Synthese und Kristallstruktur von [ReNCl(NPPh2C6H4)]2 · [Ph3PNH2]Cl · CH3CN,einem rheniumorganischen Nitrido-Phosphaniminato-Komplex

Synthesis and Crystal Structure of [ReNCl(NPPh₂C₆H₄)]₂ · [Ph₃PNH₂]Cl · CH₃CN, a Rhenium Organic Nitrido Phosphoraneiminato Complex The title compound is synthesized by the reaction of ReNCl₄ with Me₃SiNPPh₃ in boiling acetonitrile, forming colourless crystals, which are characterized by an X-ray structure determination. Space group P1 , Z = 2, 4 037 observed unique reflections, R = 0.043. Lattice dimensions at 19°C: a = 1 005.5; b = 1 695.2; c = 1 744.7 pm, α = 105.86°; β = 101.49°; γ = 104.45°. The structure consists of dimeric molecules [ReNCl(NPPh₂C₆H₄)]₂, triphenylphosphorane ammoniumchloride and included acetonitrile molecules. In the nitrido phosphoraneiminato complex the rhenium atoms are μ₂-bridged via the N-Atoms of the phosphoraneiminato ligands. Because of this bridging and a Re? Re bond, one terminal nitrido ligand, one terminal chloro ligand, and a Re? C bond of an -C-atom of one phenylene group of Re-atoms attain co-ordination number six.     

Synthese und Kristallstruktur von [Se3N2Cl]+ GaCl4−

Synthesis and Crystal Structure of [Se₃N₂Cl]⁺GaCl₄^? [Se₃N₂Cl]⁺GaCl₄^? has been prepared by the reduction of [Se₂NCl₂]⁺GaC1₄^? with SbPh₃ in CH₂Cl₂ solution, forming red crystals, which were characterized by an X-ray structure determination. Space group P2₁/n, Z = 4, 1640 observed unique reflections, R = 0.050. Lattice dimensions at ? 80 °C: a = 929.4(1), b= 1078.8(1), c = 1135.7(1) pm, β = 92.026(9)°. The cations from nearly planar Se₃N₂ five membered rings with Se? N bond lengths from 170 to 176pm and a Se? Se bond of 242.2 pm. One of the selenium atoms is bonded to the chlorine atom.     

(PPh4)2[MoN(N3)3Cl]2; Synthese,IR-Spektrum und Kristallstruktur

(PPh₄)₂[MoN(N₃)₃Cl]₂; Synthesis, IR Spectrum, and Crystal Structure The title compound is formed in the reaction of molybdenum (II) benzoate with trimethylsilyl azide and PPh₄Cl in dichloro methane forming dark red single crystals. A PPh₃Me⊕ salt of the ion [MoN(N₃)₃Cl]₂^2? is obtained from (PPh₃Me)₂MoNCl₄] treated with silver azide in CH₂Cl₂ suspension. The solvent CH₂Cl₂ participates in both reactions as oxidizing agent. (PPh₄)₂[MoN(N₃)₃Cl₂ is characterized by a structural analysis based upon X-ray data: space group P1 , Z = 1, a = 1050.7 pm; b = 1185.4 pm; c = 1190.8 pm; α = 98.90°; β = 106.87°; γ = 103.97° (4505 independent, observed reflexions, R = 0.039). The compound consists of PPh₄⊕ cations and centrosymmetric anions [MoN(N₃)₃Cl₂^2? in which the molybdenum atoms are bridged by the N_α atoms of two azide groups; the resulting Mo? N bond lengths are 208 pm and 260 pm. In trans position to the long Mo? N bond the terminal nitrido ligand is situated, the Mo?N distance of 164 pm corresponds to a triple bond. Two terminal azido ligands and the chloro ligand are filling up the coordination sphere of the molybdenum atoms to a coordination number of six. The i.r. spectrum is reported and assigned.     

