scholarly journals Tripodal Podand Ligand with a Superhalogen Nature as an Effective Molecular Trap

Symmetry ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1441
Author(s):  
Adrianna Cyraniak ◽  
Marcin Czapla
Keyword(s):  
Metal Cations ◽  
Equilibrium Structure ◽  
Binding Energies ◽  
Electron Detachment ◽  
Tripodal Ligand ◽  
Ionic Complexes ◽  
System A ◽  
Moller Plesset ◽  
Fragmentation Processes ◽  
Outer Valence

Tris(2-methoxyethyl) fluoroborate anion (TMEFA), anovel tripodal ligand based on the BF4− superhalogen anion, is proposed and was investigated theoretically using ab initio MP2 (second-order Møller-Plesset perturbational method) and OVGF (outer valence Green function) methods. The studied molecule comprises three 2-methoxyethoxy groups (-O-CH2-CH2-O-CH3) connected to a central boron atom, which results in the C3-symmetry of the compound. The resulting anion was stable against fragmentation processes and its vertical electron detachment energy was found to be 5.72 eV. Due to its equilibrium structure resembling that of classical tripodal podands, the [F-B(O-CH2-CH2-O-CH3)3]− anion is capable of binding metal cations using its three arms, and thus may form strongly bound ionic complexes such as [F-B(O-CH2-CH2-O-CH3)3]−/Li+ and [F-B(O-CH2-CH2-O-CH3)3]−/Mg2+. The binding energies predicted for such compounds far exceed those of the similar neutral classical podand ligands, which likely makes the [F-B(O-CH2-CH2-O-CH3)3]− system a more effective molecular trap or steric shielding agent with respect to selected metal cations.

THE PERFORMANCE OF SELECTED AB INITIO METHODS IN ESTIMATING ELECTRON BINDING ENERGIES OF SUPERHALOGEN ANIONS

2011 ◽  
Vol 10 (01) ◽  
pp. 93-109 ◽  
Author(s):  
CELINA SIKORSKA ◽  
DOROTA IGNATOWSKA ◽  
SYLWIA FREZA ◽  
PIOTR SKURSKI
Keyword(s):  
Ab Initio ◽  
Binding Energies ◽  
Basis Sets ◽  
Electron Detachment ◽  
Hartree Fock ◽  
Moller Plesset ◽  
Very High ◽  
Outer Valence ◽  
Electron Binding Energies ◽  
Electron Binding

The capability of reproducing the vertical electron detachment energies (VDE) of four representative superhalogen anions was tested using the selected ab initio (Hartree-Fock (HF), second, third, and fourth-order Møller-Plesset perturbational scheme (MP2, MP3, MP4), coupled-cluster CCSD(T), and outer valence Green function (OVGF)) methods together with the variety of one-electron basis sets. Certain theoretical treatments (e.g. MP2/aug–cc–pVTZ and MP2/6-311+G(3df)) were found to be satisfactory for preliminary estimates of electron binding energies of superhalogen anions, whereas the use of the OVGF/6-311+G(3df) approach has been proven to assure a very high accuracy of the results.

Mg2Cl5 - and Mg3Cl7 - Superhalogen Anions

2008 ◽  
Vol 61 (9) ◽  
pp. 712 ◽  
Author(s):  
Iwona Anusiewicz
Keyword(s):  
Green Function ◽  
Crystal Lattice ◽  
Global Minimum ◽  
Binding Energies ◽  
Basis Sets ◽  
Energy Structure ◽  
Electron Detachment ◽  
Geometrical Structures ◽  
Outer Valence ◽  
Electron Binding Energies

The vertical electron detachment energies of Mg2Cl5– and Mg3Cl7– superhalogen anions were calculated at the outer valence Green function level with 6–311+G(3df) basis sets. These species were found to form rather unusual geometrical structures, each of which corresponds to a stable anionic state exhibiting superhalogen nature. The global minimum structure of Mg2Cl5– was found to possess D3h symmetry, which can be described as a system in which two central magnesium atoms are linked via a symmetrical triangle formed by three chlorine atoms, whereas the lowest-energy structure for Mg3Cl7– was found to have C3v symmetry, which can be viewed as a fragment of chloromagnesite crystal lattice. Extremely large electron binding energies of these anions (exceeding 6.5 eV in all cases) were predicted and discussed.

The Spectroscopy of 198O11 and the 187N11 Ground State

1983 ◽  
Vol 36 (6) ◽  
pp. 825
Author(s):  
Raymond K Sheline
Keyword(s):  
Ground State ◽  
Sudden Change ◽  
Binding Energies ◽  
Ground State Spin ◽  
System A ◽  
State Spin

The spectroscopies of 190 and 21 Ne (both eleven-neutron systems) are compared. The 1-+ [211 iJ, t+ [220il and t- [lOttl bands are observed in both nuclei. On the basis of these similarities 190 is assumed to be a prolate rotor like 21 Ne. If then the recently studied IBN ground state is also considered to be a deformed system (a one-proton hole in the 190 nucleus), both the 1- ground state spin and the sudden change in the systematics of the two-neutron binding energies can be understood.

