Artículos de revistas: "Valence (theoretical chemistry)"

1

McWeeney, Roy. "Theoretical chemistry: Back to the valence bond". Nature 323, n.º 6090 (octubre de 1986): 666–67. http://dx.doi.org/10.1038/323666a0.

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2

Kefalidis, Christos E., Alistair S. P. Frey, S. Mark Roe, F. Geoffrey N. Cloke y Laurent Maron. "Formation of cyanates in low-valent uranium chemistry: a synergistic experimental/theoretical study". Dalton Trans. 43, n.º 29 (2014): 11202–8. http://dx.doi.org/10.1039/c4dt00618f.

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3

Kolditz, L. "Transition Metal Chemistry — The Valence Shell in d-Block Chemistry". Zeitschrift für Physikalische Chemie 190, Part_2 (enero de 1995): 309–10. http://dx.doi.org/10.1524/zpch.1995.190.part_2.309a.

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4

Cao, Zexing, Wei Wu y Qianer Zhang. "Valence bond theoretical study for chemical reactivity". Science in China Series B: Chemistry 41, n.º 6 (diciembre de 1998): 660–69. http://dx.doi.org/10.1007/bf02883029.

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5

Chong, Delano P. "Theoretical study of the electronic spectra of s-triazine vapour". Canadian Journal of Chemistry 87, n.º 8 (agosto de 2009): 1148–53. http://dx.doi.org/10.1139/v09-084.

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The ionization and excitation spectra of valence and core electrons of s-triazine in the gas phase are studied with ab initio, density functional, and semi-empirical methods. The results are compared with available experimental data and previous calculations. New estimates are proposed for the ionization energies of both valence and core electrons. The calculated excitation energies are consistent with experiment.

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6

Himmel, Hans-Jörg. "Valence tautomerism in copper coordination chemistry". Inorganica Chimica Acta 481 (septiembre de 2018): 56–68. http://dx.doi.org/10.1016/j.ica.2017.07.069.

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7

Sleight, Arthur W. "Valency, valence degeneracy, ferroelectricity, and superconductivity". Progress in Solid State Chemistry 37, n.º 4 (diciembre de 2009): 251–61. http://dx.doi.org/10.1016/j.progsolidstchem.2010.08.001.

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8

Kosmas, Agnie Mylona. "Theoretical Investigation of Halogen-Oxygen Bonding and Its Implications in Halogen Chemistry and Reactivity". Bioinorganic Chemistry and Applications 2007 (2007): 1–9. http://dx.doi.org/10.1155/2007/46393.

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Trends in the properties of normal valent and multivalent halogen-oxygen bonding are examined for the isomers of the halogen polyoxide families of the types (YXO2) and (YXO3), Y=Cl, Br, I, H,CH3, X=Cl, Br, I. A qualitative model is formulated on the relationship between the X-O bond distance variations, the ionic character of the bonding, and the degree of halogen valence. The relative stability and enthalpy of formation of each species are also suggested to correlate with the ionic nature of the X-O bonding and the electrostatic character of the Y, YO fragments. In the model presented, halogen hypervalence is interpreted to be the result of partialp→dpromotion of lone-pair valence electrons followed by the formation of two, four, or six additional pd hybrid bonds around the halogen atom.

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9

Huzinaga, Sigeru. "1994 Polanyi Award Lecture Concept of active electrons in chemistry". Canadian Journal of Chemistry 73, n.º 5 (1 de mayo de 1995): 619–28. http://dx.doi.org/10.1139/v95-080.

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The notion of division between active and dormant electrons has been well received and widely used in the chemists' way of thinking. The core–valence separation in atoms is the best-known example. This paper describes a theoretical and computational method called the model potential method, which deals only with active electrons in molecular and solid state calculations. The method is capable of reaching computational accuracy of testing the validity of the separation of active and dormant electrons in individual cases. Keywords: separability of electrons, model potential method, valence orbitals, relativistic effects.

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10

Xu, Zijian, Jiaguang Han, Zhiyuan Zhu y Wei Zhang. "Valence ofD5hC50Fullerene". Journal of Physical Chemistry A 111, n.º 4 (febrero de 2007): 656–65. http://dx.doi.org/10.1021/jp064500b.

