scholarly journals Isolation and structure determination of missing fullerenes Gd@C 74 (CF 3 ) n through in situ trifluoromethylation

2018 ◽  
Vol 5 (9) ◽  
pp. 181015 ◽  
Author(s):  
Ayano Nakagawa ◽  
Shinobu Aoyagi ◽  
Haruka Omachi ◽  
Katsuma Ishino ◽  
Makiko Nishino ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
High Performance ◽  
Density Functional ◽  
Crystallographic Analysis ◽  
X Ray ◽  
Multi Stage ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital

Our trifluoromethyl functionalization method enables the dissolution and isolation of missing metallofullerenes of Gd@C 74 (CF 3 ) n . After multi-stage high-performance liquid chromatography purification, Gd@C 74 (CF 3 ) 3 and two regioisomers of Gd@C 74 (CF 3 ) are isolated. X-ray crystallographic analysis reveals that all of the isolated metallofullerenes react with CF 3 groups on pentagons of the D 3 h -symmetry C 74 cages. Highest occupied molecular orbital-lowest unoccupied molecular orbital gaps of these trifluoromethylated derivatives, estimated by absorption spectra, are in the range 0.71–1.06 eV, consistent with density functional calculations.

scholarly journals A Cooperative Photoactive Class-I Hybrid Polyoxometalate With Benzothiadiazole–Imidazolium Cations

2021 ◽  
Vol 8 ◽  
Author(s):  
Alexander J. Kibler ◽  
Virginia S. Souza ◽  
Jesum Alves Fernandes ◽  
William Lewis ◽  
Stephen P. Argent ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Molecular Orbital ◽  
Crystallographic Analysis ◽  
Hybrid Species ◽  
X Ray ◽  
Imidazolium Cations ◽  
Organic Components ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital ◽  
Inorganic And Organic

An organic–inorganic hybrid species based on the Wells–Dawson polyoxotungstate [P2W18O62]6− and novel fluorescent benzothiadiazole–imidazolium cations, [BTD-4,7-ImH]2+, has been synthesized. X-ray crystallographic analysis shows that the inorganic and organic components form a hydrogen-bonded superstructure and that the cations are revealed to be non-equivalent with varying degrees of rotation between the BTD and imidazolium rings due to competition between weak intra- and intermolecular interactions. The UV–vis diffuse reflectance spectra indicate that the hybrid has a band gap of 3.13 eV, while the solid-state fluorescence properties of the cation are quenched in the hybrid material, suggesting the existence of electron transfer between the inorganic and organic components. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies of the polyoxometalate (POM) and BTD-4,7-ImH precursors, estimated through UV–vis absorption spectroscopy and cyclic voltammetry, indicate that electron transfer from the BTD cations to the POM may occur in the excited state.

scholarly journals Electrochemical trapping of metastable Mn3+ ions for activation of MnO2 oxygen evolution catalysts

2018 ◽  
Vol 115 (23) ◽  
pp. E5261-E5268 ◽  
Author(s):  
Zamyla Morgan Chan ◽  
Daniil A. Kitchaev ◽  
Johanna Nelson Weker ◽  
Christoph Schnedermann ◽  
Kipil Lim ◽  
...  
Keyword(s):  
Coordination Number ◽  
Oxygen Evolution ◽  
Molecular Orbital ◽  
Local Strain ◽  
Spectroscopic Studies ◽  
X Ray ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital ◽  
X Ray Absorption

Electrodeposited manganese oxide films are promising catalysts for promoting the oxygen evolution reaction (OER), especially in acidic solutions. The activity of these catalysts is known to be enhanced by the introduction of Mn3+. We present in situ electrochemical and X-ray absorption spectroscopic studies, which reveal that Mn3+ may be introduced into MnO2 by an electrochemically induced comproportionation reaction with Mn2+ and that Mn3+ persists in OER active films. Extended X-ray absorption fine structure (EXAFS) spectra of the Mn3+-activated films indicate a decrease in the Mn–O coordination number, and Raman microspectroscopy reveals the presence of distorted Mn–O environments. Computational studies show that Mn3+ is kinetically trapped in tetrahedral sites and in a fully oxidized structure, consistent with the reduction of coordination number observed in EXAFS. Although in a reduced state, computation shows that Mn3+ states are stabilized relative to those of oxygen and that the highest occupied molecular orbital (HOMO) is thus dominated by oxygen states. Furthermore, the Mn3+(Td) induces local strain on the oxide sublattice as observed in Raman spectra and results in a reduced gap between the HOMO and the lowest unoccupied molecular orbital (LUMO). The confluence of a reduced HOMO–LUMO gap and oxygen-based HOMO results in the facilitation of OER on the application of anodic potentials to the δ-MnO2 polymorph incorporating Mn3+ ions.

