The Role of Electron-Density Transfer and Electronegativity in Understanding Chemical Reactivity and Bonding

1996 ◽  
Vol 73 (2) ◽  
pp. 123 ◽  
Author(s):  
Russell S. Drago ◽  
Ngai M. Wong
Keyword(s):  
Electron Density ◽  
Chemical Reactivity ◽  
Electron Density Transfer ◽  
Density Transfer

scholarly journals Unveiling the Ionic Diels-Alder Reactions within the Molecular Electron Density Theory

2021 ◽  
Author(s):  
Luis R. Domingo ◽  
Mar Ríos-Gutiérrez ◽  
María J. Aurell
Keyword(s):  
Electron Density ◽  
Topological Analysis ◽  
Activation Energies ◽  
High Reactivity ◽  
Diels Alder ◽  
Electron Density Transfer ◽  
Molecular Electron ◽  
Iminium Cations ◽  
Molecular Electron Density Theory ◽  
Density Transfer

The ionic Diels-Alder (I-DA) reactions of a series of six iminium cations with cyclopentadiene have been studied within the Molecular Electron Density Theory (MEDT). The superelectrophilic character of iminium cations,  > 8.20 eV, accounts for the high reactivity of these species participating in I-DA reactions. The activation energies are found between 13 and 20 kcal·mol-1 lower in energy than those associated to the corresponding Diels-Alder (DA) reactions of neutral imines. These reactions are low endo selective as a consequence of the cationic character of the TSs, but highly regioselective. Solvents have poor effects on the relative energies, and an unappreciable effect in the geometries. In dichloromethane the activation energies increase slightly as a consequence of the better solvation of the iminium cations than the cationic TSs. ELF topological analysis of the bonding changes along the I-DA reactions shows that they are very similar to those in polar DA reactions. The present MEDT study makes it possible establishing that the global electron density transfer (GEDT) taking place at the TSs of I-DA reactions, and not steric (Pauli) repulsions such as have been recently proposed, are responsible for the features of these type of DA reactions.

On the nature of organic electron density transfer complexes within molecular electron density theory

2019 ◽  
Vol 17 (26) ◽  
pp. 6478-6488 ◽  
Author(s):  
Luis R. Domingo ◽  
Mar Ríos-Gutiérrez
Keyword(s):  
Physical Properties ◽  
Electron Density ◽  
Electron Density Transfer ◽  
Molecular Electron ◽  
Organic Electron ◽  
Molecular Electron Density Theory ◽  
Density Transfer

The global electron density transfer taking place from the nucleophile to the electrophile controls the formation and physical properties of electron density transfer complexes.

scholarly journals Orbital Interaction and Electron Density Transfer in PdII([9]aneB2A)L2 Complexes: Theoretical Approaches

Molecules ◽  
2013 ◽  
Vol 18 (10) ◽  
pp. 12687-12706 ◽  
Author(s):  
Ock Kwak ◽  
Mahreen Arooj ◽  
Yong-Jin Yoon ◽  
Euh Jeong ◽  
Jong Park
Keyword(s):  
Electron Density ◽  
Orbital Interaction ◽  
Electron Density Transfer ◽  
Theoretical Approaches ◽  
Density Transfer

scholarly journals Unveiling the Ionic Diels–Alder Reactions within the Molecular Electron Density Theory

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3638
Author(s):  
Luis R. Domingo ◽  
Mar Ríos-Gutiérrez ◽  
María José Aurell
Keyword(s):  
Electron Density ◽  
Topological Analysis ◽  
Activation Energies ◽  
High Reactivity ◽  
Diels Alder ◽  
Electron Density Transfer ◽  
Molecular Electron ◽  
Iminium Cations ◽  
Molecular Electron Density Theory ◽  
Density Transfer

