Spectroscopic and Quantum Chemical Investigations of Hypothetical m-Diacetylaminoazopyrimidine and Its Photovoltaic Properties

2021 ◽  
Vol 14 (2) ◽  
pp. 139-154
Keyword(s):  
Excited State ◽  
Quantum Chemical ◽  
Density Functional ◽  
Chemical Potential ◽  
Energy Gap ◽  
Dye Sensitized Solar Cells ◽  
Chemical Hardness ◽  
Quantum Chemical Descriptors ◽  
Photovoltaic Properties ◽  
Chemical Descriptors

Abstract: Here, an attempt is made to theoretically study and predict the electronic and spectroscopic (UV-Vis and IR) and structural properties, quantum chemical descriptors and subsequent application of diacetylaminoazopyrimidine in dye-sensitized solar cells (DSSCs). Ground- and excited-state time-dependent density functional theory (TD-DFT) calculations were carried out using material studio and ORCA software, respectively. The computed ground-state energy gap, chemical hardness, chemical softness, chemical potential, electronegativity and electrophilicity index are: 3.60 eV, 1.80 eV, 0.56 eV, 4.49 eV, -4.49 eV and 5.68, respectively. Conversely, the DFT-predicted excited-state quantum chemical descriptors are: 1.67 eV, 0.83 eV, 1.20 eV, 4.71 eV and -4.71 eV, corresponding to the energy gap, chemical hardness, chemical softness, chemical potential and electronegativity, respectively. Furthermore, vibrational frequency calculations confirm the presence of some key functional groups (N=N, C=O, C-H) present in the dye molecules. The computed optoelectronic parameters, such as light-harvesting efficiency, electron injection and open-circuit voltage are 0.06 eV, -8.59 eV and -5.75 eV, respectively. Overall, the dye possesses a relatively good current conversion efficiency as compared to other dyes studied in the literature; hence, it could be used as a novel material for photovoltaic technological applications. Keywords: Diacetylaminoazopyrimidine, DFT, Excited state, Spectroscopy, DSSCs.

scholarly journals Global chemical reactivity parameters for several chiral beta-blockers from Density Functional Theory Viewpoint

2016 ◽  
Vol 89 (4) ◽  
pp. 513-518 ◽  
Author(s):  
Mona Maria Talmaciu ◽  
Ede Bodoki ◽  
Radu Oprean
Keyword(s):  
Quantum Chemical ◽  
Density Functional ◽  
Chemical Potential ◽  
Chemical Reactivity ◽  
Beta Blockers ◽  
Chemical Hardness ◽  
Quantum Chemical Descriptors ◽  
Chemical Structures ◽  
Coronary Syndrome ◽  
Chemical Descriptors

Background and aim.  Beta-adrenergic antagonists have been established as first line treatment in the medical management of hypertension, acute coronary syndrome and other cardiovascular diseases, as well as for the prevention of initial episodes of gastrointestinal bleeding in patients with cirrhosis and esophageal varices, glaucoma, and have recently become the main form of treatment of infantile hemangiomas.The aim of the present study is to calculate for 14 beta-blockers several quantum chemical descriptors in order to interpret various molecular properties such as electronic structure, conformation, reactivity, in the interest of determining how such descriptors could have an impact on our understanding of the experimental observations and describing various aspects of chemical binding of beta-blockers in terms of these descriptors.Methods. The 2D chemical structures of the beta-blockers (14 molecules with one stereogenic center) were cleaned in 3D, their geometry was preoptimized using the software MOPAC2012, by PM6 method, and then further refined using standard settings in MOE; HOMO and LUMO descriptors were calculated using semi-empirical molecular orbital methods AM1, MNDO and PM3, for the lowest energy conformers and the quantum chemical descriptors (HLG, electronegativity, chemical potential, hardness and softness, electrophilicity) were then calculated.Results. According to HOMO-LUMO gap and the chemical hardness the most stable compounds are alprenolol, bisoprolol and esmolol. The softness values calculated for the study molecules revolve around 0.100. Propranolol, sotalol and timolol have among the highest electrophilicity index of the studied beta-blocker molecules. Results obtained from calculations showed that acebutolol, atenolol, timolol and sotalol have the highest values for the electronegativity index. Conclusions. The future aim is to determine whether it is possible to find a valid correlation between these descriptors and the physicochemical behavior of the molecules from this class. The HLG could be correlated to the experimentally recorded electrochemical properties of the molecules. HOMO could be correlated to the observed oxidation potential, since the required voltage is related to the energy of the HOMO, because only the electron from this orbital is involved in the oxidation process.

scholarly journals Estimation of n-octanol/water partition coefficients of polycyclic aromatic hydrocarbons by quantum chemical descriptors

