Bithiophene-Fused Benzo[c]phospholes: Novel P,S-Containing Hybrid π-Conjugated Systems with Small HOMO–LUMO Energy Gaps

2008 ◽  
Vol 2008 (2) ◽  
pp. 255-259 ◽  
Author(s):  
Tooru Miyajima ◽  
Yoshihiro Matano ◽  
Hiroshi Imahori
Keyword(s):  
Lumo Energy ◽  
Conjugated Systems ◽  
Energy Gaps ◽  
Homo Lumo

A detailed investigation into the geometric and electronic structures of CoBQn (n = 2–10, Q = 0, −1) clusters

2017 ◽  
Vol 41 (19) ◽  
pp. 11208-11214 ◽  
Author(s):  
Peifang Li ◽  
Guoliang Sun ◽  
Jianping Bai ◽  
Weihua Wang ◽  
Gang Bao ◽  
...  
Keyword(s):  
Electronic Structures ◽  
Size Dependence ◽  
Lumo Energy ◽  
Boron Clusters ◽  
Energy Gaps ◽  
Homo Lumo ◽  
Co Doped

The size dependence of HOMO–LUMO energy gaps of Co doped boron clusters.

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.

scholarly journals π-Conjugated Heteroles Containing Group 13 Elements

2021 ◽  
Author(s):  
Sossina Gezahegn
Keyword(s):  
Energy Gap ◽  
Theoretical Calculations ◽  
Building Blocks ◽  
Lewis Base ◽  
Group 13 ◽  
Conjugated Systems ◽  
Energy Gaps ◽  
Potential Formation ◽  
Lewis Adduct ◽  
Homo Lumo

This research targeted the synthesis of group 13 neutral heteroles via transmetallation of the tin atom in stannole moieties. The synthesis of Heteroles of 15a (1-chloro-2,3,4,5-tetraphenylborole), 15b (1-chloro-2,3,4,5-tetraphenylaluminole) and 15c (1-chloro-2,3,4,5-tetraphenylgallole) were attempted. The potential formation of Lewis base adducts were explored through the addition of a coordinating solvent of THF, Et3N, and Et2O and characterized with NMR (1H, 13C and 11B where applicable). It was attempted to synthesize Polymer 17a from the di-brominated borole monomer 16a via a Pd-catalyzed polycondensation reaction. THF was subsequently added to the polymer in an attempt to produce the polymer adduct 17a·THF. This was performed to produce a stable enough material for GPC analysis. The polymer was also characterized with NMR. Theoretical calculations were undertaken at the B3LYP/6-31G* level of DFT to help identify the effect of HOMO-LUMO energy gap of the above heteroles and their adducts. DFT calculations reveal that monomers and oligomer energy gaps can be tuned by substituents attached to the heterole, the type of Lewis adduct formed and the degree of catenation. These monomers and oligomers could potentially be novel building blocks for the synthesis of small energy gap π-conjugated systems.

Basis set effects on relative energies and HOMO–LUMO energy gaps of fullerene C36

2005 ◽  
Vol 113 (4) ◽  
pp. 233-237 ◽  
Author(s):  
Kyoung Hoon Kim ◽  
Young-Kyu Han ◽  
Jaehoon Jung
Keyword(s):  
Basis Set ◽  
Lumo Energy ◽  
Energy Gaps ◽  
Homo Lumo

scholarly journals π-Conjugated Heteroles Containing Group 13 Elements

2021 ◽  
Author(s):  
Sossina Gezahegn
Keyword(s):  
Energy Gap ◽  
Theoretical Calculations ◽  
Building Blocks ◽  
Lewis Base ◽  
Group 13 ◽  
Conjugated Systems ◽  
Energy Gaps ◽  
Potential Formation ◽  
Lewis Adduct ◽  
Homo Lumo

