(C6H16N2)Zn3(HPO3)4H2O: a new layered zinc phosphite templated by diprotonated trans-1,4-diaminocyclohexane

Employing trans-1,4-diaminocyclohexane (trans-1,4-DACH) as a template, a new two-dimensional layered zinc phosphite (C₆H₁₆N₂)Zn₃(HPO₃)₄H₂O (1) has been prepared hydrothermally. Single-crystal X-ray diffraction analysis shows that it crystallizes in the monoclinic space group P2₁/n with a=10.458(2) Å, b=14.720(3) Å, c=13.079(3) Å, β=97.93(3)°, V=1994.1(7) ų, Z=4, R₁=0.0349 (I>2σ(I)) and wR₂=0.0605 (all data). The inorganic layer is built up by alternation of ZnO₄ tetrahedra and HPO₃ pseudo pyramids forming a 4.6.8-net. The sheet is featured by a series of capped six-membered rings. The diprotonated trans-1,4-DACH molecules reside in the interlayer region and interact with the inorganic network through H-bonds.     

Crystal structure of glycine phosphite C<Subscript>2</Subscript>H<Subscript>5</Subscript>NO<Subscript>2</Subscript>·H<Subscript>3</Subscript>PO<Subscript>3</Subscript>

Single crystal X-ray diffraction study of glycine phosphite C₂H₅NO₂·H₃PO₃ was performed (monoclinic, space group P2₁/c, a = 7.401(3) Å, b = 8.465(3) Å, c = 9.737(3) Å; β = 100.73(5)°, Z = 4). It has been found that one of hydrogen atoms is located at the centre of symmetry forming two strong hydrogen bonds to yield H₄P₂O ₆ ^?2 dimers, while another hydrogen atom is statistically disordered over two positions and organizes the dimers into an infinite corrugated chain. The ordering of this hydrogen atom position and/or displacement of the other one from the centre of symmetry will lead to the loss of symmetry centre and lowering of the point group symmetry from C_2h to piezo-active group C₂ or C _s .     

Consecutive Reaction of Bis [2,2,2－trifluoroethyl] phosphite. One－pot Synthesis of Substituted 3－Cyano－β, γ－unsaturated Nitriles with Exclusive or Predominant E－Selectivity

The consecutive reaction of bis [ 2, 2, 2-trifluoroethyl] phosphite and its application to the one-pot synthesis of 3-cyano-β, γ-unsaturated nitriles with exdusive or predominant E-selectivity (E: Z = 100-85: 0-15) and excellent yields (94%-99%) are described.     

Direct and stereoselective synthesis of β-d-mannosides using 4,6-O-benzylidene-protected mannosyl diethyl phosphite as a donor

A direct and practical method for the construction of β-mannosidic linkages is described. While β-selectivities in the TMSOTf-promoted glycosidation of 2,3,4,6-tetra-O-benzyl-d-mannosyl diethyl phosphite are found to be highly dependent on the reactivity of acceptor alcohols, 2,3-di-O-benzyl-4,6-O-benzylidene-d-mannosyl diethyl phosphite reacts with a wide range of acceptor alcohols in the presence of TMSOTf in CH₂Cl₂ at −45 °C to give β-mannosides in high yields with good to high β-selectivities.     

二维层状磷酸亚磷酸钒(Ⅳ)化合物[V2O2(OH)(HPO3)(HPO3)0.7(PO3OH)0.3].(C6N2H16)0.5的水热合成与结构表征

迄今, 在中温水热条件下已合成了大量具有空旷骨架结构的过渡金属磷酸盐微孔材料[1], 这类材料在非线性光学材料、磁性材料、超导材料及催化等诸多方面具有潜在的应用前景[2～5].     

Tetraalkyl Hydroxymethylene-bisphosphonate and Dialkyl 1-Diphenylphosphinoyl-1-hydroxy-ethylphosphonate Derivatives by the Pudovik Reaction and Their Rearranged Products

The reaction of diethyl α-oxoethylphosphonate and diethyl oxobenzylphosphonate with diethyl phosphite, dimethyl phosphite, and diphenylphosphine oxide affords, depending on the substrates and conditions (nature and quantity of the amine catalyst, temperature, and solvent), the Pudovik adduct and/or the corresponding >P(O)–CH–O–P(O)< product formed by rearrangement. The nature of the substituent on the central carbon atom (a methyl or phenyl group) influences the inclination for the rearrangement. The asymmetric products (either adducts or rearranged species) with different P(O)Y functions (Y = RO or Ph) exhibit interesting NMR features.     

