Poly[propane‐1,3‐diammonium [tetra‐μ3‐oxo‐hexaoxotrimolybdenum(VI)] dihydrate]

The crystal structure of the title compound, {(C₃H₁₂N₂)[Mo₃O₁₀]·2H₂O}_n, is composed of [Mo₃O₁₀]²⁻ anionic chains, propane‐1,3‐diammonium cations and solvent water molecules. The [Mo₃O₁₀]²⁻ chain is constructed from edge‐sharing MoO₆ octahedra. The protonated propane‐1,3‐diamine cations and solvent water molecules are located between the chains and are linked to the O atoms of the inorganic chains by hydrogen bonds.     

Novel charge transfer supramolecular assemblies with Keggin anions and 2-amino-5-nitropyridine

Several novel compounds with the non-linear optical chromophore 2-amino-5-nitropyridine (2A5NP) and Keggin polyoxoanions (alpha-isomers), having the general formula (2A5NP)(m)H(n)[XM12O40].xH2O, M = Mo, W, were synthesised. Compounds were obtained with X = P, n = 3, m = 3 and 4 and X = Si, n = m = 4 (x = 2-6). Thus, for each of the anions [PMo12O40]3- and [PW12O40]3- two different compounds were obtained, with the same anion and organic counterpart but with a different stoichiometric ratio. These presented different charge transfer properties and thermal stability. All compounds were characterised by spectroscopic and analytical techniques. The single crystal X-ray diffraction structure of (2A5NP)4H3[PMo12O40].2.5H2O.0.5C2H5OH showed that the water solvent molecules and the organic chromophores are assembled via infinite one-dimensional chains of hydrogen bonds with formation of open channels, which accommodate [PMo12O40]3- and ethanol solvent molecules.     

1-丁基-3-甲基咪唑磷钨酸盐的制备及其对酯化反应的催化性能

以溴化1-丁基-3-甲基咪唑盐([bmim]Br)和磷钨酸(H3PW12O40)为原料制备了1-丁基-3-甲基咪唑磷钨酸盐([bmim]3PW12O40)催化剂,并用傅里叶变换红外光谱、热重分析-差示扫描量热法、正丁胺电位滴定及元素分析等技术对催化剂进行了表征,考察了催化剂对乙醇与乙酸酯化合成乙酸乙酯反应的催化活性.结果表明,[bmim]3PW12O40中有3个结晶水,并保持有H3PW12O40的Keggin结构和酸强度,[bmim]3PW12O40的酸量明显少于H3PW12O40的酸量.在乙醇与乙酸酯化合成乙酸乙酯反应中,[bmim]3PW12O40催化剂具有较高的催化活性和较好的重复使用性能.     

Ag(I)配位聚合物[Ag2(bpp)2(H2O)]·pydc·7H2O的合成、表征及性质研究

水热合成了基于吡啶-3,5-二羧酸(H2pydc)的含Ag(I)配位聚合物 [Ag2(bpp)2(H2O)]·pydc·7H2O (1) (其中bpp = 1,3-双(4-吡啶)丙烷)。X射线单晶结构分析表明,在一维化合物1中,发现了包含(H2O)12水簇单元的二维氢键层状结构。有趣的是,在该二维层中, 每个pydc2-阴离子作为“桥”连接了两个(H2O)12单元和两个自由水分子。另外,对化合物1的荧光、热重、粉末衍射等也进行了研究和讨论。     

Amphiphilic guest sorption of K2[Cr3O(OOCC2H5)6(H2O)3]2[alpha-SiW12O40] ionic crystal

