3-硝基-1,2,4-三唑-5-酮与NH3及H2O分子间相互作用的理论研究

在DFT-B3LYP/6-311＋＋G**水平上, 求得3-硝基-1,2,4-三唑-5-酮(NTO)/NH₃和NTO/H₂O两种超分子体系势能面上5种全优化构型. 经基组叠加误差(BSSE)和零点能(ZPE)校正, 求得NTO与NH₃和H₂O的分子间最大相互作用能依次为－37.58和－30.14 kJ/mol, 表明NTO与NH₃的分子间相互作用强于与H₂O的作用. 超分子体系中电子均由NH₃或H₂O向NTO转移, 相互作用能主要由强氢键所贡献, 由自然键轨道分析揭示了相互作用的本质. 对优化构型进行振动分析, 并基于统计热力学求得200.0～800.0 K温度范围从单体形成超分子的热力学性质变化. 发现由NTO和NH₃形成超分子II和III在常温下可自发进行; 而NTO和H₂O只在低温下才能自发形成IV, V和VI超分子.     

Oxo-fluoro-aluminates and -gallates

The preparations of (NH₄)₂HAl₂OF₇, (NH₄)H₂AlOF₄, (NH₄)₂HGa₂OF_7^·3.5H₂O and (NH₄)₂HGaOF₄ are described. IR spectra suggest the presence of MOMO chains in these compounds. On isothermal heating at 180°C (NH₄)H₂AlOF₄ decomposes to give (NH₄)HAlOF₃, and at 150°C (NH₄)₂HGaOF₄ yields (NH₄)H₂GaOF₄. At 18°C (NH₄)₂HGa₂OF_7^·3.5H₂O yields the anhydrous compound.     

Theoretical study of formation of ion pairs in (NH3��HCl)(H2O)6 and (NH3��HF)(H2O)6

We have performed theoretical studies on sixteen molecular cubes for both (NH₃·HCl)(H₂O)₆ and (NH₃·HF)(H₂O)₆. We use an empirical gauge, based upon the N?CH and H?CX bond lengths, to categorize the degree to which the cubes are neutral adduct or ion pair in character. On this basis, we describe all sixteen cubes of the former as highly ionized, but only five of the latter as greater than 85% ionic in character. Addition of one or two bridging water molecules to form (NH₃·HF)(H₂O)₇ or (NH₃·HF)(H₂O)₈ raises the percent ionic character to greater than 85% for these systems. The relative energy of the cubes can be categorized based on simple chemical principles. The computed vibrational frequency corresponding to the proton stretch in the N?CH?CF framework shows the highest degree of redshifting for systems near 50% ion-pair character. Molecular cubes close to neutral adduct or to ion-pair character show less redshifting of this vibrational motion.     

Synthesis and characterization of mixed-ligand complexes of nickel(II) with 5,5′-thiodisalicylic acid and amines

The 5,5′-thiodisalicylato complexes of nickel(II) with water, ammonia, methylamine and pyridine were synthesized and their structure established to be [Ni(TDSA)L₂·nH₂O], where TDSA = 5,5′-thiodisalicylic acid, [C₆H₃(OH)(COOH)SC₆H₃(OH)(COOH)]. LH₂O, NH₃ CH₃NH₂ or pyridine, and n=3 for H₂O, 2 for NH₃ and CH₃NH₃, and 1 for pyridine complexes, from elemental analysis, IR and electronic spectroscopy, and magnetic susceptibility measurement. The thermal behaviour of the complexes has been studied by TG and DTA. TG shows three main steps of decomposition, viz. dehydration, axial base liberation, and decarboxylation leading to the formation of NiO at the final stage.     

