N1923从碱性氰化液中萃取金(Ⅰ)的研究

采用放射性同位素198Au示踪法研究了伯胺N1923和TBP从碱性氰化液中萃取金(Ⅰ),考察了酸化率、水相pH值、萃取剂浓度等对萃取率的影响,以及NaOH对载金有机相的反萃作用。结果表明,TBP含量大于20％,酸化的N1923与KAu(CN)2摩尔比值在11时,金能够完全被萃取。载金有机相可采用0.1mol·L-1的NaOH溶液定量反萃。机理研究表明,伯胺和TBP萃取Au(CN)2-,符合BC类协同萃取机理。当金浓度大于10g·L-1时,在萃取有机相中形成纳米级的聚集体。     

Acid extraction to a hydrophobic ionic liquid: the role of added tributylphosphate investigated by experiments and simulations

We have studied the extraction of four HA acids (HNO(3), HReO(4), HClO(4), HCl) to a hydrophobic ionic liquid (IL) 1-butyl-3-methylimidazolium-bis(trifluoromethanesulfonyl)amide (BMI(+) Tf(2)N(-)) at room temperature, in a wide range of acidic concentrations in water. The effect of tributylphosphate (TBP) as co-solvent is investigated. According to experimental observations, water dragging to the IL phase increases with added TBP and/or acids. Acid extraction is found to be weak, however, for the four acids except for concentrated HNO(3) (>3 M). Molecular dynamics simulations on model biphasic systems show that TBP is not surface active, but well dissolved in the IL. They also reveal the importance of HA acid model (either totally or half dissociated) and of the TBP content on acid extraction to the IL. Furthermore, they show that "the proton" can be extracted by TBP (H(3)O(+)(TBP)(3)"complex") without its A(-) conjugated base, via a cation transfer mechanism (BMI(+) transfer to water). Experiments and simulations show that TBP plays an important role in the mutual solubility between water and ionic liquid, by different amounts, depending on the HA acid. On the other hand, both approaches indicate that a HTf(2)N containing aqueous solution completely mixes with the [BMI][Tf(2)N] IL that contains the same Tf(2)N(-) anion.     

十四烷基二甲基苄基氯化铵萃取Au(CN)2-的微观机理

通过萃取平衡、傅里叶变换红外光谱及分峰技术研究了季铵盐十四烷基二甲基苄基氯化铵(TDM-BAC)-磷酸三丁酯(TBP)-正庚烷体系萃取Au(CN)₂^-的机理及过程.提出了萃合物的结构模型是基于氢键的超分子体系,组成为[R₄N⁺]·[Au(CN)₂^-]·4H₂O·4TBP.当有机相金浓度大于3g·L^-1时,有机相中存在聚集现象.通过激光光散射技术测定了有机相中反向胶团的大小,表明萃取过程是分散在水相中的胶团在协萃剂(或助表面活性剂)作用下溶入有机相,转型为反向胶团或微乳液(W/O型)聚集状态.     

胺类杂氮硅三环化合物红外光谱研究

对γ－氨丙基杂氮硅三环、γ－乙二胺基丙基杂氮硅三环、γ－乙二撑三胺基丙基杂氮硅三环３种化合物的红外光谱进行了研究。胺基的特征吸收为：伸缩振动ｖ_（ａｓ）（ＮＨ）和ｖ_ｓ（ＮＨ）；剪式振动δ（ＮＨ_２）。三环的特征吸收为：ＣＨ_２的弯曲振动ω（ＣＨ_２Ｎ）、ω（ＣＨ_２Ｏ）和τ（ＣＨ_２Ｏ）；Ｃ－Ｏ键的伸缩振动ｖ（Ｃ－Ｏ）；Ｎ－Ｃ键的伸缩振动ｖ_（ａｓ）（ＮＣ_３）和ｖ_ｓ（ＮＣ_３）；Ｓｉ－Ｏ键的伸缩振动ｖ_（ａｓ）（Ｓｉ－Ｏ）和ｖ_ｓ（Ｓｉ－Ｏ）；Ｃ－Ｃ键的伸缩振动ｖ（Ｃ－Ｃ）；以及Ｓｉ←Ｎ配键的伸缩振动ｖ（Ｓｉ←Ｎ）。     

Incoherent inelastic neutron scattering of the strong (NHN) bond in H3Co(CN)6

The vibrations of the strong symmetric NHN hydrogen bond in H₃Co(CN)₆ have been investigated by inelastic neutron scattering spectroscopy at 80 K. The two deformation modes δ(NH) and γ(NH) have been identified. A strong protonic mode is observed in the low energy transfer region and is assigned to the antisymmetric stretching vibration of the hydrogen bond. Relative intensities of the ν(NH) fundamental, its first overtone and bending fundamentals are interpreted as suggesting a strongly anisotropic Debye-waller factor. At 5 K the ν(NH) fundamental shows a complex structure which is interpreted in terms of coupling with low frequency lattice modes.     

