Np(V)在人体体液的形态模拟研究

建立了含多种金属离子和小分子配体组成的多相Np(V)体液平衡模型.模拟研究了Np(V)在胃液、汗液、组织液、细胞液和尿液中的形态分布.结果表明:胃液中,当[Np]为1×10-15mol 形态存在.汗液中,当[Np]=1×10-6mol·L-1时,Np(V)以NpO2 形态存在,当[Np]=1×10-3mol·L-1,pH4.2～5.0时,主要以NpO2 形态存在;随着pH升高,Np(V)逐渐以固相Np2O5为主,到pH7.0时,Np2O5含量达99%.组织液中,当[Np]<4×10-6mol·L-1时,Np(V)以NpO2CO3-、NpO2 和NpO2HPO4-形态存在,随[Np]增高,固相NaNpO2CO3逐渐占据主导地位,当[Np]=1×10-4mol·L-1时,固相含量达100%.当[Np]=1×10-3mol·L-1时,随组织液中添加的EDTA的浓度增加,固相含量逐渐降低,当[EDTA]=0.0085 mol·L-1时,已无固相Np(V)形态.细胞液中,当[Np]=1×10-6mol·L-1时,Np(V)以NpO2CO3-、NpO2 和NpO2HPO4-形态存在;当[Np]=1×10-3mol·L-1时,主要以固相Np2O5存在,但在巨噬细胞极低pH值的细胞液中以NpO2 形态存在.尿液中,当[Np]=1×10-6 mol·L-1时,Np(V)以NpO2 和NpO2HPO4-两种形态存在;当[Np]=1×10-3mol·L-1,pH>5.0时,随pH升高,固相Np2O5含量增加并逐渐占主导地位,但当pH<5.0时,Np(V)主要以NpO2 形态存在,提示可降低尿液pH值促进肾脏Np(V)排出.     

Np(Ⅴ)在人体体液的形态模拟研究

建立了含多种金属离子和小分子配体组成的多相Np(Ⅴ)体液平衡模型。模拟研究了Np(Ⅴ)在胃液、汗液、组织液、细胞液和尿液中的形态分布。结果表明:胃液中,当[Np]为1×10-15mol.L-1~1×10-3mol.L-1时,Np(Ⅴ)以NpO2 形态存在。汗液中,当[Np]=1×10-6mol.L-1时,Np(Ⅴ)以NpO2 形态存在,当[Np]=1×10-3mol.L-1,pH4.2~5.0时,主要以NpO2 形态存在;随着pH升高,Np(Ⅴ)逐渐以固相Np2O5为主,到pH7.0时,Np2O5含量达99%。组织液中,当[Np]<4×10-6mol.L-1时,Np(Ⅴ)以NpO2CO3-、NpO2 和NpO2HPO4-形态存在,随[Np]增高,固相NaNpO2CO3逐渐占据主导地位,当[Np]=1×10-4mol.L-1时,固相含量达100%。当[Np]=1×10-3mol.L-1时,随组织液中添加的EDTA的浓度增加,固相含量逐渐降低,当[EDTA]=0.0085 mol.L-1时,已无固相Np(Ⅴ)形态。细胞液中,当[Np]=1×10-6mol.L-1时,Np(Ⅴ)以NpO2CO3-、NpO2 和NpO2HPO4-形态存在;当[Np]=1×10-3mol.L-1时,主要以固相Np2O5存在,但在巨噬细胞极低pH值的细胞液中以NpO2 形态存在。尿液中,当[Np]=1×10-6mol.L-1时,Np(Ⅴ)以NpO2 和NpO2HPO4-两种形态存在;当[Np]=1×10-3mol.L-1,pH>5.0时,随pH升高,固相Np2O5含量增加并逐渐占主导地位,但当pH<5.0时,Np(Ⅴ)主要以NpO2 形态存在,提示可降低尿液pH值促进肾脏Np(Ⅴ)排出。     

