三元配合物[RE(Gly)4(Im)(H2O)](ClO4)3(RE=La,Pr)的热化学研究

利用自行研制的新型恒温环境反应量热计,以2mol·L-1HCl做溶剂,分别测定了LaCl3·7H2O、PrCl3·6H2O、[La(Gly)4(Im)(H2O)](ClO4)3、[Pr(Gly)4(Im)(H2O)](ClO4)3、Im、NaClO4、Gly、NaCl在298.15K时的溶解焓,再通过设计的热化学循环求得化学反应的摩尔反应焓,利用这些结果和其它辅助数据,计算出两种配合物的标准摩尔生成焓分别为:ΔfH m{[Prm{[La(Gly)4(Im)(H2O)](ClO4)3,s}=-3459.3±0.2kJ·mol-1;ΔfH (Gly)4(Im)(H2O)](ClO4)3,s}=-3460.63±0.18kJ·mol-1。     

La(C7H5O3)2·(C9H6NO)的合成及热化学研究

研究由七水氯化镧与水杨酸、8-羟基喹啉反应合成镧与水杨酸、8-羟基喹啉多元混合配合物,并对该配合物进行表征.测定该合成反应的标准摩尔反应焓以及配合物的标准摩尔生成焓.通过红外光谱、元素分析、摩尔电导率、差热热重分析以及化学分析等方法来确定配合物的组成.应用溶解量热法分别测定了七水氯化镧、水杨酸、8-羟基喹啉和配合物在298.15 K、混合量热溶剂(VDMFVEtOHVHClO4=110.5)中的标准摩尔溶解焓.通过设计热化学循环,根据盖斯定律计算了合成反应的标准摩尔反应焓以及配合物的标准摩尔生成焓.该配合物的分子式是La(C7H5O3)2·(C9H6NO).各物质的溶解焓分别为△sH(I○)mLaCl3·7H2O(s),298.15 K]=-96.45±0.18 kJ·mol-1,△sH(I○)m[2 C7H6O3(s),298.15 K]=14.99±0.17 kJ·ml-1,△SH(I○)m[C9H7NO(s),298.15 K]=-3.86±0.06kJ·mdl-1及△S(I○)m[La(C7H5O3)2·(C9H6NO)(s),298.15K]=-117.78±0.11kJ·mol-1.反应LaCl3·7H2O(s)+2C7H6O3(s)+C9H7NO(s)=La(C7H5O3)2·(C9H6NO)(s)+3HCl(g)+7H2O(1)的标准摩尔反应焓为91.57±0.33 kJ·mol-1.La(C7H5O3)2·(C9H7NO)(s)的标准摩尔生成焓为△sH(I○)m[La(C7H5O3)2·(C9H6NO)(s),298.15 K]=-2076.5±3.9 kJ·mol-1.     

离子交换树脂在金湿法冶金中的应用

金矿石中铜的存在给矿冶工业带来许多新问题。由于氰化物可溶解矿石中的铜矿物及天然铜形成了 [Cu(CN) 3 ] 2 -配合离子 ,且铜的溶解速度比金快得多 ,使得氰化物的消耗大大增加。因此从经济和环保角度出发 ,氰化物的再生令人关注。 Versiane A.Leao等人研究了金属氰化配合物在不同化学结构的离子交换树脂上的吸附与解吸性能。用 Cu SO4· 5 H2 O、Ni SO4· 6H2 O和 K4Fe(CN) 6· 3 H2 O配制 p H=10 .5的溶液 ,加入氰化钠使Cu2 、Ni2 转化成 [Ni(CN) 4 ] 2 -及 [Cu(CN) 3 ] 2 -和 [Cu(CN) 4 ] 3 -。最终的氰化配合物溶液中 ,…     

配合物[Dy(C_7H_5O_3)_2(C_4H_6NO_2S)]·2H_2O的热化学研究

合成了镝和硫代脯氨酸、水杨酸的三元固体配合物,通过元素分析、热重分析、红外光谱、摩尔电导等手段进行表征,确定其化学组成为[Dy(C7H5O3)2(C4H6NO2S)].2H2O。根据盖斯定律设计一个热化学循环,用恒温环境溶解-反应量热法研究得到配合反应的标准反应焓为261.290.87 kJ.mol-1,进而算出配合物298.15K时的标准摩尔生成焓为-27803 kJ.mol-1。     