An ionic crystal K2[Cr3O(OOCC2H5)6(H2O)3]2[alpha-SiW12O40] x 3H2O (1a) is synthesized by the complexation of a Keggin-type polyoxometalate of [alpha-SiW12O40]4- with K+ and a macrocation of [Cr3O(OOCC2H5)6(H2O)3]+. Compound 1a possesses both hydrophilic and hydrophobic channels in the crystal lattice. The 3 mol mol(-1) of the water of crystallization in 1a resides in the hydrophilic channel. The water of crystallization is removed by the evacuation at 303 K to form the guest-free phase 1b with small changes in the lattice lengths (+/-0.2 A). The water sorption profile is reproduced by the single rate constant. Therefore, the water sorbed probably resides in the hydrophilic channel. Compound 1b sorbs various kinds of polar organic molecules, and the amounts of < or = C3 alcohols are comparable to or larger than that of water, while chlorocarbons with no hydrogen-bonding ability and nonpolar molecules are excluded. Thus, 1b showed the amphiphilic sorption property. The states of the polar organic molecules sorbed in 1b have been quantitatively investigated using ethanol as a probe molecule. The IR, NMR, and single-crystal X-ray diffraction studies combined with the sorption kinetics reveal that ethanol molecules are mainly sorbed into the hydrophilic channel at P/P0 < or = 0.5, while the sorption into the hydrophobic channel is dominant at P/P0 > or = 0.6. Thus, it is demonstrated that ethanol molecules enter both hydrophilic and hydrophobic channels of 1b.     

Synthesis, structure, and cation complexation of a novel crown ether porphyrin

A new porphyrin appended with four crown ether units at meso-positions via an acetylene bridge was synthesized and structurally characterized, and its complexation with a variety of metal and diammonium cations was investigated.     

Vapor–liquid equilibrium of systems containing alcohols,water, carbon dioxide and hydrocarbons using SAFT

The statistical associating fluid theory (SAFT) equation of state is employed for the correlation and prediction of vapor–liquid equilibrium (VLE) of eighteen binary mixtures. These include water with methane, ethane, propane, butane, propylene, carbon dioxide, methanol, ethanol and ethylene glycol (EG), ethanol with ethane, propane, butane and propylene, methanol with methane, ethane and carbon dioxide and finally EG with methane and ethane. Moreover, vapor–liquid equilibrium for nine ternary systems was predicted. The systems are water/ethanol/alkane (ethane, propane, butane), water/ethanol/propylene, water/methanol/carbon dioxide, water/methanol/methane, water/methanol/ethane, water/EG/methane and water/EG/ethane. The results were found to be in satisfactory agreement with the experimental data except for the water/methanol/methane system for which the root mean square deviations for pressure were 60–68% when the methanol concentration in the liquid phase was 60 wt.%.     

有机-无机复合磷钨酸盐[HTA]3[α-PW12O40]·6H2O的合成与晶体结构（英文）

利用CuCl2·2H2O,1,2,4-三氮唑(TA),L-丝氨酸与Na3[α-PW12O40]·6H2O在乙醇的水溶液中合成了一种有机-无机复合Keggin结构磷钨酸盐[HTA]3[α-PW12O40]·6H2O;利用红外光谱和X射线单晶衍射表征了合成产物的结构,利用元素分析测定了其组成.结果表明,标题化合物属于菱方晶系R-3空间群,晶胞参数为:a=1.793 73(12)nm,b=1.793 73(12)nm,c=2.440 7(3)nm,α=β=90°,γ=120°,Z=6,V=6.800 7(11)nm3,Dc=4.682g·cm-3,GOOF=1.079,R1=0.051 6,wR2=0.137 4.就分子结构而言,标题化合物分子由一个饱和Keggin结构多阴离子[α-PW12O40]3-,三个游离的质子化[HTA]+阳离子和六个结晶水分子组成.     

C(21)-C(40) of tetrafibricin via metal catalysis: beyond stoichiometric chiral reagents, auxiliaries, and premetalated nucleophiles

The C(21)-C(40) fragment of fibrinogen receptor inhibitor tetrafibricin was prepared in 12 steps from propane diol (longest linear sequence). In this approach, 6 C-C bonds are formed via asymmetric iridium catalyzed transfer hydrogenative carbonyl allylation and 2 C═C bonds are formed via Grubbs olefin cross-metathesis.     