2008 ◽  
Vol 6 (2) ◽  
pp. 310-318 ◽  
Author(s):  
Gui-Ning Lu ◽  
Xue-Qin Tao ◽  
Zhi Dang ◽  
Xiao-Yun Yi ◽  
Chen Yang
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Quantum Chemical ◽  
Partition Coefficients ◽  
Density Functional ◽  
Optimal Model ◽  
Quantum Chemical Descriptors ◽  
Polycyclic Aromatic ◽  
Pls Analysis ◽  
Chemical Descriptors

AbstractQuantitative structure-property relationship (QSPR) modeling is a powerful approach for predicting environmental behavior of organic pollutants with their structure descriptors. This study reports an optimal QSPR model for estimating logarithmic n-octanol/water partition coefficients (log K OW) of polycyclic aromatic hydrocarbons (PAHs). Quantum chemical descriptors computed with density functional theory at B3LYP/6-31G(d) level and partial least squares (PLS) analysis with optimizing procedure were used for generating QSPR models for log K OW of PAHs. The squared correlation coefficient (R 2) of the optimal model was 0.990, and the results of crossvalidation test (Q 2cum=0.976) showed this optimal model had high fitting precision and good predictability. The log K OW values predicted by the optimal model are very close to those observed. The PLS analysis indicated that PAHs with larger electronic spatial extent and lower total energy values tend to be more hydrophobic and lipophilic.

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.

scholarly journals Kernel Methods for Predicting Yields of Chemical Reactions

2021 ◽  
Author(s):  
Alexe Haywood ◽  
Joseph Redshaw ◽  
Magnus Hanson-Heine ◽  
Adam Taylor ◽  
Alex Brown ◽  
...  
Keyword(s):  
Quantum Chemical ◽  
Density Functional ◽  
Aryl Halide ◽  
Reaction Yield ◽  
Support Vector ◽  
Quantum Chemical Descriptors ◽  
Functional Theory ◽  
Molecular Fingerprints ◽  
Chemical Descriptors ◽  
Synthetic Assessment

The use of machine learning methods for the prediction of reaction yield is an emerging area. We demonstrate the applicability of support vector regression (SVR) for predicting reaction yields, using combinatorial data. Molecular descriptors used in regression tasks related to chemical reac?tivity have often been based on time-consuming, computationally demanding quantum chemical calculations, usually density functional theory. Structure-based descriptors (molecular fingerprints and molecular graphs) are quicker and easier to calculate, and are applicable to any molecule. In this study, SVR models built on structure-based descriptors were compared to models built on quantum chemical descriptors. The models were evaluated along the dimension of each reaction component in a set of Buchwald-Hartwig amination reactions. The structure-based SVR models out-performed the quantum chemical SVR models, along the dimension of each reaction compo?nent. The applicability of the models was assessed with respect to similarity to training. Prospec?tive predictions of unseen Buchwald-Hartwig reactions are presented for synthetic assessment, to validate the generalisability of the models, with particular interest along the aryl halide dimension.

Synthesis and DFT Quantum Chemical Calculations of 2-Oxopyrimidin-1(2H)-yl-Urea and Thiorea Derivatives

2019 ◽  
Vol 41 (5) ◽  
pp. 841-841
Author(s):  
Murat Saracoglu Murat Saracoglu ◽  
Zulbiye Kokbudak Zulbiye Kokbudak ◽  
Esra Yalcin and Fatma Kandemirli Esra Yalcin and Fatma Kandemirli
Keyword(s):  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Chemical Potential ◽  
Energy Gap ◽  
Basis Set ◽  
Chemical Hardness ◽  
Spectroscopic Techniques ◽  
Solvent Phase ◽  
B3lyp Method ◽  
Homo Lumo

A series of the new 2-oxopyrimidin-1(2H)-yl-urea (3a-c) and thiourea (4a-d) derivatives were synthesized by the reaction of arylisocyanates (2a-c) or arylisothiocyanates (2d-g) and the 1-amino-5-(4-methoxybenzoyl)-4-(4-methoxyphenyl)pyrimidin-2(1H)-one (1). The structures of the compounds 3a-c and 4a-d were characterized by elemental analysis, FT-IR, 1H and 13C-NMR spectroscopic techniques. In addition to experimental study in order to find molecular properties, quantum-chemical calculations of the synthesized compounds were carried out by using DFT/B3LYP method with basis set of the 6-311G(d,p). Quantum chemical features such as HOMO, LUMO, HOMO-LUMO energy gap, Ionization potential, chemical hardness, chemical softness, electronegativity, chemical potential, dipole moment etc. values for gas and solvent phase of neutral molecules were calculated and discussed.

