Effect of axial coordination environment on quantum tunnelling magnetization for dysprosium single ion magnet with theoretical insight

2022 ◽  
Author(s):  
Arpan Mondal ◽  
Sanjit Konar
Keyword(s):  
Structural Analysis ◽  
Coordination Environment ◽  
Quantum Tunnelling ◽  
Axial Coordination ◽  
Theoretical Insight

Herein, we report two mononuclear Dysprosium complexes [Dy(H4L){B(OMe)2(Ph)2}2](Cl)∙MeOH (1), and [Dy(H4L){MeOH)2(NCS)2](Cl) (2) (where H4L = 2,2′-(pyridine-2,6-diylbis(ethan-1-yl-1-ylidene))bis(N-phenylhydrazinecarboxamide) with different axial coordination environment. The structural analysis revealed that the pentadentate H4L ligand...

Nitrosyl–heme and anion–arene complexes: structure, reactivity and spectroscopy

2015 ◽  
Vol 87 (4) ◽  
pp. 379-390 ◽  
Author(s):  
Maria Elisa Crestoni ◽  
Barbara Chiavarino ◽  
Simonetta Fornarini
Keyword(s):  
Gas Phase ◽  
Metal Center ◽  
Arene Complexes ◽  
Biological Media ◽  
Variable Binding ◽  
Irmpd Spectroscopy ◽  
Binding Motifs ◽  
Coordination Environment ◽  
Axial Coordination ◽  
First Time

AbstractTwo topics are selected and illustrated to exemplify (i) a biological and (ii) an organic ionic intermediate. The reactivity behavior of NO adducts with ferric and ferrous hemes has shown remarkable similarities when examined in the gas phase, demonstrating that the largely different NO affinity displayed in solution and in biological media is due to the different coordination environment. In fact, ferrous hemes present a vacant or highly labile axial coordination site, prone to readily bind NO. The vibrational signatures of the NO ligand have also been probed in vacuo for the first time in the nitrosyl complexes deriving from ferrous and ferric hemes under strictly comparable five-coordination at the metal center. Negatively charged σ-adducts, from the association of anions with 1,3,5-trinitrobenzene, an exemplary π-electron-deficient arene, have been probed by IRMPD spectroscopy and found to display variable binding motifs from a strongly covalent σ-adduct (Meisenheimer complex) to a weakly covalent σ-complex, depending on the anion basicity.

scholarly journals Spin-Crossover Phenomena of Ni(cyclam)I2 Complex: Magnetostructural Correlations in Two Polymorphs

2018 ◽  
Author(s):  
Yoji Horii ◽  
Yuki Kanegae ◽  
Kiyonori Takahashi ◽  
Akira Fuyuhiro ◽  
Hal Suzuki ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Structural Analysis ◽  
Equilibrium Model ◽  
Spin Crossover ◽  
Spin States ◽  
Subtle Difference ◽  
Coordination Environment ◽  
X Ray

<div>Two crystal polymorphs of Ni(cyclam)I<sub>2</sub> (cyclam = 1,4,8,11-</div><div>tetraazacyclotetradecane) were identified by X-ray structural analysis and their magnetic properties were investigated. Gradual spin-crossover behaviors were found in both polymorphs. Entropy differences between high- and low-spin states obtained by assuming the spin equilibrium model reflected subtle difference of the coordination environment of nickel(II) ion in two polymorphs.</div>

scholarly journals Spin-Crossover Phenomena of Ni(cyclam)I2 Complex: Magnetostructural Correlations in Two Polymorphs

2018 ◽  
Author(s):  
Yoji Horii ◽  
Yuki Kanegae ◽  
Kiyonori Takahashi ◽  
Akira Fuyuhiro ◽  
Hal Suzuki ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Structural Analysis ◽  
Equilibrium Model ◽  
Spin Crossover ◽  
Spin States ◽  
Subtle Difference ◽  
Coordination Environment ◽  
X Ray

