Synthesis and structure of products of interaction of H[AuCl4] with H2DMG and pyridine

Surprises in the Solvent-Induced Self-Ionization in the Uranium Tetrahalide UX4 (X = Cl, Br, I)/Ethyl Acetate System

The reaction of the uranium(IV) halides UCl₄, UBr₄, or UI₄ with ethyl acetate (EtOAc) leads to the formation of the complexes [UX₃(EtOAc)₄][UX₅(EtOAc)] (X = Cl, Br) or [UI₄(EtOAc)₃]. Thus, both UCl₄ and UBr₄ show self-ionization in ethyl acetate to a distorted pentagonal bipyramidal [UX₃(EtOAc)₄]⁺ cation and a distorted octahedral [UX₅(EtOAc)]^- anion. Surprisingly, the chloride and bromide compounds are not isotypic. While [UCl₃(EtOAc)₄][UCl₅(EtOAc)] crystallizes in the orthorhombic crystal system, space group P2₁2₁2₁ at 250 K, the bromide compound crystallizes in the monoclinic crystal system, P12₁/n1 at 100 K. Unexpectedly, UI₄ does not show self-ionization but forms [UI₄(EtOAc)₃] molecules, which crystallize in the monoclinic crystal system, P2₁/c, at 100 K. The compounds were characterized by single-crystal X-ray diffraction, IR, Raman, and NMR spectroscopy, as well as molecular quantum chemical calculations using solvent models.

Aminkomplexe des Goldes, Teil 9: Gold(I)-halogenid-Komplexe mit primären und azyklischen sekundären Aminen und ihre Oxidation zu Gold(III)-Derivaten

The reaction of (tht)AuX (X=Cl or Br; tht=tetrahydrothiophene) with various primary amines L leads to products of the form [L2Au]+X−. Packing diagrams of the corresponding structures are dominated by N–H···X hydrogen bonds and (in some cases) aurophilic contacts. The cyclohexylamine derivative was already known as its dichloromethane ⅔-solvate; we have isolated the solvent-free compound and its pentane ¼-solvate, which all show different packing patterns. With acyclic secondary amines, the products are more varied; LAuX and [L2Au]+[AuX2]− were also found. These gold(I) products were generally formed in satisfactory quantities. The attempted oxidation to Au(III) derivatives with PhICl2 or Br2 proved impossible for the primary amine derivatives [although isopropylamine-trichloridogold(III) was obtained unexpectedly from the corresponding cyanide] and unsatisfactory for the secondary amine derivatives. Products LAuX3 and [L2AuX2]+[AuX4]− were identified but were formed in disappointing yields. In isolated cases protonated products (LH)+[AuCl4]−, (LH+)3[AuCl4]−(Cl−)2 or [(Et2N)2CH]+[AuBr4]− were formed, presumably by involvement of the dichloromethane solvent and/or adventitious water. Here also the yields were poor, and some products arose as mixtures. Direct reaction of amines with AuCl3 or (tht)AuX3 was also unsuccessful. All products were characterized by X-ray structure analysis.

Structure of a new chloroauric acid

The new tetrachloroaurate ethanol hydrate HAuCl4·0.65C2H5OH·1.35H2O was prepared from chloroauric acid trihydrate in ethanol. The compound crystallizes in the triclinic space group P \bar 1 (No. 2). The [AuCl4](-) units in the structure have approximately square-planar symmetry, forming chains parallel to the crystallographic b-axis direction.