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Tal A, Bischoff T, Pasquarello A. Absolute energy levels of liquid water from many-body perturbation theory with effective vertex corrections. Proc Natl Acad Sci U S A 2024; 121:e2311472121. [PMID: 38427604 DOI: 10.1073/pnas.2311472121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 01/31/2024] [Indexed: 03/03/2024] Open
Abstract
We demonstrate the importance of addressing the Γ vertex and thus going beyond the GW approximation for achieving the energy levels of liquid water in many-body perturbation theory. In particular, we consider an effective vertex function in both the polarizability and the self-energy, which does not produce any computational overhead compared with the GW approximation. We yield the band gap, the ionization potential, and the electron affinity in good agreement with experiment and with a hybrid functional description. The achieved electronic structure and dielectric screening further lead to a good description of the optical absorption spectrum, as obtained through the solution of the Bethe-Salpeter equation. In particular, the experimental peak position of the exciton is accurately reproduced.
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Affiliation(s)
- Alexey Tal
- Chaire de Simulation à l'Echelle Atomique, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | - Thomas Bischoff
- Chaire de Simulation à l'Echelle Atomique, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | - Alfredo Pasquarello
- Chaire de Simulation à l'Echelle Atomique, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
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2
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Fischer I, Hemberger P. Photoelectron Photoion Coincidence Spectroscopy of Biradicals. Chemphyschem 2023; 24:e202300334. [PMID: 37325876 DOI: 10.1002/cphc.202300334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/15/2023] [Accepted: 06/15/2023] [Indexed: 06/17/2023]
Abstract
The electronic structure of biradicals is characterized by the presence of two unpaired electrons in degenerate or near-degenerate molecular orbitals. In particular, some of the most relevant species are highly reactive, difficult to generate cleanly and can only be studied in the gas phase or in matrices. Unveiling their electronic structure is, however, of paramount interest to understand their chemistry. Photoelectron photoion coincidence (PEPICO) spectroscopy is an excellent approach to explore the electronic states of biradicals, because it enables a direct correlation between the detected ions and electrons. This permits to extract unique vibrationally resolved photoion mass-selected threshold photoelectron spectra (ms-TPES) to obtain insight in the electronic structure of both the neutral and the cation. In this review we highlight most recent advances on the spectroscopy of biradicals and biradicaloids, utilizing PEPICO spectroscopy and vacuum ultraviolet (VUV) synchrotron radiation.
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Affiliation(s)
- Ingo Fischer
- Julius-Maximilians-Universität Würzburg, Institut für Physikalische und Theoretische Chemie, Am Hubland, D-97074, Würzburg, Germany
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institut (PSI), CH-5232, Villigen, Switzerland
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Stewart M, Martin ST. Machine Learning for Ionization Potentials and Photoionization Cross Sections of Volatile Organic Compounds. ACS Earth Space Chem 2023; 7:863-875. [PMID: 37152449 PMCID: PMC10152554 DOI: 10.1021/acsearthspacechem.3c00009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 03/16/2023] [Accepted: 03/17/2023] [Indexed: 05/09/2023]
Abstract
Molecular ionization potentials (IP) and photoionization cross sections (σ) can affect the sensitivity of photoionization detectors (PIDs) and other sensors for gaseous species. This study employs several methods of machine learning (ML) to predict IP and σ values at 10.6 eV (117 nm) for a dataset of 1251 gaseous organic species. The explicitness of the treatment of the species electronic structure progressively increases among the methods. The study compares the ML predictions of the IP and σ values to those obtained by quantum chemical calculations. The ML predictions are comparable in performance to those of the quantum calculations when evaluated against measurements. Pretraining further reduces the mean absolute errors (ε) compared to the measurements. The graph-based attentive fingerprint model was most accurate, for which εIP = 0.23 ± 0.01 eV and εσ = 2.8 ± 0.2 Mb compared to measurements and computed cross sections, respectively. The ML predictions for IP correlate well with both the measured IPs (R 2 = 0.88) and with IPs computed at the level of M06-2X/aug-cc-pVTZ (R 2 = 0.82). The ML predictions for σ correlated reasonably well with computed cross sections (R 2 = 0.66). The developed ML methods for IP and σ values, representing the properties of a generalizable set of volatile organic compounds (VOCs) relevant to industrial applications and atmospheric chemistry, can be used to quantitatively describe the species-dependent sensitivity of chemical sensors that use ionizing radiation as part of the sensing mechanism, such as photoionization detectors.
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Affiliation(s)
- Matthew
P. Stewart
- School
of Engineering and Applied Sciences, Harvard
University, Cambridge, Massachusetts 02138, United States
| | - Scot T. Martin
- School
of Engineering and Applied Sciences, Harvard
University, Cambridge, Massachusetts 02138, United States
- Department
of Earth and Planetary Sciences, Harvard
University, Cambridge, Massachusetts 02138, United States
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Vandana M, Devendrappa H, Padova PD, Hegde G. Polymer Nanocomposite Graphene Quantum Dots for High-Efficiency Ultraviolet Photodetector. Nanomaterials (Basel) 2022; 12:3175. [PMID: 36144964 PMCID: PMC9502816 DOI: 10.3390/nano12183175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 09/07/2022] [Accepted: 09/08/2022] [Indexed: 06/16/2023]
Abstract
Influence on photocurrent sensitivity of hydrothermally synthesized electrochemically active graphene quantum dots on conjugated polymer utilized for a novel single-layer device has been performed. Fabrications of high-performance ultraviolet photodetector by depositing the polypyrrole-graphene quantum dots (PPy-GQDs) active layer of the ITO electrode were exposed to an Ultraviolet (UV) source with 265 and 355 nm wavelengths for about 200 s, and we examined the time-dependent photoresponse. The excellent performance of GQDs was exploited as a light absorber, acting as an electron donor to improve the carrier concentration. PGC4 exhibits high photoresponsivity up to the 2.33 µA/W at 6 V bias and the photocurrent changes from 2.9 to 18 µA. The electrochemical measurement was studied using an electrochemical workstation. The cyclic voltammetry (CV) results show that the hysteresis loop is optically tunable with a UV light source with 265 and 355 nm at 0.1 to 0.5 V/s. The photocurrent response in PPy-GQDs devices may be applicable to optoelectronics devices.
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Affiliation(s)
- Molahalli Vandana
- Department of Chemistry, CHRIST (Deemed to Be University), Hosur Road, Bangalore 560029, India
- Centre for Advanced Research and Development (CARD), CHRIST (Deemed to Be University), Hosur Road, Bangalore 560029, India
| | | | - Paola De Padova
- Consiglio Nazionale delle Ricerche, CNR-ISM, Via Fosso del Cavaliere, 00133 Rome, Italy
- INFN-Laboratori Nazionali di Frascati, Via Enrico Fermi Frascati 40, 00044 Rome, Italy
| | - Gurumurthy Hegde
- Department of Chemistry, CHRIST (Deemed to Be University), Hosur Road, Bangalore 560029, India
- Centre for Advanced Research and Development (CARD), CHRIST (Deemed to Be University), Hosur Road, Bangalore 560029, India
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Ogura Y, Nakano M, Maeda H, Segi M, Furuyama T. Cationic Axial Ligand Effects on Sulfur-Substituted Subphthalocyanines. Molecules 2022; 27:molecules27092766. [PMID: 35566117 PMCID: PMC9105831 DOI: 10.3390/molecules27092766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/14/2022] [Accepted: 04/22/2022] [Indexed: 11/24/2022]
Abstract
Herein, we report the synthesis of sulfur-substituted boron(III) subphthalocyanines (SubPcs) with cationic axial ligands. Subphthalocyanines were synthesized by a condensation reaction using the corresponding phthalonitriles and boron trichloride as a template. An aminoalkyl group was introduced on the central boron atom; this process was followed by N-methylation to introduce a cationic axial ligand. The peripheral sulfur groups shifted the Q band of SubPcs to a longer wavelength. The cationic axial ligands increased the polarity and enhanced the hydrophilicity of SubPcs. The effect of axial ligands on absorption and fluorescence properties is generally small. However, a further red shift was observed by introducing cationic axial ligands into the sulfur-substituted SubPcs. This change is similar to that in sulfur-substituted silicon(IV) phthalocyanines. The unique effect of the cationic axial ligand was extensively investigated by theoretical calculations and electrochemistry. In particular, the precise oxidation potential was determined using ionization potential measurements. Thus, the results of the present study provide a novel strategy for developing functional dyes and pigments based on SubPcs.