汞(Ⅱ)-硫氰酸盐-罗丹明6G多元络合物混合胶束增敏分光光度法测定环境水中痕量汞

在H2SO4介质中,Hg(Ⅱ)与硫氰酸钾和罗丹明6G形成三元离子缔合物,缔合物的组成比为n(Rh6G)∶n(Hg2+)∶n(SCN-)=2∶1∶4,阿拉伯胶-吐温20混合胶束可增敏该体系,据此建立了痕量汞的高灵敏多元络合光度分析新方法。该方法测定汞的线性范围为0.10~1.50μg/mL,检出限为0.08μg/mL,表观摩尔吸光系数为1.02×105L.mol-1.cm-1。系统考察了各种因素的影响,大多数常见离子不干扰,Fe3+,Zn2+,Cu2+等少数离子干扰严重,结合巯基棉吸附处理技术,方法可用于测定环境水样中的痕量汞。     

H2BPMPBD和TOPO协同萃取Ln3+的研究

研究了1,4-双(1'-苯基-3'-甲基-5'-氧代吡唑-4'-基)丁二酮(H2BPMPBD,简为H2A)和三正辛基氧化膦(TOPO)的氯仿溶液从硝酸介质中对Ln3+的协同萃取.用斜率法确定了萃合物的组成为LaA·HA·TOPO,考察了萃取剂浓度和溶液酸度对萃取机理的影响,测定了半萃取pH1/2值和萃取反应平衡常数Ks.e,求得了反应的焓变和熵变.     

110~*树脂吸附铜的行为研究

研究了Cu2+在110*树脂上的吸附行为。结果表明:在pH=4.19的HAc-NaAc缓冲溶液中,110*树脂吸附Cu2+效果最佳,静态饱和吸附容量为240mg/g;用1.0~2.0mol/LHCl溶液洗脱,洗脱率达100%;表观速率常数k298=1.55×10-4s-1,表观活化能Ea=37.2kJ/mol;等温吸附服从Freundlich经验式;吸附热力学参数ΔH=14.8kJ/mol,ΔS=52.0J/(mol·K),ΔG=-0.7kJ/mol。用化学和红外光谱法确定了吸附机制为化学吸附。     

N,N‘—二辛基甘氨酸萃取钯热力学研究

本文研究了 N ,N '-二辛基甘氨酸 ( DOG)从盐酸体系中萃取钯的热力学。通过考察 DOG浓度对 Pd( )萃取的影响 ,测出了萃取反应的表观平衡常数 K、焓变Δ H、自由能ΔG和熵变Δ S。     

六水氯化钕与甘氨酸丙氨酸三元固态配合物的热化学

合成了Nd3 与甘氨酸丙氨酸混配体配合物 ,通过红外光谱分析、元素分析、热重分析和化学分析 ,确定了配合物的组成为 :Nd(Gly) 2(Ala) 3Cl3·2H2 O ,并用溶解量热法分别测定了NdCl3·6H2 O(s) ,2Gly(s) 3Ala(s)和Nd(Gly) 2 (Ala) 3Cl3·2H2 O(s)在 2mol·L- 1 HCl中的溶解焓 ;再根据盖斯定律设计了一个热化学循环 ,计算得到了六水氯化钕与甘氨酸丙氨酸反应的反应焓ΔrHmθ(2 98.15K) =3 7.2 44kJ·mol- 1 ,并求出了Nd(Gly) 2 (Ala) 3Cl3·2H2 O(s)标准生成焓ΔfHmθ[Nd(Gly) 2 (Ala) 3Cl3·2H2 O ,s,2 98.15K] =-4 45 0 .1kJ·mol- 1 。     

4-(对-甲氧基苯氨基重氮基)-4'-硝基偶氮苯的合成及其与汞(Ⅱ)的显色反应

合成了新显色剂4-(对甲氧基苯氨基重氮基)-4'-硝基偶氮苯(PMADNA),并研究了该试剂在Triton X-100存在下与汞的显色反应。结果表明,在pH 10.5的Na2B4O7-NaOH缓冲介质中,Hg(Ⅱ)与试剂形成稳定的1∶2红色络合物,最大吸收波长位于576 nm,表观摩尔吸光系数为1.25×105L.mol-1.cm-1,汞的质量浓度在0~0.8μg/mL范围内服从比尔定律,用酒石酸钠-焦磷酸钠-氟化钠作混合掩蔽剂,可以提高Fe3+,Ni2+,Cu2+,Cd2+的允许量。方法用于废水中微量汞     

