Crystal structure and spectral characteristics of 2,4,7-trinitro-9-fluorenone

Миначева, Л. Х.; Сергиенко, В. С.; Страшнова, С. Б.; Avramenko, O. V.; Kovalchukova, O. V.; Egorova, O.; Зайцев, Б. Е.

doi:10.1134/1.1857248

Cited by 10 publications

(4 citation statements)

References 8 publications

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“…The signals at wide angles can only be fitted with two different π‐π distances, which may arise from donor‐acceptor interactions (star‐TNF), star‐star contacts and TNF‐TNF stacks. Since TNF π‐stacking was reported in a dense crystal to be approximately 4 Å, while the donor‐acceptor stack between TNF and hexamethylbenzene is only separated by 3.35 Å, it is more reasonable to attribute the shortest distance to the donor‐acceptor separation. The very diffuse liquid‐like signals, exclusively on the equator and especially intense for the small star 2 a , are unique and correspond to distances much shorter than the intercolumnar distance.…”

Section: Resultsmentioning

confidence: 99%

Columnar Liquid Crystals from Star‐Shaped Conjugated Mesogens as Nano‐Reservoirs for Small Acceptors

et al. 2020

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Shape‐persistent conjugated mesogens with oligothiophene arms of different lengths have been synthesized. Such mesogens possess free intrinsic space between their conjugated arms. They form columnar liquid‐crystalline phases, in which the void is filled by dense helical packing in the neat phase similar to an oligo(phenylene vinylene) derivative of equal size. The void can also be compensated by the inclusion of the small acceptor molecule 2,4,7‐trinitrofluorenone. In solution, the acceptor interacts with the core as the largest π‐surface, while in the solid material, it is incorporated between the arms and sandwiched by the star‐shaped neighbours along the columnar assemblies. The TNF acceptors are not nanosegregated from the star‐shaped donors, thus the liquid crystal structure converts to a nano‐reservoir for TNF (endo‐receptor). These host–guest arrangements are confirmed by comprehensive X‐ray scattering experiments and solid‐state NMR spectroscopy. This results in ordered columnar hexagonal phases at high temperatures, which change to helical columnar mesophases or to columnar soft crystals at room temperature.

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Section: Resultsmentioning

confidence: 99%

Columnar Liquid Crystals from Star‐Shaped Conjugated Mesogens as Nano‐Reservoirs for Small Acceptors

et al. 2020

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“…46 We assigned TNF by using DFT calculations in combination with analyses presented in earlier studies. 44,47,48 The most relevant Raman modes (Table S3) are due to symmetric C-NO 2 stretching (∼1350 cm −1 ), C-C skeleton vibration (1601 cm −1 ) and C=O stretching (1733 cm −1 ). There is good agreement between the measured and simulated Raman data ( Fig.…”

Section: B Raman Spectroscopymentioning

confidence: 99%

“…The S 4 transition of HAT6 also dominates the higher energy region in the excited CT complex. The electronic absorption spectrum of TNF has been studied elsewhere, 44,45 and contains a weak lowest-energy band at a wavelength of 435 nm due to the n-* transition and higher energy bands at 387, 302, 260, and 222 nm due to -* transitions. Thus, the 500-870 nm region where the excited CT-band is situated is clear of any electronic transitions from pure HAT6 or TNF.…”

Section: A Absorptionmentioning

confidence: 99%

Electronic and vibronic properties of a discotic liquid-crystal and its charge transfer complex

Haverkate

Zbiri

Johnson

et al. 2014

The Journal of Chemical Physics

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Discotic liquid crystalline (DLC) charge transfer (CT) complexes combine visible light absorption and rapid charge transfer characteristics, being favorable properties for photovoltaic (PV) applications. We present a detailed study of the electronic and vibrational properties of the prototypic 1:1 mixture of discotic 2,3,6,7,10,11-hexakishexyloxytriphenylene (HAT6) and 2,4,7-trinitro-9-fluorenone (TNF). It is shown that intermolecular charge transfer occurs in the ground state of the complex: a charge delocalization of about 10 −2 electron from the HAT6 core to TNF is deduced from both Raman and our previous NMR measurements (2012)], implying the presence of permanent dipoles at the donor-acceptor interface. A combined analysis of density functional theory calculations, resonant Raman and UV-VIS absorption measurements indicate that fast relaxation occurs in the UV region due to intramolecular vibronic coupling of HAT6 quinoidal modes with lower lying electronic states. Relatively slower relaxation in the visible region the excited CT-band of the complex is also indicated, which likely involves motions of the TNF nitro groups. The fast quinoidal relaxation process in the hot UV band of HAT6 relates to pseudo-Jahn-Teller interactions in a single benzene unit, suggesting that the underlying vibronic coupling mechanism can be generic for polyaromatic hydrocarbons. Both the presence of ground state CT dipoles and relatively slow relaxation processes in the excited CT band can be relevant concerning the design of DLC based organic PV systems.

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“…TNF is known to have an almost planar conformation and to crystallize into a monoclinic structure [7]. It has exceptional spectroscopic and photochemical properties [8,9]. Haverkate et.…”

Section: Introductionmentioning

confidence: 99%

New complexes of liquid crystal discotic triphenylenes: induction of the double gyroid phase

Otmakhova

Piryazev

Бондаренко

et al. 2021

Phys. Chem. Chem. Phys.

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Crystal structure and spectral characteristics of 2,4,7-trinitro-9-fluorenone

Cited by 10 publications

References 8 publications

Columnar Liquid Crystals from Star‐Shaped Conjugated Mesogens as Nano‐Reservoirs for Small Acceptors

Columnar Liquid Crystals from Star‐Shaped Conjugated Mesogens as Nano‐Reservoirs for Small Acceptors

Electronic and vibronic properties of a discotic liquid-crystal and its charge transfer complex

New complexes of liquid crystal discotic triphenylenes: induction of the double gyroid phase

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