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Affiliation(s)
- Yusaku Ogura
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan; (Y.O.); (M.N.); (H.M.); (M.S.)
| | - Masahiro Nakano
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan; (Y.O.); (M.N.); (H.M.); (M.S.)
| | - Hajime Maeda
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan; (Y.O.); (M.N.); (H.M.); (M.S.)
| | - Masahito Segi
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan; (Y.O.); (M.N.); (H.M.); (M.S.)
| | - Taniyuki Furuyama
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan; (Y.O.); (M.N.); (H.M.); (M.S.)
- Japan Science and Technology Agency (JST)-PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
- Correspondence:
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Hirao K, Bae HS, Song JW, Chan B. Vertical ionization potential benchmarks from Koopmans prediction of Kohn-Sham theory with long-range corrected (LC) functional. J Phys Condens Matter 2022; 34:194001. [PMID: 35158348 DOI: 10.1088/1361-648x/ac54e3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 02/14/2022] [Indexed: 06/14/2023]
Abstract
The Kohn-Sham density functional theory (KS-DFT) with the long-range corrected (LC) functional is applied to the benchmark dataset of 401 valence ionization potentials (IPs) of 63 small molecules of Chong, Gritsenko and Baerends (the CGB set). The vertical IP of the CGB set are estimated as negative orbital energies within the context of the Koopmans' prediction using the LCgau-core range-separation scheme in combination with PW86-PW91 exchange-correlation functional. The range separation parameterμof the functional is tuned to minimize the error of the negative HOMO orbital energy from experimental IP. The results are compared with literature data, includingab initioIP variant of the equation-of-motion coupled cluster theory with singles and doubles (IP-EOM-CCSD), the negative orbital energies calculated by KS-DFT with the statistical averaging of orbital potential, and those with the QTP family of functionals. The optimally tuned LC functional performs better than other functionals for the estimation of valence level IP. The mean absolute deviations (MAD) from experiment and from IP-EOM-CCSD are 0.31 eV (1.77%) and 0.25 eV (1.46%), respectively. LCgau-core performs quite well even with fixedμ(not system-dependent). Aμvalue around 0.36 bohr-1gives MAD of 0.40 eV (2.42%) and 0.33 eV (1.96%) relative to experiment and IP-EOM-CCSD, respectively. The LCgau-core-PW86-PW91 functional is an efficient alternative to IP-EOM-CCSD and it is reasonably accurate for outer valence orbitals. We have also examined its application to core ionization energies of C(1s), N(1s), O(1s) and F(1s). The C(1s) core ionization energies are reproduced reasonably [MAD of 46 cases is 0.76 eV (0.26%)] but N(1s), O(1s) and F(1s) core ionization energies are predicted less accurately.
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Affiliation(s)
- Kimihiko Hirao
- Fukui Institute for Fundamental Chemistry, Kyoto University, Takano, Nishihiraki-cho 34-4, Sakyo-ku, Kyoto, 606-8103, Japan
- RIKEN Center for Computational Science, 7-1-26, Minatojima-minami-machi, Chuo-ku, Kobe, 650-0047, Japan
| | - Han-Seok Bae
- Department of Chemistry Education, Daegu University, Gyeongsan, 113-8656, Korea
| | - Jong-Won Song
- Department of Chemistry Education, Daegu University, Gyeongsan, 113-8656, Korea
| | - Bun Chan
- Graduate School of Engineering, Nagasaki University, Bunkyo 1-14, Nagasaki 852-8521, Japan
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Khalil A, Kashif M. Development of UV-visible spectrophotometric methods for the quantitative and in silico studies for cilazapril optimized by response surface methodology. Drug Dev Ind Pharm 2021; 47:1100-1111. [PMID: 34286656 DOI: 10.1080/03639045.2021.1957918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
For cilazapril (CLZ), analytical methods based on donor-acceptor phenomenon that are simple, rapid with broad linear dynamic range for the quantification of drug are not available in the literature. Considering the requirement for the methods, in this study, two economic, potent analytical methods based on the complexation of CLZ with π-acceptors, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and 2,5-dichloro-3,6-dihydroxy-p-benzoquinone (CA) were developed, validated, and studied spectrophotometrically. Various analytical data were discussed. The effects of experimental variables were optimized from the results of in silico technique, i.e. Box-Behnken design under response surface methodology. Linear dynamic range was significantly good in the range of 6-60 µg mL-1 and 20-260 µg mL-1 for DDQ and CA methods. Moreover, molecular docking studies corroborated the experimental results. Further, the methods were supplemented by the pharmaceutical and biological application for the quantitative assay of CLZ. Collectively, the results of the reported method of the analysis suggest that the developed approach is simple, sensitive, accurate and precise.
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Affiliation(s)
- Adila Khalil
- Department of Chemistry, Analytical Chemistry Section, Aligarh Muslim University, Aligarh, India
| | - Mohammad Kashif
- Department of Chemistry, Analytical Chemistry Section, Aligarh Muslim University, Aligarh, India
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Dobrowolski JC, Dudek WM, Karpińska G, Baraniak A. Substituent Effect in the Cation Radicals of Monosubstituted Benzenes. Int J Mol Sci 2021; 22:6936. [PMID: 34203254 PMCID: PMC8269098 DOI: 10.3390/ijms22136936] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/19/2021] [Accepted: 06/22/2021] [Indexed: 01/30/2023] Open
Abstract
In 30 monosubstituted benzene cation radicals, studied at the ωB97XD/aug-cc-pVTZ level, the phenyl rings usually adopt a compressed form, but a differently compressed form-equivalent to an elongated one-may coexist. The computational and literature ionization potentials are well correlated. The geometrical and magnetic aromaticity, estimated using HOMA and NICS indices, show the systems to be structurally aromatic but magnetically antiaromatic or only weakly aromatic. The partial charge is split between the substituent and ring and varies the most at C(ipso). In the ring, the spin is 70%, concentrated equally at the C(ipso) and C(p) atoms. The sEDA(D) and pEDA(D) descriptors of the substituent effect in cation radicals, respectively, were determined. In cation radicals, the substituent effect on the σ-electron system is like that in the ground state. The effect on the π-electron systems is long-range, and its propagation in the radical quinone-like ring is unlike that in the neutral molecules. The pEDA(D) descriptor correlates well with the partial spin at C(ipso) and C(p) and weakly with the HOMA(D) index. The correlation of the spin at the ring π-electron system and the pEDA(D) descriptor shows that the electron charge supplied to the ring π-electron system and the spin flow oppositely.
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Affiliation(s)
- Jan Cz. Dobrowolski
- National Medicines Institute, 00-725 Warsaw, Poland; (G.K.); (A.B.)
- Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland;
| | - Wojciech M. Dudek
- Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland;
| | | | - Anna Baraniak
- National Medicines Institute, 00-725 Warsaw, Poland; (G.K.); (A.B.)
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Li M, Yang R, Wei X, Yin H, Wang S, Jin K. Display of Spin-Orbit Coupling at ReAlO 3/SrTiO 3 (Re = La, Pr, Nd, Sm, and Gd) Heterointerfaces. ACS Appl Mater Interfaces 2021; 13:21964-21970. [PMID: 33913680 DOI: 10.1021/acsami.1c02295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Complex oxide heterointerfaces provide a platform to manipulate spin-orbit coupling under the broken inversion symmetry. Moreover, their weak antilocalization (WAL) effect displays quantum coherent behavior due to the strong spin-orbit coupling. Herein, we break through the limitation of lattice mismatch at ReAlO3/STO (Re = La, Pr, Nd, Sm, and Gd) heterointerfaces and obtain their two-dimensional electric gas (2DEG) by spin coating. The effect of different Re elements in the resulting quantum corrections on the conductivity is investigated. It is observed that the conductivity of heterointerfaces is reduced with larger atomic numbers due to the ionization potential of Re elements. Moreover, magnetoresistance (MR) measurements in a perpendicular or a parallel field distinctly uncover strong Rashba spin-orbit coupling (SOC) in ReAO/STO samples besides SAO/STO (Re = Sm) and GAO/STO (Re = Gd), and the effective fields of the SOC (Hso) gradually increase from LAO/STO (Re = La, Hso = 0.82 T) to NAO/STO (Re = Nd, Hso = 1.37 T) at 2 K. The competition between SOC scattering and inelastic scattering is revealed through a temperature-dependence study of MR, and the WAL-weak localization transition is at about 6 K. Furthermore, unambiguous results of the Kondo effect, nonlinear Hall, hysteresis loop, and Rashba SOC suggest the coexistence of WAL at the PAO/STO (Re = Pr) heterointerface with exchange coupling between the localized magnetic moment and the itinerant electron. These results pave a unique route for the exploration of spin-polarized 2DEGs at oxide heterointerfaces.
