélectivité sans séparation chirale. Alors que l'unité de hpp agit comme un nucléophile dans le mécanisme de C-N réaction de couplage croisé...

Structural dependence of magnetic exchange coupling parameters in transition-metal complexes

Melo, Juan Ignacio; Phillips, Jordan J.; Peralta, Juan E.
Fonte: Elsevier Publicador: Elsevier
Tipo: info:eu-repo/semantics/article; info:ar-repo/semantics/artículo; info:eu-repo/semantics/publishedVersion Formato: application/pdf
ENG
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Magnetic exchange coupling parameters are routinely calculated within same structures for high- and low-spin states, neglecting structural relaxations and temperature effects present in measurements. To estimate these effects, we calculate magnetic couplings in a set of transition-metal complexes by relaxing the high-spin and broken-symmetry structures and taking into account the zero-point energies for both spin configurations. Structural relaxations slightly worsen results relative to experimental values, while zero-temperature ro-vibrational effects slightly improve calculated couplings. Because the complexes considered here are the gas-phase structures of the crystal units, our results can be regarded as an upper-bound for relaxation effects in the crystal-phase.; Fil: Melo, Juan Ignacio. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires; Argentina;; Fil: Phillips, Jordan J.. Central Michigan University. Science of Advanced Materials; Estados Unidos de América;; Fil: Peralta, Juan E.. Central Michigan University. Science of Advanced Materials; Estados Unidos de América; Central Michigan University. Department of Physics; Estados Unidos de América;

Nonlinear Optical and Two-Photon Absorption Properties of Octupolar Tris(bipyridyl)metal Complexes

Feuvrie, Christophe; Maury, Olivier; Bozec, Hubert Le; Ledoux, Isabelle; Morrall, Joseph; Dalton, Gulliver; Samoc, Marek; Humphrey, Mark
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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The linear (absorption and emission) and nonlinear optical (NLO) properties of a series of D3 [(Fe(II), Ru(II), Ni(II), Cu(II), Zn(II)] octupolar metal complexes featuring the 4,4'-bis[(dibutylamino)styryl]-2,2'- bipyridine ligand are reported. Zinc(II),

Ortho-metallated transition metal complexes derived from tertiary phosphine and arsine ligands

Mohr, Fabian; Priver, Steven H.; Bhargava, Suresh K.; Bennett, Martin A.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 259768 bytes; application/pdf
ENG
Relevância na Pesquisa
66.25%
38 pages, 8 figures, 64 schemesl, 2 tables.-- Referred to by: Erratum to “Ortho-metallated transition metal complexes derived from tertiary phosphine and arsine ligands” [Coordination Chemistry Reviews, Volume 251, Issues 11-12, June 2007, Page 1620]; This article reviews the synthesis, reactivity and structure of transition metal complexes containing ortho-metallated tertiary phosphines and arsines of the type [2-R2EC6H4]− (E = P, As; R = various substituents). Available synthetic routes are summarized and some general spectroscopic and structural features are discussed. In subsequent sections, ortho-metallated complexes of this type are reviewed, arranged according to the triads of the d-block series. The literature has been covered to the end of 2004. The Appendix lists all known mononuclear, binuclear and trinuclear ortho-metallated transition metal complexes which have been structurally characterized by X-ray diffraction.; Peer reviewed

Stabilization of High Oxidation States on Transition Metal Complexes

Lansing, James
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Undergraduate Thesis
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56.22%
Klaus Theopold; Redox active ligands, i.e. ligands that can be reduced or oxidized, are of considerable interest due to the fact that they potentially have the ability to stabilize unusual metal species. Previous work done by Wieghardt as well as by our lab has shown that two prime examples of these types of ligands are dithiolene and ??-diimine complexes. This work has shown that in some instances these ligands themselves are oxidized, while other times the metal oxidation state is altered. With this in mind, we set out to explore the use of 1,1???-diaminoferrocene (dafc), a redox active complex, as a ligand with divalent metal cations. The reasoning is that the ligand???s metal center, with its increased electron density (as compared to main block elements such as carbon, nitrogen, oxygen, and their respective groups), may be able to aid in oxidation-reduction reactions and achieve otherwise rare metal oxidation states. Our work focused primarily on cobalt, which contains a large number of electrons in its d orbitals (nine in the zero-valent state). Our attempts also spilled over into metal with fewer available d electrons, such as titanium, vanadium, chromium and manganese. Synthetic routes have been explored for these compounds...

Ortho -metallated transition metal complexes derived from tertiary phosphine and arsine ligands

Mohr, Fabian; Priver, Steven H; Bhargava, Suresh Kumar; Bennett, Martin
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.2%
This article reviews the synthesis, reactivity and structure of transition metal complexes containing ortho-metallated tertiary phosphines and arsines of the type [2-R2EC6H4]- (E = P, As; R = various substituents). Available synthetic routes are summarized and some general spectroscopic and structural features are discussed. In subsequent sections, ortho-metallated complexes of this type are reviewed, arranged according to the triads of the d-block series. The literature has been covered to the end of 2004. The Appendix lists all known mononuclear, binuclear and trinuclear ortho-metallated transition metal complexes which have been structurally characterized by X-ray diffraction.