NH4+-Mg2+-PO43--H+-H2O体系的优势区相图（英文）

通过优势区相图的构建对NH4+-Mg2+-PO43--H+-H2O体系的热力学平衡关系进行了研究。在不同镁、磷物质的量比和离子强度的条件下绘制了lgCT,Mg-lgCT,P和lgCT,P-pH相图,确定了MgNH4PO4.6H2O、Mg3(PO4)2.8H2O、MgHPO4.3H2O和Mg(OH)2的热力学稳定区。结果表明,在相当广的pH范围内,MgNH4PO4.6H2O和Mg3(PO4)2.8H2O都是主要存在的固相;在较低pH和较高磷浓度的条件下,MgNH4PO4.6H2O和MgHPO4.3H2O可以共存;而MgNH4PO4.6H2O和Mg(OH)2在碱性条件下更为稳定。当MgNH4PO4.6H2O、Mg3(PO4)2.8H2O与液相共存、pH=9.08~9.52时,溶液总氮浓度达到最低值。lgCT,Mg-lgCT,P和lgCT,P-pH相图可以用于指导磷酸铵镁的沉淀-溶解平衡过程,有利于废水中氨氮的脱除和回收。     

Fe3+和Fe2+对原代培养的成骨细胞增殖、分化和矿化功能的影响

采用噻唑蓝(MTT)法、碱性磷酸酶(ALP)比活性测定、油红O染色和茜素红染色及定量分析,研究了不同浓度的Fe3+和Fe2+对原代培养的成骨细胞增殖、分化及矿化功能的影响.结果表明:浓度为1×10-9～1×10-4 mol·L-1的Fe3+和Fe2+促进成骨细胞增殖,但是在较高浓度1×10-3 mol·L-1时,它们则抑制成骨细胞增殖.与成骨细胞作用48 h,浓度为1×10-8～1×10-4 mol·L-1的Fe3+和Fe2+抑制其分化,但在较低的浓度1×10-9 mol·L-1时则对其分化没有影响:进一步延长作用时间为72 h,Fe3+对成骨细胞分化没有影响,除1×10-6mol·L-1浓度的Fe2+促进成骨细胞分化外,其他浓度的Fe2+则抑制其分化;测试浓度下的Fe3+对成骨细胞向脂肪细胞的横向分化表现为抑制或没有影响,而Fe2+的影响则依赖于浓度和作用时间.在1×10-8～1×10-5mol·L-1浓度范围内,Fe3+和Fe2+对矿化结节的影响表现出相反的效应.在较高浓度(1×10-4mol·L-1)下,它们促进矿化节结的形成,而在较低浓度(1×10-9mol·L-1)下,Fe3+抑制矿化节结的形成,Fe2+则没有影响.结果提示:浓度.作用时间和铁离子的价态都是影响Fe3+和Fe2+生物效应(从毒性到活性,从损伤到保护,从上调到下调)转变的关键因素.     

Me-NaHCO3-NH3-H2O体系和Me-NaOH-NaHCO3-H2O体系的热力学分析

通过对Me(Fe2+,Ni2+,Cu2+,Zn2+)-NaHCO3-NH3-H2O体系以及Me-NaOH-NaHCO3-H2O体系的热力学分析,得到各金属离子总浓度cMe与pH值的关系,确定了2种体系的完全共沉淀区域.热力学分析结果表明:在Me-NaHCO3-NH3-H2O体系中,Ni2+,Cu2+,Zn2+这3种离子和氨的配位能力很强.当总碳的浓度cC=1 mol·L-1且总氮的浓度cN=0.01 mol·L-1时,在pH=7.5～11范围内可实现完全共沉淀:当cN=0.05 mol·L-1且cC=3 mol·L-1时,在pH=70.5时可实现完全沉淀,但共沉淀范围较窄,不利于铁氧体组分的精确控制.在Me-NaOH-NaHCO3-H2O体系中,共沉淀区域由cC决定,当cC=1 mol·L-1,pH=7.5～11时可实现完全共沉淀.     

