Ab Initio Determination of the Geometric Structure and Internal Rotation Potential of 2,2'-Bithiophene

Ortı́, Enrique; Viruela, Pedro M.; Sánchez‐Marín, José; Tomas, F.

doi:10.1021/j100014a014

Cited by 123 publications

(127 citation statements)

References 17 publications

(33 reference statements)

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“…A somewhat larger value ͑0.81 kcal/mol͒ was obtained in a recent MP2 calculation. 19 The same calculation showed that the entire potential curve for the intramolecular rotation is very flat. The energy difference between the trans-and cisgauche forms is only 0.54 kcal/mol with a barrier of 1.56 kcal/mol in between.…”

Section: →͑Lumo͒mentioning

confidence: 90%

“…19 At the same level of calculation, the twist angle between the two rings was computed to be 38°at the equilibrium geometry, with a small barrier to transplanarity ͑Ϸ1 kcal/mol͒. Electron diffraction experiments have determined that bithiophene is twisted in the gas phase.…”

Section: Computational Detailsmentioning

confidence: 99%

“…The barrier to planarity is small. 19 The situation is most probably different in the excited states. The HOMO is antibonding over the dimer while the HOMO-1 and HOMO-2 orbitals are nonbonding.…”

Section: →͑Lumo͒mentioning

confidence: 99%

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A theoretical study of the electronic spectrum of bithiophene

Rubio

Merchán

Ortı́

et al. 1995

The Journal of Chemical Physics

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The electronic spectrum of bithiophene in the energy range up to 6.0 eV has been studied using multiconfigurational second order perturbation theory ͑CASPT2͒ and a basis set of ANO type, with split valence quality and including polarization functions on all heavy atoms. Calculations were performed at a planar ͑trans͒ and twisted geometry. The calculated ordering of the excited singlet states is 1

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Section: →͑Lumo͒mentioning

confidence: 90%

Section: Computational Detailsmentioning

confidence: 99%

See 1 more Smart Citation

A theoretical study of the electronic spectrum of bithiophene

Rubio

Merchán

Ortı́

et al. 1995

The Journal of Chemical Physics

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“…[10] The HOMO-LUMO gap relates linearly to the cosine of the inter-ring twist angle, as is expected when orbital energies are proportional to the degree of orbital overlap (which is in turn proportional to the cosine of the angle between the orbitals) ( Figure 6b and 6d, inset). [51,52] As cos f= 1, at an inter-ring twist angle of zero (i.e., in a planar system) there is maximum overlap of molecular orbitals. The large change in the HOMO-LUMO gap can be explained on the basis of the effect of twisting on the frontier molecular orbitals of 6 Se.…”

Section: Twistingmentioning

confidence: 99%

Oligo‐ and Polyselenophenes: A Theoretical Study

Zade

Zamoshchik

Bendikov

2009

Chemistry A European J

138

122

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Recently, a family of conducting polyselenophenes was synthesized, and they were shown to have a number of interesting properties. Here we have studied oligoselenophenes, their cation radicals and dications up to the 50-mer (50 Se), as well as polyselenophene at the B3LYP/6-31G(d) level of theory, and compared them with the corresponding oligothiophenes. Although the calculations reveal many similarities between oligo- and polyselenophenes and their thiophene-based counterparts, they also show the important differences between those two types of conjugated systems. Oligo- and polyselenophenes have a more quinoid character, lower band gap, and importantly, they are more difficult to twist. The theoretical results suggest that the HOMO-LUMO gap (band gap), bond-length alternation (BLA), and charge distribution in oligo- and polyselenophenes are strongly dependent on inter-ring twisting, yet twisting costs little energy. The inter-ring distances in oligo- and polyselenophenes are shorter than the related distances in oligothiophenes, whereas the bond lengths within the selenophene rings are comparable to those of the corresponding oligothiophenes.

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“…DFT/B3LYP and HF methods have been used and reported in vast literature for calculation of geometric parameters, also indicating excellent agreement with the experimental data, such as observed in this work. Calculations were performed, for example, with 2,2'-Bithiophene, 26 silatran molecules 27 and 2-amino-4-Methoxy-6-Methyl-Pyrimidine as well. classification D (correlation <0.30).…”

Section: Geometric Parametersmentioning

confidence: 99%