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11

Colman, Ross H., H. Esma Okur, Winfried Kockelmann, Craig M. Brown, Annette Sans, Claudia Felser, Martin Jansen y Kosmas Prassides. "Elusive Valence Transition in Mixed-Valence Sesquioxide Cs4O6". Inorganic Chemistry 58, n.º 21 (21 de octubre de 2019): 14532–41. http://dx.doi.org/10.1021/acs.inorgchem.9b02122.

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12

Glukhovtsev, M. N. y B. Ya Simkin. "Structure and valence isomerization of antiaromatic molecules XI. Theoretical investigation of the valence isomerizations of cyclobutadiyne". Journal of Structural Chemistry 28, n.º 6 (1988): 834–40. http://dx.doi.org/10.1007/bf00745252.

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13

Fabian, Jürgen y Peter Birner. "A theoretical study of the disulfide/dithione valence isomerism". Collection of Czechoslovak Chemical Communications 53, n.º 9 (1988): 2096–115. http://dx.doi.org/10.1135/cccc19882096.

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According to MNDO calculations on 1,2-dithiete (IIIa), 1,2-dithiin (IVa) and 3,4-dimethylene-1,2-dithiane (Va) the closed-ring compounds are thermodynamically more stable than the open-chain compounds whereas the reverse holds for 4-methylene-1,2-dithiole (VIa). Substitution of the exocyclic CH2 group of VIa by O, S, NH, and OH+ stabilizes its cyclic mesoionic structure. The low triplet state energy of VIa and of some derivatives relative to the lowest singlet state energy signalizes the biradicaloid nature of these electronic structures. Replacement of hydrogen of the methine groups adjacent to sulfur of III, IV, and VII by CH3, CF3, C6H5, CHO or CN results more or less in stabilization of the cyclic tautomer whereas donor substituents such as NH2, OCH3 or SCH3 act less uniformly but mostly in a destabilizing way. Contrary to former assumptions, there is no indication for a species intermediate between the disulfide and dithione structure that defines the molecular ground state. A relatively low ground state barrier separates the two isomeric structures although thermal isomerization of IIIa belongs to Woodward-Hoffmann forbidden concerted reactions (calculated activation energy for the ring opening of IIIa about 36 kcal/mol). The thermal and photochemical isomerization is discussed in terms of the change of the energy along the reaction path of the closed shell ground state (S0) and lowest energy excited states (S1, T1). The energies are obtained by MNDO, MNDO/2 x 2 CI, MNDO/HE, and MNDO/HE/3 x 3 CI calculations.

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14

Webb, Robert J., Paula M. Hagen, Richard J. Wittebort, Michio Sorai y David N. Hendrickson. "Valence detrapping in mixed-valence biferrocenes: evidence for phase transitions". Inorganic Chemistry 31, n.º 10 (mayo de 1992): 1791–801. http://dx.doi.org/10.1021/ic00036a015.

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15

He, Bing, Bingke Li y Hongwei Zhou. "Theoretical Study on Pyramidal C7N6–H3R3 Molecules". Australian Journal of Chemistry 72, n.º 7 (2019): 501. http://dx.doi.org/10.1071/ch19015.

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The pyramidal molecule C7N6H6 and its nine symmetric tri-substituted derivatives C7N6–H3R3 (R=OH, F, CN, N3, NH2, NO2, N=NH, N2H3, and C≡CH) were investigated computationally using the GAUSSIAN 09 program package. Natural bond orbital and atoms in molecules analyses, as well as valence bond theory were applied to investigate the bonding properties. In comparison to their well known analogues C6N7–R3, i.e. generic heptazines, it is found that these 10 molecules are all reactive. Further studies on the topological structures and ionization energy values indicate that the reactive site of the molecules is located at the carbon atom of the core frame. Even though C7N6–H3R3 are neutral molecules, the structures and properties of some are consistent with those of a carbanion, and indeed, they act like carbanions, or so-called carbanionoids. These carbanionoids may have an extensive impact in organic chemistry and organometallic chemistry.

