DFT investigation of SiO2 nanotube for adsorption of methyl- and propyl-paraben

2021 ◽  
pp. 1-9
Author(s):  
Kun Harismah ◽  
Mohsen Mohammad Raei Nayini ◽  
Shadi Montazeri ◽  
Shaghayegh Ariaei ◽  
Milad Nouraliei
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Environmental Issues ◽  
Huge Number ◽  
Lumo Energy ◽  
Functional Theory ◽  
Propyl Paraben ◽  
Adsorption Energies ◽  
Precautionary Measures ◽  
Homo Lumo

A huge number of parabens, esters of p-hydroxybenzoic acid, are used in cosmetic and personal care products as preservative substances. Due to their detrimental effects on ecosystem and human health, taking precautionary measures to remove these compounds is an important task regarding the environmental issues. In this study, a silica (SiO2) nanotube has been selected as a novel sensor to adsorb the most common parabens which are methyl paraben and propyl paraben molecules. To this aim, density functional theory (DFT) calculations were used to evaluate the properties for investigated compounds. The calculated adsorption energies of the most stable configurations for methyl parban@SiO2 and propyl paraben@SiO2 complexes were found to be –0.238 and –0.242 eV, respectively. The electronic properties of nanotubes experienced dramatic changes in case of interactions with parabens, which led to declining the HOMO/LUMO energy gap of the nanotube to its original value. Such adsorption could also enhance the electrical conductivity of the nanotubes meaning that the utilized SiO2 nanotube could detect the existence of methyl and propyl parabens molecules in the environment. As a concluding remark, the investigated SiO2 nanotube could work as a possible sensor for hazardous paraben with the importance of environmental issues.

STRUCTURES, ABSORPTION SPECTRA, AND ELECTRONIC PROPERTIES OF POLYFLUORENE AND ITS DERIVATIVES: A THEORETICAL STUDY

2006 ◽  
Vol 05 (03) ◽  
pp. 595-608 ◽  
Author(s):  
KRIENGSAK SRIWICHITKAMOL ◽  
SONGWUT SURAMITR ◽  
POTJAMAN POOLMEE ◽  
SUPA HANNONGBUA
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Energy Gap ◽  
Level Energy ◽  
Excitation Energies ◽  
Lumo Energy ◽  
Functional Theory ◽  
Local Energy Minimum ◽  
Pi Systems ◽  
Homo Lumo

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.

SOLVENT EFFECTS ON THE ELECTRONIC STRUCTURE AND NON-LINEAR OPTICAL PROPERTIES OF PYRENE AND SOME OF ITS DERIVATIVES BASED ON DENSITY FUNCTIONAL THEORY

2021 ◽  
Vol 4 (4) ◽  
pp. 236-251
Author(s):  
A. S. Gidado ◽  
L. S. Taura ◽  
A. Musa
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Density Functional ◽  
Energy Gap ◽  
Chemical Reactivity ◽  
Basis Set ◽  
Lumo Energy ◽  
Functional Theory ◽  
Organic Optoelectronic ◽  
Homo Lumo

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.

Saturated N,X-Heterocyclic Carbenes (X=N, O, S, P, Si, C, and B): Stability, Nucleophilicity, and Basicity

2015 ◽  
Vol 68 (9) ◽  
pp. 1438 ◽  
Author(s):  
Zahra Azizi ◽  
Mehdi Ghambarian ◽  
Mohammad A. Rezaei ◽  
Mohammad Ghashghaee
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Energy Difference ◽  
Heterocyclic Carbenes ◽  
Structure Stability ◽  
Triplet Energy ◽  
Lumo Energy ◽  
Dft Methods ◽  
Functional Theory ◽  
Homo Lumo

Various saturated five-membered N,X-heterocyclic carbenes (X = N, O, S, P, Si, C, and B) have been studied by ab initio and density functional theory (DFT) methods. The substitutions alter the properties of the reference carbene from the viewpoint of electronic structure, stability, nucleophilicity, and basicity. Our study shows that the oxygen containing carbene (X = O) induces the highest HOMO–LUMO energy gap (ΔEHOMO–LUMO), while carbene with X = N has the widest singlet–triplet energy difference (ΔEs–t). The nucleophilicity of the carbene derivatives increased upon replacement of C, Si, and B, with the effect of the boron substituent being more pronounced. In addition, the basicity of the structure increased for the carbene derivatives with X = C and B with the latter substitution imposing a remarkably higher effect. Moreover, the substitution of boron at the α-position of the carbene increased the nucleophilicity and basicity, while inducing a reduction in the values of ΔEs–t and ΔEHOMO–LUMO.

