scholarly journals A ruthenium chloro nitrosyl derivative of dithioacetylacetone

1970 ◽  
Vol 23 (11) ◽  
pp. 2297 ◽  
Author(s):  
GA Heath ◽  
RL Martin
Keyword(s):  
Electronic Spectrum ◽  
Oxidation State ◽  
Spectral Methods ◽  
Metal Ion ◽  
Trans Configuration ◽  
The Novel ◽  
Nitrosyl Derivative

The novel dithioacetylacetonato complex [Ru(C5H7S2)2(NO)Cl] has been characterized by analytical and spectral methods. A trans configuration is suggested. The electronic spectrum is consistent with the oxidation state II for the coordinated metal ion.

scholarly journals Identification by RNA Profiling and Mutational Analysis of the Novel Copper Resistance Determinants CrdA (HP1326), CrdB (HP1327), and CzcB (HP1328) in Helicobacter pylori

2002 ◽  
Vol 184 (23) ◽  
pp. 6700-6708 ◽  
Author(s):  
Barbara Waidner ◽  
Klaus Melchers ◽  
Igor Ivanov ◽  
Hannes Loferer ◽  
Klaus W. Bensch ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Metal Ion ◽  
Specific Protein ◽  
Copper Resistance ◽  
System Component ◽  
The Novel ◽  
Rna Profiling ◽  
Metal Ion Homeostasis ◽  
Resistance Determinants ◽  
H Pylori

ABSTRACT Mechanisms involved in maintaining cytoplasmic metal ion homeostasis play a central role in the adaptation of Helicobacter pylori to the changing gastric environment. An investigation of the global regulatory responses to copper ions by using RNA profiling with a threshold factor of 4.0 revealed that copper induces transcription of 19 H. pylori genes and that only the ferritin gene pfr is repressed. The 57-fold copper induction identified the HP1326 gene encoding an H. pylori-specific protein as a candidate for a novel copper resistance determinant. The HP1326 gene is expressed as a monocistronic unit, and two small HP1326 mRNAs are copper induced. The HP1326 protein is secreted and is required for copper resistance maintained by cytoplasmic copper homeostasis, as H. pylori HP1326 mutants were copper sensitive and displayed increased copper induction of HP1326 transcription as well as elevated copper repression of ferritin synthesis. The clear copper-sensitive phenotype displayed by H. pylori HP1327 and HP1328 mutants provides strong evidence that the HP1326 protein, together with the signal peptide site of the H. pylori-specific protein HP1327, whose gene is located downstream from that encoding HP1326, and the CzcB and CzcA metal efflux system component homologs HP1328 and HP1329, constitutes a novel type of copper efflux pump, as discussed below. The HP1329 gene could not be inactivated, but the 14-fold transcriptional copper induction determined by RNA profiling points towards a function of the encoded CzcA homolog in copper resistance. In summary, results from RNA profiling identified the novel H. pylori-specific copper resistance determinants CrdA (HP1326) and CrdB (HP1327), which are required for adaptation to copper-rich environmental conditions.

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

scholarly journals The novel ECF56 SigG1-RsfG system modulates morphological differentiation and metal-ion homeostasis in Streptomyces tsukubaensis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Rute Oliveira ◽  
Matthew J. Bush ◽  
Sílvia Pires ◽  
Govind Chandra ◽  
Delia Casas-Pastor ◽  
...  
Keyword(s):  
Metal Ion ◽  
Ion Homeostasis ◽  
Morphological Differentiation ◽  
The Novel ◽  
Copper Trafficking ◽  
Streptomyces Tsukubaensis ◽  
Metal Ion Homeostasis ◽  
Σ Factor ◽  
Domain Organisation

AbstractExtracytoplasmic function (ECF) sigma factors are key transcriptional regulators that prokaryotes have evolved to respond to environmental challenges. Streptomyces tsukubaensis harbours 42 ECFs to reprogram stress-responsive gene expression. Among them, SigG1 features a minimal conserved ECF σ2–σ4 architecture and an additional C-terminal extension that encodes a SnoaL_2 domain, which is characteristic for ECF σ factors of group ECF56. Although proteins with such domain organisation are widely found among Actinobacteria, the functional role of ECFs with a fused SnoaL_2 domain remains unknown. Our results show that in addition to predicted self-regulatory intramolecular amino acid interactions between the SnoaL_2 domain and the ECF core, SigG1 activity is controlled by the cognate anti-sigma protein RsfG, encoded by a co-transcribed sigG1-neighbouring gene. Characterisation of ∆sigG1 and ∆rsfG strains combined with RNA-seq and ChIP-seq experiments, suggests the involvement of SigG1 in the morphological differentiation programme of S. tsukubaensis. SigG1 regulates the expression of alanine dehydrogenase, ald and the WhiB-like regulator, wblC required for differentiation, in addition to iron and copper trafficking systems. Overall, our work establishes a model in which the activity of a σ factor of group ECF56, regulates morphogenesis and metal-ions homeostasis during development to ensure the timely progression of multicellular differentiation.

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.

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

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.

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