The ionic Diels–Alder (I-DA) reactions of a series of six iminium cations with cyclopentadiene have been studied within the Molecular Electron Density Theory (MEDT). The superelectrophilic character of iminium cations, ω > 8.20 eV, accounts for the high reactivity of these species participating in I-DA reactions. The activation energies are found to be between 13 and 20 kcal·mol−1 lower in energy than those associated with the corresponding Diels–Alder (DA) reactions of neutral imines. These reactions are low endo selective as a consequence of the cationic character of the TSs, but highly regioselective. Solvents have poor effects on the relative energies, and an unappreciable effect on the geometries. In acetonitrile, the activation energies increase slightly as a consequence of the better solvation of the iminium cations than the cationic TSs. Electron localization function (ELF) topological analysis of the bonding changes along the I-DA reactions shows that they are very similar to those in polar DA reactions. The present MEDT study establishes that the global electron density transfer (GEDT) taking place at the TSs of I-DA reactions, and not steric (Pauli) repulsions such as have been recently proposed, are responsible for the features of these types of DA reactions.

Accurate equilibrium structure of 3-aminophthalimide from gas electron diffraction and coupled-cluster computations and diverse structural effects due to electron density transfer

2020 ◽  
Vol 22 (47) ◽  
pp. 27539-27546
Author(s):  
Natalja Vogt ◽  
Denis Savelev ◽  
Nina I. Giricheva ◽  
Georgiy V. Girichev
Keyword(s):  
Electron Diffraction ◽  
Electron Density ◽  
Structure Determination ◽  
Equilibrium Structure ◽  
Gas Electron Diffraction ◽  
Coupled Cluster ◽  
Electron Density Transfer ◽  
Structural Effects ◽  
Density Transfer

The accurate equilibrium structure determination enables the observation of fine structural effects in 3-aminophthalimide due to the electron density transfer.

scholarly journals Quantum-chemical studies of rutile nanoparticles toxicity I. Defect-free rod-like model clusters

2019 ◽  
Vol 12 (2) ◽  
pp. 168-174 ◽  
Author(s):  
Martin Breza ◽  
Peter Šimon
Keyword(s):  
Electron Density ◽  
Interaction Energies ◽  
Relative Toxicity ◽  
Electron Density Transfer ◽  
Negative Interaction ◽  
Model Cluster ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Nanoparticles Toxicity ◽  
Density Transfer

Abstract Using the semiempirical PM6 method, structures of a rod-like [Ti40O124H81]7– model cluster and of [Ti40O124H81Cu]5– with Cu2+ coordinated at various sites were optimized in order to assess the toxicity of rutile nanoparticles. If the relative toxicity of individual Ti centers in rod-like rutile nanoparticles can be evaluated by the electron density transfer to a Cu2+ probe, its maximal values can be ascribed to the pentacoordinated corner and hexacoordinated edge Ti centers with three Ti—OH bonds. However, these centers exhibit the least negative interaction energies which can be compensated by the significantly better accessibility of the corner Ti center compared with that of the remaining ones. Ti centers with the most negative interaction energy parameters exhibit the lowest extent of electron density transfer to a Cu2+ probe. Rutile nanoparticles destruction starts at pentacoordinated Ti face centers.

scholarly journals Ammonia-modified Co(ii) sites in zeolites: spin and electron density redistribution through the CoII–NO bond

2016 ◽  
Vol 18 (5) ◽  
pp. 3716-3729 ◽  
Author(s):  
Adam Stępniewski ◽  
Mariusz Radoń ◽  
Kinga Góra-Marek ◽  
Ewa Broclawik
Keyword(s):  
Electron Density ◽  
Resonance Structure ◽  
Electron Density Transfer ◽  
Electron Density Redistribution ◽  
Transfer Channels ◽  
Density Transfer

Both considerable share of the CoIII–NO− resonance structure and large π*-backdonation (evidenced by electron density transfer channels) rationalize the huge activation of the NO ligand in [Co(ii)(NH3)n]–NO adducts.

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