scholarly journals Computational Study of Structural, Molecular Orbitals, Optical and Thermodynamic Parameters of Thiophene Sulfonamide Derivatives

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 211
Author(s):  
Adeel Mubarik ◽  
Nasir Rasool ◽  
Muhammad Ali Hashmi ◽  
Asim Mansha ◽  
Muhammad Zubair ◽  
...  

Thiophene and sulfonamide derivatives serve as biologically active compounds, used for the manufacture of large numbers of new drugs. In this study, 11 selected derivatives of thiophene sulfonamide were computed for their geometric parameters, such as hyperpolarizability, chemical hardness (ƞ), electronic chemical potential (μ), electrophilicity index (ω), ionization potential (I), and electron affinity (A). In addition, FT-IR and UV-Vis spectra were also simulated through theoretical calculations. The geometrical parameters and vibrational frequencies with assignments of the vibrational spectra strongly resemble the experimentally calculated values. Besides, the frontier molecular orbitals were also determined for various intramolecular interactions that are responsible for the stability of the compounds. The isodensity surfaces of the frontier molecular orbitals (FMOs) are the same pattern in most of the compounds, but in some compounds are disturbed due to the presence of highly electronegative hetero-atoms. In this series of compounds, 3 shows the highest HOMO–LUMO energy gap and lowest hyperpolarizability, which leads to the most stable compound and less response to nonlinear optical (NLO), while 7 shows the lowest HOMO–LUMO energy gap and highest hyperpolarizability, which leads to a less stable compound and a high NLO response. All compounds have their extended three-dimensional p-electronic delocalization which plays an important role in studying NLO responses.

2019 ◽  
Vol 4 (2) ◽  
pp. 70-76
Author(s):  
Sandhya Chhakra ◽  
A. Mukherjee ◽  
H.L. Singh ◽  
Suresh Singh Chauhan

An efficient synthesis of novel 2,3,4-trisubstituted 1,5-benzothiazepines (4a-e) incorporating the sulfonyl group is described. Compound (4a-e) was synthesized by the reaction of 3-(1,4-dioxane-6-sulfonyl)-2,4-dimethyl/4-methyl-2-phenyl/2,4-diphenyl/2-ethoxy-4-methyl/2,4-diethoxy propane-1,3-dione (3ae) with 2-aminobenzenethiol with ZnOnanoparticles/pyridine. Formation of compound (3a-e) was achieved by the reaction of 1,4-dioxane-6-sulfonyl chloride (1) with 2,4-dimethyl/4-methyl-2-phenyl/2,4-diphenyl/2-ethoxy-4-methyl/2,4-diethoxy propane-1,3-dione (2a-e). The benzothiazepines (4a-e) obtained were purified by column chromatography (benzene: CHCl3, 40:60, 30:70, 20:80, 10:90) and crystallized from methanol. The purity of the compounds was checked by TLC using (CHCl3: CH3OH, 9:1) as the mobile phase. The structure of the compounds has been established by elemental, IR, 1H NMR, 13C NMR and Mass spectral analyses. Frontier molecular orbitals of the title compounds have been studied in the ground state speculatively. The reactivity of a molecule using diverse descriptors such as softness, electrophilicity, electronegativity, HOMO-LUMO energy gap is calculated additionally discussed.


Author(s):  
Meysam Shirmohammadi ◽  
Esmat Mohammadinasab ◽  
Zakiyeh Bayat

: In the present study the applicability of various molecular descriptors was tested for the QSPR study on 40 quinolones derivatives. The relationship between some of the molecular indices with physicochemical properties such as refractive index (n), polarizability (α) and HOMO-LUMO energy gap (ΔEH-L) was represented. At first, the chemical structure of quinolones derivatives was optimized by Gaussian 98 program and ab initio method at the #HF/6-31++G**level, and then the physicochemical properties such as refractive index, polarizability and HOMO-LUMO energy gap were calculated. Genetic algorithm using multiple linear regression (GA-MLR) with backward method by SPSS software was used for obtaining properties. The analytical powers of the established theoretical models were discussed using leave-one-out (LOO) cross-validation technique. A multi-parametric equation containing maximum three descriptors with suitable statistical qualities was obtained for predicting the studied properties.


Fourier Transfer infrared and Raman spectra in the range of 4000-400 cm-1 and 3500-50 cm-1 were recorded to study the vibrational spectra of 5-chloro-2-hydroxyacetophenone (CHAP). Using density functional theory (DFT/B3LYP) with 6-31+G(d,p) and 6-311++G(d,p) basis sets the various geometrical parameters such as Raman activities, infrared intensities and optimum frequencies were calculated. The HOMO-LUMO energy gap has been computed which confirms the charge transfer of the molecular system. Mulliken’s atomic charges associated with each atom and thermodynamic parameters have also been reported with the same level of DFT.


