四氯合锌酸正九烷铵的晶体结构及热化学性质

合成了四氯合锌酸正九烷铵复合物(C₉H₁₉NH₃)₂ZnCl₄(s) (C₉Zn(s)), 并使用X射线单晶衍射、化学分析以及元素分析确定了其晶体结构和化学组成. 利用其晶体学数据推导了C₉Zn(s)的晶格能U_POT=952.94 kJ·mol^-1. 在298.15 K下, 利用恒温环境溶解-反应热量计测定了C₉Zn(s)在不同质量摩尔浓度下的摩尔溶解焓. 在Pitzer电解质溶液理论基础上确定了C₉Zn(s)的无限稀释摩尔溶解焓Δ_sΗ_m^∞=20.09 kJ·mol^-1, 以及Pitzer焓参数组合(4β_C9H19NH3,Cl^(0)L+2β_Zn,Cl^(0)L+θ_C9H19NH3,Zn^L)和(2β_C9H19NH3,Cl^(1)L+β_Zn,Cl^(1)L)的值.     

烷基咪唑离子液体对脂肪酶催化酯水解反应活性的影响

考察了1-烷基-3-甲基咪唑类离子液体对柱状假丝酵母脂肪酶(CRL)催化橄榄油水解反应活性的影响,利用电导法确定了磷酸盐缓冲液中Br^-,Cl^-,[BF₄]^-系列咪唑离子液体的临界胶束浓度(CMC)和[PF₆]^-系列咪唑离子液体的溶解度.结果显示,离子液体的阴、阳离子对酶活性的影响规律与离子液体的Kosmotropicity性质无明显关联,但与离子液体在体系中的含量密切相关,在最适离子液体含量时,酶活性达到最高;阳离子[C_nMIM]⁺中的n越大,可促进酶活性的离子液体适宜含量越低;Br^-,[BF₄]^-系列离子液体的浓度超过CMC时则抑制酶活;阴离子对酶活性的最大促进作用顺序为Br^->Cl^->[BF₄]^->[PF₆]^-.离子液体对酶活性的影响随体系pH和温度的不同而改变,在最适离子液体浓度时的最适pH均为7.000.在pH 7.000,30 ^oC以及[C₈MIM]Br离子液体浓度为47.6 mmol/L的最佳条件下,最高相对酶活力和比活力分别达到1734%和54.4 U/mg protein.     

稳定的气相二价阴离子C7H22-

采用HF, MP2, CCSD以及CISD方法,研究了二价阴离子C₇H₂^2-和C₇H₃^2-及其一价阴离子的几何结构振动频率。在理论上,我们得到了C₇H₂^2-和C₇H₃^2-能量最低结构分别为：C₂C(H₂)C₄^2-和C₂CHCHCHC₂^2-,而且均没有虚频。计算这两种结构所有可能的碎片化通道,碎片化能表明这两结构都不易解离为两个一价阴离子碎片。但是这两结构的垂直电离能和绝热电离能表明C₂C(H₂)C₄^2-是稳定的,但C₂CHCHCHC₂^2-是不稳定的。     

CMPO/[Cnmim][NTf2]体系对Eu3+和UO22+的萃取行为

讨论了辛基(苯基)-N,N-二异丁基胺甲酰基甲基氧化膦(CMPO)/1-烷基-3-甲基咪唑双(三氟甲烷磺酰)亚胺盐([C_nmim][NTf₂],n=2,8,12)萃取体系分别对硝酸溶液中的铕离子(Eu³⁺)和铀酰根离子(UO₂²⁺)的萃取行为。主要研究了硝酸浓度、接触时间、温度、CMPO浓度对CMPO/[C_nmim][NTf₂]体系萃取性能的影响,并选取CMPO/[C2mim][NTf₂]体系对模拟高放废液中的镧锕元素进行了萃取分离。结果表明:随着离子液体侧链长度增长,萃取平衡时间逐渐延长;CMPO/[C2mim][NTf₂]体系对Eu³⁺的萃取是放热反应,萃取率随酸度增加而逐渐降低,对UO₂²⁺则是吸热反应,萃取率随酸度增加而逐渐升高;通过机理研究,推测出对Eu³⁺的萃取反应是离子交换,而对UO₂²⁺的萃取反应则是中性配位;CMPO/[C2mim][NTf₂]体系能有效的萃取模拟高放废液中的镧系、锕系元素,且在高酸下有一定的镧锕分离效果。     

