New Perspectives on the Role of Frontier Molecular Orbitals in the Study of Chemical Reactivity: A Review

Pereira, Douglas Henrique; Porta, Felipe A. La; Santiago, Régis T.; Garcia, Danielle Rodrigues; Ramalho, Teodorico C.

doi:10.5935/1984-6835.20160032

Cited by 42 publications

(17 citation statements)

References 32 publications

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“…It is necessary to comment that molecular orbitals are significant descriptors for the rationalization of diverse reactions, and present a special importance in the understanding of chemical reactivity. [17,59] Thus, Figure 2 exhibits a parallel between the HOMOs and LUMOs of the cobalt prototypes under study. With the augmentation in the cobalt charge over the cobalt monoxides and dioxides series, there is a decrease in the HOMO and LUMO energies.…”

Section: Resultsmentioning

confidence: 89%

Methane Activation by CoOₘⁿ⁺ (n = 0, 1, 2; m= 1, 2): Reactivity Parameters, Electronic Properties and Binding Energy Analysis

Ramalho

2019

Preprint

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The need for renewal, more efficient and conscious usage of energy resources has led to a great interest in carrying out studies aiming to find novel sources of energy, which are able to supply the growing global demand, and at the same time, providing an ecofriendly usage of natural resources. In this context, the usage of methane stands out as a promising energetic alternative for this goal, mostly due to the existence of vast reserves, its low cost and less polluting fuel. For theoretical calculations B3LYP, CCSD(t) and ZORA-B3LYP methods were used to look into the catalytic properties of (CoOₘⁿ⁺ n= 0, 1, 2 and m=1, 2) in the methane C-H bond activation. According to the EDA outcomes, the studied species presented two stabilizing factors for the global interaction energy, being the electrostatic ΔEelstat and orbital ΔEorb interactions. The HOMO and LUMO orbitals were also evaluated based on the molecular orbital diagrams for the monoxides and dioxides series. Regarding the oxidative insertion mechanism, the outcomes demonstrate that the initial interaction between oxide and methane is of great relevance in its activation process, in which EBonding is benefited by the increasingly charge on the central metal. The high electron density regarding the oxides is meaningful for the reaction kinetics and the oxo ligands influence the thermodynamics of the reaction, becoming the DHA mechanism exergonic. Regarding the OHM mechanism, better kinetic conditions are found for CoO2++ and better thermodynamics for doubly charged cobalt monoxides and dioxides.

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Section: Resultsmentioning

confidence: 89%

Methane Activation by CoOₘⁿ⁺ (n = 0, 1, 2; m= 1, 2): Reactivity Parameters, Electronic Properties and Binding Energy Analysis

Ramalho

2019

Preprint

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“…To this end, the composition of the molecular orbital, its format, and a little critical chemical sense are taken into account [19,20]. The FERMO concept is being widely used to describe acid–base behavior in organic and inorganic complexes, pericyclic reactions, and biological systems [21].…”

Section: Resultsmentioning

confidence: 99%

An Explanation about the Use of (S)-Citronellal as a Chiral Derivatizing Agent (CDA) in 1H and 13C NMR for Sec-Butylamine, Methylbenzylamine, and Amphetamine: A Theoretical-Experimental Study

et al. 2019

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A chiral derivatizing agent (CDA) with the aldehyde function has been widely used in discriminating chiral amines because of the easy formation of imines under mild conditions. There is a preference for the use of cyclic aldehydes as a CDA since their lower conformational flexibility favors the differentiation of the diastereoisomeric derivatives. In this study, the imines obtained from the reaction between (S)-citronellal and the chiral amines (sec-butylamine, methylbenzylamine, and amphetamine) were analyzed by the nuclear Overhauser effect (NOE). Through NOE, it was possible to observe that the ends of the molecules were close, suggesting a quasi-folded conformation. This conformation was confirmed by theoretical calculations that indicated the London forces and the molecular orbitals as main justifications for this conformation. This conformational locking explains the good separation of 13C NMR signals between the diastereomeric imines obtained and, consequently, a good determination of the enantiomeric excess using the open chain (S)-citronellal as a CDA.

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“…The molecular descriptors were calculated at B3LYP/6-311þþG(d,p) level of theory to estimate the reactivity of amentoflavone and apigenin from the energy values of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) [32,33]. A higher value of energy for the HOMO orbital indicates a reasonable tendency of the chemical species to donate electronic density and a lower value of the energy for the LUMO orbital shows, a propensity to receive electronic density [34].…”

Section: Dft Analysismentioning

confidence: 99%

Quantum computational investigations and molecular docking studies on amentoflavone

Marinho

Almeida-Neto

Marinho

et al. 2021

Heliyon

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Chagas disease is a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi, with approximately 6-7 million people infected worldwide, becoming a public health problem in tropical countries, thus generating an increasing demand for the development of more effective drugs, due to the low efficiency of the existing drugs. Aiming at the development of a new antichagasic pharmacological tool, the density functional theory was used to calculate the reactivity descriptors of amentoflavone, a biflavonoid with proven antitrypanosomal activity in vitro, as well as to perform a study of interactions with the enzyme cruzain, an enzyme key in the evolutionary process of T-cruzi. Structural properties (in solvents with different values of dielectric constant), the infrared spectrum, the frontier orbitals, Fukui analysis, thermodynamic properties were the parameters calculated from DFT method with the monomeric structure of the apigenin used for comparison. Furthermore, molecular docking studies were performed to assess the potential use of this biflavonoid as a pharmacological antichagasic tool. The frontier orbitals (HOMO-LUMO) study to find the band gap of compound has been extended to calculate electron affinity, ionization energy, electronegativity electrophilicity index, chemical potential, global chemical hardness and global chemical softness to study the chemical behaviour of compound. The optimized structure was subjected to molecular Docking to characterize the interaction between amentoflavone and cruzain enzyme, a classic pharmacological target for substances with anti-gas activity, where significant interactions were observed with amino acid residues from each one's catalytic sites enzyme. These results suggest that amentoflavone has the potential to interfere with the enzymatic activity of cruzain, thus being an indicative of being a promising antichagasic agent.

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New Perspectives on the Role of Frontier Molecular Orbitals in the Study of Chemical Reactivity: A Review

Cited by 42 publications

References 32 publications

Methane Activation by CoOₘⁿ⁺ (n = 0, 1, 2; m= 1, 2): Reactivity Parameters, Electronic Properties and Binding Energy Analysis

Methane Activation by CoOₘⁿ⁺ (n = 0, 1, 2; m= 1, 2): Reactivity Parameters, Electronic Properties and Binding Energy Analysis

An Explanation about the Use of (S)-Citronellal as a Chiral Derivatizing Agent (CDA) in 1H and 13C NMR for Sec-Butylamine, Methylbenzylamine, and Amphetamine: A Theoretical-Experimental Study

Quantum computational investigations and molecular docking studies on amentoflavone

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