Reaction paths of iron oxidation and hydrolysis in horse spleen and recombinant human ferritins

UV-visible spectroscopy, electrode oximetry, and pH stat were used to study Fe(II) oxidation and hydrolysis in horse spleen ferritin (HoSF) and recombinant human H-chain and L-chain ferritins (HuHF and HuLF). Appropriate test reactions and electrode responses were measured, establishing the reliability of oxygen electrode/pH stat for kinetics studies of iron uptake by ferritin. Stoichiometric ratios, Fe(II)/O2 and H+/Fe(II), and rates of oxygen uptake and proton production were simultaneously measured as a function of iron loading of the protein. The data show a clear distinction between the diiron ferroxidase site and mineral surface catalyzed oxidation of Fe(II). The oxidation/hydrolysis reaction attributed to the ferroxidase site has been determined for the first time and is given by 2Fe2+ + O2 + 3H2O --> [Fe2O(OH)2]2+ + H2O2 + 2H+ where [Fe2O(OH)2]2+ represents the hydrolyzed dinuclear iron(III) center postulated to be a mu-oxo-bridged species from UV spectrometric titration data and absorption band maxima. The transfer of iron from the ferroxidase site to the mineral core has been now established to be [Fe2O(OH)2]2+ + H2O --> 2FeOOH(core) + 2H+. Regeneration of protein ferroxidase activity with time is observed for both HoSF and HuHF, consistent with their having enzymatic properties, and is facilitated by higher pH (7.0) and temperature (37 degreesC) and by the presence of L-subunit and is complete within 10 min. In accord with previous studies, the mineral surface reaction is given by 4Fe2+ + O2 + 6H2O --> 4FeOOH(core) + 8H+. As the protein progressively acquires iron, oxidation/hydrolysis increasingly shifts from a ferroxidase site to a mineral surface based mechanism, decreasing the production of H2O2.     

Perioperative pharmacodynamics of acetaminophen analgesia in children

The nitrogenase iron (Fe) protein binds two molecules of MgATP or MgADP, which results in protein conformational changes that are important for subsequent steps of the nitrogenase reaction mechanism. In the present work, isothermal titration calorimetry has been used to deconvolute the apparent binding constants (K'a1 and K'a2) and the thermodynamic terms (delta H' degree and delta S' degree) for each of the two binding events of MgATP or MgADP to either the reduced or oxidized states of the Fe protein from Azotobacter vinelandii. The Fe protein was found to bind two nucleotides with positive cooperativity and the oxidation state of the [4Fe-4S] cluster of the Fe protein was found to influence the affinity for binding nucleotides, with the oxidized ([4Fe-4S]2+) state having up to a 15-fold higher affinity for nucleotides when compared to the reduced ([4Fe-4S]1+) state. The first nucleotide binding reaction was found to be driven by a large favorable entropy change (delta S' degree = 10-21 cal mol-1 K-1), with a less favorable or unfavorable enthalpy change (delta H' degree = +1.5 to -3.3 kcal mol-1). In contrast, the second nucleotide binding reaction was found to be driven by a favorable change in enthalpy (delta H' degree = -3.1 to -13.0 kcal mol-1), with generally less favorable entropy changes. A plot of the associated enthalpy (-delta H' degree) and entropy terms (-T delta S' degree) for each nucleotide and protein binding reaction revealed a linear relationship with a slope of 1.12, consistent with strong enthalpy-entropy compensation. These results indicate that the binding of the first nucleotide to the nitrogenase Fe protein results in structural changes accompanied by the reorganization of bound water molecules, whereas the second nucleotide binding reaction appears to result in much smaller structural changes and is probably largely driven by bonding interactions. Evidence is presented that the total free energy change (delta G' degree) derived from the binding of two nucleotides to the Fe protein accounts for the total change in the midpoint potential of the [4Fe-4S] cluster.     