scholarly journals Discrimination between Alkali Metal Cations by Yeast

1967 ◽  
Vol 50 (4) ◽  
pp. 967-988 ◽  
Author(s):  
W. McD. Armstrong ◽  
A. Rothstein
Keyword(s):  
Alkali Metal ◽  
Competitive Inhibition ◽  
Metal Cations ◽  
Competitive Inhibitor ◽  
Cation Binding ◽  
Alkali Metal Cations ◽  
System A ◽  
Low Concentrations ◽  
K Transport ◽  
Noncompetitive Inhibitors

K+ is a competitive inhibitor of the uptake of the other alkali metal cations by yeast. Rb+ is a competitive inhibitor of K+ uptake, but Li+, Na+, and Cs+ act like H+. At relatively low concentrations they behave as apparent noncompetitive inhibitors of K+ transport, but the inhibition is incomplete. At higher concentrations they inhibit the remaining K+ transport competitively. Ca++ and Mg++ in relatively low concentrations partially inhibit K+ transport in an apparently noncompetitive manner although their affinity for the transport site is very low. In each case, in concentrations that produce "noncompetitive" inhibition, very little of the inhibiting cation is transported into the cell. Competitive inhibition is accompanied by appreciable uptake of the inhibiting cation. The apparently noncompetitive effect of other cations is reversed by K+ concentrations much higher than those necessary to essentially "saturate" the transport system. A model is proposed which can account for the inhibition kinetics. This model is based on two cation-binding sites for which cations compete, a carrier or transporting site, and a second nontransporting (modifier) site with a different array of affinities for cations. The association of certain cations with the modifier site leads to a reduction in the turnover of the carrier, the degree of reduction depending on the cation bound to the modifier site and on the cation being transported.

scholarly journals A novel 1,3,5-triaminocyclohexane-based tripodal ligand forms a unique tetra(pyrazolate)-bridged tricopper(ii) core: solution equilibrium, structure and catecholase activity

2016 ◽  
Vol 45 (38) ◽  
pp. 14998-15012 ◽  
Author(s):  
Attila Szorcsik ◽  
Ferenc Matyuska ◽  
Attila Bényei ◽  
Nóra V. Nagy ◽  
Róbert K. Szilágyi ◽  
...  
Keyword(s):  
Equilibrium Structure ◽  
Low Ph ◽  
Ph Optimum ◽  
Tripodal Ligand ◽  
Solution Equilibrium ◽  
Catecholase Activity ◽  
Core Solution

A polydentate tripodal ligand forms a series of tricopper(ii) complexes, that feature unique pyrazolate-bridged linear core. The Cu3H−3L2 complex is an efficient catecholase mimic with a surprisingly low pH optimum at pH = 5.6.

scholarly journals Electronic structure and chemical bond nature in Cs2PuO2Cl4

2015 ◽  
Vol 30 (2) ◽  
pp. 99-112 ◽  
Author(s):  
Yury Teterin ◽  
Konstantin Maslakov ◽  
Mikhail Ryzhkov ◽  
Anton Teterin ◽  
Kirill Ivanov ◽  
...  
Keyword(s):  
Binding Energy ◽  
Energy Range ◽  
Chemical Bond ◽  
Theoretical Data ◽  
Molecular Orbitals ◽  
Binding Energies ◽  
Spectral Structure ◽  
Discrete Variation ◽  
X Ray ◽  
Outer Valence

X-ray photoelectron spectral analysis of dicaesiumtetrachlorodioxoplutonate (Cs2PuO2Cl4) single crystal was done in the binding energy range 0-~35 eV on the basis of binding energies and structure of the core electronic shells (~35 eV-1250 eV), as well as the relativistic discrete variation calculation results for the PuO2Cl4 (D4h). This cluster reflects Pu close environment in Cs2PuO2Cl4 containing the plutonyl group PuO2. The many-body effects due to the presence of cesium and chlorine were shown to contribute to the outer valence (0-~15 eV binding energy) spectral structure much less than to the inner valence (~15 eV- ~35 eV binding energy) one. The filled Pu 5f electronic states were theoretically calculated and experimentally con- firmed to present in the valence band of Cs2PuO2Cl4. It corroborates the suggestion on the direct participation of the Pu 5f electrons in the chemical bond. The Pu 6p atomic orbitals were shown to participate in formation of both the inner and the outer valence molecular orbitals (bands), while the filled Pu 6p and O 2s, Cl 3s electronic shells were found to take the largest part in formation of the inner valence molecular orbitals. The composition of molecular orbitals and the sequence order in the binding energy range 0-~35 eV in Cs2PuO2Cl4 were established. The quantitative scheme of molecular orbitals for Cs2PuO2Cl4 in the binding energy range 0-~15 eV was built on the basis of the experimental and theoretical data. It is fundamental for both understanding the chemical bond nature in Cs2PuO2Cl4 and the interpretation of other X-ray spectra of Cs2PuO2Cl4. The contributions to the chemical binding for the PuO2Cl4 cluster were evaluated to be: the contribution of the outer valence molecular orbitals -66 %, the contribution of the inner valence molecular orbitals -34 %.

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