<div>Two crystal polymorphs of Ni(cyclam)I<sub>2</sub> (cyclam = 1,4,8,11-</div><div>tetraazacyclotetradecane) were identified by X-ray structural analysis and their magnetic properties were investigated. Gradual spin-crossover behaviors were found in both polymorphs. Entropy differences between high- and low-spin states obtained by assuming the spin equilibrium model reflected subtle difference of the coordination environment of nickel(II) ion in two polymorphs.</div>

scholarly journals The influence of L ligands on the {RuNO}6/7 bonding situation in cis-[Ru(NO)(NO2)L1–4]q complexes: a theoretical insight

RSC Advances ◽  
2015 ◽  
Vol 5 (85) ◽  
pp. 69057-69066 ◽  
Author(s):  
K. F. Andriani ◽  
G. F. Caramori ◽  
A. Muñoz-Castro ◽  
F. G. Doro
Keyword(s):  
Coordination Environment ◽  
Before And After ◽  
In Cis ◽  
Theoretical Insight

The nature of the Ru–NO interaction before and after reduction of cis-[Ru(NO)(NO2)L1–4]q complexes is modulated by the coordination environment of the metallic center, resulting in more labile on complexes with weak π-acceptor ligands.

Structural analysis of the surface-layer protein of spirillum serpens by high-resolution electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 738-739
Author(s):  
W. H. Wu ◽  
R. M. Glaeser
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Structural Analysis ◽  
High Resolution ◽  
Low Dose ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Surface Layer Protein ◽  
Morphological Unit ◽  
Resolution Electron

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.

RNA polymerase: Preparation and structural analysis of helical polymers

1984 ◽  
Vol 42 ◽  
pp. 152-153
Author(s):  
E. Loren Buhle ◽  
Pamela Rew ◽  
Ueli Aebi
Keyword(s):  
Structural Analysis ◽  
Rna Polymerase ◽  
Molecular Level ◽  
X Ray Diffraction ◽  
Helical Polymers ◽  
X Ray ◽  
E Coli ◽  
The Past ◽  
Ordered Arrays ◽  
Low Ionic Strength

While DNA-dependent RNA polymerase represents one of the key enzymes involved in transcription and ultimately in gene expression in procaryotic and eucaryotic cells, little progress has been made towards elucidation of its 3-D structure at the molecular level over the past few years. This is mainly because to date no 3-D crystals suitable for X-ray diffraction analysis have been obtained with this rather large (MW ~500 kd) multi-subunit (α2ββ'ζ). As an alternative, we have been trying to form ordered arrays of RNA polymerase from E. coli suitable for structural analysis in the electron microscope combined with image processing. Here we report about helical polymers induced from holoenzyme (α2ββ'ζ) at low ionic strength with 5-7 mM MnCl2 (see Fig. 1a). The presence of the ζ-subunit (MW 86 kd) is required to form these polymers, since the core enzyme (α2ββ') does fail to assemble into such structures under these conditions.

Interpreting HVEM of muscle-cell impulse networks

1992 ◽  
Vol 50 (1) ◽  
pp. 126-127
Author(s):  
Paul DeCosta ◽  
Kyugon Cho ◽  
Stephen Shemlon ◽  
Heesung Jun ◽  
Stanley M. Dunn
Keyword(s):  
Structural Analysis ◽  
Muscle Cell ◽  
Electron Micrographs ◽  
Relative Size ◽  
Automatic Classification ◽  
Nerve Fibers ◽  
Analysis Algorithm ◽  
Structural Networks

Introduction: The analysis and interpretation of electron micrographs of cells and tissues, often requires the accurate extraction of structural networks, which either provide immediate 2D or 3D information, or from which the desired information can be inferred. The images of these structures contain lines and/or curves whose orientation, lengths, and intersections characterize the overall network.Some examples exist of studies that have been done in the analysis of networks of natural structures. In, Sebok and Roemer determine the complexity of nerve structures in an EM formed slide. Here the number of nodes that exist in the image describes how dense nerve fibers are in a particular region of the skin. Hildith proposes a network structural analysis algorithm for the automatic classification of chromosome spreads (type, relative size and orientation).

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