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Affiliation(s)
- Ming Li
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
| | - Ruishu Yang
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
| | - Xiangyang Wei
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
| | - Hang Yin
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
| | - Shuanhu Wang
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
| | - Kexin Jin
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
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Filatov M, Lee S, Nakata H, Choi CH. Signatures of Conical Intersection Dynamics in the Time-Resolved Photoelectron Spectrum of Furan: Theoretical Modeling with an Ensemble Density Functional Theory Method. Int J Mol Sci 2021; 22:4276. [PMID: 33924097 PMCID: PMC8074317 DOI: 10.3390/ijms22084276] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/13/2021] [Accepted: 04/15/2021] [Indexed: 12/13/2022] Open
Abstract
The non-adiabatic dynamics of furan excited in the ππ* state (S2 in the Franck-Condon geometry) was studied using non-adiabatic molecular dynamics simulations in connection with an ensemble density functional method. The time-resolved photoelectron spectra were theoretically simulated in a wide range of electron binding energies that covered the valence as well as the core electrons. The dynamics of the decay (rise) of the photoelectron signal were compared with the excited-state population dynamics. It was observed that the photoelectron signal decay parameters at certain electron binding energies displayed a good correlation with the events occurring during the excited-state dynamics. Thus, the time profile of the photoelectron intensity of the K-shell electrons of oxygen (decay constant of 34 ± 3 fs) showed a reasonable correlation with the time of passage through conical intersections with the ground state (47 ± 2 fs). The ground-state recovery constant of the photoelectron signal (121 ± 30 fs) was in good agreement with the theoretically obtained excited-state lifetime (93 ± 9 fs), as well as with the experimentally estimated recovery time constant (ca. 110 fs). Hence, it is proposed to complement the traditional TRPES observations with the trXPS (or trNEXAFS) measurements to obtain more reliable estimates of the most mechanistically important events during the excited-state dynamics.
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Affiliation(s)
- Michael Filatov
- Department of Chemistry, Kyungpook National University, Daegu 702-701, Korea
| | - Seunghoon Lee
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA;
| | - Hiroya Nakata
- R & D Center Kagoshima, Kyocera, 1-4 Kokubu Yamashita-cho, Kirishima-shi, Kagoshima 899-4312, Japan;
| | - Cheol-Ho Choi
- Department of Chemistry, Kyungpook National University, Daegu 702-701, Korea
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Krucaite G, Tavgeniene D, Blazevicius D, Zhang B, Vembris A, Grigalevicius S. New Electroactive Polymers with Electronically Isolated 4,7-Diarylfluorene Chromophores as Positive Charge Transporting Layer Materials for OLEDs. Molecules 2021; 26:1936. [PMID: 33808321 DOI: 10.3390/molecules26071936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 03/19/2021] [Accepted: 03/26/2021] [Indexed: 11/16/2022] Open
Abstract
A group of polyethers containing electroactive pendent 4,7-diarylfluorene chromophores have been prepared by the multi-step synthetic route. Full characterization of their structures has been presented. The polymeric materials represent derivatives of high thermal stability with initial thermal degradation temperatures in a range of 392-397 °C. Glass transition temperatures of the amorphous polymers range from 28 °C to 63 °C and depend on structures of the 4,7-diarylfluorene chromophores. Electron photoemission spectra of thin layers of the electroactive derivatives showed ionization potentials in the range of 5.8-6.0 eV. Hole injecting/transporting properties of the prepared polymeric materials were confirmed during formation of organic light-emitting diodes with tris(quinolin-8-olato)aluminium (Alq3) as a green emitter, which also serves as an electron transporting layer. The device using hole-transporting polymer with electronically isolated 2,7-di(4-biphenyl)fluorene chromophores demonstrated the best overall performance with low turn on voltage of 3 V, high current efficiency exceeding 1.7 cd/A, and with maximum brightness over 200 cd/m2. The organic light-emitting diode (OLED) characteristics were measured in non-optimized test devices. The efficiencies could be further improved by an optimization of device structure, formation conditions, and encapsulation of the devices.
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Teratani M, Nakamura S, Sakagami H, Fujise M, Hashimoto M, Okudaira N, Bandow K, Iijima Y, Nagai J, Uesawa Y, Wakabayashi H. Antitumor Effects and Tumor-specificity of Guaiazulene-3-Carboxylate Derivatives Against Oral Squamous Cell Carcinoma In Vitro. Anticancer Res 2020; 40:4885-4894. [PMID: 32878776 DOI: 10.21873/anticanres.14491] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 06/07/2020] [Accepted: 06/24/2020] [Indexed: 11/10/2022]
Abstract
AIM The aim of this study was to investigate the antitumor potential of guaiazulene-3-carboxylate derivatives against oral malignant cells. MATERIALS AND METHODS Twelve guaiazulene-3-carboxylate derivatives were synthesized by introduction of either with alkyl group [1-5], alkoxy group [6, 7], hydroxyl group [8, 9] or primary amine [10-12] at the end of sidechains. Tumor-specificity (TS) was calculated by the ratio of mean 50% cytotoxic concentration (CC50) against 3 human oral mesenchymal cell lines to that against 4 human oral squamous cell carcinoma (OSCC) cell lines. Potency-selectivity expression (PSE) was calculated by dividing TS value by CC50value against OSCC cell lines. Cell cycle analysis was performed by cell sorter. RESULTS [6, 7] showed the highest TS and PSE values, and induced the accumulation of both subG1 and G2/M cell populations in HSC-2 OSCC cells. Quantitative structure-activity relationship analysis demonstrated that their tumor-specificity was correlated with chemical descriptors that explain the 3D shape, electric state and ionization potential. CONCLUSION Alkoxyl guaiazulene-3-carboxylates [6, 7] can be potential candidates of lead compound for developing novel anticancer drugs.
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Affiliation(s)
| | | | - Hiroshi Sakagami
- Meikai University Research Institute of Odontology (M-RIO), Saitama, Japan
| | | | | | - Noriyuki Okudaira
- Department of Biochemistry, Teikyo University School of Medicine, Tokyo, Japan
| | - Kenjiro Bandow
- Division of Biochemistry, Meikai University School of Dentistry, Saitama, Japan
| | - Yosuke Iijima
- Department of Oral and Maxillofacial Surgery, Saitama Medical Center, Saitama Medical University, Kawagoe, Japan
| | - Junko Nagai
- Department of Medical Molecular Informatics, Meiji Pharmaceutical University, Tokyo, Japan
| | - Yoshihiro Uesawa
- Department of Medical Molecular Informatics, Meiji Pharmaceutical University, Tokyo, Japan
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Erickson ME, Ngongang M, Rasulev B. A Refractive Index Study of a Diverse Set of Polymeric Materials by QSPR with Quantum-Chemical and Additive Descriptors. Molecules 2020; 25:molecules25173772. [PMID: 32825028 PMCID: PMC7503810 DOI: 10.3390/molecules25173772] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/10/2020] [Accepted: 08/14/2020] [Indexed: 11/23/2022] Open
Abstract
Predicting the activities and properties of materials via in silico methods has been shown to be a cost- and time-effective way of aiding chemists in synthesizing materials with desired properties. Refractive index (n) is one of the most important defining characteristics of an optical material. Presented in this work is a quantitative structure–property relationship (QSPR) model that was developed to predict the refractive index for a diverse set of polymers. A number of models were created, where a four-variable model showed the best predictive performance with R2 = 0.904 and Q2LOO = 0.897. The robustness and predictability of the best model was validated using the leave-one-out technique, external set and y-scrambling methods. The predictive ability of the model was confirmed with the external set, showing the R2ext = 0.880. For the refractive index, the ionization potential, polarizability, 2D and 3D geometrical descriptors were the most influential properties. The developed model was transparent and mechanistically explainable and can be used in the prediction of the refractive index for new and untested polymers.