Synthesis and DFT Quantum Chemical Calculations of Novel Pyrazolo[1,5-c]pyrimidin-7(1H)-one Derivatives

2019 ◽  
Vol 41 (3) ◽  
pp. 479-479
Author(s):  
Murat Saracoglu Murat Saracoglu ◽  
Zulbiye Kokbudak Zulbiye Kokbudak ◽  
Zeynep imen and Fatma Kandemirli Zeynep imen and Fatma Kandemirli
Keyword(s):  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Chemical Potential ◽  
Energy Gap ◽  
Chemical Hardness ◽  
Spectroscopic Techniques ◽  
Solvent Phase ◽  
B3lyp Method ◽  
Ft Ir ◽  
Homo Lumo

In this study, a convenient procedure for the preparation of pyrazolo[1,5-c]pyrimidin-7(1H)-one derivatives is described. The new pyrazolo[1,5-c]pyrimidin-7(1H)-one derivatives (2a, b) were synthesized from the cyclocondensation reaction of the compounds 1-amino-5-(4-methoxybenzoyl)-4-(4-methoxyphenyl)pyrimidin-2(1H)-one (1a) and 1-amino-5-(4-methylbenzoyl)-4-(4-methylphenyl)pyrimidin-2(1H)-one (1b) with α-chloroacetone. The structures of the compounds (2a, b) were characterized by elemental analysis, FT-IR, 1H-NMR and 13C-NMR spectroscopic techniques. In addition to experimental study in order to find molecular properties, quantum-chemical calculations of the new pyrazolo[1,5-c]pyrimidin-7(1H)-one derivatives (2a, b) were carried out by using DFT/B3LYP method with the 6-311G(d,p) and 6-311++G(2d,2p) basic sets. Quantum chemical features such as HOMO, LUMO, HOMO-LUMO energy gap, chemical hardness, chemical softness, electronegativity, chemical potential, dipole moment etc. values for gas and solvent phase of neutral molecules were calculated and discussed.

The Influence of the Substitution of Transition Metals on Pristine C20: A DFT Study

2018 ◽  
Vol 17 (04) ◽  
pp. 1760026 ◽  
Author(s):  
Debolina Paul ◽  
Jyotirmoy Deb ◽  
Barnali Bhattacharya ◽  
Utpal Sarkar
Keyword(s):  
Density Functional ◽  
Chemical Potential ◽  
Energy Gap ◽  
Electronic Absorption Spectra ◽  
Wavelength Region ◽  
Chemical Hardness ◽  
Theory Approach ◽  
Functional Theory ◽  
Spectra Analysis ◽  
Doped Fullerenes

The stabilities and reactivities of two transition metal ([Formula: see text], Zn)-doped structures of C[Formula: see text] fullerene have been investigated by density functional theory approach. We have observed a noticeable structural change in pristine C[Formula: see text] due to the substitution of one of its carbon atom by Cu or Zn atom. From our findings, it is found that the energy gap of C[Formula: see text]Cu and C[Formula: see text]Zn increases with respect to pristine C[Formula: see text], thus making the two doped fullerenes more stable than their pristine counterpart. The reactivity parameters such as chemical hardness, chemical potential and electrophilicity index for these structures are also studied. Interestingly, our calculations reveal that both the doped fullerenes obey the maximum hardness principle and minimum electrophilicity principle. Also, from the electronic absorption spectra analysis, it can be inferred that the maximum absorption peak of the two heteroatom-substituted fullerenes C[Formula: see text]Cu and C[Formula: see text]Zn are shifted towards the longer wavelength region as compared to the pure C[Formula: see text] fullerene, which clearly indicates that a red shift is introduced on account of doping.

Prediction of the polarity parameter π for the radical derived from monomer

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Xinliang Yu ◽  
Wenhao Yu ◽  
Bing Yi ◽  
Xueye Wang
Keyword(s):  
Neural Network ◽  
Quantum Chemical ◽  
Density Functional ◽  
Ann Model ◽  
Quantum Chemical Descriptors ◽  
Functional Theory ◽  
The Neural Network ◽  
Polarity Parameter ◽  
Chemical Descriptors ◽  
Artificial Neural Network Ann

AbstractAn artificial neural network (ANN) model was successfully developed for the modelling and prediction of the polarity parameter π used in the revised patterns scheme for the prediction of monomers reactivity ratios in radical polymerizations. Four quantum chemical descriptors based on density functional theory (DFT) calculations were used to develop the ANN model. The optimal condition of the neural network was obtained by adjusting various parameters by trial-and-error. Simulated with the final optimum BP neural network 4-4-1, the results show that the predicted parameter π values are in good agreement with the experimental ones, with the root mean square (rms) errors being 0.053 (R=0.960) for the training set and 0.070 (R=0.942) for the test set. The ANN model has better statistic quality than the MLR model, which indicates there are nonlinear relationships between these quantum chemical descriptors and the parameter π.

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