Mutual Ligand-Metal Ion Oxidation State Stabilizaton in a System Containing a Quadridentate Macrocycle Analogous to the Porphyrin Ring

1970 ◽  
Vol 92 (2) ◽  
pp. 400-402 ◽  
Author(s):  
Nurhan E. Tokel ◽  
Vladimir. Katovic ◽  
Keith. Farmery ◽  
Larry B. Anderson ◽  
Daryle H. Busch
Keyword(s):  
Oxidation State ◽  
Metal Ion ◽  
Porphyrin Ring

scholarly journals Metal ion remediation by polyamidoamine dendrimers: a comparison of metal ion, oxidation state, and titania immobilization

2013 ◽  
Vol 11 (6) ◽  
pp. 1497-1502 ◽  
Author(s):  
V. A. Castillo ◽  
M. A. Barakat ◽  
M. H. Ramadan ◽  
H. L. Woodcock ◽  
J. N. Kuhn
Keyword(s):  
Oxidation State ◽  
Metal Ion ◽  
Polyamidoamine Dendrimers

Metal Ion Site Geometry and Oxidation State in Zeolites

1983 ◽  
pp. 319-332
Author(s):  
T. I. MORRISON ◽  
P. J. VICCARO ◽  
G. K. SHENOY
Keyword(s):  
Oxidation State ◽  
Metal Ion

Effects of Oxidation State on Metal Ion Binding byMedicago sativa(Alfalfa):  Atomic and X-ray Absorption Spectroscopic Studies with Fe(II) and Fe(III)

2000 ◽  
Vol 34 (4) ◽  
pp. 693-698 ◽  
Author(s):  
K. J. Tiemann ◽  
J. L. Gardea-Torresdey ◽  
G. Gamez ◽  
K. Dokken ◽  
Irene Cano-Aguilera ◽  
...  
Keyword(s):  
Oxidation State ◽  
Metal Ion ◽  
Spectroscopic Studies ◽  
Ion Binding ◽  
Metal Ion Binding ◽  
X Ray ◽  
X Ray Absorption

New Bond-Valence Sum Model

1997 ◽  
Vol 53 (6) ◽  
pp. 885-894 ◽  
Author(s):  
J. P. Naskar ◽  
S. Hati ◽  
D. Datta
Keyword(s):  
Oxidation State ◽  
Coordination Sphere ◽  
Metal Ion ◽  
Nickel Complexes ◽  
Bond Valence ◽  
Oxidation States ◽  
Linear Variation ◽  
Axial Bond ◽  
Inorganic Complexes ◽  
Bond Valence Sum

A new expression is devised empirically to accommodate zero and some negative oxidation states in the bond-valence sum approach. The method is worked out in detail for a number of homoleptic copper and nickel complexes of various coordinating atoms in several oxidation states of the metals. An implication of the expression is a linear variation between 1/r eq and 1/r ax in octahedral MX 6 moieties, where r eq and r ax are, respectively, the average equatorial and axial bond lengths. This is verified in Cu2+ X 6 chromophores for X = F, O, N and S. The usefulness of the new expression in assessing the compatibility of a coordination sphere with an oxidation state of a metal ion is demonstrated by exemplary applications to some inorganic complexes, azurin and urease.

Variations on a Cage Theme: Some Complexes of Bicyclic Polyamines as Supramolecular Synthons

2009 ◽  
Vol 62 (10) ◽  
pp. 1246 ◽  
Author(s):  
Ian J. Clark ◽  
Alessandra Crispini ◽  
Paul S. Donnelly ◽  
Lutz M. Engelhardt ◽  
Jack M. Harrowfield ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Aromatic Ring ◽  
Oxidation State ◽  
Metal Ion ◽  
Intermolecular Forces ◽  
Optically Active ◽  
Alphabetical Order ◽  
Supramolecular Synthons ◽  
Π Stacking ◽  
Parallel Arrays

Dedication: One of Alan Sargeson’s great abilities was to seek out knowledge on topics of which he was not the master from those people with the expertise. This led occasionally to publications with a ‘cricket team’ of authors but with a rich brew of information, often international. Alan also insisted that all authors were equal since, without any one, the paper would not be what it was. Hence, he endeavoured to pursue the policy, difficult to maintain over a period where an obsession with absurdities such as the order of authors and point-scoring based on meaningless publication indices became so important in the maintenance of research, of listing authors simply in alphabetical order. In describing work begun while he was still with us, we have attempted to adhere to his principles. Analysis of a body of crystallographic information concerning metal(ii) and metal(iii) complexes of macrobicyclic hexamine ligands and some of their derivatives provides evidence for the action of a variety of intermolecular forces within the lattices. Hydrogen bonding is universal and its forms depend strongly upon the oxidation state and the particular nature of the metal ion bound to the macrobicycle. The introduction of both aliphatic and aromatic substituents leads to lattices in which these substituents associate, although, in the case of aromatic substituents, this is not necessarily a consequence of ‘π-stacking’, despite the fact that the aromatic ring planes form parallel arrays. At least in the case of CoIII, stable enantiomers of the complexes can be obtained, and in {Δ-(+)589-[Co{(NH3)(CH3)sar}]}2Cl2(C6(CO2)6)·26H2O (sar = 3,6,10,13,16,19-hexa-azabicyclo[6.6.6]icosane), the benzene hexacarboxylate anion adopts a chiral conformation in the presence of the optically active cation.