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14
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Nunzi F, Pannacci G, Tarantelli F, Belpassi L, Cappelletti D, Falcinelli S, Pirani F. Leading Interaction Components in the Structure and Reactivity of Noble Gases Compounds. Molecules 2020; 25:molecules25102367. [PMID: 32443725 PMCID: PMC7287633 DOI: 10.3390/molecules25102367] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 05/15/2020] [Accepted: 05/19/2020] [Indexed: 12/12/2022] Open
Abstract
The nature, strength, range and role of the bonds in adducts of noble gas atoms with both neutral and ionic partners have been investigated by exploiting a fine-tuned integrated phenomenological–theoretical approach. The identification of the leading interaction components in the noble gases adducts and their modeling allows the encompassing of the transitions from pure noncovalent to covalent bound aggregates and to rationalize the anomalous behavior (deviations from noncovalent type interaction) pointed out in peculiar cases. Selected adducts affected by a weak chemical bond, as those promoting the formation of the intermolecular halogen bond, are also properly rationalized. The behavior of noble gas atoms excited in their long-life metastable states, showing a strongly enhanced reactivity, has been also enclosed in the present investigation.
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Affiliation(s)
- Francesca Nunzi
- Dipartimento di Chimica, Biologia e Biotecnologie, via Elce di Sotto 8, I-06123 Perugia, Italy; (G.P.); (F.T.); (D.C.)
- Istituto CNR di Scienze e Tecnologie Chimiche “Giulio Natta” (CNR-SCITEC), via Elce di Sotto, I-06123 Perugia, Italy;
- Correspondence: (F.N.); (F.P.)
| | - Giacomo Pannacci
- Dipartimento di Chimica, Biologia e Biotecnologie, via Elce di Sotto 8, I-06123 Perugia, Italy; (G.P.); (F.T.); (D.C.)
| | - Francesco Tarantelli
- Dipartimento di Chimica, Biologia e Biotecnologie, via Elce di Sotto 8, I-06123 Perugia, Italy; (G.P.); (F.T.); (D.C.)
- Istituto CNR di Scienze e Tecnologie Chimiche “Giulio Natta” (CNR-SCITEC), via Elce di Sotto, I-06123 Perugia, Italy;
| | - Leonardo Belpassi
- Istituto CNR di Scienze e Tecnologie Chimiche “Giulio Natta” (CNR-SCITEC), via Elce di Sotto, I-06123 Perugia, Italy;
| | - David Cappelletti
- Dipartimento di Chimica, Biologia e Biotecnologie, via Elce di Sotto 8, I-06123 Perugia, Italy; (G.P.); (F.T.); (D.C.)
| | - Stefano Falcinelli
- Dipartimento di Ingegneria Civile ed Ambientale, Università degli Studi di Perugia, via G. Duranti 93, 06215 Perugia, Italy;
| | - Fernando Pirani
- Dipartimento di Chimica, Biologia e Biotecnologie, via Elce di Sotto 8, I-06123 Perugia, Italy; (G.P.); (F.T.); (D.C.)
- Istituto CNR di Scienze e Tecnologie Chimiche “Giulio Natta” (CNR-SCITEC), via Elce di Sotto, I-06123 Perugia, Italy;
- Correspondence: (F.N.); (F.P.)
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Wang K, Wang F, Lou Z, Han Q, Zhao Q, Hu K, Huang Z, Li J. Relationship between the Electrical Characteristics of Molecules and Fast Streamers in Ester Insulation Oil. Int J Mol Sci 2020; 21:E974. [PMID: 32024099 DOI: 10.3390/ijms21030974] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 01/23/2020] [Accepted: 01/28/2020] [Indexed: 11/17/2022] Open
Abstract
The effects of C=C, ester and β-H groups on the ionization potential (IP) and electron affinity (EA) of molecules in natural ester insulation oil were investigated by density functional theory (DFT). The major contribution to the highest occupied molecular orbital (HOMO) comes from the carbon atoms adjacent to C=C. Thus, the IPs of triglycerides decrease as the number of C=C double bonds increases. The C=C in alkanes may also lower the IP. However, the β-H in triglycerides has little effect on the IP, and C=C and β-H have only a small effect on the EAs of the triglycerides because of the major contributions of atoms near the ester group in triglycerides to the lowest unoccupied molecular orbital (LUMO). This study calculated the IPs of 53 kinds of molecules in FR3, which are significantly lower compared with those of molecules in mineral oil (MO) and trimethylolpropane triester without C=C. However, the lightning impulse breakdown voltage (LI Vb) of trimethylolpropane triester is still significantly lower than that of MO at the large gap. Therefore, the transition from slow to fast streamers under low lighting impulse voltage is determined by the ester group rather than by C=C and β-H. The ester group may attract more electrons, impacting itself more compared to alkane in MO and facilitating the transition from slow to fast streamers.
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Wang YG, Barnes EC, Kaya S, Sharma V. The Reactivity of Ambident Nucleophiles: Marcus Theory or Hard and Soft Acids and Bases Principle? J Comput Chem 2019; 40:2761-2777. [PMID: 31429098 DOI: 10.1002/jcc.26052] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 07/22/2019] [Accepted: 07/27/2019] [Indexed: 11/09/2022]
Abstract
The model reactions CH3 X + (NH-CH=O)M ➔ CH3 -NH-NH═O or NH═CH-O-CH3 + MX (M = none, Li, Na, K, Ag, Cu; X = F, Cl, Br) are investigated to demonstrate the feasibility of Marcus theory and the hard and soft acids and bases (HSAB) principle in predicting the reactivity of ambident nucleophiles. The delocalization indices (DI) are defined in the framework of the quantum theory of atoms in molecules (QT-AIM), and are used as the scale of softness in the HSAB principle. To react with the ambident nucleophile NH═CH-O- , the carbocation H3 C+ from CH3 X (F, Cl, Br) is actually a borderline acid according to the DI values of the forming C…N and C…O bonds in the transition states (between 0.25 and 0.49), while the counter ions are divided into three groups according to the DI values of weak interactions involving M (M…X, M…N, and M…O): group I (M = none, and Me4 N) basically show zero DI values; group II species (M = Li, Na, and K) have noticeable DI values but the magnitudes are usually less than 0.15; and group III species (M = Ag and Cu(I)) have significant DI values (0.30-0.61). On a relative basis, H3 C+ is a soft acid with respect to group I and group II counter ions, and a hard acid with respect to group III counter ions. Therefore, N-regioselectivity is found in the presence of group I and group II counter ions (M = Me4 N, Li, Na, K), while O-regioselectivity is observed in the presence of the group III counter ions (M = Ag, and Cu(I)). The hardness of atoms, groups, and molecules is also calculated with new functions that depend on ionization potential (I) and electron affinity (A) and use the atomic charges obtained from localization indices (LI), so that the regioselectivity is explained by the atomic hardness of reactive nitrogen atoms in the transition states according to the maximum hardness principle (MHP). The exact Marcus equation is derived from the simple harmonic potential energy parabola, so that the concepts of activation free energy, intrinsic activation barrier, and reaction energy are completely connected. The required intrinsic activation barriers can be either estimated from ab initio calculations on reactant, transition state, and product of the model reactions, or calculated from identity reactions. The counter ions stabilize the reactant through bridging N- and O-site of reactant of identity reactions, so that the intrinsic barriers for the salts are higher than those for free ambident anions, which is explained by the increased reorganization parameter Δr. The proper application of Marcus theory should quantitatively consider all three terms of Marcus equation, and reliably represent the results with potential energy parabolas for reactants and all products. For the model reactions, both Marcus theory and HSAB principle/MHP principle predict the N-regioselectivity when M = none, Me4 N, Li, Na, K, and the O-regioselectivity when M = Ag and Cu(I). © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Yi-Gui Wang
- Department of Chemistry, Southern CT State University, 501 Crescent Street, New Haven, Connecticut, 06515
| | - Ericka C Barnes
- Department of Chemistry, Southern CT State University, 501 Crescent Street, New Haven, Connecticut, 06515
| | - Savaș Kaya
- Department of Chemistry, Faculty of Science, Cumhuriyet University, Sivas, Turkey
| | - Vinit Sharma
- Joint Institute for Computational Sciences (JICS), Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831-6173
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17
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Nunzi F, Di Erasmo B, Tarantelli F, Cappelletti D, Pirani F. The Halogen-Bond Nature in Noble Gas-Dihalogen Complexes from Scattering Experiments and Ab Initio Calculations. Molecules 2019; 24:molecules24234274. [PMID: 31771210 PMCID: PMC6930525 DOI: 10.3390/molecules24234274] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 11/21/2019] [Accepted: 11/21/2019] [Indexed: 11/16/2022] Open
Abstract
In order to clarify the nature of the halogen bond (XB), we considered the prototype noble gas–dihalogen molecule (Ng–X2) systems, focusing on the nature, range, and strength of the interaction. We exploited data gained from molecular beam scattering experiments with the measure of interference effects to obtain a suitable formulation of the interaction potential, with the support of high-level ab initio calculations, and charge displacement analysis. The essential interaction components involved in the Ng–X2 adducts were characterized, pointing at their critical balance in the definition of the XB. Particular emphasis is devoted to the energy stability of the orientational Ng–X2 isomers, the barrier for the X2 hindered rotation, and the influence of the X2 electronic state. The present integrated study returns reliable force fields for molecular dynamic simulations in Ng–X2 complexes that can be extended to systems with increasing complexity and whose properties depend on the selective formation of XB.
