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Kundu G, Dash SR, Kumar R, Vanka K, Ghosh A, Sen SS. Enhancing Diradical Character of Chichibabin's Hydrocarbon through Fluoride Substitution. Chempluschem 2023; 88:e202300273. [PMID: 37409641 DOI: 10.1002/cplu.202300273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/04/2023] [Accepted: 07/06/2023] [Indexed: 07/07/2023]
Abstract
In this work, 5-SIDipp [SIDipp=1,3-bis(2,6-diisopropylphenyl)-imidazolin-2-ylidene] (1) derived Chichibabin's hydrocarbon with an octafluorobiphenylene spacer (3) has been reported. The addition of two equivalents of 5-SIDipp with decafluorobiphenyl in presence of BF3 gives the double C-F bond activated imidazolium salt with two tetrafluoroborate anions, 2. Further reduction of 2 gives the fluorine substituted 5-SIDipp based Chichibabin's hydrocarbon, 3. Quantum chemical calculations suggested a singlet state of 3 with a singlet-triplet energy gap (ΔES-T ) of 3.7 kcal mol-1 , which is substantially lower with respect to the hydrogen substituted NHC-based Chichibabin's hydrocarbons (10.7 kcal mol-1 , B3LYP). As a result, the diradical character (y) of 3 (y=0.62) is also noticeably higher than the hydrogen substituted CHs (y=0.41-0.43). The ▵ES-T was found to be higher in CASSCF (22.24 kcal mol-1 ) and CASPT2 (11.17 kcal mol-1 ) for 3 and the diradical character (d) is 44.6 %.
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Affiliation(s)
- Gargi Kundu
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road Pashan, Pune, 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Soumya Ranjan Dash
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road Pashan, Pune, 411008, India
| | - Ravi Kumar
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road Pashan, Pune, 411008, India
| | - Kumar Vanka
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road Pashan, Pune, 411008, India
| | - Aryya Ghosh
- Department of Chemistry, Ashoka University, Sonipat, Haryana, 131029, India
| | - Sakya S Sen
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road Pashan, Pune, 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
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Dai Y, Xie Z, Bao M, Liu C, Su Y. Multiple stable redox states and tunable ground states via the marriage of viologens and Chichibabin's hydrocarbon †. Chem Sci 2023; 14:3548-3553. [PMID: 37006684 PMCID: PMC10056129 DOI: 10.1039/d3sc00102d] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 02/28/2023] [Indexed: 03/30/2023] Open
Abstract
Chichibabin's hydrocarbon and viologens are among the most famous diradicaloids and organic redox systems, respectively. However, each has its own disadvantages: the instability of the former and its charged species, and the closed-shell nature of the neutral species derived from the latter, respectively. Herein, we report that terminal borylation and central distortion of 4,4′-bipyridine allow us to readily isolate the first bis-BN-based analogues (1 and 2) of Chichibabin's hydrocarbon with three stable redox states and tunable ground states. Electrochemically, both compounds exhibit two reversible oxidation processes with wide redox ranges. One- and two-electron chemical oxidations of 1 afford the crystalline radical cation 1˙+ and dication 12+, respectively. Moreover, the ground states of 1 and 2 are tunable with 1 as a closed-shell singlet and the tetramethyl-substituted 2 as an open-shell singlet, the latter of which could be thermally excited to its triplet state because of the small singlet-triplet gap. Herein, we report the isolation of bis-BN-based species 1 and 2 with multiple stable redox states. Their ground states are tunable with 1 as a closed-shell singlet and 2 as an open-shell singlet with a small singlet-triplet gap.![]()
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Affiliation(s)
- Yuyang Dai
- College of Chemistry, Chemical Engineering and Materials Science, School of Radiation Medicine and Protection, Soochow UniversitySuzhou 215123China
| | - Zhuofeng Xie
- College of Chemistry, Chemical Engineering and Materials Science, School of Radiation Medicine and Protection, Soochow UniversitySuzhou 215123China
| | - Manling Bao
- College of Chemistry, Chemical Engineering and Materials Science, School of Radiation Medicine and Protection, Soochow UniversitySuzhou 215123China
| | - Chunmeng Liu
- College of Chemistry, Chemical Engineering and Materials Science, School of Radiation Medicine and Protection, Soochow UniversitySuzhou 215123China
| | - Yuanting Su
- College of Chemistry, Chemical Engineering and Materials Science, School of Radiation Medicine and Protection, Soochow UniversitySuzhou 215123China
- State Key Laboratory of Coordination Chemistry, Nanjing UniversityNanjing 210023China
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3
