8 results on '"Sergio Moles Quintero"'
Search Results
2. Asymmetric and zwitterionic Blatter diradicals
- Author
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Fang Miao, Yu Ji, Bo Han, Sergio Moles Quintero, Hanjiao Chen, Guodong Xue, Lulu Cai, Juan Casado, and Yonghao Zheng
- Subjects
General Chemistry - Abstract
Asymmetric diradical molecular systems with different resonance mechanisms are largely unexplored. Two conjugated asymmetric diradicals with Blatter and phenoxyl moieties (pBP and mBP) have been synthesized and studied in depth.
- Published
- 2023
3. Cross-conjugated isothianaphthene quinoids: a versatile strategy for controlling electronic structures
- Author
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Keitaro Yamamoto, Sergio Moles Quintero, Seihou Jinnai, Eunjeong Jeong, Kyohei Matsuo, Mitsuharu Suzuki, Hiroko Yamada, Juan Casado, and Yutaka Ie
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Materials Chemistry ,General Chemistry - Abstract
The elucidation of new structure–property relationships in π-conjugated molecules bearing quinoidal moieties is of relevance in organic electronics applications and as models of doped conducting polymers.
- Published
- 2022
4. Polycyclic Hydrocarbons from [4 n ]Annulenes: Correlation versus Hybridization Forces in the Formation of Diradicaloids
- Author
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Sergio Moles Quintero, Michael M. Haley, Miklos Kertesz, and Juan Casado
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Annulenesantiaromaticity ,Electroncorrelation ,Química Física ,General Chemistry ,General Medicine ,Diradicalcharacter ,Hybridization energy ,Catalysis - Abstract
The conceptual connections between [4n] Hückel antiaromaticity, disjoint orbitals, correlation energy, pro-aromaticity and diradical character for a variety of extended π-conjugated systems, including some salient recent examples of nanographenes and polycyclic aromatic radicals, are provided based on their [4n]annulene peripheries. The realization of such structure–property relationships has led to a beneficial pedagogic exercise establishing design guidelines for diradicaloids. The antiaromatic fingerprint of the [4n]annulene peripheries upon orbital interactions due to internal covalent connectors gives insights into the diradicaloid property of a diversity of π-conjugated molecules that have fascinated chemists recently. J.C. thanks MINECO/FEDER of the Spanish Government (PGC2018-098533-B-100, PID2021-127127NB−I00 and RED2018-102815-T) and the Junta de Andalucía (UMA18FEDERJA057). M.K. and M.M.H. acknowledge the NSF (CHE-2107820 to M.K., CHE-1954389 to M.M.H.) for financial support. We thank the anonymous reviewers for their helpful comments. Funding for open access charge: Universidad de Málaga / CBUA
- Published
- 2022
5. Perylene‐Fused, Aggregation‐Free Polycyclic Aromatic Hydrocarbons for Solution‐Processed Distributed Feedback Lasers
- Author
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María A. Díaz-García, Juan Casado, Guangwu Li, Ya Zou, José M. Villalvilla, José A. Quintana, Pedro G. Boj, Shaofei Wu, Víctor Bonal, Sergio Moles Quintero, Qing Jiang, Yong Ni, Jishan Wu, Universidad de Alicante. Departamento de Física Aplicada, Universidad de Alicante. Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante. Instituto Universitario de Materiales, and Física de la Materia Condensada
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Física de la Materia Condensada ,010405 organic chemistry ,Library science ,General Medicine ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Polycyclic aromatic hydrocarbons ,Catalysis ,0104 chemical sciences ,Solution processed ,chemistry.chemical_compound ,Scholarship ,chemistry ,Física Aplicada ,Tier 2 network ,Political science ,Organic lasers ,Amplified spontaneous emission ,Perylene ,Dyes ,Óptica - Abstract
Perylene‐fused, aggregation‐free polycyclic aromatic hydrocarbons with partial zigzag periphery (ZY‐01, ZY‐02, and ZY‐03) were synthesized. X‐ray crystallographic analysis reveals that there is no intermolecular π–π stacking in any of the three molecules, and as a result, they show moderate‐to‐high photoluminescence quantum yield in both solution and in the solid state. They also display the characteristic absorption and emission spectra of perylene dyes. ZY‐01 and ZY‐02 with a nearly planar π‐conjugated skeleton exhibit amplified spontaneous emission (ASE) when dispersed in polystyrene thin films. Solution‐processed distributed feedback lasers have been fabricated using ZY‐01 and ZY‐02 as active gain materials, both showing narrow emission linewidth (
- Published
- 2020
6. Normal & reversed spin mobility in a diradical by electron-vibration coupling
- Author
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Fabrizia Negri, Yonghao Zheng, Hanjiao Chen, Yasi Dai, Sergio Moles Quintero, Guodong Xue, Yi Shen, Dongsheng Wang, Fang Miao, Juan Casado, Shen Y., Xue G., Dai Y., Quintero S.M., Chen H., Wang D., Miao F., Negri F., Zheng Y., and Casado J.