Sur quelques réactions par décharge électrique dans les systèmes phosphine-eau,phosphine-eau-ammoniac et phosphine-eau-ammoniac-méthane

Electric discharge reactions in the systems PH₃ + H₂O, PH₃ + H₂O + NH₃ and PH₃ + H₂O + NH₃ + CH₄ have been studied. In the system PH₃ + H₂O, they produce polyphosphines (insoluble in water) and hypophosphorous, phosphorous and orthophosphoric acids. In the system PH₃ + H₂O + NH₃, besides the above products, hypophosphate, pyrophosphate, polyphosphates and possibly polyhyphosphates are also present. In the system PH₃ + H₂O + NH₃ + CH₄, besides all the above inorganic P compounds, organic phosphorus derivatives such as aminoalkyl phosphates and aminoalkanephosphonates are also formed, as well as other non-phosphorus containing organic products (amino acids, ethanolamine, etc.). The presence of phosphine (or its transformation products), seems to promote condensation reactions in this system since the ratio of amino acids found after hydrolysis (in 6N HCl) to amino acids found before hydrolysis is greater in this system. than in the system (CH₄+ H₂O+ NH₃)iiot containing phosphine.     

A New Predictive Equation for the Surface Tensions of Aqueous Mixed Ionic Solutions Conforming to the Linear Isopiestic Relation

The linear isopiestic relation has been used, together with the fundamental Butler equations, to establish a new simple predictive equation for the surface tensions of the mixed ionic solutions. This newly proposed equation can provide the surface tensions of multicomponent solutions using only the data of the corresponding binary subsystems of equal water activity. No binary interaction parameters are required. The predictive capability of the equation has been tested by comparing with the experimental data of the surface tensions for the systems HCl–LiCl–H₂O, HCl–NaClO₄–H₂O, HCl–CaCl₂–H₂O, HCl–SrCl₂–H₂O, HCl–BaCl₂–H₂O, LiCl–NaCl–H₂O, LiCl–KCl–H₂O, NaCl–KCl–H₂O, KNO₃–NH₄NO₃–H₂O, and LiCl–NaCl–KCl–H₂O at 298.15 K; KNO₃–NH₄Cl–H₂O, KBr–Sr(NO₃)₂–H₂O, NaNO₃–Sr(NO₃)₂–H₂O, NaNO₃ –(NH₄)₂SO₄–H₂O, KNO₃–Sr(NO₃)₂– H₂O, NH₄Cl–Sr(NO₃)₂–H₂O, NH₄Cl– (NH₄)₂SO₄–H₂O, KBr–KCl–H₂O, KBr–KCl–NH₄Cl–H₂O, KBr–KNO₃– Sr(NO₃)₂–H₂O, KBr–NH₄Cl–Sr(NO₃)₂–H₂O, KNO₃–NH₄Cl–Sr(NO₃)₂–H₂O, and NH₄Cl–(NH₄)₂SO₄–NaNO₃–H₂O at 291.15 K; and KBr–NaBr–H₂O at temperatures from 283.15 to 308.15 K. The agreement is generally quite good.     

Novel Method for Preparing NH4NiPO4·6H2O: Hydrogen Bonding Coacervate Selective Self-assembly

The single phase NH₄NiPO₄·6H₂O was synthesized by solid‐state reaction at room temperature using NiSO₄·6H₂O and (NH₄)₃PO₄·3H₂O as raw materials. The NH₄NiPO₄·6H₂O and its calcined products were characterized using X‐ray powder diffraction (XRD), thermogravimetry and differential thermal analyses (TG/DTA), Fourier transform IR (FT‐IR), ultraviolet‐visible (UV‐vis) absorption spectroscopy, and scanning electron microscopy (SEM). The results showed that the product dried at 80°C for 3 h was orthorhombic NH₄NiPO₄·6H₂O [space group Pmm2(25)], and surfactant polyethylene glycol (PEG)‐400 can direct growth of crystal NH₄NiPO₄·6H₂O. The thermal process of NH₄NiPO₄·6H₂O experienced three steps, which involve the dehydration of the five crystal water molecules at first, and then deamination, dehydration of the one crystal water, intramolecular dehydration of the protonated phosphate groups together, at last crystallization of Ni₂P₂O₇. The product of thermal decomposition at 150°C for 2 h, orthorhombic NH₄NiPO₄·H₂O, is layered compound with an interlayer distance of 0.8370 nm.     