Diiodacetylenkomplexe von Wolfram(IV). Die Kristallstruktur von PPh4[WCl5(C2l2)] · 0,5 CH2Cl2

Diiodoacetylene Complexes of Tungsten(IV). Crystal Structure of PPh₄[WCl₅(C₂I₂)] · 0.5 CH₂Cl₂ Tungsten hexachloride and diiodoacetylene react in CCl₄ solution forming [WCl₄(I? C?C? I)]₂ which has a dimer structure with chloro bridges. In CH₂Cl₂, it reacts with PPh₄Cl yielding PPh₄[WCl₅(I? C?C? I)] · 0.5 CH₂Cl₂. In both compounds the C₂I₂ ligands attain a marked increase in thermal stability by their side-one coordination to the tungsten atoms. The crystal structure of the PPh₄^⊕ salt was determined with X-ray diffraction data (3879 observed reflexions, R = 0.050). PPh₄[WCl₅(C₂I₂)] · 0.5 CH₂Cl₂ crystallizes in the space group P2₁/n with 8 formula units per unit cell. The lattice constants are a = 1723.0, b = 1681.2, c = 2214.6 pm and β = 94.38°. There are two crystallographically independent [WCl₅(C₂I₂)]^? ions which differ only slightly from one another. The C₂I₂ ligand has a staggered arrangement relative to the W? Cl groups, with C? C bond lengths of 127 pm. The infrared spectra are discussed.     

Carbocyclic galanthamin analogs: 4a,5,9,10,11,12‐hexahydro‐6H‐benzo[b]cyclohepta[cd]benzofurans

The synthesis of a novel unnatural carbocyclic analog of the acetylcholine esterase inhibitor galanthamine with a K₃[Fe(CN)₆] promoted oxidative tandem cyclization as the key step is reported.     

Phosphaniminato-Trichloroselenate(II): Synthese und Kristallstrukturen von [SeCl(NPPh3)2]+SeCl3− und [Me3SiN(H)PMe3]2+[Se2Cl6]2−

Phosphorane Iminato-Trichloroselenates(II): Syntheses and Crystal Structures of [SeCl(NPPh₃)₂]⁺SeCl₃^? and [Me₃SiN(H)PMe₃]₂⁺[Se₂Cl₆]^2? [SeCl(NPPh₃)₂]⁺SeCl₃^? has been synthesized by the reaction of Se₂Cl₂ with Me₃SiNPPh₃ in acetonitrile solution, forming orangered crystals, whereas red crystals of [Me₃SiN(H)PMe₃]₂⁺[Se₂Cl₆]^2? were obtained by the reaction of Me₃SiNPMe₃ with SeOCl₂ in acetonitrile solution. Both complexes were characterized by X-ray structure determinations. [SeCl(NPPh₃)₂]⁺SeCl₃^?: Space group P2₁/n, Z = 4, structure solution with 7 489 observed unique reflections, R = 0.057. Lattice dimensions at ?60°C: a = 1 117.0; b = 2 241, c = 1 407.5 pm, β = 95.61°. In the cation [SeCl(NPPh₃)₂]⁺ the selenium atom is φ-tetrahedrally coordinated by the chlorine atom and by the nitrogen atoms of the phosphorane iminato ligands, whereas the anion SeCl₃^? has a T-shaped structure with φ-trigonal-bipyramidale surrounding of the selenium atom. [Me₃SiN(H)PMe₃]₂⁺[Se₂Cl₆]^2?: Space group P2₁/c, Z = 4, structure solution with 2 093 observed unique reflections, R = 0.080. Lattice dimensions at ?70°C: a = 956, b = 828, c = 1 973 pm, β = 93.80°. The structure consists of [Me₃SiN(H)PMe₃]⁺ ions and planar [Se₂Cl₆]^2? anions, in which the selenium atoms are bridged nearly symmetrically by two chlorine atoms.     

121Sb-Mössbauer-Spektren von Antimon(V)-Verbindungen. II

¹²¹Sb Mössbauer Spectra of Antimony (V) Compounds. II The Mössbauer resonance effect of ¹²¹Sb has been studied at 4.2 K in a series of 11 antimony(V) compounds which are in most cases bridged. Isomer shift and quadrupole splitting variations are considered in the light of results of X-ray and vibrational spectroscopy. Preparation and the vibrational spectra of [NMe₄][SbCl₄(n₃)₂] are described. Within the limitations of available structural data related tin compounds are compared with those of corresponding ¹¹⁹Sn Mössbauer spectra.     