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16

Hiberty, Philippe C. "Thinking and computing valence bond in organic chemistry". Journal of Molecular Structure: THEOCHEM 451, n.º 3 (octubre de 1998): 237–61. http://dx.doi.org/10.1016/s0166-1280(98)00208-5.

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17

Fillaux, Clara, Jean-Claude Berthet, Steven D. Conradson, Philippe Guilbaud, Dominique Guillaumont, C. Hennig, Philippe Moisy et al. "Combining theoretical chemistry and XANES multi-edge experiments to probe actinide valence states". Comptes Rendus Chimie 10, n.º 10-11 (octubre de 2007): 859–71. http://dx.doi.org/10.1016/j.crci.2006.12.012.

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18

A.H. "Valence bond theory and chemical structure. Studies in physical and theoretical chemistry 64". Journal of Molecular Structure: THEOCHEM 226, n.º 3-4 (enero de 1991): 358. http://dx.doi.org/10.1016/0166-1280(91)85015-y.

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19

Pan, Sudip y Gernot Frenking. "A Critical Look at Linus Pauling’s Influence on the Understanding of Chemical Bonding". Molecules 26, n.º 15 (3 de agosto de 2021): 4695. http://dx.doi.org/10.3390/molecules26154695.

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The influence of Linus Pauling on the understanding of chemical bonding is critically examined. Pauling deserves credit for presenting a connection between the quantum theoretical description of chemical bonding and Gilbert Lewis’s classical bonding model of localized electron pair bonds for a wide range of chemistry. Using the concept of resonance that he introduced, he was able to present a consistent description of chemical bonding for molecules, metals, and ionic crystals which was used by many chemists and subsequently found its way into chemistry textbooks. However, his one-sided restriction to the valence bond method and his rejection of the molecular orbital approach hindered further development of chemical bonding theory for a while and his close association of the heuristic Lewis binding model with the quantum chemical VB approach led to misleading ideas until today.

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20

Xiao, Cui-Ping, Wen-Zuo Li, Qing-Zhong Li y Jian-Bo Cheng. "Theoretical prediction on the structures of the HMgN- and HNMg- anions using multiconfigurational methods". Journal of the Serbian Chemical Society 79, n.º 2 (2014): 167–73. http://dx.doi.org/10.2298/jsc130412044x.

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The nine-valence-electron HMgN- and HNMg- anions have been investigated for the first time theoretically using CASSCF (complete active space self-consistent field) and CASPT2 (multiconfiguration second-order perturbation theory) methods in conjunction with the contracted atomic natural orbital (ANO) basis sets. The structures of the low-lying electronic states of HMgN- and HNMg- were predicted. The possible unimolecular conversions between HMgN- and HNMg-were discussed. The calculated results indicated that the ground-state of HMgN-is linear, while the ground-state HNMg- is bent, which is in contradiction to Walsh?s rules predicting linear structures for the HXY systems containing 10 or less valence electrons.

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21

Bockisch, F., J. C. Rayez, H. Dreeskamp, D. Liotard y B. Duguay. "Theoretical studies of [n]paracyclophanes and their valence isomers". Theoretica Chimica Acta 85, n.º 1-3 (marzo de 1993): 69–86. http://dx.doi.org/10.1007/bf01374578.

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22

Hu, Yong-Feng, G. Michael Bancroft, Kim H. Tan, John S. Tse y Dong-Sheng Yang. "Variable-energy photoelectron spectroscopy of CpM(CO)3 (M = Mn, Re) and CpFe(CO)2I". Canadian Journal of Chemistry 74, n.º 11 (1 de noviembre de 1996): 2240–49. http://dx.doi.org/10.1139/v96-252.

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Photoelectron spectra of the valence, inner-valence, and core levels of CpM(CO)3 (M = Mn, Re) and CpFe(CO)2I were obtained using He I radiation and synchrotron radiation between 21 eV and 150 eV photon energies. The high-resolution Mn 3p, Fe 3p, and I 4d core level spectra are reported. Broadening of the I 4d spectrum is due to vibrational and ligand field splittings. Observation of the 3p spectra is critical to fully interpreting the np → nd resonance effect in the valence band spectra. This resonance effect is very useful for assigning the metal d orbital bands in the valence spectra. A Xα-SW calculation of CpMn(CO)3 was used to confirm the assignment of the valence and inner-valence orbitals. The experimental and theoretical branching ratios are in good agreement. The general trend of the metal d orbital ionization potentials for CpML3 (M = transition metal) complexes is also discussed. Key words: photoelectron, synchrotron radiation, CpMn(CO)3, CpRe(CO)3, CpFe(CO)2I, np → nd resonance, Xα-SW calculation.