Influence of Calixarenes on Chromatographic Separation of Benzene or Uracil Derivatives

The addition of calix[4]arenes to MeCN/H₂O or MeOH/MeCN/THF/H₂O mobile phases improves LC separation of benzene or uracil derivatives on Separon SGX C18 or Separon SGX NH₂ supports. Structure of the calixarenes and their host–guest supramolecular complexes with the analytes are discussed in context of the LC separation.     

Theoretical influence of third molecule on reaction channels of weakly bound complex CO2… HF systems

In this investigation, reaction channels of weakly bound complexes CO₂…HF, CO₂…HF…NH₃, CO₂…HF…H₂O and CO₂…HF…CH₃OH systems were established at the B3LYP/6‐311++G(3df,2pd) level, using the Gaussian 98 program. The conformers of syn‐fluoroformic acid or syn‐fluoroformic acid plus a third molecule (NH₃, H₂O, or CH₃OH) were found to be more stable than the conformers of the related anti‐fluoroformic acid or anti‐fluoroformic acid plus a third molecule (NH₃, H₂O, or CH₃OH). However, the weakly bound complexes were found to be more stable than either the related syn‐ and anti‐type fluoroformic acid or the acid plus third molecule (NH₃, H₂O, or CH₃OH) conformers. They decomposed into CO₂ + HF, CO₂ + NH₄F, CO₂ + H₃OF or CO₂ + (CH₃)OH₂F combined molecular systems. The weakly bound complexes have four reaction channels, each of which includes weakly bound complexes and related systems. Moreover, each reaction channel includes two transition state structures. The transition state between the weakly bound complex and anti‐fluoroformic acid type structure (T₁₃) is significantly larger than that of internal rotation (T₂₃) between the syn‐ and anti‐FCO₂H (or FCO₂H…NH₃, FCO₂H…H₂O, or FCO₂H…CH₃OH) structures. However, adding the third molecule NH₃, H₂O, or CH₃OH can significantly reduce the activation energy of T₁₃. The catalytic strengths of the third molecules are predicted to follow the order H₂O < NH₃ < CH₃OH. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006     

Contribution à l'étude du système quaternaire K+—NH4+—CrO4−−—SO4−−—H2O: I. les isothermes de 25° des systèmes ternaires limites

The four ternary limiting isotherms of the system K⁺− NH₄⁺ CrO₄⁻⁻ SO₄⁻⁻ H₂O are given for 25° C. In the systems K₂SO₄ (NH₄)₂SO₄ H₂O and K₂SO₄ K₂CrO₄ H₂O only one solid phase has been encountered; both systems belong to the type I of the ROOZEBOOM classification. A miscibility gap is present in the systems (NH₄)₂CrO₄ K₂CrO₄ H₂O and (NH₄)₂CrO₄ (NH₄)₂SO₄ H₂O; they belong to ROOZEBOOM'S type V.     

New crystal forms of tris(2-aminoethanolato-O,N)cobalt(III): Structures and properties

Crystal forms of cobalt(III) tris(2-aminoethanolate) hydrates, i.e., red cubic crystals of the composition fac-[Co(NH₂CH₂CH₂O)₃] · 5.44H₂O (fac-I · 5.44H₂O) and blue prismatic crystals of the composition mer-[Co(NH₂CH₂CH₂O)₃] · 3H₂O (mer-I · 3H₂O) were studied by the ⁵⁹Co, ¹³C NMR and X-ray diffraction methods. It was found that mer-[Co(NH₂CH₂CH₂O)₃] · 3H₂O (mer-I · 3H₂O) is a new pseudopolymorphic modification of fac-[Co(NH₂CH₂CH₂O)₃] · 3H₂O (fac-I · 3H₂O), while fac-I · 3H₂O represents a new polymorphic modification of the complex mer-[Co(NH₂CH₂CH₂O)₃] · 3H₂O (mer-I · 3H₂O) described previously. The comparative analysis of the spectra revealed dynamic equilibrium between these geometric isomers; the fac-isomer is stable in aqueous solutions.     

