ChemInform Abstract: Sulfur Dioxide and Water: Structures and Energies of the Hydrated Species SO2·nH2O, [HSO3]‐·nH2O, [SO3H]‐·nH2O,and H2SO3·nH2O (n = 0—8)

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Nanoparticle-based,spray-coated silver top contacts for efficient polymer solar cells

We demonstrate a solution-processed top electrode for large area organic electronic devices. A Ag nanoparticle solution is spray-coated directly on top of an inverted bulk-heterojunction organic solar cell through a shadow mask. After sintering the Ag nanoparticle film at 150 °C, a temperature which is compatible with processes on flexible substrates, cells show performances comparable to those of reference devices with evaporated top-contacts.     

Magnetic field-induced ΔF=±2,3,4 transitions in the Eu I-spectrum

The occurrence of ΔF=±2, ±3, and ±4 transitions in the hyperfine structure of the Eu I lineλ 629.1 nm (4f ⁷6s ² a ⁸ S _7/2?4f ⁷6s6p z ⁸ P _5/2) was investigated with the application of high-resolution laser-atomic-beam spectroscopy. It was possible to show that the appearance of such transitions depends on the magnitude of an external magnetic field. Calculations of the hyperfine Zeeman splittings of the excited and the ground state were performed. This allowed the identification of the forbidden transitions.     

Electrophilic attack on sulfur-sulfur bonds: coordination of lithium cations to sulfur-rich molecules studied by ab initio MO methods

Complex formation between gaseous Li+ ions and sulfur-containing neutral ligands, such as H2S, Me2Sn (n = 1-5; Me = CH3) and various isomers of hexasulfur (S6), has been studied by ab initio MO calculations at the G3X(MP2) level of theory. Generally, the formation of LiS(n) heterocycles and clusters is preferred in these reactions. The binding energies of the cation in the 29 complexes investigated range from -88 kJ mol(-1) for [H2SLi]+ to -189 kJ mol(-1) for the most stable isomer of [Me2S5Li]+ which contains three-coordinate Li+. Of the various S6 ligands (chair, boat, prism, branched ring, and triplet chain structures), two isomeric complexes containing the S5==S ligand have the highest binding energies (-163+/-1 kJ mol(-1)). However, the global minimum structure of [LiS6]+ is of C(3v) symmetry with the six-membered S(6) homocycle in the well-known chair conformation and three Li--S bonds with a length of 256 pm (binding energy: -134 kJ mol(-1)). Relatively unstable isomers of S6 are stabilized by complex formation with Li+. The interaction between the cation and the S6 ligands is mainly attributed to ion-dipole attraction with a little charge transfer, except in cations containing the six sulfur atoms in the form of separated neutral S2, S3, or S4 units, as in [Li(S3)2]+ and [Li(S2)(S4)]+. In the two most stable isomers of the [LiS6]+ complexes, the number of S--S bonds is at maximum and the coordination number of Li+ is either 3 or 4. A topological analysis of all investigated complexes revealed that the Li--S bonds of lengths below 280 pm are characterized by a maximum electron-density path and closed-shell interaction.     

Structures,Energies, and Fundamental Vibrations of the Sulfonium Ions H3Sn+ (n = 1–4)

Using ab initio MO calculations at the MP2/6‐311G(2df,2pd) level of theory the most stable structures of the following seven ions were determined: H₃S⁺ (C_3v), H₂S–SH⁺ (C_s), H₂S–S–SH⁺ (C₁), HS–S(H)–SH⁺ (C₁), H₂S–S–S–SH⁺ (C₁), HS–S(H)–S–SH⁺ (C₁) and S(SH)₃⁺ (C₃). In the case of the isomeric H₃S₃⁺ cations the species protonated at the terminal sulfur atom is most stable while in the case of the H₃S₄⁺ ions the protonation at the β sulfur atom is energetically preferred. However, the energy differences between isomeric cations are rather small. At the same level of theory the wavenumbers of the harmonic fundamental vibrations were calculated and compared to the available experimental data leading to a support for the existing assignments in certain cases but in some cases to revisions. The reaction enthalpies and Gibbs free energies of the proton transfer reactions H₂S_n + H₂S_n+1 → H₃S_n⁺ + HS_n+1^– were calculated by the G2 method. For n = 1–3 the enthalpies are found in the range 639–731 kJ mol^–1.     

A New Allotrope of Elemental Sulfur: Convenient Preparation of cyclo-S14 from S8

Three simple steps lead from S₈ to cyclo-S₁₄, which is stable at 20°C. The final synthetic step [Eq. (a)] provides the title compound, which was characterized spectroscopically and by X-ray structure analysis. Formally, the structure of S₁₄ is derived by insertion of an S₂ unit into S₁₂. tmeda=N,N,N′,N′-tetramethylethylenediamine.     

Crystal and Molecular Structures as well as Spectra of Two Organic Tetrasulfanes R2S4 (R = 2-benzothiazolyl and 4-chlorophenyl)

Bis(2-benzothiazolyl)tetrasulfane prepared from the mercaptane and S₂Cl₂ crystallizes in the monoclinic space group C2/c with a = 3513 pm, b = 577.28 pm, c = 800.0 pm, β = 98.74°, ρ = 1.64 g cm^?3 (at 298 K). The molecules are of C₂ symmetry with the geometrical parameters of the S₄ backbone: d_ss = 202.7 (terminal) and 207.3 pm (central), α_sss = 106.4°, τ_ssss = 78.5°. The overall conformation is all-trans. Bis(4-chlorophenyl)tetrasulfane prepared from the mercaptane and diisopropoxydisulfane crystallizes in the monoclinic space group P2₁/a with a = 1237.7 pm, b = 748.4 pm, c = 1623.9 pm, β = 105.58°, ρ = 1.61 g cm^?3 (at 298 K). The molecules occupy general positions but are approximately of C₂ symmetry with d_ss = 203.6 (terminal), 206.7 (central) and 202.3 pm (terminal), α_sss = 107.4° and 108.4°, τ_ssss = 75.5° (all-trans conformation). The intermolecular interactions are of van der Waals type. Infrared, Raman, mass and NMR spectra (¹H, ¹³C) are reported.