Synthesen des Anions S3N3O2−, eines stabilen sechsgliedrigen Schwefel-Stickstoff-Ringes mit einem 8π-Elektronengerüst

Syntheses of the Anion S₃N₃O₂^?, a Stable Six-membered Sulfur-Nitrogen Ring with an 8π-Electron Skeleton The dark blue-violet cyclotrithiazene-dioxide anion S₃N₃O₂^?has been synthesized on different pathways: 1. reaction of S₄N₄O₂ with alkali azides, 2. metathesis of (CH₃)₃ES₃N₃O₂ (E = Si, Sn) with CsF, 3. addition of S₄N₄O₂ and alkali bis(trimethylsilyl)-amides followed by cation exchange with tetraphenylarsonium chloride, and 4. reaction of S₄N₄O₂ with trimethylsilyliminotriphenylphosphorane in a molar ratio of 1:1. Excess iminophosphorane leads to the formation of a covalent 1.5-disubstituted S₄N₄ derivative. Reaction mechanisms will be discussed and structures of trithiatriazine-anions will be compared.     

Einfache Darstellungsmethoden des einzigen bekannten Perthiometallats [(S2)2 Mo(S2)2Mo(S2)2]2−. Zur Kenntnis der Einheit {Mo2(S2)2}6+

Simple Preparation Methods of the Only Known Perthiometallate [(S₂)₂(Mo)S₂)₂ Mo(S₂)₂]^2? · On the Moiety {Mo₂(S₂)₂}⁶⁺ Different aspects of the preparation of the only known perthiometallate [(S₂)₂Mo(S₂)₂Mo(S₂)₂]^2? (a compound with the unusual coordination number (9) have been discussed. Simple preparation methods could be developed. A discussion of the properties of the stabilising central moiety {Mo(S₂)₂}⁶⁺ containing a metal-metal bond follows.     

[Mo(NPPh3)4]2+ [MoNCl3(NPPh3)]2− · C7H8, ein Phosphaniminato-Komplex mit einem Dikation von Molybdän(VI)

[Mo(NPPh₃)₄]²⁺ [MoNCl₃(NPPh₃)]₂^? · C₇H₈, a Phosphoraneiminato Complex with a Dication of Molybdenum(VI). The title compound was prepared by the reaction of MoNCl₃ with Me₃SiNPPh₃ in acetonitrile solution. Red single crystals separated upon addition of toluene. They were characterized by IR spectroscopy and by an X-ray structure determination. (Space group P1 , Z = 2, 6918 observed unique reflections, R = 0.059. Lattice dimensions at 20°C: a = 1 181.4, b = 2 021.4, c =2 409.7pm; α = 65.87°, β = 101.09°, γ= 78.97°). In the dication [Mo(NPPh₃)₄]²⁺ the molybdenum atom is surrounded in a tetrahedral fashion by the four nitrogen atoms of the phosphorane iminato ligands. The MoN and PN bond lengths correspond well with double bonds. In the two anions [MoNCl₃(NPPh₃)]^?, which occur in different conformations, the molybdenum atoms are fivefold coordinated by the terminal nitride ligand Mo?N: in axial positions and by the three chlorine atoms and the nitrogen atom of the (NPPh₃)^? ligand in the equatorial positions.     

Hypervalent Pentafluoroethylgermanium Compounds, [(C2F5)nGeX5−n]− and [(C2F5)3GeF3]2− (X=F,Cl; n=2–5)

This paper gives an account on hypervalent fluoro‐ and chloro(pentafluoroethyl)germanium compounds. The selective synthesis of the tris(pentafluoroethyl)dichlorogermanate salt [PNP][(C₂F₅)₃GeCl₂] as well as its X‐ray structural analysis is described. As a representative example for pentafluoroethylfluorogermanates, the synthesis and structure of 2,4,6‐triphenylpyryliumtris(pentafluoroethyl)difluorogermanate [C₂₃H₁₇O][(C₂F₅)₃GeF₂] is reported. Fluoride‐ion affinities for pentafluoroethylgermanes were calculated using quantum chemical methods, disclosing (C₂F₅)₃GeF as a weaker Lewis acid than (C₂F₅)₃SiF or (C₂F₅)₃PF₂. The theoretical results were confirmed by experiments and give the basis of a synthetic protocol for (C₂F₅)₃GeF. Pentakis(pentafluoroethyl)germanate [PPh₄][Ge(C₂F₅)₅] was detected as an intermediate during the synthesis of [PPh₄][(C₂F₅)₄GeF] starting from tris(pentafluoroethyl)difluorogermanate and LiC₂F₅.