The tricyanomercurate(II) ion

The tricyanomercurate(II) ion, [Hg(CN)₃]^?, is isolated in the form of its solid caesium salt from a 1:1:1 ethanolic solution of CsF, KCN and Hg(CN)₂, and characterised by IR and Raman vibrational spectroscopy. Assignments are made for the CN and HgC stretching vibrations and the HgCN bending vibrations. The spectra are consistent with the [Hg(CN)₃]^? ion occupying a site of C₁ symmetry.     

Structure and spectroscopy of Tb[Au(CN)2]3.3H2O

The compound Tb[Au(CN)2]3.3H(2)O crystallizes in a layered structure in the hexagonal space group P6(3)/mcm with the 9-coordinate environment of Tb3+ comprising six (CN)- and three OH2 in a tricapped trigonal prism. The shortest Au...Au distance is 3.31 angstroms. The vibrational spectra show that the series Ln[Au(CN)2]3.3H2O (Ln = Y, Pr, Sm, Eu, Tb) are isostructural. The electronic spectra of Eu[Au(CN)2]3.3H2O clearly show that Eu3+ occupies one site of spectroscopic site symmetry D3h, in agreement with the crystallographic data. The electronic emission and absorption spectra of Tb[Au(CN)2]3.3H2O have been recorded at temperatures down to 1.5 K, and the f-f pure electronic transitions are interpreted in detail as arising from the lowest electronic states (in D3h symmetry) (7F6)E' in absorption and (5D4)E' in emission. At low energy, further bands are assigned to the vibronic structure of the CN stretching and water stretching modes, with the latter more predominant. Although the CN stretching vibrations show exclusive infrared or Raman activity in Tb[Au(CN)2]3.3H2O, both of these infrared and Raman active modes are observed in the two-center vibronic transitions. The reasons for this are discussed.     

Thermally induced linkage isomerization in KCd[Fe(CN)6]

Heating KCd[Fe(CN)₆]-5H₂O, either isothermally or in a differential scanning calorimeter, results in dehydration and linkage isomerization of the cyanides. In accord with hard—soft acid—base predictions, the product contains cyanide C-bonded to Cd₂₊. The integrated intensity of the peaks corresponding to the CN stretching vibrations indicates that two of the cyanides change bonding mode more readily than the others. Cyanide isomerization does not occur when KCd[Fe(CN)₆]-5H₂O is dehydrated at room temperature under vacuum conditions.     

Theoretical and spectroscopic study of infrared spectra of hydrogen-bonded 1-methyluracil crystal and its deuterated derivative

Theoretical simulation of the band shape and fine structure of the N-H(D) stretching band is presented for 1-methyluracil and its deuterated derivative taking into account anharmonic coupling between the high-frequency N-H(D) stretching and the low-frequency N...O stretching vibrations, resonance interaction between two equivalent hydrogen bonds in the dimer, anharmonicity of the potentials for the low-frequency vibrations in the ground and excited state of the N-H(D) stretching mode, Fermi resonance between the N-H(D) stretching and the first overtone of the N-H(D) bending vibrations, and electrical anharmonicity. The effect of deuteration has been successfully reproduced by our model calculations. Infrared, far-infrared, Raman, and low-frequency Raman spectra of the polycrystalline 1-methyluracil have been recorded. The geometry and experimental frequencies are compared with the results of harmonic and anharmonic B3LYP6-311++G(**) calculations.     

N263和TBP为协同流动载体的液膜体系分离钐(Ⅲ)和钆(Ⅲ)的研究

研究了N263和TBP为协同载体的液膜体系分离钐和钆的行为.考察了膜相添加剂、内水相反萃剂、外水相盐析剂和膜相中载体浓度对传质分离的影响.当用TBP作为膜相添加剂时,N263能很好地溶解在煤油中.N263-TBP-LMA-1-煤油和NH₄NO₃协同流动载体液膜体系在迁移稀土离子时表现出"倒序"特性,与单纯的N263体系相比,该体系对钐、钆具有较高的选择性.     

Identification of arginine residues in peptides by 2D-IR echo spectroscopy

The CN stretching vibrations of the guanidyl group in the arginine dipeptide side chain are examined by two-dimensional infrared spectroscopy. In D(2)O, the spectra display two distinct diagonal peaks. These nearly degenerate modes undergo ultrafast energy transfer. The energy-transfer rate was determined directly from the 2D-IR spectra to be 1/2.1 ps(-1). The cross peaks in 2D-IR arising from the energy transfer provide a definitive identification of arginine in larger proteins. An example of arginine in the transmembrane protein M2, found in influenza viruses, is given.     

