scholarly journals Experimental and theoretical characterization of the Zn—Zn bond in [Zn2(η5-C5Me5)2]

2007 ◽  
Vol 63 (6) ◽  
pp. 862-868 ◽  
Author(s):  
Juan F. Van der Maelen ◽  
Enrique Gutiérrez-Puebla ◽  
Ángeles Monge ◽  
Santiago García-Granda ◽  
Irene Resa ◽  
...  
Keyword(s):  
Electron Density ◽  
Density Functional ◽  
Topological Analysis ◽  
Open Shell ◽  
Synchrotron Diffraction ◽  
Functional Theory ◽  
Metal Metal ◽  
Moller Plesset ◽  
Experimental Electron Density

The existence and characterization of a bond between the Zn atoms in the recently synthesized complex [Zn2(η5-C5Me5)2], as well as between Zn and ligand C atoms is firmly based on neutron diffraction and low-temperature X-ray synchrotron diffraction experiments. The multipolar analysis of the experimental electron density and its topological analysis by means of the `Atoms in Molecules' (AIM) approach reveals details of the Zn—Zn bond, such as its open-shell intermediate character (the results are consistent with a typical metal–metal single bond), as well as many other topological properties of the compound. Experimental results are also compared with theoretical ab initio calculations of the DFT (density functional theory) and MP2 (Møller-Plesset perturbation theory) electron densities, giving a coherent view of the bonding in the complex. For instance, charges calculated from the AIM approach applied to the atomic basin of each Zn atom are, on average, +0.72 e from both the experimental and the theoretical electron density, showing a moderate charge transfer from the metal, confirmed by the calculated topological indexes.

scholarly journals Unveiling the Different Chemical Reactivity of Diphenyl Nitrilimine and Phenyl Nitrile Oxide in [3+2] Cycloaddition Reactions with (R)-Carvone through the Molecular Electron Density Theory

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1085 ◽  
Author(s):  
Mar Ríos-Gutiérrez ◽  
Luis R. Domingo ◽  
M’hamed Esseffar ◽  
Ali Oubella ◽  
My Youssef Ait Itto
Keyword(s):  
Electron Density ◽  
Density Functional ◽  
Chemical Reactivity ◽  
Topological Analysis ◽  
Nitrile Oxide ◽  
Conceptual Density Functional Theory ◽  
Functional Theory ◽  
Molecular Electron ◽  
Molecular Electron Density Theory

The [3+2] cycloaddition (32CA) reactions of diphenyl nitrilimine and phenyl nitrile oxide with (R)-carvone have been studied within the Molecular Electron Density Theory (MEDT). Electron localisation function (ELF) analysis of these three-atom-components (TACs) permits its characterisation as carbenoid and zwitterionic TACs, thus having a different reactivity. The analysis of the conceptual Density Functional Theory (DFT) indices accounts for the very low polar character of these 32CA reactions, while analysis of the DFT energies accounts for the opposite chemoselectivity experimentally observed. Topological analysis of the ELF along the single bond formation makes it possible to characterise the mechanisms of these 32CA reactions as cb- and zw-type. The present MEDT study supports the proposed classification of 32CA reactions into pdr-, pmr-, cb- and zw-type, thus asserting MEDT as the theory able to explain chemical reactivity in Organic Chemistry.

scholarly journals Quantum pressure focusing in solids: a reconstruction from experimental electron density

2019 ◽  
Vol 75 (2) ◽  
pp. 201-209 ◽  
Author(s):  
Vladimir G. Tsirelson ◽  
Adam I. Stash ◽  
Ilya V. Tokatly
Keyword(s):  
Density Functional Theory ◽  
Electron Density ◽  
Density Functional ◽  
Electron Shell ◽  
Correlation Effects ◽  
Functional Theory ◽  
Quantum Electron ◽  
The Density Functional Theory ◽  
Bonding Mechanisms ◽  
Experimental Electron Density

Here an approach is presented for reconstructing the distribution of electronic internal quantum pressure in the electronic continuum of solids from the experimental electron density. Using the formalism of the density functional theory, the spatial inner-crystal map of the quantum pressure is obtained. The results are visualized via the indicator of quantum pressure focusing (IQPF) which reveals the regions where the pressure is concentrated or depleted due to quantum effects. IQPF contains all quantum electron-shell structure-forming contributions resulting from kinetic, exchange and correlation effects, and presents a clear picture of the chemical bond features in crystals with different type of bonding mechanisms.

scholarly journals Characterization of a strong covalent Th3+–Th3+ bond inside an Ih(7)-C80 fullerene cage

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jiaxin Zhuang ◽  
Roser Morales-Martínez ◽  
Jiangwei Zhang ◽  
Yaofeng Wang ◽  
Yang-Rong Yao ◽  
...  
Keyword(s):  
Density Functional ◽  
Arc Discharge ◽  
Fullerene Cage ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
Metal Metal ◽  
Fundamental Understanding ◽  
Metal Bonds ◽  
Discharge Method

AbstractThe nature of the actinide-actinide bonds is of fundamental importance to understand the electronic structure of the 5f elements. It has attracted considerable theoretical attention, but little is known experimentally as the synthesis of these chemical bonds remains extremely challenging. Herein, we report a strong covalent Th-Th bond formed between two rarely accessible Th3+ ions, stabilized inside a fullerene cage nanocontainer as Th2@Ih(7)-C80. This compound is synthesized using the arc-discharge method and fully characterized using several techniques. The single-crystal X-Ray diffraction analysis determines that the two Th atoms are separated by 3.816 Å. Both experimental and quantum-chemical results show that the two Th atoms have formal charges of +3 and confirm the presence of a strong covalent Th-Th bond inside Ih(7)-C80. Moreover, density functional theory and ab initio multireference calculations suggest that the overlap between the 7s/6d hybrid thorium orbitals is so large that the bond still exists at Th-Th separations larger than 6 Å. This work demonstrates the authenticity of covalent actinide metal-metal bonds in a stable compound and deepens our fundamental understanding of f element metal bonds.

scholarly journals Metal–Metal and Metal–Ligand Bonding in Trinuclear Vinylidene Rhenium-Iron-Platinum Complex Studied by Topological Analysis of Electron Density

2020 ◽  
pp. 553-564
Author(s):  
Aleksey M. Shor ◽  
Svetlana S. Laletina ◽  
Anatoly I. Rubaylo ◽  
Elena A. Ivanova-Shor
Keyword(s):  
Electron Density ◽  
Density Functional ◽  
Topological Analysis ◽  
Density Functional Method ◽  
Platinum Complex ◽  
Functional Method ◽  
Iron Platinum ◽  
Metal Atoms ◽  
Metal Metal ◽  
Metal Ligand

Metal–metal and metal–ligand bonding in vinylidene ReFePt complex was studied by density functional method and topological analysis of electron density. Topological analysis did not found direct bonding between the metal atoms pointing to indirect metal–metal interaction mediated via the bridging vinylidene ligand. At the same time, the delocalization index δ(Fe,Pt) reveals the strong Fe–Pt interaction that allows for supposing a chemical bonding between these atoms

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