An infrared spectroscopic investigation of thin alumina films: measurement of acid sites and surface reactivity

The surface chemical activity of an alumina films grown on Mo(100) by oxidation of aluminum evaporated onto the surface and oxidized using water is examined using Auger, X-ray photoelectron and reflection/absorption infrared spectroscopies. The formation of alumina is confirmed using Auger and X-ray photoelectron spectroscopy from the positions and intensities of the aluminum features and using reflection-absorption infrared spectroscopy from the longitudinal optical modes of the Al–O bonds measured at 935 cm⁻¹. The presence of surface hydroxyls is monitored by forming films using D₂O which are evidenced by a feature at 2700 cm⁻¹. Ammonia adsorption on a dehydroxylated surface yields a single peak at 1260 cm⁻¹ due to ammonia adsorbed at a surface Lewis site where the principle symmetry axis of ammonia is oriented perpendicularly to the surface plane. Ammonia also appears to adsorb at Lewis sites on a hydroxylated surface with a slightly different adsorption geometry from that on a dehydroxylated surface. Finally, the chemistry of trimethyl aluminum adsorbed on the planar hydroxylated alumina surface is compared with that found on high-surface-area γ-alumina where the spectra and the chemistry found in both régimes is exactly identical except that the low-frequency methyl bending modes (at 769 and 718 cm⁻¹) are not obscured on the thin film by the intense substrate whereas they are on the high-surface-area support.     

Synthesis and properties of poly(imide‐hydrazide)s and poly(amide‐imide‐hydrazide)s from N‐[p‐(or m‐)carboxyphenyl]trimellitimide and aromatic dihydrazides or p‐aminobenzhydrazide via the phosphorylation reaction

A series of new poly(imide‐hydrazide)s and poly(amide‐imide‐hydrazide)s were obtained by the direct polycondensation of N‐[p‐(or m‐)carboxyphenyl]trimellitimide (p‐ or m‐CPTMI) with terephthalic dihydrazide (TPH), isophthalic dihydrazide (IPH), and p‐aminobenzhydrazide (p‐ABH) by means of diphenyl phosphite and pyridine in the N‐methyl‐2‐pyrrolidone (NMP) solutions containing dissolved CaCl₂. The resulting hydrazide‐containing polymers exhibited inherent viscosities in the 0.15–0.96 dL/g range. Except for that derived from p‐CPTMI with TPH or p‐ABH, the other hydrazide copolymers were readily soluble in polar solvents such as NMP and dimethyl sulfoxide (DMSO). As evidenced by X‐ray diffraction patterns, the hydrazide copolymer obtained from TPH showed a moderate level of crystallinity, whereas the others were amorphous in nature. Most of the amorphous hydrazide copolymers formed flexible and tough films by solvent casting. The amorphous hydrazide copolymers had glass‐transition temperatures (T_g) between 187 and 233 °C. All hydrazide copolymers could be thermally converted into the corresponding oxadiazole copolymers approximately in the region of 250–400 °C, as evidenced by the DSC thermograms. The oxadiazole copolymers showed a significantly decreased solubility when compared to their respective hydrazide precursors. They exhibited T_g's of 264–302 °C and did not show dramatic weight loss before 400 °C in air or nitrogen. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1599–1608, 2000     

9个PstI接头片段的合成及其酶反应研究

采用固相亚磷酸三酯法和化学与酶促相结合的方法合成了９个ＰｓｔＩ接头片段，并对它们进行了酶切反应研究．结果表明：ＰｓｔＩ识别序列中尿苷的存在只降低其互补链的切割程度，对其本链没有影响；ＰｓｔＩ切割底物是按两步单股切割机制进行，作用的最小底物是含有识别序列的８～１２聚脱氧核糖核苷酸，且对底物中识别序列两边的碱基对数目有一定要求；ＰｓｔＩ识别序列中的二个胞苷在酶反应中起的作用是不一样的     

“One‐pot” synthesis of aromatic poly(1,3,4‐oxadiazole)s in novel solvents—ionic liquids

The new convenient method for the synthesis of high molecular weight aromatic poly(1,3,4‐oxadiazole)s (PODs) has been proposed. These polymers were prepared by “one‐pot” procedure from dicarboxylic acid and hydrazine's salt (sulfate, phosphate) or dicarboxylic acid dihydrazides. The mixture of ionic liquid and triphenyl phosphite was used both as a solvent and condensing agent. The polycyclization occurred at a sufficiently low temperature of 210 °C for 2–5 h and resulted in obtaining film‐forming PODs having inherent viscosities up to 0.9 dL/g and good thermal stability. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 380–394, 2006