scholarly journals Emphasizing the Operational Role of a Novel Graphene-Based Ink into High Performance Ternary Organic Solar Cells

2019 ◽  
Author(s):  
Minas M. Stylianakis ◽  
Dimitriοs M. Kosmidis ◽  
Katerina Anagnostou ◽  
Christos Polyzoidis ◽  
Miron Krassas ◽  
...  
Keyword(s):  
Solar Cells ◽  
Molecular Orbital ◽  
Organic Solar Cells ◽  
High Performance ◽  
Energy Levels ◽  
Fullerene Derivative ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital ◽  
Synthetic Routes

A novel solution-processed graphene-based material was synthesized by treating graphene oxide (GO) with 2,5,7-trinitro-9-oxo-fluorenone-4-carboxylic acid (TNF-COOH) moieties, via simple synthetic routes. The yielded molecule N-[(carbamoyl-GO)ethyl]-N’-[(carbamoyl)-(2,5,7-trinitro-9-oxo-fluorene)] (GO-TNF) was thoroughly characterized and it was shown that it presents favorable highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels to function as a bridge component between the polymeric donor poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl)carbonyl] thieno[3,4-b]thiophenediyl}) (PTB7) and the fullerene derivative acceptor [6,6]-phenyl-C71-butyric-acid-methylester (PC71BM). In this context, a GO-TNF based ink was prepared and directly incorporated within the binary photoactive layer, in different volume ratios (1-3% ratio to the blend), for the effective realization of inverted ternary organic solar cells (OSCs) of the structure ITO/PFN/PTB7:GO-TNF:PC71BM/MoO3/Al. The addition of 2% v/v GO-TNF ink led to a champion power conversion efficiency (PCE) of 8.71% that was enhanced by ~13% as compared to the reference cell.

scholarly journals Computational Aspects of (E)-O-Carbomethoxy Methyl Oxime Ether of 1,3-Dimethyl-2,6-Diphenylpiperidin-4-One

2019 ◽  
Vol 9 (2S2) ◽  
pp. 701-706
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Atomic Charge ◽  
Molecular Geometry ◽  
Biologically Active ◽  
Oxime Ether ◽  
Structure And Property ◽  
Highest Occupied Molecular Orbital ◽  
Computational Aspects ◽  
Lowest Unoccupied Molecular Orbital

Density Functional Theoretical (DFT) studies on the biologically active oxime ether derived from 1,3-dimethyl-2,6-diphenylpiperidin-4-one has been carried out. Various quantum chemical parameters of the molecule viz. molecular geometry, Highest Occupied Molecular Orbital – Lowest Unoccupied Molecular Orbital (HOMO–LUMO) energies, Non-Linear Optical (NLO) properties, Mulliken atomic charge distribution were obtained theoretically and compared with the single crystal data. An insight into the structure and property correlation revealed the probable behavior of the molecule studied

Computational and Experimental Study onthe Adsorption and Inhibition Effects of 1,3-Benzothiazol-6-ol on the Corrosion ofSteel X80 in Acidic Solution

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Iman Danaee ◽  
Paria Nikparsa ◽  
Mohammad Reza Khosravi-Nikou
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Acidic Solution ◽  
Energy Gap ◽  
Force Microscopy ◽  
Highest Occupied Molecular Orbital ◽  
Low Concentrations ◽  
Noise Data ◽  
Chemical Factors ◽  
Lowest Unoccupied Molecular Orbital