二价铜盐沉淀-树脂吸附处理氰化提金废水的研究

采用沉淀一离子交换联合工艺处理氰化提金废水,重点考察了CuSO4·5H2O用量及沉淀时间对各种离子沉淀率的影响,以及树脂的用量及吸附时间对各种离子综合去除率的影响。试验结果表明,当取CuSO4·5H2O理论用量的1．5倍、沉淀时间为60min时,CN^-、Fe、Zn离子沉淀率均可述到93％以上,而Cu离子沉淀率为50％左右。XRD分析表明,沉淀物主要由zn2[Fe（CN）6]、Cu2[Fe（CN）6]、CuCN及Zn（OH）2组成。吸附试验表明,当201×7树脂用量为5mL、废水体积为100mL、常温吸附75min时,氰化提金废水中CN^-及Cu、Fe、Zn离子的综合去除率分别可达到99．94％、71．23％、100％和99．95％,处理后废水中游离氰及铁、锌质量浓度达到了《GB8978-1996污水综合排放标准》一级排放指标。     

模拟体系中金属氰配合物解吸性能的研究

以硫酸、氨水、盐酸作为解吸剂,对吸附在强碱性离子交换纤维上的金属氰配合物的解吸性能进行了初步研究。试验结果表明:6%的硫酸30 min就可使Zn(CN)42-顺利地从纤维上洗脱下来,但对Cu(CN)42-的洗脱效果却不明显;盐酸30 min可全部洗脱纤维上的Zn(CN)4-,Cu(CN)4-的洗脱率可达到90%以上,酸化后氰的回收率也达85%以上,且洗脱后的纤维不需要再生,直接进入吸附过程。离子交换纤维的解吸试验表明,离子交换纤维可有效处理含氰废水。     

On the partial atomic volume of aluminum in solid solutions based on the 3d transition metals and copper

The composition dependence of the average atomic volume, as well as of the enthalpy of formation, was investigated for the aluminum-containing systems with the 3d transition metals and copper. The partial atomic volume of aluminum and the partial molar enthalpy of aluminum were determined for the transition metal-based solid solutions. Independent of the type of solid-solution structure, the (negative) partial molar enthalpy of aluminum increases and the partial atomic volume of aluminum decreases with increasing filling of the 3d band. The charge transfer and the bonding in solid solutions exhibiting close-packed structures (coordination number (CN)=12) is substantially higher than in solid solutions, based on the bcc structure (CN=8). The s electron of copper, though, reduces the charge transfer and the bonding in the fcc solid-solution Cu(Al) significantly.     

金属催化剂对Fenton试剂活性的影响因素分析

在分析Fenton氧化法作用机理的基础上,研究了金属催化剂Fe~(2+)/Fe~(3+)对Fenton试剂活性的影响。结果表明:Fe~(2+)和Fe~(3+)对Fenton试剂活性均具有催化作用,Fe~(2+)催化作用远大于Fe~(3+)催化作用;在H_2O_2投加量为12 mmol/L,反应温度为25℃,反应时间为25 min条件下,[Fe~(2+)]/[H_2O_2]的物质的量比为1∶10时,焦化含酚废水COD去除率最高达到90.2%(质量分数);在光照特别是紫外线协同作用下,Fe~(2+)和Fe~(3+)活性增大,且Fe~(3+)的活性增强趋势明显高于Fe~(2+)。     

Differential effects of DNA supercoiling on radical-mediated DNA strand breaks

Supercoiling is an important feature of DNA physiology in vivo. Given the possibility that the reaction of genotoxic molecules with DNA is affected by the alterations in DNA structure and dynamics that accompany superhelical tension, we have investigated the effect of torsional tension on DNA damage produced by five oxidizing agents: gamma-radiation, peroxynitrite, Fe2+/ EDTA/H2O2, Fe2+/H2O2, and Cu2+/H2O2. With positively supercoiled plasmid DNA prepared by a recently developed technique, we compared the quantity of strand breaks produced by the five agents in negatively and positively supercoiled pUC19. It was observed that strand breaks produced by gamma-radiation, peroxynitrite, and Fe2+/EDTA/H2O2 were insensitive to DNA superhelical tension. These results are consistent with a model in which chemicals that generate highly reactive intermediates (e.g., hydroxyl radical), but do not interact directly with DNA, will be relatively insensitive to the changes in DNA structure and dynamics caused by superhelical tension. In the case of Fe2+ and Cu2+, metals that bind to DNA, only Cu2+/H2O2 proved to be sensitive to DNA superhelical tension. Strand breaks produced by Cu2+/H2O2 in the positively supercoiled substrate occurred at lower Cu concentrations than in negatively supercoiled DNA. Furthermore, a sigmoidal Cu2+/H2O2 damage response was observed in the negatively supercoiled substrate but not in positively supercoiled DNA. The results with Cu2+ suggest that the redox activity, DNA binding orientation, or DNA binding affinity of Cu1+ or Cu2+ is sensitive to superhelical tension, while the results with the other oxidizing agents warrant further investigation into the role of supercoiling in base damage.     