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Mao L, Zhou M, Shi X, Yang HB. Triphenylamine (TPA) radical cations and related macrocycles. CHINESE CHEM LETT 2021. [DOI: 10.1016/j.cclet.2021.05.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Murata T, Yamamoto Y, Ueda A, Ise T, Shiomi D, Sato K, Takui T, Morita Y. Synthesis and Physical Properties of Trioxotriangulene Having Methoxy and Hydroxy Groups at α-Positions: Electronic and Steric Effects of Substituent Groups and Intramolecular Hydrogen Bonds. J Org Chem 2021; 86:10154-10165. [PMID: 34282916 DOI: 10.1021/acs.joc.1c00880] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
New 4,8,12-trioxotriangulene (TOT) neutral radical derivatives having three methoxy and hydroxy groups at the α-positions were synthesized, and the substituent effects on the electronic spin and redox properties were elucidated in the theoretical and experimental methods. Due to the small SOMO coefficients at the α-positions of TOT, the methoxy groups in the TOT neutral radical had negligible effects on the electronic spin structure and redox ability. On the other hand, methoxy groups greatly increased the LUMO energy having large coefficients at α-positions and, thus, caused a remarkable negative-potential shift of the redox wave of anion species involving the dianion and trianion species. Converting the methoxy groups to hydroxy groups caused a dramatic change in the electronic structure of TOT, where the intramolecular hydrogen bonds between hydroxy groups and oxo groups strongly attracted a minus charge on the TOT skeleton. The HOMO energy of the monoanion species was significantly reduced, causing a blue shift of the HOMO-LUMO transition and an anodic shift of the redox potential. In addition, due to the steric repulsion smaller than that of the methoxy group, the hydroxy derivative showed a more planar molecular structure and a strong π-stacking ability.
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Affiliation(s)
- Tsuyoshi Murata
- Department of Applied Chemistry, Faculty of Engineering, Aichi Institute of Technology,1247 Yachigusa, Yakusa, Toyota, Aichi 470-0392, Japan
| | - Yosuke Yamamoto
- Department of Chemistry, Graduate School of Science, Osaka University, Machikaneyama 1-1, Toyonaka, Osaka 560-0043, Japan
| | - Akira Ueda
- Department of Chemistry, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan
| | - Tomoaki Ise
- Department of Chemistry and Molecular Materials Science, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan
| | - Daisuke Shiomi
- Department of Chemistry and Molecular Materials Science, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan
| | - Kazunobu Sato
- Department of Chemistry and Molecular Materials Science, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan
| | - Takeji Takui
- Department of Chemistry and Molecular Materials Science, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan
| | - Yasushi Morita
- Department of Applied Chemistry, Faculty of Engineering, Aichi Institute of Technology,1247 Yachigusa, Yakusa, Toyota, Aichi 470-0392, Japan
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Miyazawa Y, Wang Z, Matsumoto M, Hatano S, Antol I, Kayahara E, Yamago S, Abe M. 1,3-Diradicals Embedded in Curved Paraphenylene Units: Singlet versus Triplet State and In-Plane Aromaticity. J Am Chem Soc 2021; 143:7426-7439. [PMID: 33900091 DOI: 10.1021/jacs.1c01329] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Curved π-conjugated molecules and open-shell structures have attracted much attention from the perspective of fundamental chemistry, as well as materials science. In this study, the chemistry of 1,3-diradicals (DRs) embedded in curved cycloparaphenylene (CPPs) structures, DR-(n+3)CPPs (n = 0-5), was investigated to understand the effects of the curvature and system size on the spin-spin interactions and singlet versus triplet state, as well as their unique characteristics such as in-plane aromaticity. A triplet ground state was predicted for the larger 1,3-diradicals, such as the seven- and eight-paraphenylene-unit-containing diradicals DR-7CPP (n = 4) and DR-8CPP (n = 5), by quantum chemical calculations. The smaller-sized diradicals DR-(n+3)CPPs (n = 0-3) were found to possess singlet ground states. Thus, the ground-state spin multiplicity is controlled by the size of the paraphenylene cycle. The size effect on the ground-state spin multiplicity was confirmed by the experimental generation of DR-6CPP in the photochemical denitrogenation of its azo-containing precursor (AZ-6CPP). Intriguingly, a unique type of in-plane aromaticity emerged in the smaller-sized singlet states such as S-DR-4CPP (n = 1), as proven by nucleus-independent chemical shift calculations (NICS) and an analysis of the anisotropy of the induced current density (ACID), which demonstrate that homoconjugation between the 1,3-diradical moiety arises because of the curved and distorted bonding system.