Abstract In this work, the adsorption and inhibition behavior of 1,3-benzothiazol-6-ol were investigated by computational and experimental techniques for steel X80 corrosion in acidic solution. The density functional theory was carried out and quantum chemical factors like the energy gap, energy of highest occupied molecular orbital, the energy of lowest unoccupied molecular orbital, the fraction of electron transferred, and Mulliken charges have been calculated. In addition, according to quantum calculation, S atom in 1,3-benzothiazol-6-ol indicated more tendency for electrophilic attack in adsorption. The main reason for high inhibition efficiencies in very low concentrations is the planar and simplicity of inhibitor structure which leads to increasing the efficiency of adsorption by functional group especially sulfur. Electrochemical frequency modulation and potentiodynamic polarization indicated that this material has excellent inhibiting features in very low concentrations. The influence of DC trend on the explanation of electrochemical noise data was evaluated by polynomial fitting and the optimum polynomial order m = 5 was obtained. Noise resistance and the inhibition efficiency was calculated and compared in different methods. The theory of shot noise in frequency domain was used to obtain the electrochemical event charge. The corroded surface of steel in the absence and existence of thiazole compound was studied by Atomic force microscopy.

scholarly journals Preparation and Characterization of Quinoxaline-Pyrene-Based Conjugated Copolymers for Organic Photovoltaic Devices

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1098
Author(s):  
Bakhet A. Alqurashy ◽  
Bader M. Altayeb ◽  
Sulaiman Y. Alfaifi ◽  
Majed Alawad ◽  
Ahmed Iraqi ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Powder Diffraction ◽  
Bulk Heterojunction ◽  
Gel Permeation Chromatography ◽  
Band Gap Energy ◽  
Slight Reduction ◽  
X Ray ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital

In this study, two novel conjugated polymers, poly(4,5,9,10-tetrakis((2-ethylhexyl)oxy]pyrene-alt-2,3-bis(3-(octyloxy)phenyl)-5,8-di(2-thienyl)-6,7-difluoroquinoxaline) (PPyQxff) and poly(4,5,9,10-tetrakis((2-ethylhexyl)oxy)pyren-alt-2,3-bis(3-(octyloxy)phenyl)-5,8-di(2-thienyl)quinoxaline) (PPyQx), consisting of quinoxaline units with and without fluorine substituents, as electron-accepting moieties and pyrene flanked with dithienyl units as electron-donating moieties were prepared via Stille polymerization reactions for use as electron donor materials in bulk heterojunction (BHJ) solar cells. PPyQxff and PPyQx were characterized by X-ray powder diffraction (XRD), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), cyclic voltammetry (CV), UV−VIS absorption, and nuclear magnetic resonance (NMR) spectroscopy. PPyQxff and PPyQx revealed excellent solution processability in common organic solvents. PPyQxff and PPyQx presented decomposition temperatures above 300 °C. The inclusion of F atoms to the quinoxaline moiety made a slight reduction in the highest occupied molecular orbital (HOMO) level, relative to the unfluorinated polymer, but had no impact on the lowest unoccupied molecular orbital (LUMO) level. PPyQxff and PPyQx exhibited similar physical properties with strong and broad absorbance from 400 to 700 nm and an optical band-gap energy of 1.77 eV. The X-ray powder diffraction study indicated that PPyQxff possessed a reduced π–π stacking distance relative to PPyQx.

The Geometric and Electronic Structures of Fen-1Si(n=2-7) Clusters

2010 ◽  
Vol 150-151 ◽  
pp. 984-987
Author(s):  
Shuai Qin Yu ◽  
Li Hua Dong ◽  
Yan Sheng Yin
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Energy Difference ◽  
Ground State Structure ◽  
Magic Numbers ◽  
Highest Occupied Molecular Orbital ◽  
Hybridization Intensity ◽  
Lowest Unoccupied Molecular Orbital ◽  
The Stability

The geometric structures and electronic properties of Si doped Fen (n=2-7) clusters have been systematically studied at the BPW91 level in density-functional theory (DFT). Calculated results show that an Si impurity does not change the ground-state structure of small iron clusters and prefers to occupy surface site bonding with iron atoms as many as possible. The second-order energy difference and the vertical ionization potential show that n=4 and 6 are magic numbers within the size range studied, but the maximum value occurs at n=4 for the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital(LUMO). It is found that the hybridization intensity between Si and Fe atoms is relevant to the stability of clusters.