Thermodynamics of ionic solid solutions: III. An addendum

In two earlier papers (C.A. 117:259320(1;121:19411y) the activity coefficients of the salts in binary solid solutions at 25‡C for 38 salt pairs, in which the members of each pair differ with respect to only one kind of ion, were determined. While the activity data are correct, the conclusions regarding deviations from ideality for eight of these pairs, namely those in which there are two moles of replaceable ion per mole of salt, require modification in order to be consistent with ideal entropies of mixing. By changing the formulation of the component salts to one-half of what is usual, the inconsistencies disappear. This half-mole approach, applied to the salt pairs CU_1/2(NH₄/K)SO₄-3H₂O, Mg_1/2NH₄(SO₄/ CrO₄)-3H₂O, Mg_1/2NH₄(SeO₄/SO₄)-3H₄O, Mg_1/2NH₄(SeO₄/CrO₄)-3H₄O, Mg_1/2 (K/NH₄)SeO₄-3H₂O, (NH₄/K)(SO₄)_1/2, and Ba_1/2(ClO₃/BrO₃)-1/2 H₂O shows that these solid solutions exhibit positive, not negative, deviations from ideality at 25‡C. Only the system Pb_1/2(C1/Br) still deviates negatively.     

Kinetics and thermodynamics of thermal decomposition of NH<Subscript>4</Subscript>NiPO<Subscript>4</Subscript>·6H<Subscript>2</Subscript>O

The single phase NH₄NiPO₄·6H₂O was synthesized by solid-state reaction at room temperature using NiSO₄·6H₂O and (NH₄)₃PO₄·3H₂O as raw materials. XRD analysis showed that NH₄NiPO₄·6H₂O was a compound with orthorhombic structure. The thermal process of NH₄NiPO₄·6H₂O experienced three steps, which involves the dehydration of the five crystal water molecules at first, and then deamination, dehydration of the one crystal water, intramolecular dehydration of the protonated phosphate groups together, at last crystallization of Ni₂P₂O₇. In the DTA curve, the two endothermic peaks and an exothermic peak, respectively, corresponding to the first two steps’ mass loss of NH₄NiPO₄·6H₂O and crystallization of Ni₂P₂O₇. Based on Flynn–Wall–Ozawa equation, and Kissinger equation, the average values of the activation energies associated with the thermal decomposition of NH₄NiPO₄·6H₂O, and crystallization of Ni₂P₂O₇ were determined to be 47.81, 90.18, and 640.09 kJ mol⁻¹, respectively. Dehydration of the five crystal water molecules of NH₄NiPO₄·6H₂O, and deamination, dehydration of the crystal water of NH₄NiPO₄·H₂O, intramolecular dehydration of the protonated phosphate group from NiHPO₄ together could be multi-step reaction mechanisms. Besides, the thermodynamic parameters (ΔH ^≠, ΔG ^≠, and ΔS ^≠) of the decomposition reaction of NH₄NiPO₄·6H₂O were determined.     

A Humidity-Induced Large Electronic Conductivity Change of 107 on a Metal-Organic Framework for Highly Sensitive Water Detection