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Affiliation(s)
- Francesca Nunzi
- Dipartimento di Chimica, Biologia e Biotecnologie, via Elce di Sotto 8, I-06123 Perugia, Italy; (B.D.E.); (F.T.); (D.C.)
- Istituto CNR di Scienze e Tecnologie Chimiche “Giulio Natta” (CNR-SCITEC), via Elce di Sotto, I-06123 Perugia, Italy
- Correspondence: (F.N.); (F.P.)
| | - Benedetta Di Erasmo
- Dipartimento di Chimica, Biologia e Biotecnologie, via Elce di Sotto 8, I-06123 Perugia, Italy; (B.D.E.); (F.T.); (D.C.)
| | - Francesco Tarantelli
- Dipartimento di Chimica, Biologia e Biotecnologie, via Elce di Sotto 8, I-06123 Perugia, Italy; (B.D.E.); (F.T.); (D.C.)
- Istituto CNR di Scienze e Tecnologie Chimiche “Giulio Natta” (CNR-SCITEC), via Elce di Sotto, I-06123 Perugia, Italy
| | - David Cappelletti
- Dipartimento di Chimica, Biologia e Biotecnologie, via Elce di Sotto 8, I-06123 Perugia, Italy; (B.D.E.); (F.T.); (D.C.)
| | - Fernando Pirani
- Dipartimento di Chimica, Biologia e Biotecnologie, via Elce di Sotto 8, I-06123 Perugia, Italy; (B.D.E.); (F.T.); (D.C.)
- Correspondence: (F.N.); (F.P.)
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18
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Abstract
Iodine oxides appear as reactive intermediates in atmospheric chemistry. Here, we investigate IO and HOI by mass-selective threshold photoelectron spectroscopy (ms-TPES), using synchrotron radiation. IO and HOI are generated by photolyzing iodine in the presence of ozone. For both molecules, accurate ionization energies are determined, 9.71±0.02 eV for IO and 9.79±0.02 eV for HOI. The strong spin-spin interaction in the 3 Σ- ground state of IO+ leads to an energy splitting into the Ω=0 and Ω=±1 sublevels. Upon ionization, the I-O bond shortens significantly in both molecules; thus, a vibrational progression, assigned to the I-O stretch, is apparent in both spectra.
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Affiliation(s)
- Domenik Schleier
- Institute for Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Engelbert Reusch
- Institute for Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Lisa Lummel
- Institute for Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Patrick Hemberger
- Laboratory for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institute (PSI), 5232, Villigen, Switzerland
| | - Ingo Fischer
- Institute for Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
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19
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Whittles TJ, Veal TD, Savory CN, Yates PJ, Murgatroyd PAE, Gibbon JT, Birkett M, Potter RJ, Major JD, Durose K, Scanlon DO, Dhanak VR. Band Alignments, Band Gap, Core Levels, and Valence Band States in Cu 3BiS 3 for Photovoltaics. ACS Appl Mater Interfaces 2019; 11:27033-27047. [PMID: 31276370 DOI: 10.1021/acsami.9b04268] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The earth-abundant semiconductor Cu3BiS3 (CBS) exhibits promising photovoltaic properties and is often considered analogous to the solar absorbers copper indium gallium diselenide (CIGS) and copper zinc tin sulfide (CZTS) despite few device reports. The extent to which this is justifiable is explored via a thorough X-ray photoemission spectroscopy (XPS) analysis: spanning core levels, ionization potential, work function, surface contamination, cleaning, band alignment, and valence-band density of states. The XPS analysis overcomes and addresses the shortcomings of prior XPS studies of this material. Temperature-dependent absorption spectra determine a 1.2 eV direct band gap at room temperature; the widely reported 1.4-1.5 eV band gap is attributed to weak transitions from the low density of states of the topmost valence band previously being undetected. Density functional theory HSE06 + SOC calculations determine the band structure, optical transitions, and well-fitted absorption and Raman spectra. Valence band XPS spectra and model calculations find the CBS bonding to be superficially similar to CIGS and CZTS, but the Bi3+ cations (and formally occupied Bi 6s orbital) have fundamental impacts: giving a low ionization potential (4.98 eV), suggesting that the CdS window layer favored for CIGS and CZTS gives detrimental band alignment and should be rejected in favor of a better aligned material in order for CBS devices to progress.
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Affiliation(s)
- Thomas J Whittles
- Department of Physics and Stephenson Institute for Renewable Energy , University of Liverpool , Liverpool , L69 7ZF , U.K
| | - Tim D Veal
- Department of Physics and Stephenson Institute for Renewable Energy , University of Liverpool , Liverpool , L69 7ZF , U.K
| | - Christopher N Savory
- Department of Chemistry , University College London , Christopher Ingold Building , London WC1H 0AJ , U.K
- Thomas Young Centre , University College London , Gower Street , London WC1E 6BT , U.K
| | - Peter J Yates
- Department of Physics and Stephenson Institute for Renewable Energy , University of Liverpool , Liverpool , L69 7ZF , U.K
| | - Philip A E Murgatroyd
- Department of Physics and Stephenson Institute for Renewable Energy , University of Liverpool , Liverpool , L69 7ZF , U.K
| | - James T Gibbon
- Department of Physics and Stephenson Institute for Renewable Energy , University of Liverpool , Liverpool , L69 7ZF , U.K
| | - Max Birkett
- Department of Physics and Stephenson Institute for Renewable Energy , University of Liverpool , Liverpool , L69 7ZF , U.K
| | - Richard J Potter
- Department of Mechanical, Materials and Aerospace Engineering, School of Engineering , University of Liverpool , Liverpool , L69 3GH , U.K
| | - Jonathan D Major
- Department of Physics and Stephenson Institute for Renewable Energy , University of Liverpool , Liverpool , L69 7ZF , U.K
| | - Ken Durose
- Department of Physics and Stephenson Institute for Renewable Energy , University of Liverpool , Liverpool , L69 7ZF , U.K
| | - David O Scanlon
- Department of Chemistry , University College London , Christopher Ingold Building , London WC1H 0AJ , U.K
- Diamond Light Source Limited , Diamond House, Harwell Science and Innovation Campus , Didcot , Oxfordshire OX11 0DE , U.K
- Thomas Young Centre , University College London , Gower Street , London WC1E 6BT , U.K
| | - Vinod R Dhanak
- Department of Physics and Stephenson Institute for Renewable Energy , University of Liverpool , Liverpool , L69 7ZF , U.K
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Abstract
The GW approximation in electronic structure theory has become a widespread tool for predicting electronic excitations in chemical compounds and materials. In the realm of theoretical spectroscopy, the GW method provides access to charged excitations as measured in direct or inverse photoemission spectroscopy. The number of GW calculations in the past two decades has exploded with increased computing power and modern codes. The success of GW can be attributed to many factors: favorable scaling with respect to system size, a formal interpretation for charged excitation energies, the importance of dynamical screening in real systems, and its practical combination with other theories. In this review, we provide an overview of these formal and practical considerations. We expand, in detail, on the choices presented to the scientist performing GW calculations for the first time. We also give an introduction to the many-body theory behind GW, a review of modern applications like molecules and surfaces, and a perspective on methods which go beyond conventional GW calculations. This review addresses chemists, physicists and material scientists with an interest in theoretical spectroscopy. It is intended for newcomers to GW calculations but can also serve as an alternative perspective for experts and an up-to-date source of computational techniques.
