铬(Ⅵ)-邻菲咯啉-亚硝酸钠的氨性缓冲体系中极谱催化波机理的研究

本文报道了Cr(Ⅵ)-C₁₂H₈N₂-NaNO₂^-NH₃-NH₄Cl(pH9.4)体系极谱催化波机制的研究.阐明它不是氢催化波.而是Cr(Ⅲ)的多元配合物中NO₂^-被催化还原,同时溶液中的NO₂^-又参与了平行电极反应的催化反应.活性多元配合物的组成为:Cr(Ⅲ)·(C₁₂H₈N₂)·(NO₂^-)₂·(NH₃).     

阴离子插层镁铝水滑石结构及相互作用的理论研究

采用密度泛函理论(DFT)计算了MgAl-LDHs层板与无机阴离子(F^-、Cl^-、NO₃^-、CO₃^2-、SO₄^2-)和有机阴离子(水杨酸根离子([HO(C₆H₄)COO]^-)、苯甲酸根离子([(C₆H₅)COO]^-)、对二甲氨基苯甲酸根离子([p-(CH₃)₂N(C₆H₄)COO]^-)、十二烷基磺酸根离子[C₁₂H₂₅SO₃]^-、己烷基磺酸根离子[C₆H₁₃SO₃]^-、丙烷基磺酸根离子[C₃H₇SO₃]^-)间的相互作用,获得稳定超分子几何结构及相互作用能。层板主体与客体间存在较强的超分子作用,包括主客体间静电作用和氢键等。主、客体间相互作用能数值大小顺序为CO₃^2- > SO₄^2- > F^-> Cl^-> NO₃^-;[p-(CH₃)₂N(C₆H₄)COO]^-> [(C₆H₅)COO]^-> [HO(C₆H₄)COO]^-和[C₁₂H₂₅SO₃]^-> [C₆H₁₃SO₃]^- > [C₃H₇SO₃]^-。另外,还采用自然键轨道(NBO)计算和分析了LDHs 层板与阴离子间作用机理,从二阶微扰理论计算得到的稳定化能变化趋势与相互作用能数据基本吻合。     

Pd2X2(dpm)2(X＝NCO-,CH3CO2-,SCN-,NO3-;dpm＝Ph2PCH2PPh2配合物与H2S反应的NMR研究

采用NMR方法考察了室温和低温(-78～60℃)下Pd₂X₂(dpm)₂(X=NCO^-,CH₃CO₂^-,SCN^-和NO₃^-,dpm=Ph₂PCH₂PPh₂)与H₂S在CD₂Cl₂或CDCl₃中的反应。结果表明,在X=NCO^-和CH₃CO₂^-的情况下,H₂S优先与这些Pd配合物的阴离子作用生成相应的共轭酸HX和Pd₂(SH)₂(dpm)₂,后者在H₂S存在下又进一步转化为Pd₂(SH)₂(dpm)₂(μ-S);当X=SCN^-和NO₃^-时,反应则生成结构可能为[Pd₂(H)(SH)(μ-SH)(dpm)₂]⁺的双核Pd配合物。     

N,N′-二甲基-N,N′-二辛基-4-氧庚二酰胺萃取镧的研究

为了研究不同的酰胺夹醚化合物对萃取镧的性能，本文使用N,N′-二甲基-N,N′-二辛基-4-氧庚二酰胺(DMDOOHA)为萃取剂，以1-甲基-3-丁基咪唑六氟磷酸盐离子液体([C₄mim⁺][PF₆^-])为稀释剂，研究其在水相中萃取La³⁺的行为，考察了萃取时间，pH,萃取剂的的浓度、及温度对萃取分配比的影响。实验表明，萃取剂在离子液体[C₄mim⁺][PF₆^-]中对La³⁺的具有强烈的萃取能力。机理研究表明，在([C₄mim⁺][PF₆^-]体系中，萃取剂与La³⁺可能形成3∶1配合物。萃取过程为热力学自发的过程。     