scholarly journals Crystal structure, Hirshfeld surface analysis and DFT study of N-(2-amino-5-methylphenyl)-2-(5-methyl-1H-pyrazol-3-yl)acetamide

2021 ◽  
Vol 77 (6) ◽  
pp. 638-642
Author(s):  
Gamal Al Ati ◽  
Karim Chkirate ◽  
Joel T. Mague ◽  
Nadeem Abad ◽  
Redouane Achour ◽  
...  
Keyword(s):  
Surface Analysis ◽  
Density Functional ◽  
Energy Gap ◽  
Crystal Packing ◽  
Layer Structure ◽  
Hirshfeld Surface ◽  
Hirshfeld Surface Analysis ◽  
Lumo Energy ◽  
Functional Theory ◽  
Homo Lumo

The title molecule, C13H16N4O, adopts an angular conformation. In the crystal a layer structure is generated by N—H...O and N—H...N hydrogen bonds together with C—H...π(ring) interactions. Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H...H (53.8%), H...C/C...H (21.7%), H...N/N...H (13.6%), and H...O/O...H (10.8%) interactions. The optimized structure calculated using density functional theory (DFT) at the B3LYP/ 6–311 G(d,p) level is compared with the experimentally determined structure in the solid state. The calculated HOMO–LUMO energy gap is 5.0452 eV.

scholarly journals Crystal structure and DFT study of a zinc xanthate complex

2019 ◽  
Vol 75 (11) ◽  
pp. 1582-1585 ◽  
Author(s):  
Adnan M. Qadir ◽  
Sevgi Kansiz ◽  
Necmi Dege ◽  
Georgina M. Rosair ◽  
Igor O. Fritsky
Keyword(s):  
Molecular Structure ◽  
Electrostatic Potential ◽  
Density Functional ◽  
Molecular Electrostatic Potential ◽  
Energy Gap ◽  
Three Dimensional ◽  
Intramolecular Interactions ◽  
Lumo Energy ◽  
Functional Theory ◽  
Homo Lumo

In the title compound, bis(2-methoxyethyl xanthato-κS)(N,N,N′,N′-tetramethylethylenediamine-κ2 N,N′)zinc(II) acetone hemisolvate, [Zn(C4H7O2S2)2(C6H16N2)]·0.5C3H6O, the ZnII ion is coordinated by two N atoms of the N,N,N′,N′-tetramethylethylenediamine ligand and two S atoms from two 2-methoxyethyl xanthate ligands. The amine ligand is disordered over two orientations and was modelled with refined occupancies of 0.538 (6) and 0.462 (6). The molecular structure features two C—H...O and two C—H...S intramolecular interactions. In the crystal, molecules are linked by weak C—H...O and C—H...S hydrogen bonds, forming a three-dimensional supramolecular architecture. The molecular structure was optimized using density functional theory (DFT) at the B3LYP/6–311 G(d,p) level. The smallest HOMO–LUMO energy gap (3.19 eV) indicates the suitability of this crystal for optoelectronic applications. The molecular electrostatic potential (MEP) further identifies the positive, negative and neutral electrostatic potential regions of the molecules. Half a molecule of disordered acetone was removed with the solvent-mask procedure in OLEX2 [Dolomanov et al. (2009). J. Appl. Cryst. 42, 339–341] and this contribition is included in the formula.

scholarly journals Structure, electronic and optical properties of chalcopyrite-type nano-clusters XFeY2 (X=Cu, Ag, Au; Y=S, Se, Te): a density functional theory study

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Prabhat Ranjan ◽  
Praveen K. Surolia ◽  
Tanmoy Chakraborty
Keyword(s):  
Density Functional Theory ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Optical Properties ◽  
Solar Cells ◽  
Density Functional ◽  
Energy Gap ◽  
Lumo Energy ◽  
Functional Theory ◽  
Homo Lumo