2019 ◽  
Vol 9 (6) ◽  
pp. 570-577
Author(s):  
Yunlong Chen ◽  
Zhenghua Tang ◽  
Chong He ◽  
Yong Sheng

Using Density functional theory (DFT) to study the geometries, stability, magnetic properties and infrared spectroscopy of CrmFen (m + n = 6) and CrmFenCu (m + n = 5) clusters at the BP86/SDD level. The ground state structures of CrmFen (m + n = 6) and CrmFenCu (m + n = 5) clusters are determined according to the principles of lowest energy and no virtual frequency. On this basis, the structural and chemical stabilities are obtained by the average binding energies (Eb), chemical hardness (η) and HOMO-LUMO energy gap (Eg). The average binding energies show the substitution of a copper atom is beneficial to improve the structural stability; It can be seen Cr4Fe2 and Cr3Fe2Cu have the best chemical stability in the two cluster series from the chemical hardness and HOMO-LUMO energy gap. By calculating the magnetic moment, it is shown that Cr5Fe and CrFe4Cu have large magnetic moments, which can be understood by the spin distribution. Finally, infrared spectroscopy of the clusters are calculated, we find a copper atom substitutes the CrmFen (m + n = 6) does not change the range of vibration frequency a lot because it does not significantly change the molecular structure of the original cluster, but it changes the vibration mode of the original cluster, resulting in the strongest infrared absorption peak intensity of Cr3Fe2Cu being lower than that of Cr3Fe3.


Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7309
Author(s):  
Gulraiz Ahmad ◽  
Nasir Rasool ◽  
Adeel Mubarik ◽  
Ameer Fawad Zahoor ◽  
Muhammad Ali Hashmi ◽  
...  

Synthesis of 5-aryl-N-(pyrazin-2-yl)thiophene-2-carboxamides (4a–4n) by a Suzuki cross-coupling reaction of 5-bromo-N-(pyrazin-2-yl)thiophene-2-carboxamide (3) with various aryl/heteroaryl boronic acids/pinacol esters was observed in this article. The intermediate compound 3 was prepared by condensation of pyrazin-2-amine (1) with 5-bromothiophene-2-carboxylic acid (2) mediated by TiCl4. The target pyrazine analogs (4a–4n) were confirmed by NMR and mass spectrometry. In DFT calculation of target molecules, several reactivity parameters like FMOs (EHOMO, ELUMO), HOMO–LUMO energy gap, electron affinity (A), ionization energy (I), electrophilicity index (ω), chemical softness (σ) and chemical hardness (η) were considered and discussed. Effect of various substituents was observed on values of the HOMO–LUMO energy gap and hyperpolarizability. The p-electronic delocalization extended over pyrazine, benzene and thiophene was examined in studying the NLO behavior. The chemical shifts of 1H NMR of all the synthesized compounds 4a–4n were calculated and compared with the experimental values.


Author(s):  
Jihyeon Kim ◽  
Heechan Kim ◽  
Sechan Lee ◽  
Giyun Kwon ◽  
Taewon Kang ◽  
...  

A new bipolar-type redox-active organic material with a wide HOMO–LUMO energy gap is designed though the ‘p–n fusion’ strategy.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Aleksey E. Kuznetsov

Abstract The first comparative DFT (B3LYP/6-31G*) study of the Zn-porphyrin and its two derivatives, ZnP(P)4 and ZnP(As)4, is reported. For all three species studied, ZnP, ZnP(P)4 and ZnP(As)4, the singlet was calculated to be the lowest-energy structure and singlet-triplet gap was found to decrease from ca. 41—42 kcal/mol for N to ca. 17—18 kcal/mol for P and to ca. 10 kcal/mol for As. Both ZnP(P)4 and ZnP(As)4 were calculated to attain very pronounced bowl-like shapes. The frontier molecular orbitals (MOs) of the core-modified porphyrins are quite similar to the ZnP frontier MOs. For the HOMO-2 of the core-modified porphyrins due to the ZnP(P)4/ZnP(As)4 bowl-like shapes we might suppose the existence of “internal” electron delocalization inside the ZnP(P)4/ZnP(As)4 “bowls”. Noticeable reduction of the HOMO/LUMO gaps was calculated for ZnP(P)4 and ZnP(As)4, by ca. 1.10 and 1.47 eV, respectively, compared to ZnP. The core-modification of porphyrins by P and especially by As was found to result in significant decrease of the charge on Zn-centers, by ca. 0.61—0.67e for P and by ca. 0.69—0.76e for As. Charges on P- and As-centers were computed to have large positive values, ca. 0.41—0.45e and ca. 0.43—0.47e, for P and As, respectively, compared to significant negative values, ca. −0.65 to −0.66e for N. The porphyrin core-modification by heavier N congeners, P and As, can noticeably modify the structures, electronic, and optical properties of porphyrins, thus affecting their reactivity and potential applications.