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Affiliation(s)
- Dorothea Golze
- Department of Applied Physics, Aalto University, School of Science, Espoo, Finland
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21
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Tkachenko NV, Sun ZM, Boldyrev AI. Record Low Ionization Potentials of Alkali Metal Complexes with Crown Ethers and Cryptands. Chemphyschem 2019; 20:2060-2062. [PMID: 31184431 DOI: 10.1002/cphc.201900422] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 06/10/2019] [Indexed: 11/10/2022]
Abstract
Electronic properties of series of alkali metals complexes with crown ethers and cryptands were studied via DFT hybrid functionals. For [M([2.2.2]crypt)] (M=Li, Na, K) extremely low (1.70-1.52 eV) adiabatic ionization potentials were found. Such low values of ionization energies are significantly lower than those of alkali metal atoms. Thus, the investigated complexes can be defined as superalkalis. As a result, our investigation opens up new directions in the designing of chemical species with record low ionization potentials and extends the explanation of the ability of the cryptates and alkali crown ether complexes to stabilize multiple charged Zintl ions.
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Affiliation(s)
- Nikolay V Tkachenko
- Department of Chemistry and Biochemistry, Utah State University Logan, Utah, 84322, United States
| | - Zhong-Ming Sun
- School of Materials Science and Engineering State Key Laboratory of Elemento-Organic Chemistry Tianjin Key Lab for Rare Earth Materials and Applications, Nankai University, Tianjin, 300350, China
| | - Alexander I Boldyrev
- Department of Chemistry and Biochemistry, Utah State University Logan, Utah, 84322, United States
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22
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Brew CT, Blake JF, Mistry A, Liu F, Carreno D, Madsen D, Mu Y, Mayo M, Stahl W, Matthews D, Maclean D, Harrison S. Use of QSPR Modeling to Characterize In Vitro Binding of Drugs to a Gut-Restricted Polymer. Pharm Res 2018. [PMID: 29520505 PMCID: PMC5843698 DOI: 10.1007/s11095-018-2356-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Purpose Polymeric drugs, including patiromer (Veltassa®), bind target molecules or ions in the gut, allowing fecal elimination. Non-absorbed insoluble polymers, like patiromer, avoid common systemic drug-drug interactions (DDIs). However, the potential for DDI via polymer binding to orally administered drugs during transit of the gastrointestinal tract remains. Here we elucidate the properties correlated with drug-patiromer binding using quantitative structure-property relationship (QSPR) models. Methods We selected 28 drugs to evaluate for binding to patiromer in vitro over a range of pH and ionic conditions intended to mimic the gut environment. Using this in vitro data, we developed QSPR models using step-wise linear regression and analyzed over 100 physiochemical drug descriptors. Results Four descriptors emerged that account for ~70% of patiromer-drug binding in vitro: the computed surface area of hydrogen bond accepting atoms, ionization potential, electron affinity, and lipophilicity (R2 = 0.7, Q2 = 0.6). Further, certain molecular properties are shared by nonbinding, weak, or strong binding compounds. Conclusions These findings offer insight into drivers of in vitro binding to patiromer and describe a useful approach for assessing potential drug-binding risk of investigational polymeric drugs. Electronic supplementary material The online version of this article (10.1007/s11095-018-2356-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Christine Taylor Brew
- Research Department, Relypsa, Inc., a Vifor Pharma Group Company, 100 Cardinal Way, Redwood City, California, 94063, USA.
| | - James F Blake
- Computational Chemistry Department, Array BioPharma Inc, Boulder, Colorado, USA
| | - Anita Mistry
- Research Department, Relypsa, Inc., a Vifor Pharma Group Company, 100 Cardinal Way, Redwood City, California, 94063, USA
| | - Fengling Liu
- Research Department, Relypsa, Inc., a Vifor Pharma Group Company, 100 Cardinal Way, Redwood City, California, 94063, USA
| | - Diana Carreno
- Research Department, Relypsa, Inc., a Vifor Pharma Group Company, 100 Cardinal Way, Redwood City, California, 94063, USA
| | - Deidre Madsen
- Research Department, Relypsa, Inc., a Vifor Pharma Group Company, 100 Cardinal Way, Redwood City, California, 94063, USA
| | - YongQi Mu
- Research Department, Relypsa, Inc., a Vifor Pharma Group Company, 100 Cardinal Way, Redwood City, California, 94063, USA
| | - Martha Mayo
- Clinical Development, Relypsa, Inc., a Vifor Pharma Group Company, Redwood City, California, USA
| | - Wilhelm Stahl
- Technical Operations, Relypsa, Inc., a Vifor Pharma Group Company, Redwood City, California, USA
| | - David Matthews
- Research Department, Relypsa, Inc., a Vifor Pharma Group Company, 100 Cardinal Way, Redwood City, California, 94063, USA
| | - Derek Maclean
- Research Department, Relypsa, Inc., a Vifor Pharma Group Company, 100 Cardinal Way, Redwood City, California, 94063, USA
| | - Steve Harrison
- Research Department, Relypsa, Inc., a Vifor Pharma Group Company, 100 Cardinal Way, Redwood City, California, 94063, USA
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23
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Islam R, Chen G, Ramesh P, Suh J, Fuchigami N, Lee D, Littau KA, Weiner K, Collins RT, Saraswat KC. Investigation of the Changes in Electronic Properties of Nickel Oxide (NiO x) Due to UV/Ozone Treatment. ACS Appl Mater Interfaces 2017; 9:17201-17207. [PMID: 28447776 DOI: 10.1021/acsami.7b01629] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Drastic reduction in nickel oxide (NiOx) film resistivity and ionization potential is observed when subjected to ultraviolet (UV)/ozone (O3) treatment. X-ray photoemission spectroscopy suggests that UV/O3 treatment changes the film stoichiometry by introducing Ni vacancy defects. Oxygen-rich NiOx having Ni vacancy defects behaves as a p-type semiconductor. Therefore, in this work, a simple and effective technique to introduce doping in NiOx is shown. Angle-resolved XPS reveals that the effect of UV/O3 treatment does not only alter the film surface property but also introduces oxygen-rich stoichiometry throughout the depth of the film. Finally, simple metal/interlayer/semiconductor (MIS) contacts are fabricated on p-type Si using NiOx as the interlayer and different metals. Significant barrier height reduction is observed with respect to the control sample following UV/O3 treatment, which is in agreement with the observed reduction in film resistivity. From an energy band diagram point of view, the introduction of the UV/O3 treatment changes the defect state distribution, resulting in a change in the pinning of the Fermi level. Therefore, this work also shows that the Fermi level pinning property of NiOx can be controlled using UV/O3 treatment.
