Polymere Thiolatokomplexe [M(SPh)3]∞ der Metalle Molybdän,Wolfram, Eisen und Ruthenium mit linearen Metallketten. Synthese und Struktur von (OC)3Fe(SPh)3Fe(SPh)3Fe(CO)3 · 2(CH3)2CO

Polymeric Thiolato Complexes [M(SPh)₃]∞ of the Metals Mo, W, Fe, and Ru with Linear Metal Chains. Synthesis and Crystal Structure of (OC)₃Fe(SPh)₃Fe(SPh)₃Fe(CO)₃ · 2(CH₃)₂CO At high temperature the reaction of the metal carbonyls Mo(CO)₆, W(CO)₆ and Fe(CO)₅ with S₂Ph₂ (Ph = C₆H₅) yields the polymeric complexes [M(SPh)₃]∞. Similarly [Ru(SPh)₃]∞ can be obtained from ruthenium(III) acetylacetonate and HSPh. At room temperature under UV-irradiation Fe(CO)₅ reacts with S₂Ph₂ to form the oligomeric complex (OC)₃Fe(SPh)₃Fe(SPh)₃Fe(CO)₃. The polymeric complexes [M(SPh)₃]∞ (M = Mo, W, Fe, Ru) are composed of linear chains with bridging SPh-ligands between the metal atoms. Of these complexes [Fe(SPh)₃]∞ is paramagnetic, whereas the others exhibit antiferromagnetic behaviour. The spin coupling is presumably connected with the formation of metal pairs, resulting in alternating shortened and extended distances in the metal chain. The oligomeric complex (OC)₃Fe(SPh)₃Fe(SPh)₃Fe(CO)₃ crystallizes triclinic in the space group P1 with z = 2. It has almost the symmetry D_3d with a linear arrangement of the Fe atoms. The paramagnetism of Fe₃(CO)₆(SPh)₆ can be explained by a d⁶ high spin configuration of the central atom and low spin behaviour of the two other Fe atoms, which are bonded to CO.     

Azidokomplexe des Zirkoniums: ZrCl3N3, [ZrCl4N3]22⊝, [ZrCl4(N3)2]2⊝; die Kristallstruktur von (PPh4)2[ZrCl4N3]2

Azido Complexes of Zirconium: ZrCl₃N₃, [ZrCl₄N₃]₂^2?, [ZrCl₄(N₃)₂]^2?; Crystal Structure of (PPh₄)₂ [ZrCl₄N₃]₂ Highly explosive ZrCl₃N₃ is formed by the reaction of ZrCl₄ with iodine azide in dichloromethane suspension. According to the i.r. spectra, the compound is polymeric by azide and chlorine bridges. Zirconium tetrachloride reacts with one and two moles of tetraphenylphosphonium azide respectively, forming the thermally and mechanically stable complexes (PPh₄)₂[ZrCl₄N₃]₂ and (PPh₄)₂[ZrCl₄(N₃)₂]. The crystal structure of (PPh₄)₂[ZrCl₄N₃]₂ was determined by X-ray methods (1942 reflexions, R = 6.5%). The complex crystallizes in the monoclinic space group P2₁/n with two formula units per unit cell. The structure consists of tetraphenylphosphonium cations and dimeric anions [ZrCl₄N₃]₂^2?, in which the Zr atoms are linked by the α-N atoms of the azide groups, forming a centrosymmetric Zr₂N₂ ring with symmetry D_2h. According to the i.r. spectra, the azide groups in the complex (PPh₄)₂[ZrCl₄(N₃)₂] are covalently bonded at the Zr atom in trans positions.     

Vanadium oxides on aluminum oxide supports. 2. Structure, vibrational properties, and reducibility of V2O5 clusters on alpha-Al2O3(0001)

The structure, stability, and vibrational properties of isolated V2O5 clusters on the Al2O3(0001) surface have been studied by density functional theory and statistical thermodynamics. The most stable structure does not possess vanadyl oxygen atoms. The positions of the oxygen atoms are in registry with those of the alumina support, and both vanadium atoms occupy octahedral sites. Another structure with one vanadyl oxygen atom is only 0.12 eV less stable. Infrared spectra are calculated for the two structures. The highest frequency at 922 cm(-1) belongs to a V-O stretch in the V-O-Al interface bonds, which supports the assignment of such a mode to the band observed around 941 cm(-1) for vanadia particles on alumina. Removal of a bridging oxygen atom from the most stable cluster at the V-O-Al interface bond costs 2.79 eV. Removal of a (vanadyl) oxygen atom from a thin vanadia film on alpha-Al2O3 costs 1.3 eV more, but removal from a V2O5(001) single-crystal surface costs 0.9 eV less. Similar to the V2O5(001) surface, the facile reduction is due to substantial structure relaxations that involve formation of an additional V-O-V bond and yield a pair of V(IV)(d1) sites instead of a V(III)(d2)/V(V)(d0) pair.     

