On electronic structure of neutral and monocharged 9,9′-spirobifluorene

Matuszná, Katarı ́na; Breza, Martin; Pálszegi, T.

doi:10.1016/j.theochem.2007.11.020

Cited by 12 publications

(10 citation statements)

References 31 publications

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“…This might cause complications due to the Jahn-Teller (JT) effect (unstable geometries in degenerate electronic states, especially in the case of ions with free electrons). [31,32] With respect to these facts, we restricted our theoretical study to structures with aromatic rings oriented uniformly within the molecule (see the notation and side view on the optimized structures according to Scheme 1 and Figure 1). The selected dihedral angles of the neutral molecules in the electronic ground state are collected in Table 1.…”

Section: Neutral Statesmentioning

confidence: 99%

“…Presumably, in this case the numerical error in geometry optimization of molecules with degenerate or quasi-degenerate electronic states can be larger than or comparable to JT distortion. [32] The system undergoes a symmetry descent and its geometry stabilizes resulting in the nondegenerated electron state. The presence of various JT structures with different spin density distributions might also be accompanied by the occurrence of broad and unresolved ESR spectra for small oxidation potentials of the AS molecule.…”

Section: Charged Statesmentioning

confidence: 99%

“…A similar situation has been reported for smaller spirobifluorene anions where the original D 2d symmetry is changed to C 2v symmetry with unequal charge and spin density distributions between both fluorene fragments. [32] The detailed analysis of this effect requires more extensive and Table 3. Mulliken AM1 spin densities at nitrogen and sulfur atoms.…”

Section: Charged Statesmentioning

confidence: 99%

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Structural Changes in 2‐Diarylthiophene‐Substituted Starburst Compounds upon Charging: A Theoretical and Spectroelectrochemical Study

et al. 2008

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The role of charging in structural changes of 2-diarylaminothiophene-substituted starburst compounds is clarified by combining theoretical and spectroelectrochemical studies. A systematic and comparative theoretical calculation based on density functional theory and semiempirical Austin Model 1 (AM1) calculations is performed on the neutral and charged states of four model tris(5-diarylamino-5-thienyl)-terminated starburst compounds with a central triphenylamine and 1,3,5-triphenylbenzene moiety. Our results indicate that the charging of molecules leads to structural changes by quinoid-type components mostly on the dendrimers terminated by phenothiazinyl fragments. Based on the optimal geometries, the spectroscopic properties were calculated using the semiempirical Zerner's intermediate neglect overlap method. The presented theoretical results and the spin electron distributions of charged states and their spectra are supported by the spectroelectrochemical observations caused by the different electron localization within the studied molecules after charging. The satisfactory agreement between theoretical electronic transitions and experimental values indicates that a rational design of tunable molecular layers in organic devices based on the starburst compounds described is possible.

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Section: Neutral Statesmentioning

confidence: 99%

Section: Charged Statesmentioning

confidence: 99%

Section: Charged Statesmentioning

confidence: 99%

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Structural Changes in 2‐Diarylthiophene‐Substituted Starburst Compounds upon Charging: A Theoretical and Spectroelectrochemical Study

et al. 2008

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“…The spiro compounds are built from two mutually perpendicular p-systems connected via a common insulating tetracoordinate atom, e.g. carbon atom [13][14][15]. These systems are characterized by a tunable balance between rigidity and rotational (torsional) freedom when the single bonds between the lateral chromophores and/or chromophoric bridges, e.g p-phenylenes, p-phenylenevinylnes, are included.…”

Section: Introductionmentioning

confidence: 99%

Theoretical investigation of the structure and the electron-vibrational dynamics of 9,9′-spirobifluorene

et al. 2008

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“…The symmetries of SBF and BFD of excited state are broken due to the non-equivalent geometrical changes of the two fluorene segments. The change of symmetry has been studied by Matuszná et al [64] for the anionic structures. The optimized geometric parameters of FR, SBF, BFD, and BDA in the ground states (S 0 ) and the lowest singlet excited states (S 1 ) are presented in Table S3 in Supporting Information at B3LYP/6-31G(d) level.…”

Section: Equilibrium Geometries Between Ground State and Excited Statementioning

confidence: 99%

Toward design of high-performance optoelectronic materials: comparative theoretical studies on the photophysical and charge transport properties of fluorene-based compounds

Sun

Geng

et al. 2012

Theor Chem Acc

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As an important building block for optoelectronic applications, various chemical modifications at C9-position of fluorene have been proposed to enhance its performance by suppressing the well-known keto effect. In order to identify different substitution effects on the photophysical and charge transport properties of fluorene, we systematically study the electronic structures and photophysical behaviors of fluorene (FR) and its three dimerized counterparts, namely, 9,9 0 -spirobifluorene (SBF), 9,9 0 -bifluorenylidene (BFD), and bis(biphenyl-2-2-diyl)allene (BDA), by employing density functional theory calculations. The changes in bond length alternation indicate that the geometrical relaxations of the fluorene unit in its dimerized derivatives are smaller than FR compound. This fact was further proved by the nonradiative decay rate estimated of the first excited singlet state for each compound. Meanwhile, the vibration relaxation analyses suggest that the bridge between two fluorene fragments plays an important role in the nonradiative decay process. In addition, the injection abilities were evaluated in terms of the ionization potentials and electron affinities, and the carrier transport properties were discussed in the framework of Marcus theory. We find BFD could be a better ambipolar transport material, and BDA can be used as a high-efficient luminescent building unit with excellent hole transport property.

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On electronic structure of neutral and monocharged 9,9′-spirobifluorene

Cited by 12 publications

References 31 publications

Structural Changes in 2‐Diarylthiophene‐Substituted Starburst Compounds upon Charging: A Theoretical and Spectroelectrochemical Study

Structural Changes in 2‐Diarylthiophene‐Substituted Starburst Compounds upon Charging: A Theoretical and Spectroelectrochemical Study

Theoretical investigation of the structure and the electron-vibrational dynamics of 9,9′-spirobifluorene

Toward design of high-performance optoelectronic materials: comparative theoretical studies on the photophysical and charge transport properties of fluorene-based compounds

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