Topological aspects of chemical reactivity. A simple method for estimating the activation energies in pericyclic reactions

1986 ◽  
Vol 51 (1) ◽  
pp. 175-187
Author(s):  
Robert Ponec
Keyword(s):  
Quantum Chemical ◽  
Chemical Reactivity ◽  
Activation Energies ◽  
Topological Model ◽  
Pericyclic Reactions ◽  
Simple Method ◽  
Proposed Model ◽  
Designed Synthesis

A simple topological model allowing to estimate the activation energies in thermally initiated pericyclic reactions is proposed. The formalism of the model is closely connected with the recently formulated overlap determinant method. Due to its simplicity the proposed model is especially convenient for the semiquantitative estimate of the reactivity, e.g. in computer designed synthesis where even the simplest quantum chemical procedures are still too time consuming.

The optoelectronic properties of π-conjugated organic molecules based on terphenyl and pyrrole for BHJ solar cells: DFT / TD-DFT theoretical study

2021 ◽  
Vol 10 (4) ◽  
pp. 489-502 ◽  
Author(s):  
M. Raftani ◽  
T. Abram ◽  
W. Loued ◽  
R. Kacimi ◽  
A. Azaid ◽  
...  
Keyword(s):  
Solar Cells ◽  
Quantum Chemical ◽  
Chemical Method ◽  
Chemical Reactivity ◽  
Optoelectronic Properties ◽  
Oscillator Strengths ◽  
Frontier Molecular Orbital ◽  
Bandgap Energy ◽  
Quantum Chemical Method ◽  
Td Dft

In the present paper, four π-conjugated materials, based on terphenyl and pyrrole, with A–D–A structure have been theoretically studied to propose new organic compounds to be used in the organic solar cell field. Moreover, the geometrical and optoelectronic properties of the designed molecules M1, M2, M3 and M4 have been computed after optimization in their fundamental states, using the quantum chemical method DFT / B3LYP/ 6−311G (d, p). Different parameters including HOMO and LUMO energy levels, bandgap energy, frontier molecular orbital (FMO), chemical reactivity indices, the density of states (DOS), Voc, electrostatic potential (ESP), and thermodynamic parameters at several temperatures in the range of 0-500 K have been determined. The absorption properties including the transition energy, the wavelengths (λmax), the excitation vertical energy, and the corresponding oscillator strengths of these molecules have been studied using the quantum chemical method TD−DFT / CAM–B3LYP / 6–311G (d, p). The obtained results of our studied compounds show that M3 (with 2H, 2'H-1, 1'-biisoindole moiety) as a donor group has special optoelectronic, absorption, and good photovoltaic characteristics. Thus, they can be utilized as an electron-donating in organic solar cells BHJ type.

Similarity approach to chemical reactivity. Torquoselectivity in pericyclic reactions

1996 ◽  
Vol 20 (2) ◽  
pp. 301-310 ◽  
Author(s):  
Robert Ponec ◽  
Gleb Yuzhakov ◽  
Jaroslav Pecka
Keyword(s):  
Chemical Reactivity ◽  
Pericyclic Reactions

scholarly journals A Comparative Study of Two Quantum Chemical Descriptors in Predicting Toxicity of Aliphatic Compounds towards Tetrahymena pyriformis

2010 ◽  
Vol 2010 ◽  
pp. 1-17 ◽  
Author(s):  
Altaf Hussain Pandith ◽  
S. Giri ◽  
P. K. Chattaraj
Keyword(s):  
Quantum Chemical ◽  
Chemical Potential ◽  
Chemical Reactivity ◽  
Molecular Descriptor ◽  
Tetrahymena Pyriformis ◽  
Quantitative Structure Activity Relationship ◽  
Quantum Chemical Descriptors ◽  
Data Set ◽  
Aliphatic Compounds ◽  
Chemical Descriptors

Quantum chemical parameters such as LUMO energy, HOMO energy, ionization energy (I), electron affinity (A), chemical potential (μ), hardness (η) electronegativity (χ), philicity (ωα), and electrophilicity (ω) of a series of aliphatic compounds are calculated at the B3LYP/6-31G(d) level of theory. Quantitative structure-activity relationship (QSAR) models are developed for predicting the toxicity (pIGC50) of 13 classes of aliphatic compounds, including 171 electron acceptors and 81 electron donors, towards Tetrahymena pyriformis. The multiple linear regression modeling of toxicity of these compounds is performed by using the molecular descriptor log P (1-octanol/water partition coefficient) in conjunction with two other quantum chemical descriptors, electrophilicity (ω) and energy of the lowest unoccupied molecular orbital (ELUMO). A comparison is made towards the toxicity predicting the ability of electrophilicity (ω) versus ELUMO as a global chemical reactivity descriptor in addition to log P. The former works marginally better in most cases. There is a slight improvement in the quality of regression by changing the unit of IGC50 from mg/L to molarity and by removing the racemates and the diastereoisomers from the data set.

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