[Ru(phen)2(H2biim)](PF6)2配合物与阴离子的选择性作用

研究了[Ru(phen)₂(H₂biim)](PF₆)₂(1)与各种阴离子之间的选择性作用, 发现配合物1与Cl^-, Br^-, I^-, NO₃^-, HSO₄^-和H₂PO₄^-阴离子之间存在氢键作用. OAc^-阴离子与配合物1作用, 由于强的氢键作用使H₂biim上的一个H转移到OAc^-上, 使配合物1脱去一个质子, 形成{[Ru(phen)₂(H₂biim)](OAc)}结合体, 溶液颜色由黄色变为橙棕色. 由于F^-能形成非常稳定的HF₂^-, 配合物1逐步脱去2个质子, 溶液颜色由黄色变为紫色, 因此可作为裸眼检测阴离子的识别剂.     

醋酸铀酰负离子气相分解反应的密度泛函理论研究

采用密度泛函理论(DFT), 选择杂化密度泛函TPSSh和TZVP基组, 对一个UO₂(CO₃)₃^4-负离子的结构进行优化, 理论计算所得结果(键长等参数)与实验数据一致. 应用TPSSh/TZVP(ECP)方法对醋酸铀酰负离子UO₂(CH₃COO)₃^-的气相分解反应进行了理论计算, 成功地解释了含+5价铀的气相自由基负离子的稳定性, 并对2个负离子(CH₃COO)UO₂CH₃^-和CH₃UO₂OH^-分别与水的复分解反应进行了理论计算, 所得数据与质谱的实验结果较好地吻合.     

γ辐射下CMPO/[C2mim][NTf2]的辐解及其对Eu3+萃取的影响

主要考察了辛基(苯基)-N, N-二异丁基胺甲酰基甲基氧化膦(CMPO)在1-乙基-3-甲基咪唑双三氟甲基磺酰胺酸盐([C₂mim][NTf₂])中的γ辐解行为,同时考察辐射对CMPO/[C₂mim][NTf₂]萃取能力的影响。通过超高效液相色谱-四极杆飞行时间质谱联用仪(UPLC/Q-TOF-MS)进行定量分析、辐解产物认定以及产物半定量分析。CMPO/正十二烷作为对比条件进行了相同研究。结果表明：CMPO在[C₂mim][NTf₂]中的辐解率低于其在正十二烷中,并且辐解路径不同。在正十二烷体系中,CMPO主要发生C―P、C―N键的断链,而在离子液体体系中CMPO主要发生异丁基脱除反应,并与[C₂mim]^+·、·CF₃等离子液体产生的自由基发生取代反应。综合辐解研究结果,我们提出CMPO/[C₂mim][NTf₂]的辐解路径,这加深了CMPO在离子液体中辐解机理的认识。最后,通过萃取实验发现,当硝酸浓度为0.01 mol·L^-1,辐照剂量为800 kGy时,CMPO/[C₂mim][NTf₂]对Eu³⁺的萃取率依旧达到99%以上。     

室温离子液体对氨基苯磺酸的萃取性能

系统研究了[C₄mim][PF₆], [C₆mim][PF₆], [C₆mim][BF₄]和[C₈mim][BF₄]室温离子液体对间氨基苯磺酸、对氨基苯磺酸稀水溶液的萃取平衡. 实验结果表明: 萃取温度和相体积比的变化对分配比影响不大; 水相pH值对萃取平衡有较大的影响, 氨基苯磺酸在离子液体/水体系中的分配比在pH＝4.2时达到最大值; 水相中CaCl₂或Na₂SO₄的存在能较大幅度地提高氨基苯磺酸的分配比; 离子液体的阴离子的性质对分配比有显著的影响, 阴离子为[BF₄]^－的离子液体对氨基苯磺酸的萃取能力大于阴离子为[PF₆]^－的离子液体; 咪唑环上烷基链的长度也对萃取效果有一定的影响. 在所研究的离子液体中, [C₆mim][BF₄]和[C₈mim][BF₄]对氨基苯磺酸有较好的萃取性能, 且萃取相中的氨基苯磺酸可回收利用, 离子液体也可循环使用.     