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23

Tomin, Vladimir I. "Opportunities to use interactive tasks in chemistry within the Middle Years Programme (basic school) of the International Baccalaureate". RUDN Journal of Informatization in Education 17, n.º 4 (15 de diciembre de 2020): 337–48. http://dx.doi.org/10.22363/2312-8631-2020-17-4-337-348.

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Problem and purpose. Information and communication technologies (ICT) are considered one of the most progressive and effective means of increasing interest in learning, as well as developing students in modern teaching methods. In Russia, the use of ICT and the development of its theoretical aspects in teaching chemistry under the Middle Years Programme (MYP, basic school) of the International Baccalaureate is at an embryonic level and, therefore, is a modern and very urgent problem of the education system within the framework of the International Baccalaureate. New methods and means based on the use of ICT in the educational process contribute to the growing interest in the study of chemistry. Increasing the level of independence in educational activities within the framework of working with ICT contributes to the formation of a competent, developed personality, teaches children to make adequate decisions, and motivates to improve self-preparation for lessons. Thanks to the continuous movement of modern education towards change and progress, there are more and more new developments and teaching aids that can be used in teaching chemistry. All this contributes to the creation and maintenance of a stable interest in educational processes, both in the independent search and solution of problems, and at school in the classroom. Often, the generally accepted approaches to the study of the topic of valence, existing today, do not give the desired and desired results. And the insufficient assimilation of this topic by students leads to a deterioration in academic performance in the further paragraphs of the chemistry course of the basic school curriculum. In the MYP (basic school), the study of the topic Valence is replaced by an explanation of the concepts of electronegativity and oxidation state, which leads to the loss of one of the fundamental concepts in chemistry. That fact defines the problem of the article. The purpose of the article is to describe approaches to increasing the interest and attention of students in the context of the use of innovative interactive technologies. Methodology. The methodological basis was the scientific and methodological works of A.K. Akhlebinin, N.P. Bezrukova, G. Vern, L.S. Vygotsky, P.Ya. Galperin, S.A. Gerus, A.A. Zhurin, V.V. Zagorsky, L. S. Zaznobina, O.S. Zaitsev, M.V. Zueva, R.G. Ivanova, N.E. Kuznetsova, G.Ya. Lastushkina, T.S. Nazarova, E.I. Mashbitsa, E.S. Polat, L.F. Pleukhova, I.V. Robert, T.A. Sergeeva, N.F. Talyzina, S.G. Chaikova, G.M. Chernobelskaya, L.L. Chunikhina, M. Shanon. Results. The expediency of using interactive tasks in chemistry (on the example of the topic Valence) in teaching schoolchildren under the MYP has been substantiated by increasing the general level of academic performance on this topic, as well as interest in chemistry lessons. Approaches to the selection of content (on the example of the topic Valence) for the creation of interactive tasks, including scientific, systematic, age-appropriate, are determined. A system of interactive tasks for studying the topic Valence under the MYP was developed and tested, which contains teaching materials for preparing students on the specified topic, including the theoretical part and analysis of examples. Conclusion. The results allowed to conclude that the creation and use of a specially prepared system of interactive tasks in chemistry (using the example of the Valence topic) for the MYP leads to a significant simplification of the study of this topic and an increase in the level of intrinsic motivation to study chemistry.

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24

Chen, Zhenhua, Jinshuai Song, Sason Shaik, Philippe C. Hiberty y Wei Wu. "Valence Bond Perturbation Theory. A Valence Bond Method That Incorporates Perturbation Theory†". Journal of Physical Chemistry A 113, n.º 43 (29 de octubre de 2009): 11560–69. http://dx.doi.org/10.1021/jp903011j.

