Resonance spectra of spontaneous Raman scattering of negative and positive tetracene ions

Sidorov, A. N.; Александров, И. В.; Bobovich, Ya. S.

doi:10.1007/bf00526682

Cited by 3 publications

(6 citation statements)

References 2 publications

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“…However, no peaks attributable to tetracene are seen in the sample for which x = 2 (nominally ‘K 2 Tetracene’). Comparison of the Raman spectrum of K 2 Tetracene with that of pristine tetracene reveals that there are no vibrational modes associated with neutral tetracene (Figure c) and that the spectrum is consistent with formation of tetracene 2– anions . When either pentacene and picene are directly reacted with K metal, there are significant signs of molecular decomposition .…”

Section: Resultsmentioning

confidence: 96%

“…Comparison of the Raman spectrum of K 2 Tetracene with that of pristine tetracene reveals that there are no vibrational modes associated with neutral tetracene ( Figure 1 c) and that the spectrum is consistent with formation of tetracene 2– anions. 32 When either pentacene and picene are directly reacted with K metal, there are significant signs of molecular decomposition. 10 However, this is not the case with tetracene, demonstrating its increased stability.…”

Section: Resultsmentioning

confidence: 99%

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Crystal Structure and Stoichiometric Composition of Potassium-Intercalated Tetracene

et al. 2020

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The products of the solid-state reactions between potassium metal and tetracene (K:Tetracene, 1:1, 1.5:1, and 2:1) are fully structurally characterized. Synchrotron X-ray powder diffraction shows that only K 2 Tetracene forms under the reaction conditions studied, with unreacted tetracene always present for x < 2. Diffraction and 13 C MAS NMR show that K 2 Tetracene has a crystal structure that is analogous to that of K 2 Pentacene, but with the cations ordered on two sites because of the influence of the length of the hydrocarbon on possible cation positions. K 2 Tetracene is a nonmagnetic insulator, thus further questioning the nature of reported superconductivity in this class of materials.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Crystal Structure and Stoichiometric Composition of Potassium-Intercalated Tetracene

et al. 2020

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“…The spontaneous RR spectra of Tc monomer and nanocrystals (Figure ) were acquired in the spectral region blue of the onset of the fluorescence signal . Although a number of Raman measurements have been reported on Tc monomer and nanocrystals, these are the first spontaneous Raman measurements made on resonance in both systems. ,− The contributions of scattering from the solvent and the broad featureless baselines have been subtracted. The time-dependent wavepacket model was used to model the absorption, fluorescence, and Raman spectra in acetone.…”

Section: Resultsmentioning

confidence: 99%

“…23 The gas phase absorption not only showed that in the Tc monomer the S 1 potential energy surface is strongly displaced along totally symmetric aromatic ringbreathing modes but also revealed vibronic activity involving nontotally symmetric b 3g ring-distortion modes. The offresonance spontaneous Raman spectra of Tc monomer in solution 24,25 and crystalline Tc have been reported. 26−28 The impulsive Raman spectrum of crystalline Tc has also been measured in the time domain under preresonance conditions with a four-pulse transient-grating experiment 6 and under resonance conditions with femtosecond transient absorption.…”

Section: ■ Introductionmentioning

confidence: 99%

Resonance Raman Characterization of Tetracene Monomer and Nanocrystals: Excited State Lattice Distortions With Implications For Efficient Singlet Fission

et al. 2019

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The characterization of specific phonon modes and exciton states that lead to efficient singlet fission (SF) may be instrumental in the design of the next generation of highefficiency photovoltaic devices. To this end, we analyze the absolute resonance Raman (RR) cross sections for tetracene (Tc) both as a monomer in solution and as a crystalline solid in an aqueous suspension of nanocrystals. For both systems, a time-dependent wavepacket model is developed that is consistent with the absolute RR cross sections, the magnitude of the absorption cross sections, and the vibronic line shapes of the fluorescence. In the monomer, the intramolecular reorganization energy is between 1500 and 1800 cm −1 and the solvent reorganization energy is 70 cm −1 . In nanocrystals, the total reorganization is diminished to less than 600 cm −1 . The lowest energy exciton has an estimated intramolecular reorganization energy between 300 and 500 cm −1 while intermolecular librational phonons have a reorganization energy of about 130 cm −1 . The diminished reorganization energy of the nanocrystal is interpreted in the context of the delocalization of the band-edge exciton onto about ∼7 molecules. When electron and electron−hole correlations are included within many-body perturbation theory, the polarized absorption spectra of crystalline Tc are calculated and found to be in agreement with experiment. The low-lying exciton states and optically active phonons that contribute to the polarized crystal absorption are identified. The likely role of coherent exciton phonon evolution in the SF process is discussed.

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“…[41] In contrast to the large number of IR spectroscopic studies on ARCs, there is only one publication that reports a Raman spectrum of [4] + • in 90 % H 2 SO 4 . [42] Unfortunately, we observed strong fluorescence and decomposition while measuring the Raman spectra, which has led to unmeaningful spectra for 3). This might be due to the use of a different solvent…”

Section: Ir and Raman Spectroscopymentioning

confidence: 95%

Isolation, Structural and Physical Characterization as well as Reactivity of Persistent Acenium Radical Cation Salts

Sellin

Seiler

Mayländer

et al. 2023

Chemistry A European J

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The unsubstituted acenium radical cations (ARCs) are extremely sensitive and were hitherto only studied in situ, i. e. in the gas phase, as dilute solutions in strong acids or by matrix isolation spectroscopy at about 10 K. In this study, room temperature stable ARC salts with the weakly coordinating anion [F{Al(OR F ) 3 } 2 ] À (OR F =À OC(CF 3 ) 3 ) supported by the weakly coordinating solvent 1,2,3,4-tetrafluorobenzene (TFB) were prepared and structurally, electrochemically and spectroscopically characterized. Reaction of the neutral acenes with Ag + [F{Al(OR F ) 3 } 2 ] À led, non-innocent, [54] to intermediate [Ag 2 (acene) 2 ] 2 + complexes, which decompose over time to Ag 0 and the corresponding (impure) ARC salts. By contrast, direct deelectronation with the recently developed innocent [54] deelectronator radical cation salt [anthracene Hal ] + • [F{Al-(OR F ) 3 } 2 ] À led to phase-pure products [acene] + • [F{Al(OR F ) 3 } 2 ] À (anthracene Hal = 9,10-dichlorooctafluoroanthracene; acene = anthra-, tetra-, pentacene). For the first time, a homogenous set of spectroscopic data on analytically pure ARC salts was obtained. In addition, cyclovoltammetric measurements of the acenes connected the potentials in solution with those in the gas-phase. Hence, the data complement the existing isolated gas-phase, strong acid or matrix isolation studies. A first entry to follow-up chemistry of the acenium radical cations as ligand forming oxidizers was demonstrated by reaction with 1 = 2 Co 2 (CO) 8 giving [Co(anthracene)(CO) 2 ] + .

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Resonance spectra of spontaneous Raman scattering of negative and positive tetracene ions

Cited by 3 publications

References 2 publications

Crystal Structure and Stoichiometric Composition of Potassium-Intercalated Tetracene

Crystal Structure and Stoichiometric Composition of Potassium-Intercalated Tetracene

Resonance Raman Characterization of Tetracene Monomer and Nanocrystals: Excited State Lattice Distortions With Implications For Efficient Singlet Fission

Isolation, Structural and Physical Characterization as well as Reactivity of Persistent Acenium Radical Cation Salts

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