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.     

Die Kristallstrukturen von {Li3(12-Krone-4)2[HC(CN)2]3}, {Na(15-Krone-5)-[HC(CN)2]} und {Na[N(nBu)4][HC(CN)2]2 · THF}

The Crystal Structures of {Li₃(12-crown-4)₂[HC(CN)₂]₃}, {Na(15-crown-5)[HC(CN)₂]}, and {NaN(nBu)₄[HC(CN)₂]₂ · THF} The preparation and the crystal structures of the title compounds 1 — 3 are described. 1 forms a polymeric chain structure, in which one of the lithium ions is linked by Li…NCC(H)CN… bridges. The remaining lithium ions form (12-crown-4)Li[NCC(H)CN] units, which are coordinated by one of the nitrogen atoms of the dicyanomethanide ions with the lithium ions of the chain. 2 forms an ion pair, in which the sodium ion is coordinated by the five oxygen atoms of the crown ether molecule and by one nitrogen atom of the dicyanomethanide ion. 3 has a threedimensional network, in which the sodium ions are coordinated in a distorted tetrahedral manner by the nitrogen atoms of the dicyanomethanide ions. In the cavities of the network the tetrabutylammonium ions and the THF molecules are found.     

Dimethylarsenazid (CH3)2AsN3, Dimethylwismutazid (CH3)2BiN3 und Dimethylthalliumzid (CH3)2TiN3

The reaction of (CH₃)₂AsJ and AgN₃ yields (CH₃)₂AsN₃; a colourless liquid (b. p. 136°C) which dissolves as a monomeric in benzene. (CH₃)₂BiN₃ is precipitated in form of colourless needles (dec. temp. 150°C) from an etherical solution of Bi(CH₃)₃ and HN₃. According to its vibrational and mass spectra the molecules are not associated although the (CH₃)₂BiN₃ is not soluble; dipole association of this polar molecules is assumed for the crystal structure. (CH₃)₂TlN₃ can be obtained from TI(CH₃)₃ and ClN₃ as well as from (CH₃)₂TlOH and HN₃ in form of colourless needles and leaves (dec. temp. 245°C). According to its vibrational spectra it has an ionic structure, (CH₃? Tl? CH₃)⁺N^?₃.     

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.     

A 2,2′-diphosphinotolane as a versatile precursor for the synthesis of P-ylidic mesoionic carbenes via reversible C–P bond formation

A metal-templated synthetic route to cyclic (aryl)(ylidic) mesoionic carbenes (CArY-MICs) featuring an endocyclic P-ylide is presented. This approach, which requires metal templates with two cis-positioned open coordination sites, is based on the controlled cyclisation of a P,P′-diisopropyl-substituted 2,2′-diphosphinotolane (1) and leads to chelate complexes coordinated by a phosphine donor and the CArY-MIC carbon atom. The C–P bond formation involved in the former partial cyclisation of 1 proceeds under mild conditions and was shown to be applicable all over the d-block. In the presence of a third fac-positioned open coordination site, the P–C bond formation was found to be reversible, as shown for a series of molybdenum complexes. DFT modelling studies are in line with an interpretation of the target compounds as CArY-MICs.

A metal-templated synthesis of cyclic (aryl)(ylidic)mesoionic carbene complexes (CArY-MICs) is presented. In the case of molybdenum carbonyls, the crucial P–C bond formation, which occurs during CArY-MIC formation, was found to be reversible.     

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)°.     

Field-force alignment of disc-type pi systems.

The ability of electric fields to align nonpolar semiconducting molecules was demonstrated using hexa(para-n-dodecylphenyl)hexabenzocoronene (HBC-PhC12) as a model compound. A solution of HBC-PhC12 was applied to a glass surface by drop-casting and the molecules were oriented into highly ordered structures by an electric field during solvent evaporation. Atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) showed a long-range alignment where the disclike molecules were organized in columns perpendicular to the direction of the imposed electric field. The high anisotropy of the uniaxially aligned films was characterized by cross-polarized light microscopy. The birefringence of the HBC-PhC12 films was related to the presence of extended domains of unidirectionally aligned columns in which the aromatic cores of the HBC-PhC12 molecules were perpendicular to the columnar axis. The packing and the arrangement of the molecules in the field-force ordered films were proven by electron diffraction and X-ray analyses.