Relation between structure and enthalpy for stacking interactions of aromatic molecules

An approximately linear correlation has been found between the enthalpy of complexation and the area of overlap of the chromophores using published structural and thermodynamical data on the self- and hetero-association of aromatic molecules measured under similar solution conditions. This finding is consistent with the assumption that short-range van-der-Waals forces dominate over other contributions to the enthalpy of stacking of aromatic molecules. It provides a ‘model-independent’ approach for a priori estimation of the enthalpy of aromatic–aromatic stacking interactions from knowledge of the structural properties or vice versa.     

K10Ga3Bi6.65 – The First Compound in the Ternary A-Ga-Bi System Comprising Cyclic Tris-meta Borate-Analogous [Ga3Bi6]9– Units and Bi2 Dumbbells

K₁₀Ga₃Bi_6.65 is the first representative in the ternary system A-Ga-Bi (A = alkali metal). It contains [Ga₃Bi₆]^9– anions with planar triangular-coordinated Ga atoms as the main structural feature, accompanied by isolated Bi–Bi dumbbells. Alkali metal cations are counterbalancing the charges and fill the space between the anionic units. According to the Zintl-Klemm concept charge balance is reached if an almost equal ratio of single and double-bonded Bi₂ dumbbells are present according to (K⁺)₁₀[Ga₃Bi₆]^9–([Bi-Bi]^4–)_1/6([Bi=Bi]^2–)_1/6.     

Synthesis,X-ray and DFT Studies of 6-halo-3-(hydroxymethyl)cinnolin-4(1H)-ones

Chemistry of Heterocyclic Compounds - The Richter cyclization was used for the synthesis of 6-halo-3-(hydroxymethyl)cinnolin-4(1H)-ones. X-ray analysis revealed that these compounds exist as dimers...     

Vibrational Spectra of Magnesium Hydrogenphosphate Trihydrate and of its Manganese Analogue

Abstract

The infrared (IR) and Raman spectra of MgHPO₄. 3H₂O and of a series of partially deuterated analogues as well as the IR spectra of MnHPO₄. 3H₂O have been recorded and interpreted. The analysis of the IR spectra in the HOD bending region rules out the possibility of existence of H₃OC⁺ ions in the structure.     

Reaction of Trialkylphosphine Carbon Disulfide Adducts with Cyclopentadienones

Abstract

It has been known more than for 100 year that triethylphosphine forms the 1:1 adducts with carbon disulfide and isothiocyanates. However, little is know on the reaction of the adducts and the formation of reactive alkylidenephosphoranes was recently reported by the reaction of adducts with electron-poor double bonds.