Spectral studies of new organic conductors: κ-(BDH-TTP)4Hg3X8, where X=Cl, Br

Barszcz, Bolesław; Łapiński, Andrzej; Graja, A.; Flakina, A. M.; Zhilyaeva, E. I.; Yamada, Jun; Lyubovskaya, Rimma N.

doi:10.1016/j.synthmet.2006.06.018

Cited by 8 publications

(2 citation statements)

References 17 publications

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“…For fully optimised DOEO 0 it is nonplanar, whereas for DOEO þ it is almost planar (except for the outer ethylene groups). A similar situation is observed for other organic donors: ET [21][22][23], EDT-DTDSF [24], and BDH-TTP [25].…”

Section: Results and Discussion 31 Ground Statesupporting

confidence: 80%

TD-DFT investigation of the electronic spectra of (DOEO)₄HgBr₄· TCE salt

Łapiński

Kotov

2008

Molecular Physics

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In this work the, intrinsic properties of the ground and excited states of the DOEO 0 neutral molecule and the DOEO þ cation are studied;The ground-state optimised structures and energies were obtained using the density functional theory (DFT) as approximated by the various functionals (B3LYP, B3PW91, and LSDA) in restricted and unrestricted models for neutral DOEO 0 and DOEO þ cation, respectively. The character and energy of the first 30 singlet-singlet electronic transitions were investigated by applying the time-dependent DFT approximations, TD-B3LYP, TD-B3PW91, and TD-LSDA, to the corresponding optimised ground-state geometries. Moreover, excites states were calculated for DOEO dimer with one hole at the TD-B3LYP/3-21 þ G(d) level of theory; the initial geometry of the dimer was taken from X-ray data. A comparison is made between the different theoretical methodologies used to study the electronic ground and excited states. We also report the polarised optical conductivity spectra (500-18,000 cm À1 ) and the absorption spectra (400-47,000 cm À1 ) of (DOEO) 4 HgBr 4 Á TCE salt.

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Section: Results and Discussion 31 Ground Statesupporting

confidence: 80%

TD-DFT investigation of the electronic spectra of (DOEO)₄HgBr₄· TCE salt

Łapiński

Kotov

2008

Molecular Physics

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“…Full-geometry optimizations were performed to afford the nonplanar MeEDO-TTF 0 and the planar MeEDO-TTF + . The tendency of the charge-dependent molecular shape is similar to those of TTF derivatives such as ET, BO, BDH-TTP, and EDO-TTF . The calculated 63 modes including frequencies, infrared intensities, and Raman activities are listed in Table S1 in Supporting Information.…”

Section: Resultsmentioning

confidence: 84%

Room-Temperature First-Order Phase Transition in a Charge-Disproportionated Molecular Conductor (MeEDO-TTF)₂PF₆

et al. 2008

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Electrochemical oxidation of 4,5-ethylenedioxy-4′-methyl-tetrathiafulvalene (MeEDO-TTF) afforded three types of (MeEDO-TTF)2PF6 radical cation salts under different conditions: black powder, dark green plates, and black plates. The optical absorption spectra of these modifications were very similar to each other. The black powder and dark-green plate modifications were semiconducting and metallic, respectively, and the latter showed a semiconducting behavior below 200 K. The black plate modification exhibited a semiconductor-to-semiconductor first-order phase transition at around room temperature (303 K). The donor molecules in both the high- and low-temperature phases of this modification showed similar packing patterns, based on which the tight-binding approximation afforded similar two-dimensional Fermi surfaces. The phase transition of this modification is accompanied by a subtle change in the relative orientation of the neighboring donor molecules. The vibrational spectra proved that a nearly localized charge disproportionation takes place in the high-temperature phase and the distinct charge disproportionation is developed in the low-temperature phase. These results indicate that the slight lattice distortion assists the stabilization of charge disproportionation. The comparison of the isostructural salts of metallic (MeEDO-TTF)2X (X = BF4, ClO4) and the semiconducting high-temperature phase of the (MeEDO-TTF)2PF6 demonstrated that the side-by-side intermolecular interaction is most effectively modulated according to the anion size. The unit cell parameter corresponding to this intermolecular interaction was varied only ca. 2% among these isostructural salts. This observation demonstrates the very sensitive nature of the transport property to the lattice modulation.

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