The electronic conductivity (EC) of metal–organic frameworks (MOFs) is sensitive to strongly oxidizing guest molecules. Water is a relatively mild species, however, the effect of H₂O on the EC of MOFs is rarely reported. We explored the effect of H₂O on the EC in the MOFs (NH₂)₂-MIL-125 and its derivatives with experimental and theoretical investigations. Unexpectedly, a large EC increase of 10⁷ on H₂SO₄@(NH₂)₂-MIL-125 by H₂O was observed. Brønsted acid–base pairs formed with the −NH₂ groups, and H₂SO₄ played an important role in promoting the charge transfer from H₂O to the MOF. Based on H₂SO₄@(NH₂)₂-MIL-125, a high-performance chemiresistive humidity sensor was developed with the highest sensitivity, broadest detection range, and lowest limit of detection amongst all reported sensing materials to date. This work not only demonstrated that H₂O can remarkably influence the EC of MOFs, but it also revealed that post-modification of the structure of MOFs could enhance the influence of the guest molecule on their EC to design high-performance sensing materials.     

层状钨基氧化物复合材料的合成与电子特性

W₂O₆·H₂O /一元烷基胺复合物[(C_nH_2n+1NH₂，n=4、8、12、16)嵌入层状氧化钨W₂O₆·H₂O] 的XRD、IR、TG-DSC分析表明：烷基胺C_nH_2n+1NH₂能基于质子加合的机制嵌入W₂O₆·H₂O层间，且插层复合物之间烷基胺的插入与抽出是个可逆过程；烷基胺嵌入层间后以全反式构象双层排布，层间距d随烷基胺碳原子数的增加而线性增长，烷基链与层板的夹角为71.6°。插层复合物UV-Vis分析发现，各种复合物的禁带宽度相对半导体氧化钨的禁带宽度变宽了很多，这表明可以通过嵌入不同的物质来调节氧化钨层与层之间的电子传递能力。     

New Perspectives in Polyoxometalate Chemistry by isolation of compounds containing very large moieties as transferable building blocks: (NMe4)5[As2Mo8V4AsO40] · 3H2O, (NH4)21[H3Mo57V6(NO)6O183(H2O)18] · 65 H2O, (NH2Me2)18(NH4)6[Mo57V6(NO)6O183(H2O)18] · 14 H2O,and (NH4)12[Mo36(NO)4O108(H2O)16] · 33 H2O

The compounds (NMe₄)₅[As₂Mo₈V₄AsO₄₀] · 3 H₂O 2a , (NH₄)₂₁[H₃Mo₅₇V₆(NO)₆O₁₈₃(H₂O)₁₈] · 65 H₂O 3a , (NH₂Me₂)₁₈(NH₄)₆[Mo₅₇V₆(NO)₆O₁₈₃(H₂O)₁₈] · 14 H₂O 3b and (NH₄)₁₂[Mo₃₆(NO)₄O₁₀₈(H₂O)₁₆] · 33 H₂O 4a ( 3a and 4a were not correctly reported in the literature regarding to their composition, structures and the oxidation states of the metal centres) which contain large isolated anionic species, have been prepared (among them 3a, 3b , and 4a in rather high yield) and characterized by complete crystal structure analysis as well as IR/Raman, UV/VIS/NIR, ESR spectroscopy and magnetic susceptibility measurements, redox titrations, bond valence sum calculations, elemental analyses and thermogravimetric studies. Perspectives for polyoxometalate chemistry referring to the synthesis of “extremely” large nanoscaled species are discussed, together with the occurrence of a large transferable {Mo₁₇} building block in the compounds 3a, 3b and 4a which also exists in the corresponding iron compound Na₃(NH₄)₁₂[H₁₅Mo₅₇Fe₆(NO)₆O₁₈₃(H₂O)₁₈] · 76 H₂O 7a .     