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25

Hermosilla-Ibáñez, Patricio, Kerry Wrighton-Araneda, Laura Scarpetta-Pizo, Walter Cañón-Mancisidor, Marlen Gutierrez-Cutiño, Eric Le Fur, Verónica Paredes-García y Diego Venegas-Yazigi. "The origin of the electronic transitions of mixed valence polyoxovanadoborates [V12B18O60]: from an experimental to a theoretical understanding". New Journal of Chemistry 43, n.º 45 (2019): 17538–47. http://dx.doi.org/10.1039/c9nj02549a.

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26

Ehara, Masahiro, Mayumi Ishida y Hiroshi Nakatsuji. "Theoretical Fine Spectroscopy with SAC-CI Method: Outer- and Inner-Valence Ionization Spectra of CO and N2". Collection of Czechoslovak Chemical Communications 70, n.º 7 (2005): 881–904. http://dx.doi.org/10.1135/cccc20050881.

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Outer- and inner-valence ionization spectra of CO and N2 were studied by the SAC-CI (symmetry-adapted-cluster configuration-interaction) general-R method. Fine details of experimental spectra of these molecules were reproduced and quantitative assignments of the peaks were proposed. Both outer- and inner-valence satellites were classified into the shake-up states including the valence or Rydberg excitations. For CO, theoretical satellite spectrum up to 50 eV was presented and the nine bands of 22-50 eV observed by EMS and eight bands of 22-34 eV by XPS (C-K) were characterized in detail. Numerous satellite peaks with distributed intensity were obtained and some of them, especially for bands 4, 5, 6 and 7, were predominantly described by triple-electron processes. For N2, the spectrum up to 45 eV was calculated and the complex satellite peaks observed by XPS in the lower energy region 20-33 eV were interpreted. The detailed assignments for the (2σg-1) satellite states in the higher-energy region 33-45 eV were also presented.

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27

Qiu, Rulin y Jun Zhu. "Adaptive aromaticity in 16-valence-electron metallazapentalenes". Dalton Transactions 50, n.º 45 (2021): 16842–48. http://dx.doi.org/10.1039/d1dt03244e.

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Theoretical studies reveal that metallazapentalenes display rare adaptive aromaticity (being aromatic in both the S0 and T1 states) whereas metalloxapentalenes exhibit nonaromaticity in these two states, expanding the family of adaptive aromatics.

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28

Bock, Charles W., Philip George, John J. Stezowski y Jenny P. Glusker. "Theoretical studies of the benzene oxide?oxepin valence tautomerism". Structural Chemistry 1, n.º 1 (enero de 1990): 33–39. http://dx.doi.org/10.1007/bf00675782.

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29

Jansen, Helen, J. Chris Slootweg, Andreas W. Ehlers y Koop Lammertsma. "Valence Isomerization of Phosphepines†". Organometallics 29, n.º 24 (27 de diciembre de 2010): 6653–59. http://dx.doi.org/10.1021/om1004379.

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30

Grekov, F. F. "Structure of valence crystals". Journal of Structural Chemistry 27, n.º 1 (1986): 87–91. http://dx.doi.org/10.1007/bf00763574.

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31

Koropchanu, V. P., M. E. Guerrero y V. Ya Gamurar'. "Group-theoretical classification of the resonance states of mixed-valence clusters". Journal of Structural Chemistry 36, n.º 4 (julio de 1995): 673–77. http://dx.doi.org/10.1007/bf02578663.

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32

Wan, Hongliu, Xing-Wu Liu, Ming Qing, Jin-Jia Liu, Yu Zhang, Suyao Liu, Hong Wang, Xiao-Dong Wen, Yong Yang y Yong-Wang Li. "Insight into the magnetic moment of iron borides: theoretical consideration from the local coordinative and electronic environment". Dalton Transactions 49, n.º 7 (2020): 2168–75. http://dx.doi.org/10.1039/c9dt04193a.

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33

Zhang, Feng-Yu, Sicheng Liu, Anwei Huang, Yi-Ning Li, Xiao-Yan Liu y Peng Zhang. "A Theoretical Analysis of the Differential Chemical Reaction Results Caused by Chirality Induction". Molecules 28, n.º 17 (28 de agosto de 2023): 6286. http://dx.doi.org/10.3390/molecules28176286.