The decomposition of permanganate in molten alkali-metal nitrates

1974 ◽  
Vol 27 (5) ◽  
pp. 943 ◽  
Author(s):  
RB Temple ◽  
GW Thickett
Keyword(s):  
Heavy Metal ◽  
Thermal Decomposition ◽  
Alkali Metal ◽  
Metal Ions ◽  
Oxidation State ◽  
Rate Constant ◽  
Metal Ion ◽  
Heavy Metal Ions ◽  
Metal Nitrates ◽  
Fixed Weight

The decomposition of MnO4- has been studied in molten (K/Li)NO3 eutectic at temperatures between 150� and 200�C. The rate of decomposition in a Pyrex vessel increased in the presence of traces of NO2-, Br- and CN- and of the manganate(1V) precipitate produced in the decomposition. Various transition and heavy metal ions were also found to accelerate the decomposition of MnO4- : the rate law appears to be -d[MnO4-]/dt = k[Mn+]2/n[MnO4-] where n = oxidation state of metal ion M which was added to the melt solution of MnO4- (in the presence of a fixed weight of insoluble reaction product). Nickel and cobalt(11) ions are oxidized by MnO4- to insoluble nickel(111) and cobalt(111) manganates(1V). Whilst NO2- produced by the thermal decomposition of NO3- appears to be the active reductant in (K/Li)NO3 melts, the reaction is complicated by being partly heterogeneous. The method of preparation of the reaction product critically affects the rate constant k.

scholarly journals Binding Specificity of the Porphyromonas gingivalis Heme and Hemoglobin Receptor HmuR, Gingipain K, and Gingipain R1 for Heme, Porphyrins, and Metalloporphyrins

2001 ◽  
Vol 183 (19) ◽  
pp. 5599-5608 ◽  
Author(s):  
Teresa Olczak ◽  
Dabney White Dixon ◽  
Caroline Attardo Genco
Keyword(s):  
Outer Membrane ◽  
Porphyromonas Gingivalis ◽  
Cysteine Protease ◽  
Metal Ion ◽  
Binding Specificity ◽  
Cysteine Proteases ◽  
Side Chains ◽  
Porphyrin Ring ◽  
Iron Copper ◽  
Copper And Zinc

ABSTRACT Previous genetic and biochemical studies have confirmed that hemoglobin and hemin utilization in Porphyromonas gingivalis is mediated by the outer membrane hemoglobin and heme receptor HmuR, as well as gingipain K (Kgp), a lysine-specific cysteine protease, and gingipain R1 (HRgpA), one of two arginine-specific cysteine proteases. In this study we report on the binding specificity of the recombinant P. gingivalis HmuR protein and native gingipains for hemoglobin, hemin, various porphyrins, and metalloporphyrins as assessed by spectrophotometric assays, by affinity chromatography, and by enzyme-linked immunosorbent assay. Protoporphyrin, mesoporphyrin, deuteroporphyrin, hematoporphyrin, and some of their iron, copper, and zinc derivatives were examined to evaluate the role of both the central metal ion and the peripheral substituents on binding to recombinant HmuR and soluble gingipains. Scatchard analysis of hemin binding to Escherichia coli cells expressing recombinant membrane-associated six-His-tagged HmuR yielded a linear plot with a binding affinity of 2.4 × 10−5 M. RecombinantE. coli cells bound the iron, copper, and zinc derivatives of protoporphyrin IX (PPIX) with similar affinities, and approximately four times more tightly than PPIX itself, which suggests that the active site of HmuR contains a histidine that binds the metal ion in the porphyrin ring. Furthermore, we found that recombinant HmuR prefers the ethyl and vinyl side chains of the PPIX molecule to either the larger hydroxyethyl or smaller hydrogen side chains. Kgp and HRgpA were demonstrated to bind various porphyrins and metalloporphyrins with affinities similar to those for hemin, indicating that the binding of Kgp and HRgpA to these porphyrins does not require a metal within the porphyrin ring. We did not detect the binding of RgpB, the arginine-specific cysteine protease that lacks a C-terminal hemagglutinin domain, to hemoglobin, porphyrins, or metalloporphyrins. Kgp and HRgpA, but not RgpB, were demonstrated to bind directly to soluble recombinant six-His-tagged HmuR. Several possible mechanisms for the cooperation between outer membrane receptor HmuR and proteases Kgp and HRgpA in hemin and hemoglobin binding and utilization are discussed.

From Bent to Linear Uranium Metallocenes:  Influence of Counterion, Solvent, and Metal Ion Oxidation State

2006 ◽  
Vol 25 (23) ◽  
pp. 5603-5611 ◽  
Author(s):  
Jérôme Maynadié, ◽  
Jean-Claude Berthet ◽  
Pierre Thuéry ◽  
Michel Ephritikhine
Keyword(s):  
Oxidation State ◽  
Metal Ion
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