α-二亚胺钴配合物催化1,3-丁二烯高活性与高顺式-1,4选择性聚合

合成了一系列α-二亚胺钴配合物[ArN=C(Me)-(Me)C=NAr]CoCl₂(Ar=C₆H₅, 3a; 4-MeC₆H₄, 3b; 4-MeOC₆H₄, 3c; 4-FC₆H₄, 3d; 4-ClC₆H₄, 3e; 2-MeC₆H₄, 3f; 2-EtC₆H₄, 3g; 2-ⁱPrC₆H₄, 3h; 2,4,6-Me₃C₆H₂, 3i; 2,6-Et₂C₆H₃, 3j; 2,6-ⁱPrC₆H₃, 3k)和作为对比的吡啶双亚胺二氯化钴配合物(4a), 并用X射线单晶衍射方法研究了配合物3i, 3k和4a的分子结构. α-二亚胺钴配合物在倍半乙基氯化铝的作用下对丁二烯聚合有较高的催化活性,得到的顺式-1,4结构含量达98%,且有较高分子量(M_n≈1×10⁴-1×10⁵)的聚丁二烯. 配体的电子效应影响催化剂的活性及顺式-1,4选择性, 而配体的空间位阻对丁二烯聚合几乎没有影响. 详细研究了聚合时间、聚合温度、烷基铝助催化剂及铝比等条件对丁二烯聚合行为的影响.     

离子液体[bmim][BF4]对联苯甲酰光化学反应影响的瞬态吸收光谱

利用纳秒级激光光解瞬态吸收光谱研究了联苯甲酰(BZ)在离子液体1-丁基-3-甲基咪唑四氟硼酸盐([bmim][BF₄])与乙腈(MeCN)混合体系中的光化学反应行为. 考察了探针分子BZ存在下[bmim][BF₄]/MeCN比例对体系中化学反应动力学的影响. 实验发现: 在N₂饱和条件下, BZ溶液经激光辐照后产生的激发三线态³BZ^*遵循一级反应动力学规律衰减. 离子液体(IL)相对比例增加对³BZ^*瞬态吸收峰的位置和强度没有产生明显影响. 但离子液体体积分数V_IL的变化对[bmim][BF₄]/MeCN混合溶剂中光诱导电子转移的影响却非常显著, 总体上电子转移产生的自由基的表观生成速率常数k_gr随[bmim][BF₄]的V_IL增大而减小. 在[bmim]BF₄]比例足够大的情况下, ³BZ^*与三乙胺或四甲基对苯二胺之间的电子转移被抑制.     

稀土配合物[Pr(C3H7NO2)2(C3H4N2)(H2O)](ClO4)3的标准生成焓及热分解动力学研究

合成了高氯酸镨和咪唑(C₃H₄N₂), DL-α-丙氨酸(C₃H₇NO₂)混配配合物晶体. 经傅立叶变换红外光谱、化学分析和元素分析确定其组成为[Pr(C₃H₇NO₂)₂(C₃H₄N₂)(H₂O)](ClO₄)₃. 使用具有恒温环境的溶解-反应量热计, 以2.0 mol•L^－1 HCl为量热溶剂, 在T＝(298.150±0.001) K时测定出化学反应PrCl₃•6H₂O(s)＋2C₃H₇NO₂(s)＋C₃H₄N₂(s)＋3NaClO₄(s)＝[Pr(C₃H₇NO₂)₂(C₃H₄N₂)(H₂O)](ClO₄)₃(s)＋3NaCl(s)＋5H₂O(1)的标准摩尔反应焓为Δ_rH_m^ө＝(39.26±0.11) kJ•mol^－1. 根据盖斯定律, 计算出配合物的标准摩尔生成焓为Δ_fH_m^ө{[Pr(C₃H₇NO₂)₂(C₃H₄N₂)(H₂O)](ClO₄)₃(s), 298.150 K}＝(－2424.2±3.3) kJ•mol^－1. 采用TG-DTG技术研究了配合物在流动高纯氮气(99.99%)气氛中的非等温热分解动力学, 运用微分法(Achar-Brindley-sharp和Kissinger法)和积分法(Satava-Sestak和Coats-Redfern法)对非等温动力学数据进行分析, 求得分解反应的表观活化能E＝108.9 kJ•mol^－1, 动力学方程式为dα/dt＝2(5.90×10⁸/3)(1－α)[－ln(1－α)]^－1exp(－108.9×10³/RT).     

