Covalent bond orders and atomic valence indices using the topological theory of atoms in molecules

1995 ◽  
Author(s):  
János G. Ángyán ◽  
Michel Loos ◽  
István Mayer
Keyword(s):  
Covalent Bond ◽  
Atoms In Molecules ◽  
Bond Orders ◽  
Topological Theory ◽  
Atomic Valence

Determination of covalent bond orders and atomic valence indices using topological features of the experimental electron density

2007 ◽  
Vol 63 (1) ◽  
pp. 142-150 ◽  
Author(s):  
Vladimir G. Tsirelson ◽  
Ekaterina V. Bartashevich ◽  
Adam I. Stash ◽  
Vladimir A. Potemkin
Keyword(s):  
Electron Density ◽  
Reasonable Agreement ◽  
Covalent Bond ◽  
Bond Orders ◽  
Orbital Theory ◽  
Topological Features ◽  
Experimental Electron Density ◽  
Atomic Valence

We present an approach for the determination of covalent bond orders from the experimental electron density and its derivatives at the bond critical points. An application of this method to a series of organic compounds has shown that it provides a bonding quantification that is in reasonable agreement with that obtained by orbital theory. The `experimental' atomic valence indices are also defined and their significance for the characterization of chemical problems is discussed.

scholarly journals Decomposition of d- and f-Shell Contributions to Uranium Bonding from the Quantum Theory of Atoms in Molecules: Application to Uranium and Uranyl Halides

Inorganics ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 88 ◽  
Author(s):  
Jonathan Tanti ◽  
Meghan Lincoln ◽  
Andy Kerridge
Keyword(s):  
Quantum Theory ◽  
Electronic Structures ◽  
Density Functional ◽  
Covalent Bond ◽  
Vibrational Frequencies ◽  
Atoms In Molecules ◽  
High Symmetry ◽  
Strong Correlations ◽  
Bond Stability ◽  
Fluoride Ligands

The electronic structures of a series of uranium hexahalide and uranyl tetrahalide complexes were simulated at the density functional theoretical (DFT) level. The resulting electronic structures were analyzed using a novel application of the Quantum Theory of Atoms in Molecules (QTAIM) by exploiting the high symmetry of the complexes to determine 5f- and 6d-shell contributions to bonding via symmetry arguments. This analysis revealed fluoride ligation to result in strong bonds with a significant covalent character while ligation by chloride and bromide species resulted in more ionic interactions with little differentiation between the ligands. Fluoride ligands were also found to be most capable of perturbing an existing electronic structure. 5f contributions to overlap-driven covalency were found to be larger than 6d contributions for all interactions in all complexes studied while degeneracy-driven covalent contributions showed significantly greater variation. σ-contributions to degeneracy-driven covalency were found to be consistently larger than those of individual π-components while the total π-contribution was, in some cases, larger. Strong correlations were found between overlap-driven covalent bond contributions, U–O vibrational frequencies, and energetic stability, which indicates that overlap-driven covalency leads to bond stabilization in these complexes and that uranyl vibrational frequencies can be used to quantitatively probe equatorial bond covalency. For uranium hexahalides, degeneracy-driven covalency was found to anti-correlate with bond stability.

SCI: a robust and reliable density-based descriptor to determine multiple covalent bond orders

2018 ◽  
Vol 24 (8) ◽  
Author(s):  
Ying Huang ◽  
Lianghong Liu ◽  
Chunying Rong ◽  
Tian Lu ◽  
Paul W. Ayers ◽  
...  
Keyword(s):  
Covalent Bond ◽  
Bond Orders

scholarly journals Tetrel Bonding Interactions in Perchlorinated Cyclopenta- and Cyclohexatetrelanes: A Combined DFT and CSD Study

Molecules ◽  
2018 ◽  
Vol 23 (7) ◽  
pp. 1770 ◽  
Author(s):  
Antonio Bauzá ◽  
Antonio Frontera
Keyword(s):  
Dft Calculations ◽  
Crystal Structures ◽  
Electron Donor ◽  
Halogen Atom ◽  
Lone Pair ◽  
Covalent Bond ◽  
Atoms In Molecules ◽  
Aim Analysis ◽  
Structural Database ◽  
Close Contacts

In this manuscript, we combined DFT calculations (PBE0-D3/def2-TZVP level of theory) and a Cambridge Structural Database (CSD) survey to evaluate the ability of perchlorinated cyclopenta- and cyclohexatetrelanes in establishing tetrel bonding interactions. For this purpose, we used Tr5Cl10 and Tr6Cl12 (Tr = Si and Ge) and HCN, HF, OH− and Cl− as electron donor entities. Furthermore, we performed an Atoms in Molecules (AIM) analysis to further describe and characterize the interactions studied herein. A survey of crystal structures in the CSD reveals that close contacts between Si and lone-pair-possessing atoms are quite common and oriented along the extension of the covalent bond formed by the silicon with the halogen atom.

Covalent bond orders revisited: the open-shell case

2008 ◽  
Vol 10 (33) ◽  
pp. 5144 ◽  
Author(s):  
Diego R. Alcoba ◽  
Roberto C. Bochicchio ◽  
Luis Lain ◽  
Alicia Torre
Keyword(s):  
Covalent Bond ◽  
Open Shell ◽  
Bond Orders

Distributed polarizabilities using the topological theory of atoms in molecules

1995 ◽  
Author(s):  
János G. Ángyán ◽  
Georg Jansen ◽  
Michel Loos ◽  
Christof Hättig ◽  
Bernd A. Hess
Keyword(s):  
Atoms In Molecules ◽  
Topological Theory
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