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Showing 1 to 13 of 13 for “"pentacoordinate"”.
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Structural correlations in pentacoordinate zinc and nickel systems
The structure correlation principle has been applied to five-coordinate zinc and nickel complexes in order to map the mechanism for a bimolecular ligand substitution reaction at typical tetrahedral and square-planar centres.
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Intramolecular Ligand Permutation at Tetracoordinate and Pentacoordinate Silicon (Pseudorotation, Hypervalent)
The X-ray crystal structures of 3,3,3',3'-tetrakis(trifluoromethyl)-1,1'(3H,3'H)-spirobi{2,1-benzoxasilole}(silane 1) and tetramethylammonium bis {(alpha),(alpha)-bis(trifluoromethyl)benzene-methanolato(2-)-C('2),O} phenylsilicate (2) are described. Silane 1 is a distorted tetrahedron at silicon …
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Compounds of Pentacoordinate (10-Boron-5) and Hexacoordinate (12-Boron-6) Hypervalent Boron
Efficient synthetic routes to 2-substituted pyridines and 2,6-disubstituted pyridine 1-oxides are described, involving direct ortho lithiation with the sterically hindered base, lithium 2,2,6,6-tetramethylpiperidide, in the presence of electrophiles that are compatible with the base, e.g., …
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Investigations concerning the reactions of small molecules with a series of pentacoordinate manganese complexes and the characterization of a solvent refined coal
Manganese(II) complexes with linear potentially pentadentate Schiff base ligands have been prepared and characterized. Their reactions with dioxygen and nitric oxide has been studied. The ligands were synthesized from substituted salicylaldehydes and selected hiamines containing a central nitrogen …
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Molecular assembly and function of Androglobin, a novel chimeric globin.
… members. The 3D haem domain model suggests a pentacoordinate haem geometry. The purified haem domain protein partially supports this, revealing mixed penta/hexa-coordinated properties. Using 3D modelling it was predicted that Adgb contains two surface-exposed Cys in close proximity to form a …
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Stereoisomerization of Hexacoordinate Sulfur and Tellurium
… 3 occurs by a dissociative mechanism through a pentacoordinate cationic sulfur intermediate, a 10-S-5 persulfonium ion, which was isolated as its hexafluorophosphate salt. A lower limit for the activation barrier of the unobserved nondissociative isomerization of 2 to 3 is 50 kcal/mol in …
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Mechanistic studies of nitrile hydratases and their activator proteins
… this research proposes a high-spin Co(II) pentacoordinate metal center. This study also confirms the ATP/GTPase activity of the activator, aligning with previous findings. Collectively, this dissertation advances the understanding of NHase catalysis, emphasizing the important roles of …
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The fate of organotin biocides in marine antifouling elastomers.
… the large f(80K) = 0.34 is more typical of the pentacoordinate structure exhibited by pure TBT-chloride.The presence of TBT and TPT additives on the curing behaviour of the basic coating formulation was investigated and it was found that TBTO effectively delayed the onset of curing in this …
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X-ray and spectroscopic studies of organotin compounds.
… geometries with definite Sn--N linkages. Pentacoordinate tin atoms have also been found in the following: ClPh2SnCH2CH2CH2SC6H4Me-p (1), ClMe2SnCH2CH2CH2PPhBut (2) and 3-C-(dibutyliodostannyl)methyl-l,2:5,6-di-Omicron-isopropylidene-alpha-D-allofuranose (3). In methyl …
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Mechanistic studies of nitrile hydratases and their activator proteins
… this research proposes a high-spin Co(II) pentacoordinate metal center. This study also confirms the ATP/GTPase activity of the activator, aligning with previous findings. Collectively, this dissertation advances the understanding of NHase catalysis, emphasizing the important roles of …
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Delineation of the active site structure of chloroperoxidase from C. fumago
… chloroperoxidase is predominantly a high spin, pentacoordinate complex between the pH values of 2 to 7. The structure of the distal side of the chloroperoxidase heme pocket was also examined. Previous investigations had led to the proposal by a number of investigators that chloroperoxidase …
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Contributions to the chemistry of higher-coordinate Silicon : synthesis, structure, and stereodynamics of new Silicon(IV) complexes with SiO2N2C, SiO4C, or SiO6 skeletons
This thesis contributes to the field of silicon chemistry, with a special emphasis on the chemistry of penta- and hexacoordinate silicon.The spirocyclic zwitterionic Lambda5Si-silicates 1–6 with a (2,2,6,6-tetramethylpiperidinio)- methyl group and two identical bidentate chelate ligands derived …
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Redox-Active Trivalent Metallosurfactants With Low Global Symmetry For Molecule-Based Electronics: Spectroscopic, Electrochemical, And Amphiphilic Properties Of New Molecular Materials For Current-Voltage Measurements In M|lb-Monolayer|m Devices
… were investigated. Both complexes showed pentacoordinate geometry around the metal ion. These two iron(III) complexes showed excellent redox properties with lower potential differences between the first oxidation and reduction peaks, when compared to alkyl substituted iron(III) complexes. …