Synthesis of Tricyclic (λ5)-Phosphoranes; unusual N-demethylation/N-alkylation reactions during the oxidative addition of hexafluoroacetone and tetrachloro-ortho-benzoquinone to benzodiaza-λ3-phosphorinones. Single crystal X-ray diffraction studies of various products

The reaction of methylisatoic acid anhydride 1 with benzylamines led to the N-benzyl-N′-methylanthranilamide derivatives 2 – 4 . Their reaction with phosphorus trichloride furnished the 2-chloro-1-halobenzyl/benzyl-3-methyl-4(1 H)-1,3,2-benzodiazaphosphorin-4-ones 5 – 7 which, upon reaction with bis-(2-chloroethyl)ammonium chloride/triethylamine, were converted into the P-bis-(2-chloroethyl)amino-1-halobenzyl/benzyl-3-methyl-4(1 H)-1,3,2-benzodiazaphosphorin-4-ones 8 – 10 and 12 . With 2-chloroethylammonium chloride/triethyl-amine the P? NHCH₂CH₂Cl-substituted compound 11 was obtained from the P^IIICl-species 6 . The reaction of 8 – 10 and 12 with hexafluoroacetone (HFA) took an unusual course: apart from the oxidative addition of HFA and formation of the perfluoropinacolyl ring system, one of the two CH₂CH₂Cl groups was found to alkylate the CH₃N atom with formation of a five-membered (diazaphospholane) ring in the tricyclic phosphoranes 13 – 16 . The reaction of 11 with HFA also produced a spirophosphorane 17 which involved a λ⁵-oxazaphosphetidine ring system. In the reaction of 8, 10 and 12 with tetrachloro-o-benzoquinone, an oxidative addition reaction with concomitant N-alkylation and formation of the tricyclic phosphoranes 18 – 20 was found to take place. Single crystal X-ray structure determinations are described for the phosphoranes 13, 14 and 16 , and for the precursor compound 9 . The following features are common to the isostructural compounds 13 and 16 and the diethyl ether hemisolvate of 14 : the (λ⁵)-spiro phosphorus atom lies out of the plane of the other atoms of the rings to which it is common, and the dioxaphospholane rings display a twist conformation. In the λ³P-compound 9 the phosphorus atom also lies out of the plane of the other ring atoms.     

Synthesis and Characterization of ASnOAsO4(A = K and Rb)

Crystals of two alkali-metal tin(IV) arsenates, KSnOAsO₄ and RbSnOAsO₄, were grown from a flux and structurally characterized by single-crystal X-ray diffraction. Crystal data: RSnOAsO₄, orthorhombic, Pna2₁ (No. 33), a = 13.406(3) Å, b = 6.678(1) Å, c = 10.921(2) Å, Z = 8, R = 0.037 for 1173 independent reflections with I > 2.5ó(l); RbSnOAsO₄, as above except a = 13.567(3) Å, b = 6.791( 1) Å, c = 10.891(2) Å, R = 0.035 for 1958 independent reflections. The two compounds are isostructural with the nonlinear optical material KTiOPO₄. The oxygen frameworks of both tin compounds approximate closely to a centrosymmetric arrangement, as indicated from the analysis of atomic coordinates. Second harmonics were generated in powdered RbSnOAsO₄ to confirm the absence of a center of symmetry in the structure.     

碳纤维微电极研究(Ⅺ)——利用温度效应测定电极反应的热力学和动力学参数

研究了温度对碳纤维微电极上伏安曲线的影响及温度与电极电位的关系,测定了电极反应的热力学参数.由电流与温度的关系测定了去极剂的扩散活化能E_(al)和D_o,利用微电极具有高速传质的特性,测定了常规电极上为可逆反应的电极反应标准速率常数(?),并通过(?)与温度的关系测定了电极反应的活化能.     

Structural refinement of Nd[Fe(CN)6]·4H2O and study of NdFeO3 obtained by its oxidative thermal decomposition at very low temperatures

The crystal structure of Nd[Fe(CN)₆]·4H₂O has been refined by Rietveld analysis using high resolution synchrotron powder X-ray diffraction data. It belonged to the orthorhombic crystal system, Cmcm space group, with cell parameters: , and . The change in space group from P6₃/m which is observed in the pentahydrates (LnFe(CN)₆·5H₂O) to Cmcm in the tetrahydrates has been analyzed to be a consequence of the change in 9-fold coordination of Nd³⁺ in the pentahydrates to 8-fold coordination in the tetrahydrates, which changes the Nd³⁺ environment from tricapped trigonal prism to a distorted tricapped trigonal prism or square antiprism. Its decomposition process in air to produce NdFeO₃ has been followed by thermogravimetric and differential thermal analysis, IR spectroscopy and laboratory powder XRD. We found that it is possible to synthesize crystalline NdFeO₃ at temperatures as low as 380 °C and refine the structure of single phase crystalline NdFeO₃ synthesized by this method at 600 °C.     

Spectroscopic study of hydrogen exchange processes and structure of intermediate complexes with intermolecular hydrogen bonds

The kinetics of hydrogen exchange in molecular systems with H-bonds has been studied by means of kinetic IR spectroscopy and low-temperature NMR spectroscopy. The experimental values of the rate constants and activation energies for molecules capable of forming H-bonds as both proton donors and proton acceptor are collected and analyzed from the point of view of the influence of H-bond formation ability of the molecules-partners. The evidence available testifies to a molecular mechanism of the H-exchange reactions in inert solvents and in the gas phase via the formation of cyclic bimolecular intermediates. The different mechanisms and the structure of intermediate complex of molecular H-exchange process in inert media are discussed and the possible paths of experimental elucidation of reaction mechanism are offered.     