Investigation of Carbon Monoxide Adsorption on Cationic Gold- Palladium Clusters

2013 ◽  
Vol 68 (10-11) ◽  
pp. 651-658 ◽  
Author(s):  
Yang-Mei Chen ◽  
Xiao-Yu Kuang ◽  
Xiao-Wei Sheng ◽  
Huai-Qian Wang ◽  
Peng Shao ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Molecular Orbital ◽  
Density Functional ◽  
Co Adsorption ◽  
Vibration Strength ◽  
Au Clusters ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital ◽  
Pd Clusters ◽  
Homo Lumo

Density functional calculations have been performed for the carbon monoxide molecule adsorption on AunPd+m(n+m ≤ 6) clusters. In the process of CO adsorption, small Au clusters and Pd clusters tend to be an Au atom and three Pd atoms adsorption, respectively. For the mixed Au-Pd clusters, an Au atom, a Pd atom, two atoms consisted of an Au atom and a Pd atom, two Pd atoms, and three Pd atoms adsorption structures are displayed. The highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gaps and natural bond orbital charge population are calculated. Moreover, CO adsorption energy, CO stretching frequency, and CO bond length (upon adsorption) are also analysed in detail. The results predict that the adsorption strength of Au clusters with CO and the C-O vibration strength is enhanced and reduced after doping of Pd in the AunPdmCO+ complexes, respectively

Cross-conjugation as a Motif for Organic Non-Linear Optical Molecules

2014 ◽  
Vol 1698 ◽  
Author(s):  
Meghana Rawal ◽  
Kerry Garrett ◽  
Andreas F. Tillack ◽  
Werner Kaminsky ◽  
Evgheni Jucov ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Dipole Moments ◽  
X Ray Diffraction ◽  
Conjugated Molecules ◽  
Functional Theory ◽  
Highest Occupied Molecular Orbital ◽  
Donor And Acceptor ◽  
Vis Spectroscopy ◽  
Lowest Unoccupied Molecular Orbital

ABSTRACTWe studied the effect of a cross-conjugated bridging group (χC) on charge-transfer in a push-pull chromophore system. The hyperpolarizability of such molecules was found to be comparable to that of a fully π-conjugated molecule (πC) with the same donor and acceptor. The cross-conjugated moiety was then applied as a pendant to a fully π-conjugated chromophore containing a tricyanopyrroline acceptor (TCP). The addition of a χC moiety did not alter the intrinsic hyperpolarizability and provides an avenue for extending and aiding πC systems. The molecules were examined by X-ray diffraction (XRD), hyper-Raleigh scattering (HRS) and UV-visible (UV-vis) spectroscopy. Experimental results were compared with the predictions of density functional theory (DFT). Cross-conjugated molecules have comparable β values, relative to πC molecules, due to reduced spatial overlap between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). Thus, the χC architecture could facilitate independent modification of donor and acceptor strengths while minimizing unfavorable effects on electronic transitions and dipole moments.

AB INITIO AND DFT THEORETICAL INVESTIGATIONS ON NOVEL PORPHYRIN–FULLERENE SUPRAMOLECULAR DYADS FOR PHOTOVOLTAIC DEVICES

2008 ◽  
Vol 07 (05) ◽  
pp. 1055-1069 ◽  
Author(s):  
TAPAS MANNA ◽  
SUMANTA BHATTACHARYA
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Density Functional ◽  
Conformational Stability ◽  
Density Functional Theory Calculations ◽  
Orbital State ◽  
Highest Occupied Molecular Orbital ◽  
Theoretical Investigations ◽  
Lowest Unoccupied Molecular Orbital ◽  
Porphyrin Moiety

The conformational stability and electronic structures of novel H 2-(1) and Zn-tetraphenylporphyrin–[60]fullerene (2) dyads, in which the [60]fullerene is directly linked to the tetrapyrrolic rings by ethynylenephenylene subunits, have been studied by ab initio and density functional theory calculations. From the investigation on frontier molecular orbitals, it was found that the lowest unoccupied molecular orbital state of these supramolecules is localized on the fullerene and that the highest occupied molecular orbital state is localized on the porphyrin moiety. Molecular electrostatic potential maps clearly demonstrate the electron transfer phenomena from the porphyrin moiety to the fullerene in dyads 1 and 2.

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