大气中HSO-3异构体的“量子化学后”研究

在量子化学计算的基础上，用统计热力学方法，计算了亚硫酸氢根离子的两种异构体HOSO^-₂(C_S)和HSO^-₃(C₃V)的热力学性质及它们相互转化的平衡常数(相对稳定性随温度的变化)等。通过计算数据的回归分析，给出了摩尔熵、摩尔热容等随温度变化的表达式。     

H键连接的三维超分子化合物[M(H2O)6](HL)2的合成、表征与结构[H2L=1-(4-羟基苯)-5-四氮唑硫乙酸，M=MnⅡ，CoⅡ，NiⅡ，ZnⅡ]

利用配体1-(4-羟基苯)-5-巯基四氮唑(H₂L)和金属盐酸盐在水溶液中反应,合成了4种离子型化合物,并测定了它们的晶体结构。分析结果显示它们是异质同晶,都属于P1空间群,分子通式为[M(H₂O)₆](HL)₂[M=Mn^Ⅱ (1),Co^Ⅱ (2),Ni^Ⅱ (3),Zn^Ⅱ (4     

Gemini表面活性剂(12-6-12)和DNA的相互作用

应用紫外光谱、荧光探针、zeta 电位、动态光散射和凝胶电泳等方法探讨了阳离子gemini 表面活性剂C₁₂H₂₅N⁺(CH₃)₂―(CH₂)₆―(CH₃)₂N⁺C₁₂H₂₅·2Br^-(12-6-12)与DNA之间的相互作用. 研究结果表明, 与传统表面活性剂相比, 偶联表面活性剂特殊的分子结构使其与DNA的作用更强烈. DNA引导表面活性剂在其链周围形成类胶束结构, 开始形成类胶束时对应的表面活性剂临界聚集浓度(CAC)比纯表面活性剂临界胶束浓度(CMC)低两个数量级. CAC与DNA的浓度无关, 而与表面活性剂之间的疏水作用以及表面活性剂与DNA之间的静电吸引作用密切相关. Zeta 电位和凝胶电泳结果显示了DNA链所带负电荷逐渐被阳离子表面活性剂中和的过程. 借助原子力显微镜(AFM)成功观察到了松散的线团状DNA, 球状体随机地分散在DNA链上形成类似于串珠的结构、尺寸较大的球形复合物以及其由于吸附多余的表面活性剂重新带正电而被溶解得到的较小DNA/12-6-12聚集体. 圆二色(CD)光谱结果显示, 12-6-12可以诱导DNA的构象发生改变.     

Concentration-dependent dual behavior of hydrophilic ionic liquid in changing properties of aqueous sodium dodecyl sulfate

Modifying physicochemical properties of aqueous surfactant solutions in favorable fashion by addition of environmentally benign room-temperature ionic liquids (ILs) has enormous future potential. Due to its unusual properties, an IL may demonstrate a unique role in altering the properties of aqueous surfactant solutions. Changes in the properties of aqueous sodium dodecyl sulfate (SDS), an anionic surfactant, upon addition of a common and popular "hydrophilic" ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF4] are presented. Addition of low concentrations of [bmim][BF4] (i.e., 相似文献   

Dynamics of solvent and rotational relaxation of coumarin-153 in room-temperature ionic liquid 1-butyl-3-methyl imidazolium tetrafluoroborate confined in poly(oxyethylene glycol) ethers containing micelles

