聚乙二醇2000-吐温80-(NH4)2SO4-H2O液-固萃取体系

研究了聚乙二醇2000-吐温80混合聚合物水溶液在(NH₄)₂SO₄存在下分成液-固两相的条件和水溶性螫合剂及金属离子螫合物在两相间的分配行为,实现了Zr(Ⅳ)-Sc(Ⅲ)、Fe(Ⅲ)-Sc(Ⅲ)的定量萃取分离,初步探讨了混合聚合物相的萃取机理。     

两相pH滴定法对二-(2-乙基己基)磷酸萃取Cu~( )、Co~( )、Ni~( )机理的研究

本文提出一种十分快速简便的两相pH滴定法,研究HDEHP萃取Cu~( )、Co~( )、Ni~( )机理。此法在两相平衡时,只要测定水相的pH,通过预先假定的有机相萃合物的形式及种类,确定数学计算式,用实验数据验算萃合常数,来证实设想的反应机理的合理性。它比常用的研究络合物的溶剂萃取法省略了测定两相金属离子浓度这一步骤,但也带来了本法的局限性。本文提出在金属离子Cu~( )、Co~( )、Ni~( )不发生水解、聚合、有机相只存在一种萃合物MA_2·2HA情况下,研究萃取机理的数学假定及实验方法。实验确定HDEHP萃取Cu~( )、Co~( )、Ni~( )时,萃合常数1gβ_(Gu)=11.58;1gβ_c。=10.63:1gβ_(Ni)=8.97。     

两相滴定法研究RE(Ⅲ)-HTTA-TBPO协萃体系

HTTA与中性膦类萃取剂协同萃取稀土元素的报导多数采用分配比法。用两相滴定法研究HTTA-TBPO协同萃取稀土元素,尚未见报导。本文用pH计测出滴定过程平衡水相的pH值,根据文献[1]的计算原理,求出HTTA的两相电离常数K_aE及HTTA-TBPO在有机相中的缔合常数K,并确定有机相中稀土萃合物的组成及其稳定常数。两相滴定法省去了测定两相中稀土离子平衡浓度的繁杂手续,仪器和试剂简单,不仅节约时间,还可得到与分配法同样可靠的结果,是研究协萃体系的一种简便方法。     

三正辛胺-二甲苯液膜迁移Cd(Ⅱ)的研究

研究了三正辛胺-二甲苯支撑液膜体系中搅拌速率、反萃剂、三正辛胺浓度、料液中H+浓度等因素对Cd(Ⅱ)离子迁移的影响.用大块液膜测定了不同温度时Cd(Ⅱ)离子跨膜迁移的萃取及反萃取的表观速率常数k₁和k_2.实验表明,温度升高,k₁和k₂均增大(k₁>k₂),且达到膜相最大镉离子浓度时所需的时间逐渐减少.膜相积累的镉离子浓度达最大时,Cd(Ⅱ)离子跨膜传输为稳态传输.根据Arrhenious关系得到膜相萃取反应和反萃取反应的活化能分别为23.8和19.3kJ/mol.     

金属萃取平衡与软-硬酸碱规则

软硬酸碱规则从宏观角度描述化合物的形成及性质,在配合物稳定性的判断方面有广泛应用.前文^[1]报道了萃取速率常数与金属离子的软硬酸碱强度的关系,本文研究了萃取平衡常数与金属离子的软硬酸碱强度的关系.     

两相滴定法研究溶剂萃取机理的通用计算机程序

基于Marquardt-Fletcher改进的Gauss-Newton法,编写了1个从pH滴定结果计算酸性萃取剂在两相溶液中的分配常数、在水溶液中的电离常数及其金属络合物在水相和有机相中形成常数的通用计算机程序SCTPT。本程序能计算含有20个M_iA_iH_k型络合物存在的两相体系,对初值无严格要求,可在4～15个数量级内变化,并已用于PMBP--Cu²⁺,PMBPZn²⁺的苯-水体系,结果满意。     