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Affiliation(s)
- Yuki Miyazawa
- Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Zhe Wang
- Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Misaki Matsumoto
- Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Sayaka Hatano
- Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Ivana Antol
- Laboratory for Physical Organic Chemistry, Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Eiichi Kayahara
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Shigeru Yamago
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Manabu Abe
- Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
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Akisaka R, Ohga Y, Abe M. Dynamic solvent effects in radical-radical coupling reactions: an almost bottleable localised singlet diradical. Phys Chem Chem Phys 2020; 22:27949-27954. [PMID: 33184617 DOI: 10.1039/d0cp05235c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Localised singlet diradicals are key intermediates in bond homolysis, which plays a crucial role in chemical reactions. However, thorough experimental analyses of the reaction dynamics and chemical properties are generally difficult because bond formation is rapid, even under low-temperature matrix conditions. In this study, the effects of solvent and pressure on the lifetimes of long-lived singlet diradicals with bulky substituents were investigated. The solvent dynamic effect was revealed to provide control over the rate constant of radical-radical coupling reactions, and an almost bottleable singlet diradical with a lifetime of ∼2 s at 293 K was obtained.
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Affiliation(s)
- Rikuo Akisaka
- Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
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Escayola S, Callís M, Poater A, Solà M. Effect of Exocyclic Substituents and π-System Length on the Electronic Structure of Chichibabin Diradical(oid)s. ACS OMEGA 2019; 4:10845-10853. [PMID: 31460182 PMCID: PMC6648453 DOI: 10.1021/acsomega.9b00916] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 06/03/2019] [Indexed: 06/10/2023]
Abstract
The ground state (GS) of Chichibabin's polycyclic hydrocarbons (CPHs) can be singlet [open- or closed-shell (OSS or CS)] or triplet (T), depending on the elongation of the π-system and the exocyclic substituents. CPHs with either a small singlet-triplet energy gap (ΔE ST) or even a triplet GS have potential applications in optoelectronics. To analyze the effect of the size and exocyclic substituents on the nature of the GS of CPHs, we have selected a number of them with different substituents in the exocyclic carbon atoms and different ring chain lengths. The OPBE/cc-pVTZ level of theory was used for the optimization of the systems. The aromaticity of the resulting electronic structures was evaluated with HOMA, NICS, FLU, PDI, Iring, and MCI aromaticity indices. Our results show that the shortest π-systems (one or two rings) have a singlet GS. However, systems with three to five rings favor OSS GSs. Electron-withdrawing groups (EWGs) and aromatic substituents in the exocyclic carbons tend to stabilize the OSS and T states, whereas electron-donating groups slightly destabilize them. For CS, OSS, and T states, aromaticity measures indicate a gain of aromaticity of the 6-membered rings of the CPHs with the increase in their size and when CPHs incorporate EWGs or aromatic substituents. In general, the CPHs analyzed present small singlet-triplet energy gaps, and in particular, the ones containing EWGs or aromatic substituents present the smallest singlet-triplet energy gaps.
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Affiliation(s)
- Sílvia Escayola
- Institut de Química
Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/Maria Aurèlia Capmany, 69, 17003 Girona, Catalonia, Spain
| | - Marc Callís
- Institut de Química
Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/Maria Aurèlia Capmany, 69, 17003 Girona, Catalonia, Spain
| | - Albert Poater
- Institut de Química
Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/Maria Aurèlia Capmany, 69, 17003 Girona, Catalonia, Spain
| | - Miquel Solà
- Institut de Química
Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/Maria Aurèlia Capmany, 69, 17003 Girona, Catalonia, Spain
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Majewski MA, Chmielewski PJ, Chien A, Hong Y, Lis T, Witwicki M, Kim D, Zimmerman PM, Stępień M. 5,10-Dimesityldiindeno[1,2- a:2',1'- i]phenanthrene: a stable biradicaloid derived from Chichibabin's hydrocarbon. Chem Sci 2019; 10:3413-3420. [PMID: 30996930 PMCID: PMC6429611 DOI: 10.1039/c9sc00170k] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 02/05/2019] [Indexed: 11/21/2022] Open
Abstract
A diindenophenanthrene biradicaloid, formally derived from Chichibabin's hydrocarbon, is obtained in a short, scalable synthesis.