We have investigated solvent and rotational relaxation of coumarin 153 (C-153) in room-temperature ionic liquid (RTILs) 1-butyl-3-methyl-imidazolium tetrafluoroborate ([bmim][BF(4)]) and the ionic liquid confined in alkyl poly(oxyethylene glycol) ethers containing micelles. We have used octaethylene glycol monotetradecyl ether (C(14)E(8)) and octaethylene glycol monododecyl ether (C(12)E(8)) as surfactants. In the [bmim][BF(4)]-C(14)E(8) micelle, we have observed only a 22% increase in solvation time compared to neat [bmim][BF(4)], whereas in the [bmim][BF(4)]-C(12)E(8) system, we have observed approximately 57% increase in average solvation time due to micelle formation. However, the slowing down in solvation time on going from neat RTIL to RTIL-confined micelles is much smaller compared to that on going from water to water confined micellar aggregates. The 22-57% increase in solvation time is attributed to the slowing down of collective motions of cations and anions in micelles. The rotational relaxation times become faster in both the micelles compare to neat [bmim][BF(4)].     

Ionic liquid induced changes in the properties of aqueous zwitterionic surfactant solution

Modifying properties of aqueous surfactant solutions by addition of external additives is an important area of research. Unusual properties of ionic liquids (ILs) make them ideal candidates for this purpose. Changes in important physicochemical properties of aqueous zwitterionic N-dodecyl- N, N-dimethyl-3-ammonio-1-propanesulfonate (SB-12) surfactant solution upon addition of hydrophilic IL 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF 4], are reported. Dynamic light scattering results indicate a dramatic reduction in the average micellar size in the presence of [bmim][BF 4]; micellar (or micelle-like) aggregation in the presence of as high as 30 wt % [bmim][BF 4] is confirmed. Responses from fluorescence probes are used to obtain critical micelle concentration (cmc), aggregation number ( N agg), and dipolarity and microfluidity of the micellar pseudophase of aqueous SB-12 in the presence of [bmim][BF 4]. In general, increasing the amount of [bmim][BF 4] to 30 wt % results in decrease in N agg and increase in cmc. Increase in the dipolarity and the microfluidity of the probe cybotactic region within the micellar pseudophase is observed on increasing [bmim][BF 4] concentration in the solution. It is attributed to increased water penetration into the micellar pseudophase as [bmim][BF 4] is added to aqueous SB-12. It is proposed that IL [bmim][BF 4] behaves similar to an electrolyte and/or a cosurfactant when present at low concentrations and as a polar cosolvent when present at high concentrations. Electrostatic attraction between cation of IL and anion of zwitterion, and anion of IL and cation of zwitterion at low concentrations of [bmim][BF 4] is evoked to explain the observed changes. Presence of IL as cosolvent appears to reduce the efficiency of micellization process by reducing the hydrophobic effect.     

Study on physicochemical properties of ionic liquids based on alanine [Cnmim][Ala] (N=2,3,4,5,6)

According to Fukumoto's method, a new series of ionic liquids (ILs) based on alanine, [Cnmim][Ala] ( n=2,3,4,5,6), which comprise 1-alkyl-3-methylimidazolium cation ([Cnmim](+)) and alanine anions ([Ala] (-)), were prepared and characterized. In terms of standard addition method, the density and surface tension of amino acid ILs [Cnmim][Ala] (1-alkyl-3-methylimidazolium alpha-aminopropionic acid salt) were measured in the temperature range 293.15-343.15+/-0.05 K. The volume and surface properties of the ILs [Cnmim][Ala] were discussed. A new method of determining parachor of ionic compound was proposed and was applied to estimate the physicochemical properties of amino acid ionic liquids (AAILs): molecular volume, surface tension, molar enthalpy of vaporization, and thermal expansion coefficient. In comparison with Deetlefs's method of using neutral parachor contribution, the method proposed in this work makes smaller error in estimating properties of AAILs.     

Unique role of hydrophilic ionic liquid in modifying properties of aqueous Triton X-100