(7-甲氧基-4-亚甲基)香豆素基-单氮杂-18-冠-6的阳离子识别性能研究

基于题示光敏离子载体MMC-MAC(O₅)与金属离子配位时荧光或延迟荧光性质的变化,研究了它作为光敏主体在乙腈或水溶液中对Li⁺,Na⁺,K⁺,Mg²⁺,Ba²⁺和Pb²⁺离子的识别性能,由改进的H-B方程计算得主客识别的稳定常数和敏感因子.结果表明,由于该光敏离子载体的香豆素的羰基能以七元环形式参与对金属离子的配位,在一定程度上增大了对客体离子的络合能力;在水溶液中,由于金属离子的溶剂化作用和因香豆素的羰基易与水形成氢键,影响了MMC-MAC(O₅)与客体离子的结合,稳定常数明显降低.基于MMC-MAC(O₅)的分子结构和与金属离子结合时荧光强度的增强,讨论了识别机理     

丙醇-硫酸铵双水相体系萃取金(Ⅲ)-氯化物-罗丹明B

水溶性聚合物如聚乙二醇 (ＰＥＧ )、吐温(Ｔｗｅｅｎ) 80的水溶液在电解质存在下萃取分离贵金属离子已有报道[1] ;小分子的有机物如乙醇、丙醇在硫酸铵、氯化钠等电解质存在下也能分为两相形成双水相体系 ,可应用于金属离子的分离[2 ] ;该类体系也可以用于萃取分离贵金属络阴离子[3,4] 。我们发现金 (Ⅲ )与氯离子在碱性染料罗丹明Ｂ(ＲｈＢ)参与下所形成的三元缔合物 ,可被丙醇 硫酸铵双水相体系定量萃取而与大量常见贱金属分离 ,体系同时具有溶剂萃取法及溶剂浮选法的优点 :既可以分离简单贵金属络阴离子[3,4] ,又可以分离贵金属三元缔…     

螯合-螯合萃取剂对铀(VI)的协同萃取

有关协同萃取的研究已十分广泛,但文献报道的大多是有关螯合(或酸性磷)-中性萃取剂组成的协萃体系,关于螯合-螯合萃取剂对金属离子的协萃研究报道甚少。Newman[1],Sekine[2.3]以及Sudersanan等[4-6]曾研究过β-二酮类萃取剂之间的协同萃取,但这类体系的协萃机理和规律性尚有待探讨。本文研究了1-苯基-3-甲基-4-苯甲酰基-5-吡唑啉酮-(PMBP)与噻吩甲酰三氟丙酮(TTA)及PMBP与1-苯基-3-甲基-4-三氟乙酰-5-吡唑啉酮-(PMTFP)两种协萃体系从硝酸介质中对铀(VI)的萃取,这两种协萃体系文献中均未见报道.采用斜率法测求协萃配合物组成,计算了它们的干衡常数,并对协萃反应机理和规律性进行了讨论。     

二甲酚橙作萃取剂的Zr(Ⅳ)、Bi(Ⅲ)、Cu(Ⅱ)非有机溶剂液-液萃取行为

水溶性高聚物的水溶液在无机盐存在下能分成两相,文献提出了用其分离金属离子的可能性。作者在前文中,系统研究了聚乙二醇2000-盐-水体系的分相条件,用偶氮胂Ⅲ作萃取剂,实现了该体系的La(Ⅲ)-Zr(Ⅳ)定量萃取分离。非有机溶剂萃取体系,能萃取水溶性螯合物,并可用显色剂作萃取剂,使整个萃取操作具有安全、无毒害、简便,快速的特点。     

Ab initio vibration—rotation coupling constants and the equilibrium geometries of NCCN and CNCN

The equilibrium geometries of NCCN and CNCN were calculated from experimental ground-state rotational constants and ab initio values for the vibration—rotation coupling constants. For NCCN, R_1e(NC) = 1.1578(5) Å and R_2e(CC) = 1.3839(5) Å were obtained, where estimated error bars are given in parentheses. The calculated equilibrium bond lengths of CNCN are R_1e(CN) = 1.1813(5) Å, R_2e(NC) = 1.3116(5) Å and R_3e(CN) = 1.1581(5) Å. Ground-state rotational and centrifugal distortion constants are predicted with high accuracy for various isotopomers of NCCN.     