Density functional theory study of the properties of N-H...N, non-cooperativities, and intermolecular interactions in linear trans-diazene clusters up to ten molecules

We investigate aspects of N-H...N hydrogen bonding in the linear trans-diazene clusters (n=2-10) such as the N...H and N-H lengths, n(N) --> sigma(N-H) interactions, N...H strengths, and frequencies of the N-H stretching vibrations utilizing the DFT/B3LYP theory, the natural bond orbital (NBO) method, and the theory of atoms in molecules (AIM). Our calculations indicate that the structure and energetics are qualitatively different from the conventional H-bonded systems, which usually exhibit distinct cooperative effects, as cluster size increases. First, a shortening rather than lengthening of the N-H bond is found and thus a blue rather than red shift is predicted. Second, for the title clusters, any sizable cooperative changes in the N-H and N...H lengths, n(N) --> sigma(N-H) charge transfers, N...H strengths, and frequencies of the N-H stretching vibrations for the linear H-bonded trans-diazene clusters do not exist. Because the n(N) --> sigma(N-H) interaction hardly exhibits cooperative effects, the capability of the linear trans-diazene cluster to localize electrons at the N...H bond critical point is almost independent of cluster size and thereby leads to the noncooperative changes in the N...H lengths and strengths and the N-H stretching frequencies. Third, the dispersion energy is sizable and important; more than 30% of short-range dispersion energy not being reproduced by the DFT leads to the underestimation of the interaction energies by DFT/B3LYP. The calculated nonadditive interaction energies show that, unlike the conventional H-boned systems, the trans-diazene clusters indeed exhibit very weak nonadditive interactions.     

IR, 1H NMR, mass, XRD and TGA/DTA investigations on the ciprofloxacin/iodine charge-transfer complex

Raman and infrared spectra of two polymorphous minerals with the chemical formula Fe3+(SO4)(OH)·2H2O, monoclinic butlerite and orthorhombic parabutlerite, are studied and the spectra assigned. Observed bands are attributed to the (SO4)2- stretching and bending vibrations, hydrogen bonded water molecules, stretching and bending vibrations of hydroxyl ions, water librational modes, Fe-O and Fe-OH stretching vibrations, Fe-OH bending vibrations and lattice vibrations. The O-H?O hydrogen bond lengths in the structures of both minerals are calculated from the wavenumbers of the stretching vibrations. One symmetrically distinct (SO4)2- unit in the structure of butlerite and two symmetrically distinct (SO4)2- units in the structure of parabutlerite are inferred from the Raman and infrared spectra. This conclusion agrees with the published crystal structures of both mineral phases.     

Study of the binding sites in the biomass of <Emphasis Type="Italic">Aspergillus niger</Emphasis> wild-type strains by FTIR spectroscopy

Fourier transform infrared (FTIR) spectroscopy studies were performed to confirm and to provide information on the identity and binding characteristics of the chemical groups responsible for the binding of elements using Aspergillus niger (A. niger) wild-type strains. Two absorption bands in the 3690–3615 and 2970–2895 cm^?1 regions can characterize stretching vibrations OH and CH groups in fatty acids, respectively, and intensive bands around of 1600 cm^?1 and by 1048 cm^?1 correspond to stretching vibrations of C=O groups of amides (amide I) or stretching vibrations ν(C–N). The FTIR results confirmed that no extra differences between IR spectra of A. niger in raw biomass and in solid rest after extraction with chloroform were observed. The small differences were observed in IR spectra of A. niger in chloroform after extraction.     

Studium des gegenseitigen Einflusses der Bindungen in Thiocyanat-Kupfer(II)-Komplexen mit Methyl- und Dimethylpyridinen mittels Infrarotspektroskopie

The infrared spectra of thiocyanato-copper(II) complexes of the type Cu(NCS)₂ L ₂ with all isomeric picolines and lutidines (L) as well as those of the type Cu(NCS)₂ L ₃ withL=3- and 4-picoline, 3,4- and 3,5-lutidine were measured. The behaviour of the (CN) stretching vibrations of the Cu(NCS)₂ L ₂ complexes led to conclusions on the different kind of coordination of the NCS groups in dependence on the ligandL. The mutually conditioned strength of the Cu–NCS and Cu–N(L) bonds in the equatorial plane, especially in the presence of ligandsL with the steric effect, was determined from the frequency shift of the Cu–NCS and Cu–N(L) stretching vibrations with regard to the vibrations for Cu(NCS)₂(pyridine)₂.