Gas hydrate phase equilibria for propane in the presence of additive components

A proper discussion on the possibility and feasibility of technological applications for gas hydrates requires knowledge of the phase behaviour and its relation to the gas hydrate structure and its occupation. This paper presents experimental data on gas hydrate phase equilibria for the system water+propane and for various systems of the kind water+propane+additive. The additives considered are tetrahydropyran, cyclobutanone and cyclohexane, which are assumed to occupy the large cavity of structure II (sII) hydrate, and methylcyclohexane that is a typical structure H (sH) hydrate former. All additives have in common that they are very poorly soluble in water and, therefore, an additional liquid phase is present in these systems. The pressure for the equilibrium hydrate–liquid water–vapour (H–L_w–V) in the system water+propane is reduced upon addition of each of these components. Simultaneously, the hydrate equilibrium hydrate–liquid water–liquid propane (H–L_w–L_C3H8) is shifted to lower temperatures. These observations can be explained in terms of mutual miscibility of propane and the additive component. However, it cannot be excluded that propane molecules are exchanged by additive molecules in occupying the large cavity of sII.     

A quantum chemical study of the decomposition of Keggin-structured heteropolyacids

Heterpolyacids (HPAs) demonstrate catalytic activity for oxidative and acid-catalyzed hydrocarbon conversion processes. Deactivation and thermal instability, however, have prevented their widespread use. Herein, ab initio density functional theory is used to study the thermal decomposition of the Keggin molecular HPA structure through the desorption of constitutional water molecules. The overall reaction energy and activation barrier are computed for the overall reaction HnXM12O40-->Hn-2XM12O39+H2O. and subsequently used to predict the effect of HPA composition on thermal stability. For example, the desorption of a constitutional water molecule is found to be increasingly endothermic in the order silicomolybdic acid (H4SiMo12O40)相似文献   

Ionothermal Synthesis and Characterization of a Layered Propylene Diammonium Gallium Phosphate, (C3H12N2)6[Ga12P16O64] · 4.3 H2O

A new propylene‐1,3‐diammonium gallium phosphate of composition (C₃H₁₂N₂)₆[Ga₁₂P₁₆O₆₄] · 4.3 H₂O (LUH‐1) was obtained by ionothermal synthesis using a deep‐eutectic solvent (DES) composed of choline chloride and tetrahydro‐2‐pyrimidione as reaction medium. The structure‐directing agent propylene‐1,3‐diammonium was generated in situ by the thermally induced decomposition of the amide component of the DES. Single‐crystal X‐ray structure analysis revealed that LUH‐1 is built from macroanionic tetrahedral gallium phosphate layers and layers of interlamellar propylene‐1,3‐diammonium cations, with the latter exhibiting two‐fold disorder. The one‐dimensional 12‐membered ring channel system is occupied by highly disordered water molecules. As indicated by thermogravimetry and powder X‐ray diffraction the water molecules can be desorbed from LUH‐1 at ca. 100 °C with retention of the layered inorganic‐organic hybrid structure. Crystal data for LUH‐1: Trigonal system, space group c1 (No. 165), Z = 1, a = 12.905(4), c = 18.317(8) Å, T = 297 K.     

Hybrid Tungstocuprate [Cu(2,2'-bpy)3]2H4[CuW12O40]·6H2O Based on Keggin Polyoxoanion [CuW12O40]6-with CuⅡas Heteroatom

A novel hybrid tungstocuprate(Ⅱ) [Cu(2,2'-bpy)3]2H4[CuW12O40]·6H2O(2,2'-bpy=2,2'-bipyridine) was synthesized via hydrothermal method and characterized using elemental analyses, IR, UV, XPS, TG-DSC, EPR, and X-ray single crystal diffraction. The structural analysis shows that the complex consists of an unusual Keggin-type polyoxoanion [CuW12O40]6- and a pair of chiral complex cations [Cu(2,2'-bpy)3] together with four protons and six crystallization water molecules, and the Keggin polyoxoanion is connected with [Cu(2,2'-bpy)3] via multiple C-H…O hydrogen bonds resulting in a dimer.     

