Anthracene-Based Zwitterion with a Small HOMO‒LUMO Energy Gap

Synthesis ◽  
2021 ◽  
Author(s):  
Ayane Kayama ◽  
Akihiro Shimizu ◽  
Ryo Shintani
Keyword(s):  
Electronic Structure ◽  
Dft Calculations ◽  
Light Absorption ◽  
Energy Gap ◽  
Redox Properties ◽  
Low Energy ◽  
Structure And Properties ◽  
Lumo Energy ◽  
Homo Lumo

We have designed and synthesized an anthracene-based zwitterion, 2-methyl-2-azoniaanthracene-7-olate. The zwitterion shows amphoteric redox properties and low-energy light absorption originating from the small HOMO‒LUMO energy gap of ca. 1.7 eV. DFT calculations show that the combination of replacing the C–H with N+–Me and introducing O− is necessary to alter the electronic structure and properties of anthracene significantly.

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

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.

scholarly journals Theoretical insights into a colorimetric azo-based probe to detect copper ions

RSC Advances ◽  
2020 ◽  
Vol 10 (39) ◽  
pp. 23196-23202
Author(s):  
Juan Pang ◽  
Li Shu ◽  
Ming Li ◽  
Xiaohong Hu
Keyword(s):  
Dft Calculations ◽  
Energy Gap ◽  
Copper Ions ◽  
Colour Change ◽  
Amino Group ◽  
Lumo Energy ◽  
Homo Lumo

DFT calculations indicated that the rotation of the N,N-di(carboxymethyl)amino group around the N–CAr bond by approximately 90°, resulted in a larger HOMO–LUMO energy gap, and led to the observed colour change.

TDDFT study of the UV-vis spectra of subporphyrazines and subphthalocyanines

2011 ◽  
Vol 15 (11n12) ◽  
pp. 1220-1230 ◽  
Author(s):  
Al Mokhtar Lamsabhi ◽  
Manuel Yáñez ◽  
Otilia Mó ◽  
Cristina Trujillo ◽  
Fernando Blanco ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Absorption Spectra ◽  
Boron Atom ◽  
Energy Gap ◽  
Red Shift ◽  
Lumo Energy ◽  
Td Dft ◽  
Homo Lumo

The UV-vis spectra of a series of subporphyrazines, SubPz(A,R), and subphthalocyanines, SubPc(A,R) ( A = F, Cl; R = H, F, CH3, C3H7, SCH3, SC2H5 and SPh), where A is the substituent attached to the central boron atom and R is the substituent attached to the periphery of the molecule have been analyzed through the use of TD–DFT calculations in vacuum and using chloroform as a solvent. The absorption spectra depend on both, the characteristics of the substituent attached to the periphery of the molecule and the extension of the π-system on going from SubPz to the SubPc analog. These latter effects lead to a red-shift of both the Q-band and the B-band, although the effect is larger for the former, mainly due to the increase of HOMO–LUMO energy gap on going from the SubPz to the SubPc analog. The effect of the substituents R is more intricate, because the profile of the absorption spectra changes depending on whether both substituents are on the same side (uu or dd) or on opposite sides (ud) of the molecular cone. Since the three conformers are rather close in energy, the observed spectra correspond, very likely, to the sum of the spectra of all of them.

ELECTRONIC STRUCTURE OF THE FINITE-SIZED SINGLE-WALLED CARBON NANOTUBES

2003 ◽  
Vol 02 (03) ◽  
pp. 141-152 ◽  
Author(s):  
ANURAK UDOMVECH ◽  
TEERAKIAT KERDCHAROEN ◽  
VUDHICHAI PARASUK ◽  
YUTHANA TANTIRUNGROTECHAI ◽  
TANAKORN OSOTCHAN
Keyword(s):  
Carbon Nanotubes ◽  
Electronic Structure ◽  
Energy Gap ◽  
Single Walled Carbon Nanotubes ◽  
Scanning Tunneling ◽  
Lumo Energy ◽  
Single Walled Carbon ◽  
Semi Empirical ◽  
Walled Carbon Nanotubes ◽  
Homo Lumo