分光光度法研究镧与间硝基偶氮氯膦(CPAmN)的络合物形成反应

本文研究了CPAmN试剂的特性、La-GPAmN络合物的组成和β-型络合物的生成条件,并测定了其积累稳定常数。     

Preparation of Nanocrystalline Titania Directly from Industrial Titanium Hydroxide

Nanocrystalline titania was prepared directly from industrial titanium hydroxide by NH₄NO₃ decomposition at 573K. DTA-TG, XRD, TEM and BET were employed to character the sample.The DTA-TG curves were measured by differential thermal balance to detect the phase transformation temperature of samples. Using α-Al₂O₃ as the standard substance. XRD was used to determine the phase composition of titania powders on a diffractometer (RIGUKU, Cu K_α=0.15406 nm, 40 kV). Crystallite sizes were determined from line broadening measurements by using Scherrer formula. TEM image of sample was obtained on a Phillips EM420 microscope, operating at l00kV and the special surface and pore volume are examined by BET method.     

Dibenzo[b, e]-7,7,8,8-tetraneopentyl- and dibenzo[b, e]-7,7,8,8-tetraisopropyl-7,8-disilabicyclo[2.2.2]octa-2,5-dienes: interaction with tetracyanoethylene and transition metal chlorides

Dibenzo[b,e]-7,7,8,8-tetraalkyl-7,8-disilabicyclo[2.2.2]octa-2,5-dienes (1: R = ^tBuCH₂; 2: R = ⁱPr) were prepared by the reaction of ClR₂SiSiR₂Cl with lithium anthracenide in 1,2-dimethoxyethane (DME) at room temperature. The structure of 1 was determined by X-ray crystallography. Crystal data for 1: monoclinic, rC2/c, A = 12.941(2), B = 14.601(1), C = 35.109(6) Å, β = 94.957(7)°, V = 6609(2) ų, Z= 8, R = 0.048, R_w = 0.053 for 4037 reflections. Compounds 1 and 2 show the bathochromic shift of ¹L_a and ¹L_b bands in UV spectra and exhibit considerably low oxidation potentials due to effective σ-π conjugation. Compounds 1 and 2 form charge-transfer complexes with tetracyanoethylene (TCNE). In the case of 1, the charge-transfer complex (1: TCNE = 2: 1) could be isolated as crystals and the structure was determined by X-ray crystallography. Crystal data for the 1-TCNE complex: monoclinic, C2/c, A= 10.267(2), b = 36.077(4), C = 20.022(4) Å, β = 100.680(8)°, V = 7288(2) ų, Z = 4, R = 0.045, R_w = 0.077 for 4120 reflections. The action of transition metal chlorides on 2 resulted in [4+2] cycloreversion to form ClⁱPr₂SiSiⁱPr₂Cl and anthracene.     

A new series of nematic and smectic liquid crystals with negative dielectric anisotropy: the effect of terminal chain substitution on thermal and electro-optical properties

Two alkyl (1b and 1c) and four fluoroalkyl derivatives (1d-1f) of 4-arylbutyric acid (1c, 1d and 1e) and 4-arylbutanol (1b, 1f and 1g) [aryl = 2',3'-difluoro-4'-(2-(E-4-pentylcyclohexyl)ethyl)-biphenyl-1-yl] were prepared and investigated in the pure form as nematic materials (1b and 1c) and as additives to a ferroelectric liquid crystal (FLC) host (1d-1f). A comparison of 1b and 1c with the decyl analogue 1a demonstrates the effect of terminal chain modification on thermal and electro-optical properties. The substitution of the -CH₂O- (1b) or -COO- (1c) for -CH₂CH₂- in 1a destabilized the N and SmA phases or completely eliminated the smectic behaviour (1c). Dielectric analysis revealed that the chain modification increased the negative Δε, reduced elastic constant K ₁₁ and moderately decreased rotational viscosity γ₁. The temperature dependence of the key electro-optical parameters was analysed for ester 2, the methyl analogue of 1c, which exhibits a 45 K wide N phase. All four fluoroalkyl derivatives 1d-1f showed enantiotropic SmA phases and 1e also exhibited a monotropic SmC phase. Solutions of 1d-1f in a FLC host (0.2 mmol g^-1) increased the tilt angle Θ (up to 45° for 1g), reduced rotational viscosity γ₁ and the risetime τ. The most dramatic changes were observed for 1g, which contains 15 fluorine atoms.     