This research targeted the synthesis of group 13 neutral heteroles via transmetallation of the tin atom in stannole moieties. The synthesis of Heteroles of 15a (1-chloro-2,3,4,5-tetraphenylborole), 15b (1-chloro-2,3,4,5-tetraphenylaluminole) and 15c (1-chloro-2,3,4,5-tetraphenylgallole) were attempted. The potential formation of Lewis base adducts were explored through the addition of a coordinating solvent of THF, Et3N, and Et2O and characterized with NMR (1H, 13C and 11B where applicable). It was attempted to synthesize Polymer 17a from the di-brominated borole monomer 16a via a Pd-catalyzed polycondensation reaction. THF was subsequently added to the polymer in an attempt to produce the polymer adduct 17a·THF. This was performed to produce a stable enough material for GPC analysis. The polymer was also characterized with NMR. Theoretical calculations were undertaken at the B3LYP/6-31G* level of DFT to help identify the effect of HOMO-LUMO energy gap of the above heteroles and their adducts. DFT calculations reveal that monomers and oligomer energy gaps can be tuned by substituents attached to the heterole, the type of Lewis adduct formed and the degree of catenation. These monomers and oligomers could potentially be novel building blocks for the synthesis of small energy gap π-conjugated systems.

Synthesis and characterization of a new meso-tetra-dihydro benzocyclobutacenaphthylene free-base porphyrin

2018 ◽  
Vol 22 (01n03) ◽  
pp. 173-180 ◽  
Author(s):  
Ümit İşci ◽  
Sevinc Zehra Topal ◽  
Emel Önal ◽  
İsmail Fidan ◽  
Savaş Berber ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Synthesis And Characterization ◽  
Free Base ◽  
Frontier Orbitals ◽  
Lumo Energy ◽  
Energy Gaps ◽  
Homo Lumo

A meso-tetra-6b,10b-dihydrobenzo[j]cyclobut[a]acenaphthylene free-base porphyrin was synthesised and its photophysical, photochemical and electrochemical properties were compared with those of free-base meso-tetraphenylporphyrin. The frontier orbitals and the HOMO–LUMO energy gaps of both compounds were also determined. It was demonstrated that the meso6b,10b-Dihydrobenzo[j]cyclobut[a]acenaphthylene porphyrin retained the same properties as the tetraphenylporphyrin.

A DFT study on the electronic and redox properties of [X8V14O50]n– (X = SiIV, GeIV, PV, and AsV)

2010 ◽  
Vol 88 (5) ◽  
pp. 434-442 ◽  
Author(s):  
Muhammad Ramzan Saeed Ashraf Janjua ◽  
Zhong-Min Su ◽  
Wei Guan ◽  
Ahmad Irfan ◽  
Shabbir Muhammad ◽  
...  
Keyword(s):  
Density Functional ◽  
Open Shell ◽  
Electronic Configuration ◽  
Redox Properties ◽  
Lumo Energy ◽  
Functional Theory ◽  
Energy Gaps ◽  
System 2 ◽  
System 1 ◽  
Homo Lumo

The electronic and redox properties of the title polyanions have been calculated by means of density functional theory (DFT). These were unrestricted open-shell systems with electronic configuration of d1 of V. In this behalf, energies and compositions of α-LUMO, β-LUMO, α-HOMO, and β-HOMO were also analyzed. First of all, electronic and redox properties of vanadosilicate [Si8V14O50]12– (system 1) were calculated and then SiIV was substituted with GeIV, PV, and AsV for further investigations of systems 2, 3, and 4, respectively. The substitution greatly modifies the electronic properties as α-LUMOs are quite different in all the studied systems. The α-LUMO is mainly composed of V and O in system 1, V and Ge in system 2, V and O in system 3, and As, O, and V in system 4. The alpha HOMO–LUMO energy gaps are greatly reduced in systems 2, 3, and 4 as compared with system 1. The system 4 [As8V14O50]4– has minimal value of total bonding energy, whereas system 2 [Ge8V14O50]12– has maximal, so energetically system 4 is more favourable than the others. After the first reduction, α-LUMO in [Si8V14O50]14– is made up of V and Si, β-LUMO in [Ge8V14O50]13– is concentrated on V and Ge, β-LUMO in [P8V14O50]5– is composed of V only, whereas β-LUMO in [As8V14O50]5– is delocalized over V, O, and As with almost the same contribution of all three atoms.