离子液体对木瓜蛋白酶催化特性的影响

研究了以1-丁基-3-甲基咪唑、四乙基铵及N-乙基吡啶为阳离子, 配以多种阴离子(H₂PO₄^-, ClO₄^-, HSO₄^-, CH₃COO^-, Cl^-, Br^-, NO₃^-, SCN^-, BF₄^-, PF₆^-)的离子液体对木瓜蛋白酶催化N-苯甲酰-L-精氨酸乙酯(BAEE)水解的活性及热稳定性的影响. 通过分析含离子液体体系中木瓜蛋白酶的水解活性和热力学失活参数, 发现该酶活性及稳定性与离子液体的Kosmotropicity性质无关. 因此, 离子的Hofmeister效应并不适合解释离子液体对木瓜蛋白酶催化特性的影响规律. 当以BF₄^-为阴离子, 改变阳离子结构时, 仅[BMIm][BF₄]可提高酶活性, 其它含官能团的咪唑类离子液体则降低酶活性, 但大部分离子液体明显提高木瓜蛋白酶的热稳定性. 在所研究的离子液体中, 基于PF₆^-或BF₄^-阴离子的离子液体可提高木瓜蛋白酶的活性及其热稳定性. 在含[BMIm][PF₆]介质中, 木瓜蛋白酶的水解活性最高; 在含[HOEtMIm][BF₄]介质中其热稳定性最好.     

1-苯基-3-甲基-4-苯甲酰基吡唑酮-(5)与中性磷萃取剂对铀(Ⅵ)、铈(Ⅲ)、钙(Ⅱ)的协同萃取

本文研究了1-苯基-3-甲基-4-苯甲酰基吡唑酮-(5)与中性磷萃取剂磷酸三丁酯(TBP),甲基瞵酸二异戊酯(DIAMP),丁基膦酸二丁酯(DBBP)和三丁基氧化膦(TBPO)的苯溶液从硝酸介质中对铀(Ⅵ)、铈(Ⅲ)、钙(Ⅱ)的萃取,发现均有程度不同的协同效应.测定了协萃络合物组成为UO₂X₂·B(其中B为TBP,DIAMP,DBBP,TBPO),CeX₃·2B(B为DIAMP,DBBP,TBPO)和CaX₂·2TBPO.分别计算了它们的萃取平衡常数.简单讨论了协同效应的机理与中性磷萃取剂的Lewis碱性的关系.     

Synthesis, structural and spectroscopic characterisation of three di-μ-fluoro-bis[dioxouranyl] complexes

Three novel uranyl complexes with organic phosphine oxide ligands and bridging fluorides have been synthesised and structurally characterised. In [ UO₂(μ-F)(TPPO)_{3 2}][BF₄]₂ · ⁿC₆H₁₄, 1, and [ UO₂(-μF)(TBPO)_{3 2}][BF₄]₂ 2, (where TPPO and TBPO are triphenylphosphine oxide and tri-n-butylphosphine oxide, respectively) two UO₂ ²⁺ moieties are bridged by two fluorides with three additional terminal PO donor ligands coordinated to each uranium centre. The dicationic complexes are both charge balanced by two uncoordinated tetrafluoroborate anions. In the related structure, [UO₂(μ-F)(F)(DPPMO₂)]₂ · 2MeOH (3), terminal fluoride is also coordinated to both uranyl centres (where DPPMO₂ = bis(diphenylphosphine oxide)methane). All three complexes were prepared during attempted syntheses of complexes with tetrafluoroborate directly coordinated to uranium. It is clear from these results that the fluorophilicity of UO₂ ²⁺ causes the abstraction of fluoride from [BF₄]⁻, with the weakly coordinating anion only present as a counter cation in 1 and 2, and absent completely in 3.     