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CN在 Pt(100)表面吸附的密度泛函研究

采用密度泛函方法,以原子簇Pt14为模拟表面,对CN自由基分子在Pt(100)表面上不同吸附位的吸附情况进行了研究.结果表明,CN分子吸附在Pt(100)面上时,通过原子C垂直吸附在表面顶位是其最佳吸附方式,CN键振动频率明显发生蓝移,与实验事实相吻合;而在桥位及四方穴位吸附时CN键振动频率均发生红移.吸附前后,CN分子的σ、π电子与底物间的电荷转移的差异决定了CN键振动频率的不同变化.     

Investigation on the Extraction Mechanism of Au（I） from Cyanide Solution with Quaternary Ammonium System

During the past decades, there has been a renewed interest in the application of solvent extraction to the recovery of Au (I) from cyanide solutions1,2. Among those various extractants, the amine extractants with the addition of organic phosphorus oxide as cosolvent have been widely investigated3,4. Various diluents and modifiers have been selected to optimize the extraction system so as to increase the loading capacity, improve the selectivity and/or reduce emulsification5. Quaternary amm…     

Vibrational spectra of 1-methyluracilate complex with silver(I) and theoretical studies of the 1-MeU anion

The FT-Raman and FT-infrared spectra of (1-methyluracilato)silver, [Ag(C(5)H(5)N(2)O(2))] in the solid state have been studied. The complex is a polymer in which one silver ion is linearly bonded to two 1-MeU ligands through the deprotonated N(3) sites and another silver ion is tetrahedrally coordinated to the four 1-MeU ligands through the O2 and O4 carbonyl oxygen atoms. The harmonic vibrational frequencies, infrared intensities and Raman scattering activities of the N(3)-deprotonated 1-methyluracilate anion have been calculated using density functional (B3LYP) and ab initio (HF and MP2) methods with the 6-31G(d,p) and 6-31++G(df,pd) basis sets. The calculated potential energy distribution (PED) for the 1-MeU anion has proved to be of great help in assigning the spectra of the title complex. It can be concluded that the two strong Raman bands at 1263 and 796 cm(-1) are diagnostic for the N3-deprotonation of the 1-methyluracilate ring and complexation with silver ion. The linear N-Ag-N stretching vibrations are assigned to the bands at 448 and 362 cm(-1) (IR) and 453, 362 cm(-1) (Raman). The Ag-O stretching vibrations are assigned to the bands in the range of 280-250 cm(-1).     

Raman spectroscopic investigation of gas interactions with an aligned multiwalled carbon nanotube membrane

Raman spectroscopy has been used to investigate ethane, propane, and SF6 interactions with an aligned multiwalled carbon nanotube (MWNT) membrane. Pressures of 7.5-9.3 atm and temperatures of 293-333 K were examined for propane and SF6, whereas slightly lower temperatures (263-293 K) and pressures (6.7-7.5 atm) were used for ethane. Red-shifting and broadening is seen for the C-C stretching vibrations of the two hydrocarbons, as well as for the A1g symmetric vibration (nu1) of SF6. These spectral features indicate that the interaction between the gas and the nanotube membrane is capable of perturbing molecular vibrations and creating red-shifted features. Control experiments done on polycrystalline graphite and a polystyrene blank indicate that this spectral behavior is unique to gases interacting with the nanotubes in the membrane.     

Photoinduced nitrosyl linkage isomers in complexes based on the photochromic cation [RuNO(NH3)5] with the paramagnetic anion [Cr(CN)6] and the diamagnetic anions [Co(CN)6] and [ZrF6]

Two metastable nitrosyl linkage isomers SI and SII are generated by light irradiation in the spectral range 370–500 nm in the two diamagnetic compounds [RuNO(NH₃)₅][Co(CN)₆] and [RuNO(NH₃)₅]₂[ZrF₆]₃ as well as in the paramagnetic compound [RuNO(NH₃)₅][Cr(CN)₆]. The frequencies of the ν(NO) stretching vibrations of SI and SII identify SI as the isonitrosyl Ru–O–N isomer and SII as the side-on η² isomer of NO. The population, i.e., the number of generated linkage isomers, is determined from the decrease of the area of the fundamental ν(NO) and of the higher harmonic 2 · ν(NO) of the ν(NO) stretching vibration of the ground state. Using differential scanning calorimetry (DSC) the heat release during the thermal decay of the metastable linkage isomers is determined. The activation energies, frequency factors, and the energetic position of the metastable linkage isomers are determined from the DSC and infrared spectroscopic experiments. It is found that the exchange of the counter ion significantly influences the energetic positions of the linkage isomers, while the activation energy and frequency factor are much less affected.