Synthese und Kristallstrukturen der Phosphaniminato-Komplexe [MCl2(NPPh3)]2 mit M = Al und Ga, [SbCl2(NPMe3)(DMF)]2 sowie des Phosphanimin-Komplexes [Ph3PNH · BF3] · THF

Syntheses and Crystal Structures of the Phosphorane Iminato Complexes [MCl₂(NPPh₃)]₂ with M = Al and Ga, [SbCl₂(NPMe₃)(DMF)]₂, and of the Phosphorane Imine Complex [Ph₃PNH · BF₃] · THF The phosphorane iminato complexes [MCl₂(NPPh₃)]₂ with M = Al and Ga and [SbCl₂(NPMe₃)(DMF)]₂ are formed as colourless crystals by reactions of the anhydrous trichlorides MCl₃ (M = Al, Ga, Sb) with the corresponding silylated phosphorane imines Me₃SiNPR₃ in acetonitrile and in dimethyl formamide, respectively. The phosphorane imine derivative [Ph₃PNH · BF₃] · THF is formed from Me₃SiNPPh₃ and boron trifluoride etherate in boiling tetrahydrofuran. The compounds are characterized by their i. r. spectra and by crystal structure analyses. [AlCl₂(NPPh₃)]₂ : Space group P1 , Z = 1, structure solution with 1 585 observed unique reflections, R = 0.061. Lattice dimensions at ?70°C: a = 917.6, b = 1 053.5, c = 1 145.2 pm, α = 111.72°, β = 100.80°, γ = 109.95°. [GaCl₂(NPPh₃)]₂ : Space group P1 , Z = 1, structure solution with 2 586 observed unique reflections, R = 0.066. Lattice dimensions at ?70°C: a = 917.5, b = 1 058.3, c = 1 153.7 pm, α = 105.52°, β = 107.75°, γ = 109.88°. In both compounds the metal atoms are linked to planar M₂N₂ four-membered rings via the N-atoms of the phosphorane iminato groups. [SbCl₂(NPMe₃)(DMF)]₂ : Space group P2₁/n, Z = 4, structure solution with 3 805 observed unique reflections, R = 0.038. Lattice dimensions at ?70°C: a = 1 913.0, b = 726.8, c = 2 040.7 pm, β = 113.62°. The unit cell contains two symmetry independent dimeric molecules, in which the antimony atoms are centrosymmetricly μ₂ linked via the N-atoms of the phosphorane iminato groups. Along with the oxygen atom of the dimethyl formamide molecule the Sb atoms achieve a ψ-octahedral environment. [Ph₃PNH · BF₃] · THF : Space group C2/c, Z = 8, structure solution with 2 048 observed unique reflections, R = 0.058. Lattice dimensions at ?70°C: a = 2 460.4, b = 869.2, c = 1 978.0 pm, β = 116.35°.     

(Me2NH2)[(Ph3Sn)3(MoO4)2], ein Triorganozinnmolybdat mit Schichtstruktur

(Me₂NH₂)[(Ph₃Sn)₃(MoO₄)₂], a Triorganotin Molybdate with Layer Structure The reaction of [(Ph₃Sn)₂MoO₄] with (Me₂NH₂)Cl in an acetonitrile/water mixture leads to the formation of (Me₂NH₂)[(Ph₃Sn)₃(MoO₄)₂] ( 1 ). ( 1 ) crystallizes in the space group Pca2₁ with a = 1967.0(4), b = 1353.1(2) and c = 2176.6(5) pm. In the crystal structure of 1 Ph₃SnO₂ bipyramides and MoO₄ tetrahedra are linked by corner sharing to give a layer structure. Additionally the layers are connected by O···H···N hydrogen bridges between MoO₄ groups and [Me₂NH₂]⁺ ions to give a 3D network structure.     

Contribution à la phytochimie du genre Gentiana. VII. Etude des composés flavoniques et xanthoniques dans les feuilles de Gentiana vernaL. (1ère communication)

A new xanthone-O-glycoside, the 1,7-dihydroxy-3-methoxyxanthone-8-O-β-D-glucopyranoside ( 7 ), has been isolated from the leaves of Gentiana verna L. by means of column chromatography on polyamid. Six known xanthones: 1-hydroxy-3,7,8-trimethoxyxanthone-1-O-primerveroside ( 2 ); 1,7,8-trihydroxy-3-methoxyxanthone ( 3 ); 7-hydroxy-3,8-dimethoxyxanthone-1-O-primeveroside ( 4 ); 7,8-dihydroxy-3-methoxyxanthone-1-O-primeveroside ( 5 ); mangiferin 6 and the flavone C-glycoside isoorientin 8 have also been isolated and identified.