HOMO–LUMO Energy-Gap Tuning of π-Conjugated Zwitterions Composed of Electron-Donating Anion and Electron-Accepting Cation

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.

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5-Methyl-1,3-phenylene bis[5-(dimethylamino)naphthalene-1-sulfonate]: crystal structure and DFT calculations

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s2056989019009058 ◽

2019 ◽

Vol 75 (7) ◽

pp. 1079-1083

Author(s):

Tanwawan Duangthongyou ◽

Ramida Rattanakam ◽

Kittipong Chainok ◽

Songwut Suramitr ◽

Thawatchai Tuntulani ◽

...

Keyword(s):

Dft Calculations ◽

Energy Gap ◽

Rotation Axis ◽

Three Dimensional ◽

Hydrogen Atoms ◽

Lumo Energy ◽

Compound C ◽

Dansyl Group ◽

Weak Hydrogen Bonds ◽

Homo Lumo

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.

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

FUDMA Journal of Sciences ◽

10.33003/fjs-2020-0404-477 ◽

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.

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Strategic design of thiophene-fused nickel dithiolene derivatives for efficient NLO response

Physical Chemistry Chemical Physics ◽

10.1039/c8cp01592a ◽

2018 ◽

Vol 20 (28) ◽

pp. 19007-19016 ◽

Cited By ~ 3

Author(s):

Manoj Majumder ◽

Anirban Misra

Keyword(s):

Energy Gap ◽

First Hyperpolarizability ◽

Lumo Energy ◽

Strategic Design ◽

Nlo Response ◽

Acceptor Group ◽

Donor Acceptor ◽

Homo Lumo

The zwitterionic donor–acceptor group significantly reduces the HOMO–LUMO energy gap resulting in an enormous increase in the first hyperpolarizability values.

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Trans influence and substituent effects on the HOMO-LUMO energy gap and Stokes shift in Ru mono-diimine derivatives

Journal of Molecular Structure ◽

10.1016/j.molstruc.2019.06.005 ◽

2019 ◽

Vol 1195 ◽

pp. 620-631 ◽

Cited By ~ 2

Author(s):

Sanaa AlAbbad ◽

Tova Sardot ◽

Oliko Lekashvili ◽

Daniel Decato ◽

Francesco Lelj ◽

...

Keyword(s):

Energy Gap ◽

Stokes Shift ◽

Substituent Effects ◽

Lumo Energy ◽

Trans Influence ◽

Homo Lumo

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Thermal routes to low HOMO–LUMO energy gap poly(arylenevinylene)s

Journal of Materials Chemistry ◽

10.1039/b107044b ◽

2001 ◽

Vol 12 (2) ◽

pp. 200-205 ◽

Cited By ~ 15

Author(s):

William J. Mitchell ◽

Christophe Pena ◽

Paul L. Burn

Keyword(s):

Energy Gap ◽

Lumo Energy ◽

Homo Lumo

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Synthesis of Novel Substituted 1,5-Benzothiazepines Containing 1,4-Benzodioxane Sulfonyl Moiety

Asian Journal of Organic & Medicinal Chemistry ◽

10.14233/ajomc.2019.ajomc-p159 ◽

2019 ◽

Vol 4 (2) ◽

pp. 70-76

Author(s):

Sandhya Chhakra ◽

A. Mukherjee ◽

H.L. Singh ◽

Suresh Singh Chauhan

Keyword(s):

13C Nmr ◽

Ground State ◽

Mobile Phase ◽

Energy Gap ◽

Sulfonyl Chloride ◽

Frontier Molecular Orbitals ◽

Efficient Synthesis ◽

Lumo Energy ◽

Mass Spectral ◽

Homo Lumo

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.

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HOMO–LUMO energy gap control in platinum(ii) biphenyl complexes containing 2,2′-bipyridine ligands

Dalton Transactions ◽

10.1039/c5dt01891a ◽

2015 ◽

Vol 44 (39) ◽

pp. 17075-17090 ◽

Cited By ~ 13

Author(s):

D. Paul Rillema ◽

Stanislav R. Stoyanov ◽

Arvin J. Cruz ◽

Huy Nguyen ◽

Curtis Moore ◽

...

Keyword(s):

Electronic Properties ◽

Energy Gap ◽

Lumo Energy ◽

Covalently Bonded ◽

Gap Control ◽

Homo Lumo

Electronic properties including the HOMO–LUMO energy gap in Pt(ii) complexes can be effectively controlled using electron-donating and electron-withdrawing moieties covalently bonded to the ligands.

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