Abstract Iron-based chalcopyrite materials have diverse applications in solar cells, spintronic, thermoelectric devices, LEDs and medical sciences. In this report we have studied structure, electronic and optical properties of chalcopyrite-type nano-cluster XFeY2 (X=Cu, Ag, Au; Y=S, Se, Te) systematically by using Density Functional Theory (DFT). Our computed HOMO-LUMO energy gap of XFeY2 is in the range of 1.568–3.982 eV, which endorses its potential application in optoelectronic devices and solar cells. The result shows that chalcopyrite-type material AuFeS2 having a star-type structure with point group C2v and sextet spin multiplicity, is the most stable cluster with HOMO-LUMO energy gap of 3.982 eV. The optical properties viz. optical electronegativity, refractive index, dielectric constant, IR and Raman activity of these nano-clusters are also investigated. The result exhibits that HOMO-LUMO energy gap of XFeY2 along with optical electronegativity and vibrational frequency decreases from S to Se to Te, whereas refractive index and dielectric constant increases in the reverse order.

scholarly journals Vibrational Spectroscopic and Computational Analysis of 5-chloro-2-hydroxy Acetophenone

2020 ◽  
Vol 8 (4S4) ◽  
pp. 254-259
Keyword(s):  
Density Functional ◽  
Computational Analysis ◽  
Energy Gap ◽  
Molecular System ◽  
Basis Sets ◽  
Geometrical Parameters ◽  
Lumo Energy ◽  
Functional Theory ◽  
Infrared Intensities ◽  
Homo Lumo

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.

DFT study on [4+2] and [2+2] cycloadditions to [60] fullerene

2014 ◽  
Vol 68 (3) ◽  
Author(s):  
Ali Peyghan ◽  
Maziar Noei
Keyword(s):  
Density Functional Theory ◽  
Electron Emission ◽  
Density Functional ◽  
Energy Gap ◽  
Density Functional Theory Calculations ◽  
C60 Fullerene ◽  
Lumo Energy ◽  
Functional Theory ◽  
Reaction Energies ◽  
Homo Lumo

AbstractThe functionalisation of C60 fullerene with 2,3-dimethylene-1,4-dioxane (I) and 2,5-dioxabicyclo [4.2.0]octa-1(8),6-diene (II) was investigated by the use of density functional theory calculations in terms of its energetic, structural, field emission, and electronic properties. The functionalisation of C60 with I was previously reported experimentally. The I and II molecules are preferentially attached to a C—C bond shared and located between two hexagons of C60 via [4+2] and [2+2] cycloadditions bearing reaction energies of −15.9 kcal mol−1 and −72.4 kcal mol−1, respectively. The HOMO-LUMO energy gap and work function of C60 are significantly reduced following completion of the reactions. The field electron emission current of the C60 surface will increase after functionalisation of either the I or II molecule.

A DFT Study of Geometric Structure and Stability of Iron-Silicon Clusters

2014 ◽  
Vol 1048 ◽  
pp. 369-372
Author(s):  
Shuai Qin Yu ◽  
Hong Nan Ye
Keyword(s):  
Density Functional Theory ◽  
Geometric Structure ◽  
Density Functional ◽  
Energy Gap ◽  
Surface Site ◽  
Silicon Clusters ◽  
Lumo Energy ◽  
Functional Theory ◽  
The Stability ◽  
Homo Lumo

Geometric structures of Fe6-xSix(x=1-5) clusters have been systematically studied at the BPW91 level by density-functional theory (DFT). Calculated results show that the Fe atoms of the lowest-energy structures of Fe6-xSix clusters tend to go together, and Si atoms tend to occupy surface site bonding with iron atoms as many as possible. Further, we analyze the stability of the lowest-energy structures of Fe6-xSix clusters, and the corresponding results of the HOMO, LUMO as well as the HOMO-LUMO energy gap show that the Fe5Si and Fe4Si2 clusters have special stability.

Density functional theory study of structural, magnetic and spectral properties of the CrmFen (m + n = 6) and CrmFenCu (m + n = 5) clusters

2019 ◽  
Vol 9 (6) ◽  
pp. 570-577
Author(s):  
Yunlong Chen ◽  
Zhenghua Tang ◽  
Chong He ◽  
Yong Sheng
Keyword(s):  
Density Functional Theory ◽  
Infrared Spectroscopy ◽  
Density Functional ◽  
Energy Gap ◽  
Binding Energies ◽  
Chemical Hardness ◽  
Lumo Energy ◽  
Functional Theory ◽  
Homo Lumo ◽  
Original Cluster

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.

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