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Jasinski, Jerry P.; Jasinski, John M.; Crosby, Daniel J.

doi:10.1023/a:1024273912911

Cited by 5 publications

(3 citation statements)

References 7 publications

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“…This interruption of π-conjugation of two fluorene segments may be caused by intermolecular intermolecular C-H•••π interactions between neighboring molecules (Table 1). All bond lengths and bond angles are normal and comparable to those of observed in the structures of other fluorene derivatives (Han et al, 2006;Jasinski et al, 2003;Suchod et al, 2000).…”

Section: S1 Commentsupporting

confidence: 82%

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2,2′-Bi(9,9-diethylfluorene)

Park

Kang

2014

Acta Cryst E

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The title compound, C34H34, systematic name 9,9,9′,9′-tetraethyl-2,2′-bi(9H-fluorene), crystallized with two crystallographically independent molecules (A and B) in the asymmetric unit. These differ mainly in the orientation of the lateral ethyl chains: in molecule A, they are both on the same side of the molecule whereas in molecule B, one diethylfluorene moiety has undergone a 180° rotation such that the two pairs of ethyl residues appear on opposite sides of the molecule. The fluorene ring systems subtend dihedral angles of 31.37 (4) and 43.18 (3)° in molecules A and B, respectively. Hence the two fluorene moieties are tilted slightly toward one another. This may be due to the presence of intermolecular C—H⋯π interactions between neighboring molecules. The lateral ethyl chains (excluding H atoms) are also almost planar, with each pair almost perpendicular to the plane of the fluorene system to which they are attached with dihedral angles between the ethyl and fluorene planes in the range 86.04 (8)–89.5 (1)°.

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Section: S1 Commentsupporting

confidence: 82%

“…For details of the synthesis of the title compound, see: Hapiot et al (2005). For the crystal structures of other fluorene derivatives, see: Han et al (2006); Jasinski et al (2003); Suchod et al (2000).…”

Section: Related Literaturementioning

confidence: 99%

2,2′-Bi(9,9-diethylfluorene)

Park

Kang

2014

Acta Cryst E

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“…For bifluorene, only a few tests have been done at the DFT level and the results are given in Table S2 of the ESI,w together with the experimental values. 32 As for fluorene, the calculated lengths are longer than the experimental ones, except for C 9 -C 10 which is too small. The dihedral angles between the two fluorene moieties have been calculated to be 37.55 and 142.431 for the cis and trans conformers, respectively, in agreement with the experimental results and with previous calculations with B3LYP/6-311G(d).…”

Section: Geometry Optimization Influence Of the Methods And Of The Ba...mentioning

confidence: 66%

A TD-DFT investigation of two-photon absorption of fluorene derivatives

Zein

Delbecq

Simon

2009

Phys. Chem. Chem. Phys.

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We report time-dependent density functional theory (TD-DFT) calculations on the two-photon absorption (TPA) properties of fluorene and derivatives. The influence of donor and acceptor groups and of dimerisation is investigated. Firstly the choice of a DFT functional and of the basis set is performed by comparison of experimental and calculated excitation energies and two-photon cross sections. Then, the calculations display an enhancement of the cross section with acceptor groups or with a combination of one donor and one acceptor groups (push-pull), at some positions on the cycles. Moreover, the largest cross section is obtained for bifluorene. The replacement of carbon atoms by nitrogen atoms, giving heterocycles, is not efficient. In chloroform as solvent, the excitation energy decreases and the two-photon cross section increases, mainly with a polar molecule. Finally, a rationalization of the results is given based on the three-level model by analysis of the transition moments and of the molecular orbitals.

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Optimizing LED Properties of 2,7-Bis(phenylethenyl)fluorenes

et al. 2005

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Bis(3,4,fluorene, 1, and a segmented copolymer 2 composed of the same chromophore alternated with nonconjugated 1, 6-hexanediyl (alt-oligo(2,6-dimethoxylphenylene-4-vinylene-[9,9-diethylfluoren-2-yl-7-vinylene]-3,5-dimethoxy-phenylene-4-[1,6-hexanedioxyl]) were synthesized. They have solution photoluminescence emission maxima at 420-460 nm, with quantum efficiencies of 0.93 and 0.68, respectively, in chloroform. Electroluminescent spectra in an LED configuration ITO/PEDOT-PSS/(1 or 2)/Ca-Al both showed maxima at 470-480 nm, although the spectrum from 2 was significantly broader. The luminance of LEDs with 1 was over 10-fold higher than those with copolymer 2, 0.515 versus 0.040 cd/A, with turn-on voltages of 3 and 5 V, respectively. The crystallography of 1 showed no chromophore π-stacking; this absence should limit tendencies for emission wavelength shifts due to solid state interchromophore interactions. When 1 was heated in air before incorporation into an LED emissive layer, a 540 nm emission component was produced, which did not occur if 1 was not heated before use. Emissive layers of 1 with PMMA gave stronger luminance than either neat 1 or 2, with only a modest increase in turn-on voltage. A 10% (w/w) 1:PMMA based LED emission showed a maximum at 444 nm (blue emission with CIE color coefficients of (0.153,0.312)), with a luminance efficiency of 4.5 cd/A and a turn on voltage of 4.5 V.

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Untitled

Cited by 5 publications

References 7 publications

2,2′-Bi(9,9-diethylfluorene)

2,2′-Bi(9,9-diethylfluorene)

A TD-DFT investigation of two-photon absorption of fluorene derivatives

Optimizing LED Properties of 2,7-Bis(phenylethenyl)fluorenes

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