非化学计量钨氧化物及钨青铜类化合物氧指数的精确测定

本文提出了非化学计量钨氧化物中氧指数精确测定的方法。在有KOH存在的情况下,将氧化物或多钨酸盐样品溶于K₃[Fe(CN)₆]溶液中,在氧化-还原反应中,钨被氧化为正六价,Fe(CN)₆3-定量地被还原为Fe(CN)₆4-。用重铬酸钾溶液进行滴定,以求出试样中的氧指数(O/W)。
本文进行了分析方法鉴定,并与其他方法,如高锰酸钾容量法进行了对比,结果表明,本法准确度高,操作快速简便。     

Thermochemical studies on complex of [Sm(o-NBA)_3phen]_2

A ternary complex [Sm(o-NBA)3phen]2 (o-NBA: o-Nitrobenzoate; phen: 1,10-phenanthroline) was synthesized and characterized by elemental analysis, IR, molar conductance, and thermogravimetric analysis. The dissolution enthalpies of SmCl3·6H2O(s), o-HNBA(s) and phen·H2O(s) in mixed solvent (VHCl :VDMF :VDMSO=2:2:1) were determined by calorimetry at 298.15 K. The enthalpy change of the reaction was determined to be rHmΔθ=252.49±1.60 kJ/mol. Using the relevant data in the literature and a thermochemical recycle according to Hess’s Law, the standard molar enthalpy of formation of [Sm(o-NBA)3 phen]2 (s) was estimated to be f mHΔθ=–4109.2±7.3 kJ/mol.     

Spectral and kinetic properties of the Fet3 protein from Saccharomyces cerevisiae, a multinuclear copper ferroxidase enzyme

High affinity iron uptake in Saccharomyces cerevisiae requires Fet3p. Fet3p is proposed to facilitate iron uptake by catalyzing the oxidation of Fe(II) to Fe(III) by O2; in this model, Fe(III) is the substrate for the iron permease, encoded by FTR1. Here, a recombinant Fet3p has been produced in yeast that, lacking the C-terminal membrane-spanning domain, is secreted directly into the growth medium. Solutions of this Fet3p at >1 mg/ml have the characteristic blue color of a type 1 Cu(II)-containing protein, consistent with the sequence homology that placed this protein in the class of multinuclear copper oxidases that includes ceruloplasmin. Fet3p has an intense absorption at 607 nm (epsilon = 5500 M-1 cm-1) due to this type 1 Cu(II) and a shoulder in the near UV at 330 nm (epsilon = 5000 M-1 cm-1) characteristic of a type 3 binuclear Cu(II) cluster. The EPR spectrum of this Fet3p showed the presence of one type 1 Cu(II) and one type 2 Cu(II) (A parallel = 91 and 190 x 10(-4) cm-1, respectively). Copper analysis showed this protein to have 3.85 g atom copper/mol, consistent with the presence of one each of the three types of Cu(II) sites found in multinuclear copper oxidases. N-terminal analysis demonstrated that cleavage of a signal peptide occurred after Ala-21 in the primary translation product. Mass spectral and carbohydrate analysis of the protein following Endo H treatment indicated that the preparation was still 15% (w/w) carbohydrate, probably O-linked. Kinetic analysis of the in vitro ferroxidase reaction catalyzed by this soluble Fet3p yielded precise kinetic constants. The Km values for Fe(II) and O2 were 4.8 and 1.3 microM, respectively, while kcat values for Fe(II) and O2 turnover were 9.5 and 2.3 min-1, consistent with an Fe(II):O2 reaction stoichiometry of 4:1.