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The theory of electron spin has been proposed for a century, but the study of quantum effects in biological molecules is still in its infancy. Chirality-induced spin selectivity (CISS) is a very modern theory that can explain many biochemical phenomena. In this paper, we propose a new theoretical model based on CISS theory and quantum chemistry theory, which can well explain the theoretical explanation of the chiral selectivity of chiral proteins. Moreover, this theory can predict the spin state of corresponding chiral molecules. Taking the L-DOPA and AADC enzymes as examples, this theoretical model elucidates the AADC enzyme’s chiral catalysis selectivity and successfully predicts the spin state of L-DOPA and D-DOPA’s valence electrons.

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34

Nakashima, Satoru, Masahiro Kai y Masanobu Watanabe. "Intermediate mixed-valence state between the valence-trapped and valence-detrapped states in 1′,1‴-bis(3-phenylpropyl)-1,1″-biferrocenium triiodide". Inorganic Chemistry Communications 2, n.º 8 (agosto de 1999): 341–43. http://dx.doi.org/10.1016/s1387-7003(99)00082-9.

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35

Büchler, Stefan, René Monnier, Leo Degiorgi y Louis Schlapbach. "Valence Transition in Yb Hydrides*". Zeitschrift für Physikalische Chemie 163, Part_2 (enero de 1989): 579–84. http://dx.doi.org/10.1524/zpch.1989.163.part_2.0579.

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36

Cooper, D. L., J. Gerratt y M. Raimondi. "Spin-coupled valence bond theory". International Reviews in Physical Chemistry 7, n.º 1 (enero de 1988): 59–80. http://dx.doi.org/10.1080/01442358809353205.

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37

Hiberty, Philippe C. y Sason Shaik. "Breathing-orbital valence bond method - a modern valence bond method that includes dynamic correlation". Theoretical Chemistry Accounts: Theory, Computation, and Modeling (Theoretica Chimica Acta) 108, n.º 5 (1 de noviembre de 2002): 255–72. http://dx.doi.org/10.1007/s00214-002-0364-8.

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38

Rzepiela, Kacper, Jakub Kaminský, Aneta Buczek, Małgorzata A. Broda y Teobald Kupka. "Electron Correlation or Basis Set Quality: How to Obtain Converged and Accurate NMR Shieldings for the Third-Row Elements?" Molecules 27, n.º 23 (25 de noviembre de 2022): 8230. http://dx.doi.org/10.3390/molecules27238230.

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The quality of theoretical NMR shieldings calculated at the quantum-chemical level depends on various theoretical aspects, of which the basis set type and size are among the most important factors. Nevertheless, not much information is available on the basis set effect on theoretical shieldings of the NMR-active nuclei of the third row. Here, we report on the importance of proper basis set selection to obtain accurate and reliable NMR shielding parameters for nuclei from the third row of the periodic table. All calculations were performed on a set of eleven compounds containing the elements Na, Mg, Al, Si, P, S, or Cl. NMR shielding tensors were calculated using the SCF-HF, DFT-B3LYP, and CCSD(T) methods, combined with the Dunning valence aug-cc-pVXZ, core-valence aug-cc-pCVXZ, Jensen polarized-convergent aug-pcSseg-n and Karlsruhe x2c-Def2 basis set families. We also estimated the complete basis set limit (CBS) values of the NMR parameters. Widely scattered nuclear shieldings were observed for the Dunning polarized-valence basis set, which provides irregular convergence. We show that the use of Dunning core-valence or Jensen basis sets effectively reduces the scatter of theoretical NMR results and leads to their exponential-like convergence to CBS. We also assessed the effect of vibrational, temperature, and relativistic corrections on the predicted shieldings. For systems with single bonds, all corrections are relatively small, amounting to less than 4% of the CCSD(T)/CBS value. Vibrational and temperature corrections were less reliable for H3PO and HSiCH due to the high anharmonicity of the molecules. An abnormally high relativistic correction was observed for phosphorus in PN, reaching ~20% of the CCSD(T)/CBS value, while the correction was less than 7% for other tested molecules.