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Affiliation(s)
- Raisul Islam
- Department of Electrical Engineering, Stanford University , 420 Via Palou Mall, Stanford, California 94305, United States
| | - Gang Chen
- Department of Physics, Colorado School of Mines , Meyer Hall 466, Golden, Colorado 80401, United States
| | - Pranav Ramesh
- Department of Electrical Engineering, Stanford University , 420 Via Palou Mall, Stanford, California 94305, United States
| | - Junkyo Suh
- Department of Electrical Engineering, Stanford University , 420 Via Palou Mall, Stanford, California 94305, United States
| | - Nobi Fuchigami
- Intermolecular Inc. , 3011 N. First Street, San Jose, California 95134, United States
| | - Donovan Lee
- Intermolecular Inc. , 3011 N. First Street, San Jose, California 95134, United States
| | - Karl A Littau
- Intermolecular Inc. , 3011 N. First Street, San Jose, California 95134, United States
| | - Kurt Weiner
- Intermolecular Inc. , 3011 N. First Street, San Jose, California 95134, United States
| | - Reuben T Collins
- Department of Physics, Colorado School of Mines , Meyer Hall 466, Golden, Colorado 80401, United States
| | - Krishna C Saraswat
- Department of Electrical Engineering, Stanford University , 420 Via Palou Mall, Stanford, California 94305, United States
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Daskeviciene M, Bubniene G, Malinauskas T, Jankauskas V, Gaidelis V, Paulauskas V, Getautis V. 1,3-diphenylethenylcarbazolyl-based monomer for cross-linked hole transporting layers. Molecules 2015; 20:9124-38. [PMID: 25996215 PMCID: PMC6272464 DOI: 10.3390/molecules20059124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Revised: 04/21/2015] [Accepted: 04/30/2015] [Indexed: 11/17/2022] Open
Abstract
A new cross-linkable monomer containing 1,3-diphenylethenylcarbazolyl-based hole-transporting moieties and four reactive epoxy groups, was prepared by a multistep synthesis route from 1,3-bis(2,2-diphenylethenyl)-9H-carbazol-2-ol and its application for the in situ formation of cross-linked hole transporting layers was investigated. A high concentration of flexible aliphatic epoxy chains ensures good solubility and makes this compound an attractive cross-linking agent. The synthesized compounds were characterized by various techniques, including differential scanning calorimetry, xerographic time of flight, and electron photoemission in air methods.
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Affiliation(s)
- Maryte Daskeviciene
- Department of Organic Chemistry, Kaunas University of Technology, Radvilenu pl. 19, 50254 Kaunas, Lithuania.
| | - Giedre Bubniene
- Department of Organic Chemistry, Kaunas University of Technology, Radvilenu pl. 19, 50254 Kaunas, Lithuania.
| | - Tadas Malinauskas
- Department of Organic Chemistry, Kaunas University of Technology, Radvilenu pl. 19, 50254 Kaunas, Lithuania.
| | - Vygintas Jankauskas
- Department of Solid State Electronics, Vilnius University, Sauletekio 9, 10222 Vilnius, Lithuania.
| | - Valentas Gaidelis
- Department of Solid State Electronics, Vilnius University, Sauletekio 9, 10222 Vilnius, Lithuania.
| | - Valdas Paulauskas
- Institute of Environment and Ecology, Aleksandras Stulginskis University, Studentu 11, Kaunas Dist., 53361 Akademija, Lithuania.
| | - Vytautas Getautis
- Department of Organic Chemistry, Kaunas University of Technology, Radvilenu pl. 19, 50254 Kaunas, Lithuania.
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Zhang R, Liu J, Yang H, Wang S, Zhang M, Bu Y. Computational insights into the charge relaying properties of β-turn peptides in protein charge transfers. Chemphyschem 2014; 16:436-46. [PMID: 25430869 DOI: 10.1002/cphc.201402657] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Indexed: 11/11/2022]
Abstract
Density functional theory calculations suggest that β-turn peptide segments can act as a novel dual-relay elements to facilitate long-range charge hopping transport in proteins, with the N terminus relaying electron hopping transfer and the C terminus relaying hole hopping migration. The electron- or hole-binding ability of such a β-turn is subject to the conformations of oligopeptides and lengths of its linking strands. On the one hand, strand extension at the C-terminal end of a β-turn considerably enhances the electron-binding of the β-turn N terminus, due to its unique electropositivity in the macro-dipole, but does not enhance hole-forming of the β-turn C terminus because of competition from other sites within the β-strand. On the other hand, strand extension at the N terminal end of the β-turn greatly enhances hole-binding of the β-turn C terminus, due to its distinct electronegativity in the macro-dipole, but does not considerably enhance electron-binding ability of the N terminus because of the shared responsibility of other sites in the β-strand. Thus, in the β-hairpin structures, electron- or hole-binding abilities of both termini of the β-turn motif degenerate compared with those of the two hook structures, due to the decreased macro-dipole polarity caused by the extending the two terminal strands. In general, the high polarity of a macro-dipole always plays a principal role in determining charge-relay properties through modifying the components and energies of the highest occupied and lowest unoccupied molecular orbitals of the β-turn motif, whereas local dipoles with low polarity only play a cooperative assisting role. Further exploration is needed to identify other factors that influence relay properties in these protein motifs.
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Affiliation(s)
- Ru Zhang
- Institute of Theoretical Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100 (P.R. China)
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26
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Adriaanse C, Cheng J, Chau V, Sulpizi M, VandeVondele J, Sprik M. Aqueous Redox Chemistry and the Electronic Band Structure of Liquid Water. J Phys Chem Lett 2012; 3:3411-5. [PMID: 26290964 DOI: 10.1021/jz3015293] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The electronic states of aqueous species can mix with the extended states of the solvent if they are close in energy to the band edges of water. Using density functional theory-based molecular dynamics simulation, we show that this is the case for OH(-) and Cl(-). The effect is, however, badly exaggerated by the generalized gradient approximation leading to systematic underestimation of redox potentials and spurious nonlinearity in the solvent reorganization. Drawing a parallel to charged defects in wide gap solid oxides, we conclude that misalignment of the valence band of water is the main source of error turning the redox levels of OH(-) and Cl(-) in resonant impurity states. On the other hand, the accuracy of energies of levels corresponding to strongly negative redox potentials is acceptable. We therefore predict that mixing of the vertical attachment level of CO2 and the unoccupied states of water is a real effect.
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Affiliation(s)
- Christopher Adriaanse
- †Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Jun Cheng
- †Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Vincent Chau
- †Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Marialore Sulpizi
- †Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Joost VandeVondele
- ‡Physical Chemistry Institute, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Michiel Sprik
- †Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
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Abstract
Gas-phase cytosine exists in five different tautomer/rotamer forms 1, 2a, 2b, 3a, and 3b. We determine the threshold ionization energy (IE) of the keto-amino tautomer 1 as 8.73 ± 0.02 eV, using resonant two-photon ionization mass spectrometry in a supersonic molecular beam via the (1)ππ* excited state. This is the first IE threshold measurement for the biologically relevant tautomer 1. The IE of the thermal gas-phase mixture of cytosine has been measured as 8.60 ± 0.05 eV by Kostko et al. using single-photon VUV photoionization [Phys. Chem. Chem. Phys., 2010, 12, 2860]. Given the tautomer distribution and ionization energies calculated in that work, our determination of the keto-amino tautomer IE implies that the IE measured by Kostko et al. is dominated by the enol-amino tautomers 2a and 2b. Upon excitation of keto-amino cytosine to its (1)ππ* state, relaxation occurs to a lower-lying long-lived state. The IE threshold measured via this state places its energy about 0.69 eV below the (1)ππ* state, in good agreement with the triplet T1 energy of keto-amino cytosine calculated by several high-level ab initio methods. The identification of keto-amino cytosine T1 is the basis for characterizing the intersystem crossing rates into and the photochemical reactions of this long-lived state.