A diindenophenanthrene biradicaloid, formally derived from Chichibabin's hydrocarbon, is obtained in a short, scalable synthesis. The present system is electron-rich and devoid of conjugated substituents, and still exhibits very good stability under ambient conditions. The introduction of the diindeno[1,2-a:2′,1′-i] phenanthrene ring framework results in a singlet biradicaloid system with an easily accessible triplet state (ΔES–T = –1.30 kcal mol–1) and a small electronic bandgap (1.39 V). The stability limits of the title hydrocarbon were explored systematically in the solid state, to reveal an unusual thermally initiated hydrogen-scrambling oligomerization process.
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Affiliation(s)
- Marcin A Majewski
- Wydział Chemii , Uniwersytet Wrocławski , ul. F. Joliot-Curie 14 , 50-383 Wrocław , Poland . ; http://www.mstepien.edu.pl
| | - Piotr J Chmielewski
- Wydział Chemii , Uniwersytet Wrocławski , ul. F. Joliot-Curie 14 , 50-383 Wrocław , Poland . ; http://www.mstepien.edu.pl
| | - Alan Chien
- Department of Chemistry , University of Michigan , 930 N. University Ave , Ann Arbor , MI 48109 , USA .
| | - Yongseok Hong
- Department of Chemistry , Yonsei University , 50 Yonsei-ro , Seoul 120-749 , Korea .
| | - Tadeusz Lis
- Wydział Chemii , Uniwersytet Wrocławski , ul. F. Joliot-Curie 14 , 50-383 Wrocław , Poland . ; http://www.mstepien.edu.pl
| | - Maciej Witwicki
- Wydział Chemii , Uniwersytet Wrocławski , ul. F. Joliot-Curie 14 , 50-383 Wrocław , Poland . ; http://www.mstepien.edu.pl
| | - Dongho Kim
- Department of Chemistry , Yonsei University , 50 Yonsei-ro , Seoul 120-749 , Korea .
| | - Paul M Zimmerman
- Department of Chemistry , University of Michigan , 930 N. University Ave , Ann Arbor , MI 48109 , USA .
| | - Marcin Stępień
- Wydział Chemii , Uniwersytet Wrocławski , ul. F. Joliot-Curie 14 , 50-383 Wrocław , Poland . ; http://www.mstepien.edu.pl
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Synthesis and structural characterization of some novel methoxyamino derivatives with acid-base and redox behavior. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2018.06.114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Messelberger J, Grünwald A, Pinter P, Hansmann MM, Munz D. Carbene derived diradicaloids - building blocks for singlet fission? Chem Sci 2018; 9:6107-6117. [PMID: 30090299 PMCID: PMC6053972 DOI: 10.1039/c8sc01999a] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 06/25/2018] [Indexed: 12/13/2022] Open
Abstract
Organic singlet diradicaloids promise application in non-linear optics, electronic devices and singlet fission. The stabilization of carbon allotropes/cumulenes (C1, C2, C4) by carbenes has been equally an area of high activity. Combining these fields, we showed recently that carbene scaffolds allow as well for the design of diradicaloids. Herein, we report a comprehensive computational investigation (CASSCF/NEVPT2; fractional occupation DFT) on the electronic properties of carbene-bridge-carbene type diradicaloids. We delineate how to adjust the properties of these ensembles through the choice of carbene and bridge and show that already a short C2 bridge results in remarkable diradicaloid character. The choice of the carbene separately tunes the energies of the S1 and T1 excited states, whereas the bridge adjusts the overall energy level of the excited states. Accordingly, we develop guidelines on how to tailor the electronic properties of these molecules. Of particular note, fractional occupation DFT is an excellent tool to predict singlet-triplet gaps.
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Affiliation(s)
- Julian Messelberger
- Friedrich-Alexander Universität Erlangen-Nürnberg , Anorganische und Allgemeine Chemie , Egerlandstr. 1 , 91058 Erlangen , Germany .
| | - Annette Grünwald
- Friedrich-Alexander Universität Erlangen-Nürnberg , Anorganische und Allgemeine Chemie , Egerlandstr. 1 , 91058 Erlangen , Germany .
| | - Piermaria Pinter
- Technische Universität Dresden, Physikalische Organische Chemie , Bergstr. 66 , 01069 Dresden , Germany
| | - Max M Hansmann
- Georg-August Universität Göttingen , Institut für Organische und Biomolekulare Chemie , Tammannstraße 2 , 37073 Göttingen , Germany
| | - Dominik Munz
- Friedrich-Alexander Universität Erlangen-Nürnberg , Anorganische und Allgemeine Chemie , Egerlandstr. 1 , 91058 Erlangen , Germany .
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