Modification of important physicochemical properties of aqueous surfactant solutions can be achieved by addition of environmentally benign room temperature ionic liquids (ILs). While low aqueous solubility of "hydrophobic" ILs limits the amount of IL that may be added to achieve desired changes in the physicochemical properties, hydrophilic ILs do not have such restrictions associated to them. Alterations in the key physicochemical properties of aqueous solutions of a common nonionic surfactant Triton X-100 (TX100) on addition of up to 30 wt % hydrophilic IL 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) are reported. The presence of micellar aggregates in as high as 30 wt % [bmim][BF4]-added aqueous TX100 solutions is established by dynamic light scattering and fluorescence probe behavior. Increasing the concentration of [bmim][BF4] results in decrease in average micellar size and aggregation number and increase in critical micelle concentration, indicating an overall unfavorable aggregation process. Increase in the dipolarity and the microfluidity of the probe cybotactic region within the palisade layer of the micellar phase upon [bmim][BF4] addition implies increased water penetration and the possibility of TX100-[bmim][BF4] interactions. While the changes in some of the physicochemical properties indicate the role of [bmim][BF4] to be similar to a cosurfactant, the IL acts like a cosolvent as far as changes in other properties are concerned. Effectiveness of IL [bmim][BF4] in modifying physicochemical properties of aqueous TX100 is demonstrated.     

正负离子表面活性剂/离子液体双水相性质研究

本文把短链离子液体(IL)四氟硼酸1-乙基-3-甲基咪唑鎓[C2mim]BF4引入正负离子表面活性剂十二烷基硫酸钠(SDS)和十二烷基三甲基溴化铵(DTAB)双水相体系(SDS/DTAB/H2O)中,研究了IL对双水相相图及相分离体系性质的影响。结果表明,[C2mim]BF4的阳离子性质是影响阴离子表面活性剂过量区域性质的主要因素,IL通过静电作用、氢键作用等改变体系中聚集体的形貌,最终导致阴离子双水相(ATPSa)的消失。IL的阴离子对阳离子双水相(ATPSc)区域性质起着决定作用;IL的盐效应引起的对表面活性剂混合胶束扩散双电层的压缩作用,不但促进胶团的形成,缩短了形成稳定胶团所需要的时间,加快了双水相的相分离速度,而且也造成了形成ATPSc所需DTAB含量的提高。IL的引入改变了ATPSc上、下相表面活性剂的组成及含量,使富含表面活性剂的上相中阳离子表面活性剂含量更高,进而提高了双水相的萃取性能,其上相对甲基橙的萃取效率可高达96.67%。     

Electrical conductivity study on micelle formation of long-chain imidazolium ionic liquids in aqueous solution

Electrical conductivity was measured for aqueous solutions of long-chain imidazolium ionic liquids (IL), 1-alkyl-3-methylimidazolium bromides with C(12)-C(16) alkyl chains. The break points appeared in specific conductivity (kappa) vs concentration (c) plot indicates that the molecular aggregates, i.e., micelles, are formed in aqueous solutions of these IL species. The critical micelle concentration (cmc) determined from the kappa vs c plot is somewhat lower than those for typical cationic surfactants, alkyltrimethylammonium bromides with the same hydrocarbon chain length. The electrical conductivity data were analyzed according to the mixed electrolyte model of micellar solution, and the aggregation number, n, and the degree of counter ion binding, beta, were estimated. The n values of the present ILs are somewhat smaller than those reported for alkyltrimethylammonium bromides, which may be attributed to bulkiness of the cationic head group of the IL species. The thermodynamic parameters for micelle formation of the present ILs were estimated using the values of cmc and beta as a function of temperature. The contribution of entropy term to the micelle formation is superior to that of enthalpy term below about 30 degrees C, and it becomes opposite at higher temperature. This coincides with the picture drawn for the micelle formation of conventional ionic surfactants.     

Thermodynamic characterization of 3-[(3-cholamidopropyl)-dimethylammonium]-1-propanesulfonate (CHAPS) micellization using isothermal titration calorimetry: temperature, salt, and pH dependence