Diastereoselectivity and molecular recognition in the self-assembly of double-stranded dinuclear metal complexes of the type {M 2 {( R *, S *)-tetraphos} 2 ] (PF 6 ) 2 (M = Ag and Au)

Blake, Christopher; Cook, Vernon; Keniry, Max; Kitto, Heather; Rae, A David; Swiegers, Gerhard; Willis, Anthony; Zank, Johann; Wild, Stanley (Bruce)
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
56.23%
The ligand (R*,S*)-Ph2PCH2CH 2P(Ph)CH2CH2P(Ph)CH2CH 2PPh2, (R*,S*)-tetraphos, combines with silver(I) and gold(I) ions in the presence of hexafluorophosphate to diastereoselectively self-assemble the head-to-head (H,H) diastereomers of the double-stranded, dinuclear metal complexes [M2{(R*,S* )-tetraphos}2](PF6)2 in which the two chiral metal centers in the complexes have M (R end of phosphine) and P (S end of phosphine) configurations. The crystal and molecular structures of the compounds have been determined: (H,H)-(M,P)-[Ag2{(R*,S* )-tetraphos}2](PF6)2, monoclinic, P2 1/c, a = 10.3784(2), b = 47.320(1), c = 17.3385(4) Å, β = 103.8963(5)°, Z = 4; (H,H)-(M,P)-[Au2{(R*,S* )-tetraphos}2](PF6)2, monoclinic, P..2 1 (No. 4, c unique axis), a = 24.385(4), b = 46.175(3), c = 14.820(4) Å, Z = 8. The complexes crystallize as racemic compounds in which the unit cell in each case contains equal numbers of enantiomorphic molecules of the cation and associated anions. The cations in both structures have similar side-by-side structures of idealized C2 symmetry, the bulk helicity of each molecule in the solid state being due solely to the twist of the central ten-membered ring containing the two metal ions of opposite configuration, which has the chiral twist-boat-chair-boat conformation. When 1 equiv each of (R*...

Metal Complexes with N-(Phosphonomethyl)glycine (Glyphosate): the Preparation and Characterization of the Group 2 Metal Complexes with Glyphosate and the Crystal Structure of Barium Glyphosate Dihydrate

Sagatys, Dalius; Dahlgren, Cathrine; Smith, Graham; Bott, R; Willis, Anthony
Fonte: CSIRO Publishing Publicador: CSIRO Publishing
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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A series of the Group 2 metal complexes with the herbicide N-(phosphonomethyl)glycine (glyphosate, H 3L) with general formula [M(HL)·2H 2O] has been prepared and characterized by using infrared spectroscopy and in the case of the Ba analogue, by single-c

Study of Structure and Spectral Characteristics of the Zinc(II) and Copper(II) Complexes With 5,5-Dimethyl-2-(2-(3-nitrophenyl) hydrazono)cyclohexane-1,3-dione and Their Effects on Optical Properties and the Developing of the Energy Band Gap and Investigation of Antibacterial Activity

Turan,Nevin; Gündüz,Bayram; Körkoca,Hanifi; Adigüzel,Ragip; Çolak,Naki; Buldurun,Kenan
Fonte: Sociedad Química de México A.C. Publicador: Sociedad Química de México A.C.
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2014 EN
Relevância na Pesquisa
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A new chelating ligand, 5,5-dimethyl-2-(2-(3-nitrophenyl) hydrazono)cyclohexane-1,3-dione (L), and four transition metal complexes were synthesized. The ligand and its complexes were characterized by IR, ¹H and 13C-NMR spectra, elemental analyses, magnetic susceptibility, mass spectra, UV-Vis. and thermogravimetry-differential thermal analysis (TGA-DTA). The metal complexes showed different geometric structures. Antibacterial tests of the ligand and complexes were also done. The Zn(II) complexes showed antibacterial activity against Staphylococcus aureus ATCC-25923 at middle level. The optical properties of the ligand and its complexes were extensively investigated by optical measurements. The average transmittance value of the ligand was the highest value, while the average transmittance value of the [CuL2(NO3)2]·6H2Ocomplex was the lowest value. The optical band gap of the ligand, [(Zn)2L(OH)4]·2DMF, [ZnL(NO3)2(H2O)2]·5H2O, [CuL2(OAc)]·OAc·3.5H2O and [CuL2(NO3)2]·6H2O complexes were calculated and 3.121 eV, 2.180 eV, 1.551 eV, 2.489 eV and 1.556 eV values were found, respectively. The complexes decreased the optical band gap of the ligand. The optical band gap value of the [ZnL(NO3)2(H2O)2]·5H2O complex is the lowest value. The optical band gap value of the ligand is the highest value. The complexes decrease the angle of incidence of the ligand...