Competitive binding of methanol and propane for water via matrix-isolation spectroscopy: implications for inhibition of clathrate nucleation

Methanol is a well-known thermodynamic inhibitor of clathrate hydrate formation. The interactions responsible for the inhibition, however, are not well-identified. Propane is a relatively simple hydrocarbon that forms a clathrate hydrate under mild conditions. This paper reports data about the interaction of methanol with water-propane complex. Methanol, water, and propane are isolated in carbon tetrachloride, and the interaction is probed with infrared spectroscopy. Water is known to interact with propane via the oxygen lone pairs and the propane methylene hydrogens. Experimental evidence indicates that methanol hydrogen bonds to water via donation of the hydroxyl hydrogen (K = 4.4 × 10(2)). Methanol does not have a direct interaction with propane. These results are consistent with an inhibitory mechanism in which methanol competes with propane for the oxygen atom of water.     

Micropolarity of sodium bis(2-ethylhexyl) sulfosuccinate reverse micelles prepared in supercritical ethane and near-critical propane

The micropolarity of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micelles prepared in supercritical ethane and near-critical propane has been determined in terms of a solvent polarity parameter, E _T(30) values, by using absorption probes, 1-ethyl-4-methoxycarbonyl pyridinium iodide and 2,6-diphenyl-4-(2,4,6-triphenylpyridinio)-phenolate as a functions of pressure and the molar ratio of water to AOT, W ₀, at a constant temperature of 310 K. The micropolarity comparable to that of ethanol was observed for reverse micelles containing water of W ₀ = 2. The micropolarity increased with the water content and became independent of pressure after the system changed to a one-phase reverse micelle solution. For a given W ₀ value, no difference in the micropolarity was noticed in the micelles prepared in ethane and propane. Phase behaviour investigations have revealed that complete dissolution of 50 mM AOT occurred at 20 MPa in supercritical ethane, while a much lower pressure of 1 MPa was required in near-critical propane. The amount of water solubilized in reverse micelles formed in supercritical ethane was relatively low, reaching a W ₀ value of 7 at 36 MPa. In contrast, the amount of water solubilized in near-critical propane reverse micelles was W ₀ = 11 at a much lower pressure of 6 MPa. A higher pressure was required to solubilize larger amount of water in reverse micelles prepared in both ethane and propane. Received: 9 October 1998 Accepted in revised form: 12 February 1999     

Transformations of griseofulvin in strong acidic conditions--crystal structures of 2'-demethylgriseofulvin and dimerized griseofulvin

The structure of griseofulvic acid, C16H15ClO6, at 100 K has orthorhombic (P2(1)2(1)2) symmetry. It is of interest with respect to biological activity. The structure displays intermolecular O-H...O, C-H...O hydrogen bonding as well as week C-H...pi and pi...pi interactions. In strong acidic conditions the griseofulvin undergoes dimerization. The structure of dimerized griseofulvin, C34H32C12O12 x C2H6O x H2O, at 100 K has monoclinic (P2(1)) symmetry. The molecule crystallized as a solvate with one ethanol and one water molecule. The dimeric molecules form intermolecular O-H...O hydrogen bonds to solvents molecules only but they interact via week C-H...O, C-H...pi, C-Cl...pi and pi...pi interactions with other dimerized molecules.     