2006 ◽  
Vol 05 (03) ◽  
pp. 595-608 ◽  
Author(s):  
KRIENGSAK SRIWICHITKAMOL ◽  
SONGWUT SURAMITR ◽  
POTJAMAN POOLMEE ◽  
SUPA HANNONGBUA

The structural and energetic properties of polyfluorene and its derivatives were investigated, using quantum chemical calculations. Conformational analysis of bifluorene was performed by using ab initio (HF/6-31G* and MP2/6-31G*) and density functional theory (B3LYP/6-31G*) calculations. The results showed that the local energy minimum of bifluorene lies between the coplanar and perpendicular conformation, and the B3LYP/6-31G* calculations led to the overestimation of the stability of the planar pi systems. The HOMO-LUMO energy differences of fluorene oligomers and its derivatives — 9,9-dihexylfluorene (DHPF), 9,9-dioctylfluorene (PFO), and bis(2-ethylhexyl)fluorene (BEHPF) — were calculated at the B3LYP/6-31G* level. Energy gaps and effective conjugation lengths of the corresponding polymers were obtained by extrapolating HOMO-LUMO energy differences and the lowest excitation energies to infinite chain length. The lowest excitation energies and the maximum absorption wavelength of polyfluorene were also performed, employing the time-dependent density functional theory (TDDFT) and ZINDO methods. The extrapolations, based on TDDFT and ZINDO calculations, agree well with experimental results. These theoretical methods can be useful for the design of new polymeric structures with a reducing energy gap.


2019 ◽  
Vol 75 (7) ◽  
pp. 1079-1083
Author(s):  
Tanwawan Duangthongyou ◽  
Ramida Rattanakam ◽  
Kittipong Chainok ◽  
Songwut Suramitr ◽  
Thawatchai Tuntulani ◽  
...  

The title compound, C31H30N2S2O6, possesses crystallographically imposed twofold symmetry with the two C atoms of the central benzene ring and the C atom of its methyl substituent lying on the twofold rotation axis. The two dansyl groups are twisted away from the plane of methylphenyl bridging unit in opposite directions. The three-dimensional arrangement in the crystal is mainly stabilized by weak hydrogen bonds between the sulfonyl oxygen atoms and the hydrogen atoms from the N-methyl groups. Stacking of the dansyl group is not observed. From the DFT calculations, the HOMO–LUMO energy gap was found to be 2.99 eV and indicates n→π* and π→π* transitions within the molecule.


2021 ◽  
Vol 4 (4) ◽  
pp. 236-251
Author(s):  
A. S. Gidado ◽  
L. S. Taura ◽  
A. Musa

Pyrene (C16H10) is an organic semiconductor which has wide applications in the field of organic electronics suitable for the development of organic light emitting diodes (OLED) and organic photovoltaic cells (OPV). In this work, Density Functional Theory (DFT) using Becke’s three and Lee Yang Parr (B3LYP) functional with basis set 6-311++G(d, p) implemented in Gaussian 03 package was  used to compute total energy, bond parameters, HOMO-LUMO energy gap, electron affinity, ionization potential, chemical reactivity descriptors, dipole moment, isotropic polarizability (α), anisotropy of polarizability ( Δ∝) total first order hyper-polarizability () and second order hyperpolarizability (). The molecules used are pyrene, 1-chloropyrene and 4-chloropyrene  in gas phase and in five different solvents: benzene, chloroform, acetone, DMSO and water. The results obtained show that solvents and chlorination actually influenced the properties of the molecules. The isolated pyrene in acetone has the largest value of HOMO-LUMO energy gap of and is a bit closer to a previously reported experimental value of  and hence is the most stable. Thus, the pyrene molecule has more kinetic stability and can be described as low reactive molecule. The calculated dipole moments are in the order of 4-chloropyrene (1.7645 D) < 1-chloropyrene (1.9663 D) in gas phase. The anisotropy of polarizability ( for pyrene and its derivatives were found to increase with increasing polarity of the solvents.  In a nutshell, the molecules will be promising for organic optoelectronic devices based on their computed properties as reported by this work.


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