Identification of Thermal Decomposition Products and Reactions for Liquid Ammonium Nitrate on the Basis of Ab Initio Calculation

This work analyzed the thermal decomposition of ammonium nitrate (AN) in the liquid phase, using computations based on quantum mechanics to confirm the identity of the products observed in past experimental studies. During these ab initio calculations, the CBS‐QB3//ωB97XD/6–311++G(d,p) method was employed. It was found that one of the most reasonable reaction pathways is HNO₃ + NH₄⁺ → NH₃NO₂⁺ + H₂O followed by NH₃NO₂⁺ + NO₃^– → NH₂NO₂ + HNO₃. In the case in which HNO₃ accumulates in the molten AN, alternate reactions producing NH₂NO₂ are HNO₃ + HNO₃ → N₂O₅ + H₂O and subsequently N₂O₅ + NH₄⁺ → NH₂NO₂ + H₂O. In both scenarios, HNO₃ plays the role of a catalyst and the overall reaction can be written as NH₄⁺ + NO₃^– (AN) → NH₂NO₂ + H₂O. Although the unimolecular decomposition of NH₂NO₂ is thermodynamically unfavorable, water and bases both promote the decomposition of this molecule to N₂O and H₂O. Thus AN thermal decomposition in the liquid phase can be summarized as NH₄⁺ + NO₃^– (AN) → N₂O + 2H₂O.     

Reversible Ammonium Ion Intercalation/de-intercalation with Crystal Water Promotion Effect in Layered VOPO4⋅2 H2O**

The non-metal NH₄⁺ carrier has attracted tremendous interests for aqueous energy storage owing to its light molar mass and fast diffusion in aqueous electrolytes. Previous study inferred that NH₄⁺ ion storage in layered VOPO₄⋅2 H₂O is impossible due to the removal of NH₄⁺ from NH₄VOPO₄ leads to a phase change inevitably. Herein, we update this cognition and demonstrated highly reversible intercalation/de-intercalation behavior of NH₄⁺ in layered VOPO₄⋅2 H₂O host. Satisfactory specific capacity of 154.6 mAh g⁻¹ at 0.1 A g⁻¹ and very stable discharge potential plateau at 0.4 V based on reference electrode was achieved in VOPO₄⋅2 H₂O. A rocking-chair ammonium-ion full cell with the VOPO₄⋅2 H₂O//2.0 M NH₄OTf//PTCDI configuration exhibited a specific capacity of 55 mAh g⁻¹, an average operating voltage of about 1.0 V and excellent long-term cycling stability over 500 cycles with a coulombic efficiency of ≈99 %. Theoretical DFT calculations suggest a unique crystal water substitution process by ammonium ion during the intercalation process. Our results provide new insight into the intercalation/de-intercalation of NH₄⁺ ions in layered hydrated phosphates through crystal water enhancement effect.     

Intermolecular dihydrogen‐ and hydrogen‐bonding interactions in diammonium closo‐decahydrodecaborate sesquihydrate

The asymmetric unit of the title salt, 2NH₄⁺·B₁₀H₁₀²⁻·1.5H₂O or (NH₄)₂B₁₀H₁₀·1.5H₂O, (I), contains two B₁₀H₁₀²⁻ anions, four NH₄⁺ cations and three water molecules. (I) was converted to the anhydrous compound (NH₄)₂B₁₀H₁₀, (II), by heating to 343 K and its X‐ray powder pattern was obtained. The extended structure of (I) shows two types of hydrogen‐bonding interactions (N—H...O and O—H...O) and two types of dihydrogen‐bonding interactions (N—H...H—B and O—H...H—B). The N—H...H—B dihydrogen bonding forms a two‐dimensional sheet structure, and hydrogen bonding (N—H...O and O—H...O) and O—H...H—B dihydrogen bonding link the respective sheets to form a three‐dimensional polymeric network structure. Compound (II) has been shown to form a polymer with the accompanying loss of H₂ at a faster rate than (NH₄)₂B₁₂H₁₂ and we believe that this is due to the stronger dihydrogen‐bonding interactions shown in the hydrate (I).     

K-shell ionization energies in molecules by SCF GF calculations

Energies of CH₄, NH₃, H₂O and C₂H₄ K-ionized molecules are calculated by means of a Group Function method using minimal or near minimal basis sets of STO's. Further results from very large basis sets are reported for CH₄, NH₃, and H₂O. Results seemingly do not suffer the shortcomings of a previous SCF MO treatment.