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Materials science ,Science ,Chemical physics ,General Physics and Astronomy ,conjugated diradical ,General Biochemistry, Genetics and Molecular Biology ,Article ,symbols.namesake ,chemistry.chemical_compound ,Electronic devices ,Physics::Chemical Physics ,Spin (physics) ,quinoidal ,Multidisciplinary ,Spintronics ,Diradical ,Intermolecular force ,General Chemistry ,Vibronic coupling ,azobenzene ,Azobenzene ,chemistry ,Intramolecular force ,symbols ,Raman spectroscopy ,organic spintronic - Abstract
π−conjugated radicals have great promise for use in organic spintronics, however, the mechanisms of spin relaxation and mobility related to radical structural flexibility remain unexplored. Here, we describe a dumbbell shape azobenzene diradical and correlate its solid-state flexibility with spin relaxation and mobility. We employ a combination of X-ray diffraction and Raman spectroscopy to determine the molecular changes with temperature. Heating leads to: i) a modulation of the spin distribution; and ii) a “normal” quinoidal → aromatic transformation at low temperatures driven by the intramolecular rotational vibrations of the azobenzene core and a “reversed” aromatic → quinoidal change at high temperatures activated by an azobenzene bicycle pedal motion amplified by anisotropic intermolecular interactions. Thermal excitation of these vibrational states modulates the diradical electronic and spin structures featuring vibronic coupling mechanisms that might be relevant for future design of high spin organic molecules with tunable magnetic properties for solid state spintronics., In this manuscript, Negri, Zheng, Casado et al develop a stable and flexible diradical. Using a combination of experimental and theoretical techniques, they show how heating leads to change in the electronic and spin delocalizations ocurring between quinoidal and aromatic forms, and elucidate a unique spin-vibrational coupling.
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- 2021
7. Oligoene and cyanine features of tetracyano quinoidal oligothiophenes
- Author
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Keitaro Yamamoto, Sergio Moles Quintero, Yutaka Ie, José L. Zafra, Yoshio Aso, and Juan Casado
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Materials science ,Valence (chemistry) ,Spin states ,Diradical ,General Chemistry ,Electronic structure ,Oligoene ,Cyanine ,Espectroscopía ,Delocalized electron ,Dark state ,Chemical physics ,Excited state ,Tetracyano quinoidal oligothiophenes ,Physics::Atomic and Molecular Clusters ,Materials Chemistry ,Singlet state ,Physics::Chemical Physics - Abstract
This paper interprets a palette of spectroscopic data on tetracyano thienoquinoidal molecules of different sizes oriented towards the elucidation of their electronic behavior and other aspects of interest in materials chemistry. It also provides a contextualization of these properties between those of even oligoenes (carotene-like) and those of odd cyanines as a function of the reduction state. A complete UV-Vis-NIR electronic absorption, fluorescence emission and infrared spectroscopic study in part helped by quantum chemical calculations in the framework of the DFT theory has been carried out. The study encompasses the neutral and charged states. The optical properties of these compounds in the neutral state are controlled by the competition of bright (electric dipole–dipole allowed) and dark (electric dipole–dipole forbidden) singlet excited states. In the anionic state, the trimeric compounds disclose behaviors compatible with being either charge localized or delocalized mixed valence systems. Interestingly, we show the π-dimerization of a radical anion of a thienoquinoidal compound forming a π-dimer dianion as a manifestation of the delocalization of the charge in the charged monomer. The hexamer compound in the neutral state discloses incipient diradical character which permits the detection of a NIR emission band from the dark state at energies well below 1 eV. As thiophene benzo-annulation minimizes the diradical character, it forces the confinement of the charge in the vicinity of the terminal dicyanomethylene groups in the dianion. The oxidized species of the compounds have been also analyzed as models of charge localization states. The competition between doublet and quartet high spin states in the radical cations has been explored with the objective of visualizing potential molecules able to produce SOMO–HOMO energy inversion. (...) The authors thank the Spanish Ministry of Science, Innovation and Universities MCIU (PGC2018-098533-B-100 and RED2018-102815-T), and the Junta de Andalucı´a, Spain (UMA18FEDERJA057). We also thank the Research Central Services (SCAI) of the University of Málaga.
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- 2021
8. Normal & Reversed Spin Mobility in a Diradical By Electron-Vibration Coupling
- Author
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Yi Shen, Guodong Xue, Yasi Dai, Sergio Moles Quintero, Hanjiao Chen, Dongsheng Wang, Fang Miao, Fabrizia Negri, Yonghao Zheng, and Juan Casado Cordon
- Abstract
New insights on the mechanisms of spin relaxation and spin mobility in connection with the structural flexibility of π-conjugated radicals are fundamental solid-state issues in organic spintronics. Here, we describe a new azobenzene-based organic diradical with a dumbbell shape in the crystal and correlate its solid-state flexibility and its spin diradical structure. X-ray temperature-dependent studies were carried out showing two main effects on heating: i) modulation of the spin distribution and of the low-to-high spin magnetic transitions; and ii) “normal” quinoidal→aromatic transformation at low temperatures driven by the intramolecular rotational motions/mobility of the azobenzene core, and a “reversed” aromatic→quinoidal change at high temperatures activated by a bicycle pedal motion in the azobenzene unit amplified by anisotropic intermolecular interactions. Sequential versus simultaneous thermal excitation of the vibrational states associated to these motions reveal a unique and unprecedented spin-vibration mechanism.
- Published
- 2020
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