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39

Biasin, Elisa, Daniel R. Nascimento, Benjamin I. Poulter, Baxter Abraham, Kristjan Kunnus, Angel T. Garcia-Esparza, Stanislaw H. Nowak et al. "Revealing the bonding of solvated Ru complexes with valence-to-core resonant inelastic X-ray scattering". Chemical Science 12, n.º 10 (2021): 3713–25. http://dx.doi.org/10.1039/d0sc06227h.

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40

Harcourt, Richard D. "Pseudo one-electron bonds and atomic valencies for some increased-valence and non-paired spatial orbital valence bond structures". Journal of Molecular Structure: THEOCHEM 684, n.º 1-3 (septiembre de 2004): 167–69. http://dx.doi.org/10.1016/j.theochem.2004.04.068.

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41

Barresi, Elisabetta, Iogann Tolbatov, Alessandro Pratesi, Valentina Notarstefano, Emma Baglini, Simona Daniele, Sabrina Taliani et al. "A mixed-valence diruthenium(ii,iii) complex endowed with high stability: from experimental evidence to theoretical interpretation". Dalton Transactions 49, n.º 41 (2020): 14520–27. http://dx.doi.org/10.1039/d0dt02527e.

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42

Kochetov, Vladislav, Md Sabbir Ahsan, Dennis Hein, Iain Wilkinson y Sergey I. Bokarev. "Valence and Core Photoelectron Spectra of Aqueous I3− from Multi-Reference Quantum Chemistry". Molecules 28, n.º 14 (10 de julio de 2023): 5319. http://dx.doi.org/10.3390/molecules28145319.

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The I3− molecule is known to undergo substantial structural reorganization upon solvation by a protic solvent, e.g., water. However, the details of this process are still controversially discussed in the literature. In the present study, we combined experimental and theoretical efforts to disentangle this controversy. The valence (5p), N4,5 (4d), and M4,5 (3d) edge photoelectron spectra were measured in an aqueous solution and computed using high-level multi-reference methods. Our previous publication mainly focused on obtaining reliable experimental evidence, whereas in the present article, we focused primarily on theoretical aspects. The complex electronic structure of I3− requires the inclusion of both static and dynamic correlation, e.g., via the multi-configurational perturbation theory treatment. However, the resulting photoelectron spectra appear to be very sensitive to problems with variational stability and intruder states. We attempted to obtain artifact-free spectra, allowing for a more reliable interpretation of experiments. Finally, we concluded that the 3d Photoelectron Spectrum (PES) is particularly informative, evidencing an almost linear structure with a smaller degree of bond asymmetry than previously reported.

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Orti, Enrique y Jean Luc Bredas. "Photoelectron spectra of phthalocyanine thin films: a valence band theoretical interpretation". Journal of the American Chemical Society 114, n.º 22 (octubre de 1992): 8669–75. http://dx.doi.org/10.1021/ja00048a046.

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Levi, Elena, Doron Aurbach y Carlo Gatti. "Metal–Metal Bond in the Light of Pauling’s Rules". Molecules 26, n.º 2 (8 de enero de 2021): 304. http://dx.doi.org/10.3390/molecules26020304.

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About 70 years ago, in the framework of his theory of chemical bonding, Pauling proposed an empirical correlation between the bond valences (or effective bond orders (BOs)) and the bond lengths. Till now, this simple correlation, basic in the bond valence model (BVM), is widely used in crystal chemistry, but it was considered irrelevant for metal–metal bonds. An extensive analysis of the quantum chemistry data computed in the last years confirms very well the validity of Pauling’s correlation for both localized and delocalized interactions. This paper briefly summarizes advances in the application of the BVM for compounds with TM–TM bonds (TM = transition metal) and provides further convincing examples. In particular, the BVM model allows for very simple but precise calculations of the effective BOs of the TM–TM interactions. Based on the comparison between formal and effective BOs, we can easily describe steric and electrostatic effects. A possible influence of these effects on materials stability is discussed.

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45

Umam, Kholid Khairul y Dwi Wahyudiati. "Ethno-chemistry: Relevance Analysis of Electron Valence Subject Material to Sasak Local Wisdom as a Chemistry Learning Resource". Hydrogen: Jurnal Kependidikan Kimia 11, n.º 5 (16 de octubre de 2023): 710. http://dx.doi.org/10.33394/hjkk.v11i5.9069.