Thermogravimetry of some uranium 8-hydroxyquinolates

The thermogravimetric behaviour of UO₂(C₉H₆NO)₂.C₉H₆NOH and [UO₂(C₉H₆NO)₂]₂.C₉H₆NOH prepared by precipitation from homogeneous solution with 8-acetoxy-quinoline has been found to closely resemble that of UO₂(C₉H₆NO)₂.C₉H₆NOH prepared by direct precipitation of uranium^VI with 8-hydroxyquinoline.     

分子动力学方法模拟不同温度下铀酰在叶腊石上的吸附和扩散行为

采用分子动力学方法研究了铀酰在叶腊石表面的吸附和扩散。在碳酸根离子存在的情况下,探究了温度对铀酰吸附和扩散的影响。碳酸根离子与铀酰存在较强的作用力,不同数目的碳酸根离子与铀酰结合会形成多种铀酰种态。在不同温度的模拟中,得到了UO_2~(2+)、UO_2CO_3、UO_2(CO_3)_2~(2-)、UO_2(CO_3)_3~(4-)四种铀酰种态和铀酰聚合物。通过原子密度图,观察了粒子在溶液中的分布情况。发现UO_2~(2+)+和UO_2CO_3容易吸附在叶腊石上,而UO_2(CO_3)_2~(2-)和UO_2(CO_3)_3~(4-)主要存在于扩散层中。随着时间的推移,越来越多的碳酸根离子与铀酰配位,使得铀酰在叶腊石上的吸附逐渐减少。本文计算了不同温度下,各铀酰种态的扩散系数。在扩散层中,各种态的扩散系数随温度的变化较为一致,而在吸附层中,UO_2~(2+)和UO_2CO_3的扩散速率随温度的变化较UO_2(CO_3)_2~(2-)和UO_2(CO_3)_3~(4-)慢。但是在同一温度下,同一个吸附层或扩散层中,铀酰种态的扩散系数大小顺序始终保持不变:UO_2~(2+)UO_2CO_3UO_2(CO_3)_2~(2-)UO_2(CO_3)_3~(4-)。说明在碳酸根存在的情况下,UO_2~(2+)可能是主要的扩散形式。     

Preparation and characterization of single crystals[Ln(TBPO)4(NO3)2]NTf2 (Ln=Eu,Gd)

Two single crystals[Ln(TBPO)₄(NO₃)₂]NTf₂ (Ln=Eu, Gd) were prepared and characterized by element analysis, single crystal X-ray diffraction, PXRD, FT-IR, TGA and fluorescence spectroscopy. The two compounds have similar coordinate structures, in which the central metal ion is coordinated by four TBPO (Tri-n-butylphosphine oxide) molecules and two bidentate nitrates, while NTf₂^-(bis(trifluor-(bis(trifluoromethylsulfonyl) imide anion) acts as the counter anion. The packing modes of the two crystals are same. The two single crystals are the focus on 8-coordinate tetra-TRPO complexes (TRPO is Trialkyphosphine oxides).     

Syntheses and X-ray crystal structures of [Co(η-CO3)(NH3)4](NO3)·0.5H2O and [(NH3)3Co(μ-OH)2(μ-CO3)Co(NH3)3][NO3]2·H2O

[Co(η²-CO₃)(NH₃)₄](NO₃)·0.5H₂O and [(NH₃)₃Co(μ-OH)₂(μ-CO₃)Co(NH₃)₃][NO₃]₂·H₂O were prepared by prolonged aerial oxidation of a solution of Co(NO₃)₂·6H₂O and ammonium carbonate in aqueous ammonia. The formation of these side products highlights the richness of the chemistry of these systems and the possibility of by products if methods are not strictly adhered to. The X-ray crystal structures of [Co(η²-CO₃)(NH₃)₄][NO₃]·0.5H₂O and [(NH₃)₃Co(μ-OH)₂(μ-CO₃)Co(NH₃)₃][NO₃]₂·H₂O reveal a monomeric octahedral cobalt center with η²-bound CO₃²⁻ in the former, while the latter consists of a dimeric array where the two cobalt centers are bridged by two OH⁻ and one μ₂-CO₃²⁻ groups with three terminal NH₃ ligands for each Co center. In both complexes extensive hydrogen bonding interactions are evident.     