Structure-type separation of diesel fuels by solid phase extraction and identification of the two- and three-ring aromatics by capillary GC-mass spectrometry

A simple and effective solid phase extraction (SPE) method using silica gel micro glass columns has been developed for the separation of diesel fuel into groups of aliphatic, and mono-, di- and polyaromatic hydrocarbons. It is based on a stepwise gradient of dichloromethane in n-pentane. The resulting fractions were analyzed by capillary gas chromatography with a flame ionization detector and coupled gas chromatography-mass spectrometry. Commercially available standards, and retention indices and mass spectra were used for identification of individual aromatic compounds. The principal polycyclic aromatic hydrocarbons (PAHs) in diesel fuel are naphthalene, biphenyl, fluorene, phen-anthrene and their alkylated derivatives. Sulfur-containing PAHs are mainly represented by methyl-substituted dibenzo-thiophenes.     

Gold-Stickstoff-Heterocyclen. 3. Synthese,Eigenschaften und Struktur von trimerem Amido-dimethylgold(III), [(CH3)2 AuNH2]3

Gold Nitrogen Heterocycles. 3. Synthesis, Properties, and Structure of Amido Dimethyl Gold(III), [(CH₃)₂ AuNH₂]₃ The reaction of [(CH₃)₂AuI]₂ with KNH₂ in liquid NH₃ yields tetrameric and trimeric amido dimethyl gold(III). The tetrameric form transforms at ambient temperature easily in the more stable trimeric complex. [(CH₃)₂AuNH₂]₃ forms air-stable, colorless crystals, which are sensitive against irridiation with light. It crystallizes in the orthorhombic space group Ama2 with the lattice constants a = 1653.4, b = 1844.4, c = 448.1 pm, Z = 4. In the trimeric complex the Au(CH₃)₂ groups are linked together by symmetrical amido bridges forming a six membered Au? N heterocycle in the chair conformation. The Au atoms exhibit a square-planar coordination of two CH₃ groups (Au? C = 203 pm) and two N atoms (Au? N = 215 pm) in a cis arrangement. The symmetry C_3v was confirmed for the complex in solution and in the solid state. The vibrational spectra as well as the H-NMR and mass spectra are discussed.     

Die Kristallstrukturen von Triphenylarsin-p-toluolsulfonylimin und seines Donor-Akzeptorkomplexes [ZrCl4(Ph3AsNSO2Tol)]2

The Crystal Structures of Triphenylarsin-p-toluene Sulfonylimine and of its Donor-Acceptor Complex [ZrCl₄(Ph₃AsNSO₂Tol)]₂ The molecular structures of the title compounds are reported. In the donor-acceptor complex [ZrCl₄(Ph₃AsNSO₂Tol)]₂ the zirconium atoms are bridged by the oxygen atoms of the triphenylarsin-p-toluene sulfonylimine molecules, forming a centrosymmetric dimer with a puckered Zr₂O₄S₂ eight-membered ring in the chair conformation. Ph₃AsNSO₂Tol: Space group P1 , Z = 2, structure determination with 4 010 observed unique reflections, R = 0.036. Lattice dimensions at 19°C: a = 897.52(4), b = 1 071.82(6), c = 1 337,49(5) pm, α = 110.280(4)°, β = 98.814(4)°, γ = 109.872(4)°. [ZrCl₄(Ph₃AsNSO₂Tol)]₂: Space group P2₁/n, Z = 4, structure determination with 3 762 observed unique reflections, R = 0.078. Lattice dimensions at ?60°C: a = 1 387.3(4), b = 1 434.9(2), c = 1 404.7(4) pm, β = 92.71(1)°.     

New copper-mediated O-arylations of phenols with arylstannanes

A novel method for the synthesis of diaryl ethers with phenols and arylstannanes under mild conditions is described. This copper-mediated O-arylation is feasible using DMAP in acetonitrile and is complementary to the use of boronic acids as aryl donors. The reaction is tolerant of a wide range of substituents and sterically hindered coupling partners.