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The lack of learning resources in the form of teaching materials is one of the problems found in the chemistry learning process, both within the scope of high schools and universities so that the development of contextual teaching materials is very important to do as an implementation of the ethno-chemistry approach in education. The purpose of this research is to explore and reveal the wisdom or local wisdom of the Sasak community, which is developed into teaching materials. This research approach uses a qualitative approach with data collection techniques using interviews, literature studies and documentation methods. A qualitative research approach with interview techniques, literature studies, and documentation methods was used to collect information in the form of individual views, theoretical understandings, and historical data related to the research topic, with the aim of gaining in-depth insights, contextual understanding, and theoretical support needed in the analysis and explanation of the phenomenon under study. The data obtained Analyze by Miles and Huberman qualitative analysis. Research subjects include community leaders, chemical content experts, and reading books relevant to the research. Based on the research findings. It is concluded that Sasak Begibung Culture can be used as a source of learning chemistry through integrating Sasak Begibung culture with valence electron material. Thus, the implementation of this research can be used as a reference in the development of contextualized chemistry teaching materials so that lessons become more meaningful and effective.

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Abu-Eittah, R. H., M. El-Esawy, N. Ghoneim y A. T. Aly. "A comparative theoretical study of the electronic structure of some nickel(II) azides, thiocyanates, and isothiocyanates". Canadian Journal of Chemistry 76, n.º 7 (1 de julio de 1998): 1006–14. http://dx.doi.org/10.1139/v98-109.

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The electronic structure, conformation, and molecular orbitals of some nickel(II) azides, thiocyanates, and isothiocyanates have been studied. Three different basis sets: split valence (SV), split valence with six d-Gaussians (SV6D), and double zeta (DZ) sets, were used to find the best ground state for nickel. It has been found that the combination, DZ-3F, gives results closest to the experimental values. The electronic structures of the nickel azides studied were completely different from those of the nickel thiocyanates. On the other hand, the electronic structures of the nickel thiocyanates studied were highly comparable to those of the corresponding nickel isothiocyanates. Molecular orbitals were computed for the complexes studied and the types of electronic transitions expected were identified and discussed.Key words: Ni(II) azides, thiocyanates, and isothiocyanates: ab initio SCF calculations; MO calculations on some Ni(II) complexes; theoretical treatment of some Ni(II) ions and salts; geometry and energetics of some nickel(II) azides, thiocyanates, and isothiocyanates.

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47

Roos, A. Hult, J. H. D. Eland, J. Andersson, R. J. Squibb y R. Feifel. "Dissociations of water ions after valence and inner-valence ionization". Journal of Chemical Physics 149, n.º 20 (28 de noviembre de 2018): 204307. http://dx.doi.org/10.1063/1.5055593.

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48

Richa, Muni Rathnam, Akhilesh Kumar, Indresh Verma, Julia Kłak, Joan Cano, Antonio J. Mota, Amit Rajput y Himanshu Arora. "Discrete unusual mixed-bridged trinuclear CoIII2CoII and pentanuclear NiII coordination complexes supported by a phenolate-based ligand: theoretical and experimental magneto-structural study". New Journal of Chemistry 45, n.º 13 (2021): 6053–66. http://dx.doi.org/10.1039/d1nj00228g.

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49

McCusker, James K., Ho G. Jang, Maruta Zvagulis, Walter Ley, Harry G. Drickamer y David N. Hendrickson. "Valence trapping of mixed-valence solvated hexakis(acetato)oxotris(pyridine)triiron complex at high pressure". Inorganic Chemistry 30, n.º 9 (mayo de 1991): 1985–90. http://dx.doi.org/10.1021/ic00009a009.

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50

Mangione, Giulia, Silvia Carlotto, Mauro Sambi, Giovanni Ligorio, Melanie Timpel, Andrea Vittadini, Marco Vittorio Nardi y Maurizio Casarin. "Electronic structures of CuTPP and CuTPP(F) complexes. A combined experimental and theoretical study I". Physical Chemistry Chemical Physics 18, n.º 28 (2016): 18727–38. http://dx.doi.org/10.1039/c6cp01423b.

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