Formation of a novel “bedspring”-like framework structure by a neodymium nitrate complex with N,N′-butylenebis(2-pyridone)

Reaction of N,N′-butylenebis(2-pyridone) (BBP) with hydrated M(NO₃)₃ salts (M = Y or a lanthanide ion) affords the complexes M₂(BBP)₃(NO₃)₆. Thorium(IV) nitrate and dioxouranium(VI) nitrate give Th₂(BBP)₃(NO₃)₈·0.5Me₂CO and UO₂(BBP)(NO₃)₂, respectively. X-ray diffraction studies on the Nd complex show it to contain arrays of contiguous 66-membered macrocyclic rings arranged so as to form as unusual “bedspring”-like network structure.     

Potential characteristics of a pseudoliquid membrane electrode including coordinatively solvated UO(2)(NO(3))(2).2TBP complexes

Mechanisms of formation of electrode potential with a pseudoliquid membrane phase including uranyl nitrate complexes coordinatively solvated by tri-n-butyl phosphate were investigated. It was stated that the electrode function of these membranes could be of cationic or anionic character depending on concentration UO₂ (NO₃)₂ in an aqueous phase. The influence of extraction and salting out on membrane phase composition and the slope of calibration curve was studied. It was shown that in the concentration range c > 0.1M the electrode potential depends on value of salt distribution coefficient between aqueous and organic phases. The dependence describing the electrode function in this concentration range was derived.     

Synthesis and X-ray crystal structures of bis(bis(μ2-2-aminoethanolato–N,O,O)–cobalt(III))–cobalt(II) hydrate, tris(biscyclohexylammonium)μ-hydroxo–bis(μ2-nitro–N,O)–hexanitro–dicobaltate(III) and biscyclohexylammonium nitrate(III)

Two new cobalt complexes: Co₃(NO₂)₄(NH₂CH₂CH₂O)₄·H₂O (1) and (NH₂(C₆H₁₁)₂)₃[Co₂(NO₂)₈OH]·3H₂O (2) and the compound (NH₂(C₆H₁₁)₂)NO₂ (3) were synthesised and their structures have been determined using single-crystal X-ray diffraction. Compound 1 consists of two centrosymmetrical trinuclear complexes and a water molecule of crystallization. Ligands coordinated to Co atoms are nitro and aminoethanolato groups. Structure 2 is built up of biscyclohexylammonium cations, dinuclear anions with hydroxo and nitro groups coordinated to Co atoms and water molecules. The coordination of Co atoms in both structures is roughly octahedral.     

Tetra(μ3-hydroxo)hexa(μ2-carboxylato-O,O′)-bridged tetranuclear terbium(III) cubane complex

A novel tetranuclear terbium(III) complex [Tb₄(OH)₄(pybet)₆(H₂O)₈][Tb₄(OH)₄(pybet)₆(H₂O)₇ (NO₃)](ClO₄)₁₄·6H₂O has been synthesized and shown by X-ray crystallography to have a cubane-like Tb₄(μ₃-OH)₄(μ₂-carboxylato-O,O′)₆ core. The ligand pybet is pyridinoacetate, C₅H₅⁺N-CH₂CO₂⁻. Magnetic susceptibility data were measured for this Tb₄ complex in the range of 2.0–320 K and in fields of 1.0 G to 50.0 kG. It is concluded that either there is very weak antiferromagnetic exchange interaction (J = −0.015 cm⁻¹) or there is a small crystal-field splitting of the ⁷F₆ Tb^III ground state.