Semi-empirical molecular orbital conformational study of benzannelated cyclooctatetraenes and related compounds, and x-ray crystal structure of benzocyclooctatetraene

Semi-empirical molecular orbital conformational analyses of benzocyclooctatetraene, 1, dibenzo [a, c] cyclooetatetraene, 2 dibenzo [a, e] cyclooctatetraene, 3 tribenzo[a, c, e]-cyclooctatetraene, 4 tetrabenzo[a, c, e, g] cyclooetatetraene, 5 octafluorocyclooetatetraene, 6A, and cyclooctatetraene, 6B, have been done at the MNDO and MINDO/3 (excluding 4 and 5) levels of approximation. Comparison of these results with the X-ray structural data for 1 (as determined in the present work and the other benzannelated cyclooctatetraenes showed that, while MNDO is vastly superior to MINDO/3 both fail to account for the subtle effects of benzannelation on the conformation of the cyclooetatetraene ring. The experimental data indicate that the tub conformation of cyclooetatetraene is only slightly perturbed by the successive fusion of one and two non-adjacent benzene rings, but steric repulsion between adjacent annelated benzene rings, when present, predominates and gives rise to more folded configurations. Compound 1 crystallizes in space group P2₁/n with a = 1 1.856(2 B = 6.327(1 c = 12.470(3 Å, β = 110.03(2)°, and Z = 4. The structure has been solved by direct methods and refined to R = 0.049 for 1435 observed Mo-K diffractometer data.     

The cyclopalladation of benzylidenebenzylamines

A number of isomeric N-benzylbenzalimine palladium(II) complexes of the type [P ·CH₂Ph]₂ (with C=N endo to the palladocycle) and [P =C(CH₃Ph]₂ (with C=N exo to the palladocycle), have been prepared and charcterised by ¹H and ¹³C NMR methods. The crystal structures of two analogous monomeric acac complexes, synthesized independently by oxidative addition of o-BrC₆H₄CH₂N=CH · Ph to Ph to Pd(dibenzylideneacetone)₂ have also been determined. These are [P · CH₂Ph)] (15a) and [P =CHPh)] (20a). Crystals of 15a are monoclinic, space group P2₁/a with Z = 4 in a cell of dimensions a 10.286(2), b 11.902(3), c 13.895(5) Å, β 93.52(2)° while 20a is monoclinic, space group P2₁/c with Z = 8 and a 10.353(3), b 20.600(5), c 16.545(7) Å, β 92.14(3)°. The structures 15a and 20a were refined to residuals R = 0.041 and 0.055 for 1661 and 2525 observed reflections respectively.     

某些稀土硝酸盐与N,N-二亚水杨基乙二胺-二甲基亚砜三元配合物的合成和晶体结构

合成了Tb(Ⅲ)、Y(Ⅲ)、Nd(Ⅲ)硝酸盐与N,N-二亚水杨基乙二胺、二甲基亚观的配合物[RE(C₆H₄OHCHNC₂H₄NCHC₆H₄OH)(NO₃)₃(CH₃SOCH₃)］.Tb(Ⅲ)配合物晶体为单斜晶系,空间群P2₁/n,a=0.9628(3)nm,b=1.6439(4)nm,C=1.6256(2)nm,β=102.78(2)°,V=2.509(2)nm₃,D_x=1.830g/cm³,Z=4,μ=2.996mm^-1,F(000)=1368,R=0.043,R_w=0.046.Tb(Ⅲ)的配位数是9,配位几何为单帽四方反核柱.所有的配位原子都是氧原子.两个中心离子被双Schiff碱桥联,形成一维无限长链.     