Adduct Formation Between γ-Cyclodextrin and the Bifluorophore 1,3-Bis(1-pyrenyl)propane

The complexation of the bifluorophore 1,3-bis(pyrenyl)propane with γ-cyclodextrin in water has been studied by means of steady state and time-resolved fluorescence spectroscopy. It was found that in the association with γ-cyclodextrin the propane chain of 1,3-bis(pyrenyl)propane folds and the two pyrene units enter the same cyclodextrin cavity where they form weakly bound ground state dimers, which upon excitation emit excimer fluorescence. In addition to this 1:1 excimer emitting complex, two more complexes were detected, which emit monomer pyrene fluorescence. One has 1:1 stoichiometry, i.e. isomeric to the previous complex, and the other, with 2:1 stoichiometry, is comprised of two γ-cyclodextrin units and one 1,3-bis(pyrenyl)propane.     

13C chemical shifts of propane molecules encaged in structure II clathrate hydrate

Experimental NMR measurements for (13)C chemical shifts of propane molecules encaged in 16-hedral cages of structure II clathrate hydrate were conducted to investigate the effects of guest-host interaction of pure propane clathrate on the (13)C chemical shifts of propane guests. Experimental (13)C NMR measurements revealed that the clathrate hydration of propane reverses the (13)C chemical shifts of methyl and methylene carbons in propane guests to gaseous propane at room temperature and atmospheric pressure or isolated propane, suggesting a change in magnetic environment around the propane guest by the clathrate hydration. Inversion of the (13)C chemical shifts of propane clathrate suggests that the deshielding effect of the water cage on the methyl carbons of the propane molecule encaged in the 16-hedral cage is greater than that on its methylene carbon.     

Enhanced Propene/Propane Separation by Directional Decoration of the 12‐Membered Rings of Mordenite with ZIF Fragments

Propene/propane separation is challenging due to the very small difference in molecular sizes, boiling points and condensabilities between these molecules. Herein, we report a strategy of introducing ZIF fragments into traditional mordenite (MOR) zeolite to decorate the 12‐membered ring of MOR. After decoration, the originally ineffective zeolite MOR exhibited high kinetic propene/propane selectivities (139 at 25 °C) and achieved efficient propene/propane separation. The propene/propane separation potentials of the resulting adsorbents were further confirmed by breakthrough experiments with equimolar propene/propane (50/50) mixtures.     

Recognition of small polar molecules with an ionic crystal of alpha-Keggin-type polyoxometalate with a macrocation

The complexation of Keggin-type polyoxometalates [alpha-XW12O40]n- (X = P, Si, B, Co), macrocation [Cr3O(OOCH)6(H2O)3]+, and alkali-metal ions forms ionic crystals of Na2[Cr3O(OOCH)6(H2O)3][alpha-PW12O40].16H2O (1a), K3[Cr3O(OOCH)6(H2O)3][alpha-SiW12O40].16H2O (2a), Rb4[Cr3O(OOCH)6(H2O)3][alpha-BW12O40].16H2O (3a), and Cs5[Cr3O(OOCH)6(H2O)3][alpha-CoW12O40].7.5H2O (4a). The space volumes of the ionic crystals decrease in the order of 1a > 2a > 3a > 4a. The water of crystallization in 1a-3a is completely desorbed by evacuation at room temperature, while about 50% of the water of crystallization in 4a is desorbed. The respective 1a-4a after evacuation at room temperature are denoted by 1b-4b, which show the close packing of the constituent ions. The calculated cell volumes per formula decreased in the order of 1b > 2b > 3b > 4b, which would be related to the increase in n. Compound 1b sorbs various < or =C5 polar organic molecules such as 1-butanol, valeronitrile, and methyl propionate. Compound 2b sorbs ethanol, acetonitrile, and methyl formate. Compound 3b sorbs water and methanol, and 4b sorbs only water. Thus, the ionic crystals can discriminate < or =C5 polar organic molecules such as alcohols, nitriles, and esters by one methylene chain, and the decrease in n of [alpha-XW12O40]n- enables the sorption of molecules with the longer methylene chain. The nature of the sorption properties of 1b-4b can be explained by the lattice energy needed for the expansion of 1b-4b. The selective sorption properties of 1b-4b are successfully applied to the separation of mixtures of alcohols, nitriles, esters, and water.