The effects of tubule length and terminal capping on the geometrical and electronic properties of finite-sized zig-zag (9, 0) single-walled carbon nanotubes (SWNT), which length varying from 2 up to 12 unit cells (~50 Å), were investigated using molecular mechanics, semi-empirical methods (AM1 and EHMO) and density functional theory (B3LYP). AM1 method indicates how the nanotube ends are capped affects strongly the tubule geometric parameters. Although these effects seem to decrease exponentially as the tube gets longer, the converging values for C–C bond length in the open- and closed-end structures are slightly different. It was learned that combination of low-level methods like AM1 and EHMO (which tend to overestimate and underestimate the HOMO–LUMO energy gap, respectively) together with high-level method such as DFT is efficient to estimate band gap for finite-sized nanostructures. The HOMO–LUMO energy gaps obtained from semi-empirical and DFT methods decrease as the tubule length increases. Terminal capping also affects strongly the electronic structure of finite-sized nanotube. Thus, closing the terminal ends by fullerene hemisphere broadens the energy gap of the hydrogen-saturated open-end nanotube. Although the open-end SWNT has much lower AM1 HOMO–LUMO energy gap than the closed-end SWNT, these orbitals unfortunately are localized near the capping hydrogen, thereby do not provide conducting channels for electrons. By comparing only the delocalized frontier orbitals, both structures yield closer energy gap. Analysis of the energy gap based on EHMO, AM1 and DFT results suggests that both open- and closed-end finite-sized SWNT are semiconductor, in agreement with recent scanning tunneling experiment. It was found that the slight accumulated negative charges are likely to locate at the nanotube's fullerene tips.

A p–n fusion strategy to design bipolar organic materials for high-energy-density symmetric batteries

2021 ◽  
Author(s):  
Jihyeon Kim ◽  
Heechan Kim ◽  
Sechan Lee ◽  
Giyun Kwon ◽  
Taewon Kang ◽  
...  
Keyword(s):  
Energy Density ◽  
Organic Material ◽  
Energy Gap ◽  
High Energy ◽  
High Energy Density ◽  
Lumo Energy ◽  
Fusion Strategy ◽  
Redox Active ◽  
Bipolar Type ◽  
Homo Lumo

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

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.

Meso-alkynyl corroles and their cobalt(III), manganese(III) and gallium(III) complexes

2020 ◽  
Vol 24 (05n07) ◽  
pp. 737-749
Author(s):  
Michael Haas ◽  
Sabrina Gonglach ◽  
Wolfgang Schöfberger
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Theoretical Study ◽  
Lumo Energy ◽  
Functional Theory ◽  
Energy Gaps ◽  
Peak Broadening ◽  
Homo And Lumo ◽  
Homo Lumo

We report routes towards synthesis of novel [Formula: see text]-conjugated freebase cobalt, copper, gallium and manganese meso-alkynylcorroles. UV-vis spectra show that extensive peak broadening, red shifts, and changes in the oscillator strength of absorptions increase with the extension of [Formula: see text]-conjugation. Using density functional theory (DFT), we have carried out a first theoretical study of the electronic structure of these metallocorroles. Decreased energy gaps of about 0.3–0.4 eV between the HOMO and LUMO orbitals compared to the corresponding copper, gallium and manganese meso-5,10,15 triphenylcorrole are observed. In all cases, the HOMO energies are nearly unperturbed as the [Formula: see text]-conjugation is expanded. The contraction of the HOMO–LUMO energy gaps is attributed to the lowered LUMO energies.

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

2020 ◽  
Vol 86 (1) ◽  
pp. 770-781
Author(s):  
Akihiro Shimizu ◽  
Yu Ishizaki ◽  
Shun Horiuchi ◽  
Takashi Hirose ◽  
Kenji Matsuda ◽  
...  
Keyword(s):  
Energy Gap ◽  
Lumo Energy ◽  
Homo Lumo
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