نتایج جستجو برای: metal ion complex
تعداد نتایج: 1140454 فیلتر نتایج به سال:
The title compound, [Cd(C(12)H(8)N(2))(2)(H(2)O)(2)]SO(4)·6H(2)O, was obtained unexpectedly during an attempt to synthesize a cadmium complex with bidentate bridging sulfate ligands via hydro-thermal synthesis. The Cd(II) metal ion is six-coordinated by two chelating 1,10-phenanthroline ligands and two water mol-ecules, resulting in a distorted octa-hedral geometry for the metal ion. The two ch...
ABSTRACT A high yield preparation, spectroscopic and crystallographic investigation of the crystalline Zn-complex of a di(β,β'-sulfoleno)pyrrin are reported here. In the brightly green fluorescent Zn-complex of the hardly luminescent di(β,β'-sulfoleno)pyrrin, the metal ion is bound by two di(β,β'-sulfoleno)pyrrin ligands, as revealed first by its mass spectra. The crystal structure of this Zn-c...
The new Mannich base VEP (N,N’-bis-(5,5’-diethyl-barbituryl-1-methyl)-piperazine), has been synthetized by condensation of veronal with formaldehyde and piperazine following a Mannich procedure. The new binuclear complex Cu2VEP(X)4·4H2O , X=ClO4where VEP stands for N,N’-bis-(5,5’-diethyl-barbituryl-1-methyl)-piperazine, were obtained by metal ligand direct synthesis. Tetrahedral geometry of the...
Recent studies of the hairpin ribozyme have revealed a distinct catalytic mechanism for this small RNA motif. Inner-sphere coordinated metal ions are not required, as the inert metal ion complex cobalt hexammine promotes catalysis. Detailed kinetic analyses have defined rates of individual steps in the catalytic cycle. Functional group modification, NMR studies of subdomains and cross-linking e...
Reaction of equimolar quantities of MX (M = Au, Cu, X = Cl; M = Ag, X = OTf) and GaCl(3) in CH(2)Cl(2) with P(4) leads to phosphorus ligating a cationic coinage metal centre. For Cu and Ag, ion-contacted coordination polymers are formed; for Au, an ion-separated complex is observed that features the [Au(η(2)-P(4))(2)](+) cation, which is the first homoleptic Au-P(4) complex to be characterised ...
Approximately one-half of all known protein crystal structures in the protein data bank (PDB) contain metal ion cofactors, which play vital roles in charge neutralization, structure, and function.1,2 These proteins range in size from 5000-107 Da with the metal ion corresponding to only on the order of 0.1 wt % of the molecule. Yet, for a wide range of these metalloproteins, the metal ion and it...
The trivalent metal ion (M(III)=Cm, Eu)/polyacrylic acid (PAA) system was studied in the pH range between 3 and 5.5 for a molar PAA-to-metal ratio above 1. The interaction was studied for a wide range of PAA (0.05 mg L(-1)-50 g L(-1)) and metal ion concentrations (2x10(-9)-10(-3) M). This work aimed at 3 goals (i) to determine the stoichiometry of M(III)-PAA complexes, (ii) to determine the num...
Metal ions can serve as a centre of molecular motions due to their coordination geometry, reversible bonding nature and external stimuli responsiveness. Such essential features of metal ions have been utilized for metal-mediated molecular machines with the ability to motion switch via metallation/demetallation or coordination number variation at the metal centre; however, motion switching based...
Biological membranes are complex assemblies of lipids and proteins that serve as platforms for cell signaling. We have developed a novel method for measuring the structure and dynamics of the membrane based on fluorescence resonance energy transfer (FRET). The method marries four technologies: (1) unroofing cells to isolate and access the cytoplasmic leaflet of the plasma membrane; (2) patch-cl...
a proton nmr method for the drtermination of salvation numbers of alkaline earth cations with hexamethyl phosphoramide (hmpa) in nitromethane (nm) as diluents is described. the method is based on monitoring the resonance frequency of hmpa protons as a function of hmpa / metal ion molar ratio at constant metalion concentration. the average salvation number of cations, , at any hmpa / metal ion ...
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