Andreas Rauschenbach

Structurally recognizable electron density transfer in the donor–acceptor complex {1,2,4,5-tetra(thioethyl) benzene⋯bromine2}∞

The crystal structure determination of a sulfur lone pair donor complex with bromine reveals an increase of the Br–Br bond length from 228 pm (gas-phase) to 241 pm, for which density functional theory calculations predict a –0.25 charge transfer in the ground state.

EINKRISTALL-MOLEKÜLSTRUKTUREN 1071.2: STRUKTURÄNDERUNGEN VON THIANTHREN, 2,3,6,7-TETRAMETHOXYTHIANTHREN UND 2,3,6,7-TETRAMETHOXYSELENANTHREN BEI KOMPLEXBILDUNG MIT ELEKTRONENAKZEPTOREN SOWIE BEI EINELEKTRONENOXIDATION ZU DEN RADIKALKATIONEN

Abstract Information on structural changes due to partial and full one-electron transfer is obtained by comparing the single crystal structures of both donor/acceptor complexes of thianthrene and selenanthrene derivatives with those of their radical cation salts: The single crystal structures of {thianthrene pyromelliticdianhydride}, {2,3,6,7-tetramethoxythianthrene 1,2,4,5-tetracyanobenzene} and 2,3,6,7-tetramethoxyselenanthrene 1,2,4,5-tetracyanobenzene} do not exhibit any significant differences relative to that of their components. On the contrary, in the corresponding radical cation salts [2,3,6,7-tetramethoxythianthrene⊕][Br3 ⊖] as well as [2,3,6,7-totramethoxyselenanthrene⊕][I3 ⊖] severe structural changes are observed such as the flattening of the molecular skeletons or beginning cyanine distortions along the chains H3CO[sbnd]C3[sbnd]X[sbnd]C3[sbnd]OCH3. Accompanying UN/VIS measurements of solutions containing both donor and acceptor prove long-wavelengths charge transfer bands with drastically re...

EINKRISTALL-MOLEKÜLSTRUKTUREN 551,2 DITHIOLO-DITHIOL-DITHION C4S6 UND DITHIOLO-DITHIOL-DION C4O2S4

Abstract The two iso(valence)electronic molecules, the violet-blue 3H,6H-1,2-Dithiolo[4,3-c]-1,2-dithiol-3,6-dithione and its yellow oxygen analogue, the corresponding dione, are characterized by single crystal structure determinations and quantum chemical calculations to gain information on similarities and differences: The molecular structures are comparable except for the O perturbation, which causes short C[dbnd]O and long (O)C[dbnd]S bonds; the carbon chain CC bond lengths alternate between 143 and 134 pm. The crystal lattices are both monoclinic (P21/c), but with molecules arranged differently in β-type and γ-type layered staples due to 293 pm short (S[dbnd]O)2 dimer contacts. The color differences can be rationalized by extensive PM3/Cl-calculations: Accordingly, both molecules exhibit long wavelength π→π∗ transitions [xbar](1Ag) → [Abar](1Bu), with the one of the sulfur derivative further lowered by a strong nσ s→σ∗ss admixture. In addition, structural changes are discussed, which are expected for...