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Affiliation(s)
- Simon Lobsiger
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Samuel Leutwyler
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
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28
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Borges RS, Queiroz AN, Mendes AP, Araújo SC, França LC, Franco EC, Leal WG, da Silva AB. Density functional theory (DFT) study of edaravone derivatives as antioxidants. Int J Mol Sci 2012; 13:7594-606. [PMID: 22837715 DOI: 10.3390/ijms13067594] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 06/09/2012] [Accepted: 06/11/2012] [Indexed: 11/16/2022] Open
Abstract
Quantum chemical calculations at the B3LYP/6–31G* level of theory were employed for the structure-activity relationship and prediction of the antioxidant activity of edaravone and structurally related derivatives using energy (E), ionization potential (IP), bond dissociation energy (BDE), and stabilization energies (ΔEiso). Spin density calculations were also performed for the proposed antioxidant activity mechanism. The electron abstraction is related to electron-donating groups (EDG) at position 3, decreasing the IP when compared to substitution at position 4. The hydrogen abstraction is related to electron-withdrawing groups (EDG) at position 4, decreasing the BDECH when compared to other substitutions, resulting in a better antioxidant activity. The unpaired electron formed by the hydrogen abstraction from the C–H group of the pyrazole ring is localized at 2, 4, and 6 positions. The highest scavenging activity prediction is related to the lowest contribution at the carbon atom. The likely mechanism is related to hydrogen transfer. It was found that antioxidant activity depends on the presence of EDG at the C2 and C4 positions and there is a correlation between IP and BDE. Our results identified three different classes of new derivatives more potent than edaravone.
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Kumar A, Sevilla MD. Density functional theory studies of the extent of hole delocalization in one-electron oxidized adenine and guanine base stacks. J Phys Chem B 2011; 115:4990-5000. [PMID: 21417208 PMCID: PMC3084348 DOI: 10.1021/jp200537t] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study investigates the extent of hole delocalization in one-electron oxidized adenine (A) and guanine (G) stacks and shows that new IR vibrational bands are predicted that are characteristic of hole delocalization within A-stacks. The geometries of A-stacks (A(i); i = 2-8) and G-stacks (GG and GGG) in their neutral and one-electron oxidized states were optimized with the bases in a B-DNA conformation using the M06-2X/6-31G* method. The highest occupied molecular orbital (HOMO) is localized on a single adenine in A-stacks and on a single guanine in GG and GGG stacks located at the 5'-site of the stack. On one-electron oxidation (removal of an electron from the HOMO of the neutral A- and G-stacks) a "hole" is created. Mulliken charge analysis shows that these "holes" are delocalized over two to three adenine bases in the A-stack. The calculated spin density distribution of A(i)(•+) (i = 2-8) also showed delocalization of the hole predominantly on two adenine bases, with some delocalization on a neighboring base. For GG and GGG radical cations, the hole was found to be localized on a single G in the stack. The calculated HFCCs of GG and GGG are in good agreement with the experiment. Further, from the vibrational frequency analysis, it was found that IR spectra of neutral and the corresponding one-electron oxidized adenine stacks are quite different. The IR spectra of A(2)(•+) has intense IR peaks between 900 and 1500 cm(-1) that are not present in the neutral A(2) stack. The presence of A(2)(•+) in the adenine stack has a characteristic intense peak at ~1100 cm(-1). Thus, IR and Raman spectroscopy has potential for monitoring the extent of hole delocalization in A stacks.
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Affiliation(s)
- Anil Kumar
- Department of Chemistry, Oakland University, Rochester, Michigan 48309, USA
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Gogonea V, Shy JM, Biswas PK. Electronic structure, ionization potential, and electron affinity of the enzyme cofactor (6R)-5,6,7,8-tetrahydrobiopterin in the gas phase, solution, and protein environments. J Phys Chem B 2006; 110:22861-71. [PMID: 17092038 PMCID: PMC2533135 DOI: 10.1021/jp061653q] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
(6R)-5,6,7,8-Tetrahydrobiopterin (BH(4)) is a key cofactor involved in the electron transfer to the P(450) heme of nitric oxide synthase. We calculated the electronic structure of the neutral, cationic, and anionic forms of BH(4) in the gas phase, in solution (both dielectric and explicit water), and in the protein environment using density functional theory (B3LYP/6-31+G(d,p)). Subsequently, we derived the ionization potential (IP) and electron affinity (EA) of the cofactor in these chemical environments. We found that the electronic structure of BH(4) is susceptible to the presence of an external electric field and that conformational changes in the structure of BH(4) alone do not affect its electronic structure significantly. In the gas phase, water, and protein environments neutral BH(4) is the most stable species, while in the dielectric environment the anion becomes the most stable species. The IP of BH(4) in the protein environment is about half of that in the gas phase, and its EA is about 5 times smaller than that in the gas phase. Our results indicate that changes in the external electric field created by moving charged amino acid residues around BH(4) may lead to configurations that have the BH(4) ion as stable as or more stable than the neutral form, thus facilitating the electron transfer.
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Affiliation(s)
- Valentin Gogonea
- Department of Chemistry, Cleveland State University, Cleveland, Ohio 44115, USA.
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31
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Argentar H. Structure- and Solvent-Property Relationships for the Electronic Energies of Charge-Transfer Complexes Between Certain Benzene Derivatives. J Res Natl Bur Stand A Phys Chem 1976; 80A:173-187. [PMID: 32196292 PMCID: PMC5296186 DOI: 10.6028/jres.080a.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
A chemical model is proposed for describing charge-transfer complexes between aromatic amines and electron-accepting benzene derivatives containing a group having a double- or triple-bond conjugated with the benzene ring. According to this model, an electron migrates from the nitrogen atom of the amine to one of the atoms of the multiple-bonded group during charge-transfer interaction. Structure-property relationships were derived for correlating: (1), the transition energies of the complexes; (2), the ionization, or oxidation, potentials of the amines, and (3), the electron affinities or reduction potentials of the electron acceptors, with the electron-donating abilities of the substituents of the various compounds. Transition energies calculated from reported spectroscopic data for these complexes were correlated using equations derived in this study. Similarly correlated were reported data for the above properties of the amine and electron acceptor. Equations were derived for correlating the effect of variation in solvent on the transition energies of the complexes. Correlation of reported spectroscopic data indicated that the greatest effect is caused by variation in the refractive index; of secondary importance was the change in dielectric constant.
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Affiliation(s)
- Harold Argentar
- Institute for Materials Research, National Bureau of Standards, Washington, D.C. 20234
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32
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Abstract
An analysis of Cu iii based on observations from 500 to 6900 Å is presented. The low structures 3d 9 and 3d 84s are complete, including the rarely, if ever before, found 3d 8(1S)4s 2S. The 3d 74s 2 includes 4F, 2F, 2G, and 2H but the 4P, 2P, a 2D, b 2D have eluded all attempts to find them. The ionization potential calculated from 4s, 5s, 6s 44 F 4 1 / 2 is 296 980 cm-1 but by a comparison with Ni II which has a longer series an approximate value of 297 140 can be estimated. The 3d 84d group is complete, except for one level, as is 5dbased on 3F and 1G, the other 5d groups being incomplete. 3d 8(3F)4f is complete and 26 levels based on 1D, 3P, 1G are known. 3d 8(3F)5g is incomplete and a few levels based on 1D and 1G have been found. A discussion of the validity of the analysis of Cu iv by J. F. Schröder and Th. A. M. Van Kleef is given.
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33
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Abstract
This paper provides additional information which came to light too late for the original publication [J. Res. Nat. Bur. Stand. (U.S.) 74A, 801 (1970)].
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Affiliation(s)
- A G Shenstone
- Institute for Basic Standards, National Bureau of Standards, Washington, D.C. 20234
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34
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Abstract
An analysis of Ni II based on 4300 observed lines is presented. The low structures are 3d 9 , 3d 8 4s and 3d 7 4s 2 which are now complete except for 3d 8(1S)4s 2S and 3d 7 4s 2 2P½ and the higher of the two 2D terms of 3d 7 4s 2. Long series occur such as 3d 84s to 9s, 4d to 8d, 4f to 7f, 5g to 7g. The analysis also includes many terms of the complex structure 3d 7 4s 4p but only 55 percent of the levels within reach of the hollow cathode source have been found. The identification of the levels of 3d 8 4d and 5d was assisted by the calculations of N. Spector. The 4d 7 4s 2 levels were calculated by Y. Shadmi, who also provided calculated positions for all the levels of 3d 7 4s 4p without which much of the analysis would have been impossible. The 3d 8 ns and 3d 8 nd series give a limit of 146532.0 but the 3d 8 ng series gives 146541.56. The latter has been adopted though no explanation of the discrepancy has been found.
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Affiliation(s)
- A G Shenstone
- Institute for Basic Standards, National Bureau of Standards, Washington, D.C. 20234
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