scholarly journals Density functional study of structures, stabilities and electronic properties of AgAunλ(λ=0,±1;n=1-12){\rm{AgAu}}_n^\lambda \left( {\lambda = 0, \pm 1;n = 1 - 12} \right) clusters: comparison with pure gold clusters

2020 ◽  
Vol 38 (1) ◽  
pp. 97-107 ◽  
Author(s):  
Prabhat Ranjan ◽  
Tanmoy Chakraborty ◽  
Ajay Kumar
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Gold Clusters ◽  
Pure Gold ◽  
Functional Study ◽  
Bimetallic Clusters ◽  
Planar Geometry ◽  
Lumo Energy ◽  
Energy Gaps ◽  
Homo Lumo

AbstractGeometrical structures, relative stabilities and electronic properties of neutral, cationic and anionic pure gold {\rm{A}}u_{n + 1}^\lambda and Ag-doped bimetallic {\rm{AgAu}}_n^\lambda \left( {\lambda = 0, \pm 1;n = 1 - 12} \right) clusters have been systematically investigated by using density functional theory methodology. The optimized structures show that planar to three-dimensional structural transition occurs at n = 5 for cationic clusters. Due to strong relativistic effect of Au clusters, the ground state configurations of neutral and anionic bimetallic clusters favor planar geometry till n = 12. Silver atoms tend to occupy the most highly coordinated position and form the maximum number of bonds with Au atoms. The computed HOMO-LUMO energy gaps, fragmentation energies and second-order difference of energies show interesting odd-even oscillation behavior. The result indicates that AgAu5, {\rm{AgAu}}_2^ + and {\rm{AgAu}}_2^ - are the most stable clusters in this molecular system. The DFT based descriptors of bimetallic clusters are also discussed and compared with pure gold clusters. The high value of correlation coefficient between HOMO-LUMO energy gaps and DFT based descriptors supports our analysis. A good agreement between experimental and theoretical data has been obtained in this study.

Fluorinated Poly(N-vinylcarbazole) Host for Triplet Energy Confinement on Phosphorescent Emitter in Organic Light-emitting Diodes

2009 ◽  
Vol 1197 ◽  
Author(s):  
Yukitami Mizuno ◽  
Isao Takasu ◽  
Shuichi Uchikoga ◽  
Shintaro Enomoto ◽  
Tomoaki Sawabe ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Energy Gap ◽  
Organic Light Emitting Diodes ◽  
Lumo Energy ◽  
Light Emitting ◽  
Energy Gaps ◽  
Organic Light ◽  
Host Materials ◽  
Homo Lumo ◽  
Polymer Host

AbstractFluorinated carbazoles as host materials have been investigated for highly efficient organic light emitting diodes (OLEDs). By molecular orbital calculations, we found that fluorinations at position 2, 4, 5 and 7 of carbazole ring were effective for widening HOMO-LUMO energy gap. The energy gaps of our synthesized 2,7-difluorocarbazole (F2-Cz) and 2,4,5,7-tetrafluorocarbazole (F4-Cz), were estimated to be 3.71 eV and 3.87 eV by the absorption spectra, respectively. These energy gaps were higher than that of the non-substituted carbazole (Cz, 3.59 eV). We synthesized poly(N-vinyl-2,7-difluorocarbazole) (F2-PVK) and poly(N-vinyl-2,4,5,7-tetrafluorocarbazole) (F4-PVK) as solution processable polymer host materials. However, the F4-PVK was found to be an unsolved polymer. The F2-PVK could be compared with non substituted poly(N-vinylcarbazole) (PVK) in OLEDs. The emission layer (EML) contained iridium(III) bis [(4,6-di-fluorophenyl)-pyridinato-N,C2′] picolinate (FIrpic) as a blue phosphorescent dopant, and iridium(III) bis [2-(9,9-dihexylfluorenyl)-1-pyridine] acetylacetonate as a yellow dopant. The white OLED with the F2-PVK showed 1.4 times higher luminous current efficiency (24 cd/A) than the PVK (17 cd/A). These data show that the excitation energy is confined on dopants by using fluorinated polymer host material with higher T1 corresponding to wider HOMO-LUMO energy gap.

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