Deuterium NMR studies of inositol liquid crystals [1]

Deuterium NMR investigations are presented on members of two new mesogenic series derived from the naturally occurring stereoisomers myo- and scW/o-inositol. Tetraethers of these two series exhibit thermotropic columnar phases in which the columns are apparently formed by stacked hydrogen bonded dimers of these molecules which chemically are vicinal diols. Deuterium NMR measurements were performed on the tetraoctyl homologues 2e (a cis diol) and 3e (a trans diol) of these series. We have investigated mixtures of these diols with small amounts of benzene-d₆ as probe molecules as well as samples of the neat diol compounds deuteriated at their hydroxyl groups. The results obtained show that the mesophases of both compounds are uniaxial and align partially in a magnetic field upon slow cooling from their isotropic liquids. The alignment is with the director parallel to the field direction indicating that the anisotropic magnetic susceptibility of this mesophase is positive. The deuterium quadrupole splitting of the benzene-d₆ probe in both systems is temperature dependent and in the trans diol 3e it even changes sign. This is interpreted in terms of a model in which the benzene-d₆ probe equilibrates rapidly between two (or more) solvation sites with quadrupole splittings of opposite signs The deuterium spectra of the neat deuterium labelled cis diol 2e exhibit two different signals due to the two deuterons which are located at the axial and equatorial hydroxyl groups. This indicates that there is no fast intra- or intermolecular exchange of the hydroxyl hydrogens. The overall quadrupole splittings of the hydroxyl deuterons in this compound are highly reduced compared to their static values and this is interpreted in terms of motional modes involving both reorientation of the hydroxyl deuterons about their C-O axis and overall reorientation of the molecules (or pairs of molecules) around the columnar axes. The corresponding spectra of the neat deuteriated trans diol 3e exhibit a single spectrum indicating that both hydroxyl deuterons in this compound are equivalent, or very nearly so. Within the mesophase region the spectrum undergoes gradual changes due to the increase in the molecular mobility, but the overall motional narrowing is less than in the cis isomer 2e. Apparently due to stronger hydrogen bonding in the trans isomer 3e the precession of the hydroxyl groups is hindered and a fast molecular reorientation is only possible at high temperatures.     

Reductive dehalogenation of chloro(alkynyl)phosphines by octacarbonyldicobalt

Reductive dehalogenation of the (chloro)(phenylethynyl)phosphine (2,4,6-^tBu₃C₆H₂O)(PhCC)PCl, I, by Co₂(CO)₈, II, yields the neutral phosphenium ion complex [(R)(R′)]P=Co(CO)₃, III, (R = 2,4,6-^tBu₃C₆H₂O; R′ = (η²-C≡CPh)Co₂(CO)₆), which contains a trigonally planar coordinated phosphorus atom. When NaCo(CO)₄, V, is used instead of II a dinuclear complex, Co₂(CO)₆[μ²-P(R)(R′)]₂, VI, (R = 2,4,6-^tBu₃C₆H₂O; R′ = C≡CPh) is formed in which the phosphido ligands P(R)(R′), bridge in a μ₂ fashion two Co(CO)₃ units. The mechanism of formation of VI, involving a formal dimerization of two [(2,4,6-^tBu₃C₆H₂O)(PhC≡C)]P=Co(CO)₃ fragments, is discussed. However, (^tBu)(PhC≡C)PCl, VII, reacts with II, to yield the cluster compound VIII, containing the two μ₂-bridging units (^tBu)[(η²-C≡CPh)Co₂(CO)₅]P and (^tBu)(PhC≡C)P.

Compounds II and VI–VIII were identified from their analytical and spectroscopic (IR, ¹H-, ¹³C- and ³¹P-NMR) data. The molecular structure of the cluster compound VIII was determined by an X-ray diffraction study.