Darstellung,Kristallstruktur und Normalkoordinatenanalyse der bindungsisomeren Pentachlororhodanoosmate(IV)

Preparation, Crystal Structure and Normal Coordinate Analysis of Linkage Isomeric Pentachlororhodanoosmates(IV) By treatment of [OsCl₅I]^2? with (SCN)₂ in dichloromethane the linkage isomers [OsCl₅(NCS)]^2? and [OsCl₅(SCN)]^2? are formed which have been separated by ion exchange chromatography on diethylaminoethyl cellulose. The X-ray structure determination on single crystals of (Ph₄As)₂[OsCl₅(NCS)] (monoclinic, space group P2₁/a, a = 18.872(2), b = 11.6024(2), c = 22.786(1), β = 109.057(1)°, Z = 4) and (Ph₄As)₂[OsCl₅(SCN)] (monoclinic, space group P2₁/a, a = 19.057(2), b = 11.306(2), c = 22.612(1), β = 106.64(2)°, Z = 4) reveals the complete ordering of the complex anions. The thiocyanate group is located above one of the Cl ligands of the equatorial plane with the Os? N? C angle of 166.1° for N bonding and the Os? S? C angle of 109.9° for S bonding. The IR and Raman spectra of both linkage isomers known from literature are assigned by normal coordinate analysis based on the general valence force field using the molecular parameters of the X-ray determination. The valence force constants are f_d(OsN) = 1,81 and f_d(OsS) = 1,32 mdyn/Å. Taking into account increments of the trans influence a good adjustment between observed and calculated frequencies is achieved.     

有机铵盐对FC-SAA表面活性及溶度的影响

测定了一系列有机铵盐与一种全氟烷磺酸盐１：１混合体系水 溶液的表面张力，由此研究有机铵盐对碳氟表面活性剂表面活性及溶度的影响，导出应用于此种混合体系的Ｇｉｂｂｓ吸附公式，并讨论了混合体系中两表面活性组分的表面分子相互作用和表面层的结构。     

Das Hexagallan [Ga6{SiMe(SiMe3)2}6] und das closo‐Hexagallanat [Ga6{Si(CMe3)3}4(CH2C6H5)2]2— — der Übergang zu einem ungewöhnlichen precloso‐Cluster

The Hexagallane [Ga₆{SiMe(SiMe₃)₂}₆] and the closo‐Hexagallanate [Ga₆{Si(CMe₃)₃}₄ (CH₂C₆H₅)₂]^2— — the Transition to an Unusual precloso‐Cluster The closo hexagallanate [Ga₆R₄(CH₂Ph)₂]^2— (R = Si^tBu₃) as well as the hexagallane Ga₆R₆ (R = SiMe(SiMe₃)₂) with only six cluster electron pairs were isolated from reactions of “GaI” with the corresponding silanides. The structure of the latter is derived from an octahedron by a Jahn‐Teller‐distortion and is different from the capped trigonal bipyramidal one expected by the Wade‐Mingos rules. Both compounds were characterized by X‐ray crystallography. The bonding is discussed with simplified Ga₆H₆ and Ga₆H₆^2— models via DFT methods.     

Optimization of the process parameters of synthesis of vinblastine imprinted polymer

Molecularly imprinted polymers (MIPs) are tailor-made polymers with high selectivity for the template molecule. This selectivity arises from the synthetic procedure followed to prepare the MIP. In this work, the influence of process parameters on the preparation of vinblastine (VLB) imprinted polymers was presented. In the procedure of polymerization, VLB (0.1 mmol) was used as the template molecule and a commonly used initiator, azobisisobutyronitrile (AIBN), was employed to initiate the reaction at 60 °C. The influence of the following parameters was investigated: the moles of functional monomer (MAA, 0.3-1.0 mmol), the moles of cross-linker (EDMA, 1.5-5.0 mmol) and the porogenic solvent (toluene or acetonitrile). A mathematical method of uniform design was applied to optimize these selected parameters in order to increase the selectivity of MIP for template molecule. The experimental data were analyzed to obtain the regression model and the optimal conditions were achieved by optimization with uniform design software. The MIP was synthesized under the optimal conditions that 1.0 mmol of MAA and 5.0 mmol of EDMA copolymerized in toluene in the presence of 0.1 mmol of VLB. After removal of the template molecule, the obtained MIP was then employed as the sorbents of solid-phase extraction (SPE) to separate VLB from Catharanthus roseus extract. The results showed that the polymer exhibited high affinity to the template molecule and could separate and enrich VLB from C. roseus extract effectively. The recovery of VLB on the optimal MIP was 89.00%, which agreed closely with the predicted recovery. Therefore it is possible to further improve the nature of the polymer by optimizing the polymerization parameters with the method of uniform design.     

Zur Kenntnis von BaTiVO4 und SrTiVO4

On BaTiVO₄ and SrTiVO₄ BaTiVO₄ and SrTiVO₄ were prepared in closed systems by solid state reactions. They crystallize with orthorhombic symmetry (BaTiVO₄: space group D-Pmnb; a = 5.889; b = 7.889; c ?10.397 Å; Z = 4; SrTiVO₄: space group D-P2¹,2¹,2¹,2¹; a = 5.855; b = 7.572; c = 10.012 Å; Z = 4) and belong to β-K₂SO₄-type. The ordered occupation of point positions by Ba²⁺ and Tl⁺ as well as the decrease in symmetry of SrTiVO₄ are discussed.