A systematic investigation of the micellization process of a biocompatible zwitterionic surfactant 3-[(3-cholamidopropyl)-dimethylammonium]-1-propanesulfonate (CHAPS) has been carried out by isothermal titration calorimetry (ITC) at temperatures between 278.15 K and 328.15 K in water, aqueous NaCl (0.1, 0.5, and 1 M), and buffer solutions (pH = 3.0, 6.8, and 7.8). The effect of different cations and anions on the micellization of CHAPS surfactant has been also examined in LiCl, CsCl, NaBr, and NaI solutions at 308.15 K. It turned out that the critical micelle concentration, cmc, is only slightly shifted toward lower values in salt solutions, whereas in buffer media it remains similar to its value in water. From the results obtained, it could be assumed that CHAPS behaves as a weakly charged cationic surfactant in salt solutions and as a nonionic surfactant in water and buffer medium. Conventional surfactants alike, CHAPS micellization is endothermic at low and exothermic at high temperatures, but the estimated enthalpy of micellization, ΔHM0, is considerably lower in comparison with that obtained for ionic surfactants in water and NaCl solutions. The standard Gibbs free energy, ΔGM0, and entropy, ΔSM0, of micellization were estimated by fitting the model equation based on the mass action model to the experimental data. The aggregation numbers of CHAPS surfactant around cmc, obtained by the fitting procedure also, are considerably low (nagg ≈ 5 ± 1). Furthermore, some predictions about the hydration of the micelle interior based on the correlation between heat capacity change, Δcp,M0, and changes in solvent-accessible surface upon micelle formation were made. CHAPS molecules are believed to stay in contact with water upon aggregation, which is somehow similar to the micellization process of short alkyl chain cationic surfactants.     

Effects of temperature, salt, and deuterium oxide on the self-aggregation of alkylglycosides in dilute solution. 1. n-nonyl-beta-D-glucoside

The influence of salt, temperature, and deuterium oxide on the self-aggregation of n-nonyl-beta-D-glucoside (beta-C9G1) in dilute solution has been investigated by static and dynamic light scattering, neutron scattering, and tensiometry. Scattering data show that the micelles can be described as relatively stiff, elongated structures with a circular cross section. With a decrease of temperature, the micelles grow in one dimension, which makes it surprising that the critical micelle concentration (cmc) shows a concomitant increase. On the other hand, substitution of D2O for H2O causes a large increase in micelle size at low temperatures, without any appreciable effect on cmc. With increasing temperature, the deuterium effect on the micelle size diminishes. The effects of salt on the micelle size and cmc were found to follow the Hofmeister series. Thus, at constant salt concentration, the micelle size decreased according to the sequence SO4(2-) > Cl- > Br- > NO3- > I- > SCN-, whereas the effect on cmc displays the opposite trend. Here, I- and SCN are salting-in anions. Similarly, the effects of cations decrease with increasing polarizability in the sequence Li+ > Na+ > K+ > Cs+. At high ionic strength, the systems separate into two micellar phases. The results imply that the size of beta-C9G1 micelles is extremely sensitive to changes in the headgroup size. More specifically, temperature and salt effects on effective headgroup size, including intermolecular interactions and water ofhydration, are suggested to be more decisive for the micelle morphology than the corresponding effects on unimer solubility.     

Analysis of interfacial and micellar behavior of sodium dioctyl sulphosuccinate salt (AOT) with zwitterionic surfactants in aqueous media

The interfacial and bulk properties of mixtures of the anionic surfactant (dioctyl sulphosuccinate sodium salt, AOT) with zwitterionic surfactants 3-(N,N-dimethyldodecylammonio) propane sulfonate (DPS), 3-(N,N-dimethyltetradecylammonio) propane sulfonate (TPS), 3-(N,N-dimethylhexadecylammonio) propane sulfonate (HPS) have been studied employing surface tension, fluorescence, and viscometric techniques in aqueous media at 25 °C. It is observed that these mixtures exhibit synergism and these synergistic interactions increase with the enhancement of the hydrocarbon chain of the zwitterionic surfactant. The various physicochemical properties such as critical micelle concentration (cmc), surface excess concentration (Г(max)), minimum area per molecule (A(min)), aggregation number (N(agg)), interaction parameters (β(σ), β(m)), and thermodynamic parameters such as standard Gibbs free energy of adsorption (ΔG(ads)(o)), excess free energy of micellization (ΔG(ex)), and standard Gibbs free energy of micellization (ΔG(m)(o)) have been evaluated. The negative values of ΔG(m)(o) and ΔG(ads)(o) show that the micelle formation and adsorption of surfactant at the air/solution interface is energetically favorable, while a negative value of ΔG(ex) ensures stability of the mixed micelles formed. The Regular Solution Approximation, Motomura and Rosen's approaches have been used to explain and compare the results. The packing parameter (p) ensures the formation of vesicles or bilayers for AOT+DPS/TPS mixtures, which can potentially be used as delivery agents for industrial applications.