纳米Eu2O3和Eu3+抑制人肝癌细胞HepG2增殖的作用

稀土纳米氧化物和稀土化合物的生物效应已引起人们的广泛关注.利用3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐(MTT),流式细胞术法和激光共聚焦显微镜初步探讨了纳米Eu2O3和Eu3+对体外培养的人肝癌细胞HepG2生长的影响.结果发现,较低浓度的纳米Eu2O3对细胞生长没有明显影响,浓度达到600μg mL-1作用癌细胞仅24 h,细胞就停止分裂,表现为细胞被阻滞在S期,大量细胞坏死.利用激光共聚焦显微镜观察到纳米Eu2O3能进入活的HepG2细胞中.而Eu3+则在较低含量,即≤100μmol L-1时能较弱地抑制癌细胞的生长,细胞被阻滞在G0/G1期,并诱导细胞发生凋亡.     

Li2O-TiO2-SiO2-P2O5和Li2O-TiO2-Al2O3-P2O5体系锂离子固体电解质的制备及性能研究

一些具有NASICON型网格结构的固体电解质具有高的电导率和好的稳定性,NASICON的意思是Na Super Ionic Conductor[1]。当NaZr2(PO4)3中P5 被Si4 部分取代时便可以得到具有NASICON结构的Na1 xZr2SixP3-xO12体系,其具有高的钠离子电导率。然而有相同结构的Li1 xZr2SixP3-xO12体系的离子电导率却很低,这是因为Li 半径太小,而NASICON三维网格结构的离子通道太大,两者不匹配而使电导率下降[2]。但当LiZr2(PO4)3中Zr4 被离子半径小些的Ti4 取代,所得LiTi2(PO4)3的通道就与Li 半径相匹配,适合于锂离子的迁移,从而使其电导率…     

Fe3+/Ba2+/Co2+/Zn2+/Cu2+在NH4HCO3-NH3·H2O和NaOH-Na2CO3体系中的热力学分析

通过对Fe3+/Ba2+/Co2+/Zn2+/Cu2+在NH4HCO3-NH3·H2O和NaOH-Na2CO3体系中的热力学分析,得到各金属离子总浓度(cMe)与pH值的关系,确定了2种体系中5种离子完全共沉淀的pH值范围.结果表明:在NH4HCO3-NH3·H2O体系中,Co2+、Zn2+、Cu2+3种离子和氨的配位能力很强,其中Cu2+与氨的配位能力最强,在相同的pH值条件下,Cu2+沉淀困难,5种金属离子的完全共沉淀区域由Cu2+决定.在NaOH-Na2CO3体系中,随总碳浓度(cc)的增加,Ba、Co、Zn、Cu的溶解度都随之减小,当cc=1.0 mol·L-1时,各金属离子完全共沉淀的pH值范围为7.5～11.在两种体系中,Fe的溶解度都是随pH值的增大而减小,最终达到平衡.以NaOH-Na2CO3 为沉淀剂.在pH=10.0的条件下,采用化学共沉淀法合成出了晶粒细小、粒度均匀的Y型纯相结构的平面六角铁氧体微粉.     

Gd3+/Yb3+掺杂ZnO量子点作为双模式磁共振/CT成像探针

基于结合磁共振成像(MRI)的高空间分辨率和CT成像的深穿透能力设计思想,在乙醇溶液中水解醋酸锌、醋酸钆和醋酸镱,制备了油酸稳定的Gd3+/Yb3+掺杂ZnO量子点(ZnO∶Gd/Yb),并对其表面进行了氨基修饰。研究了ZnO∶Gd/Yb量子点的弛豫性能、X射线吸收性能、细胞毒性及体外MRI和CT成像。当Zn2+,Gd3+,Yb3+的摩尔比为1.0∶0.12∶0.20时,ZnO∶Gd/Yb量子点展现了最高的弛豫效率6.06 mmol/(L.s)对X-射线的吸收能力也显著高于临床CT造影剂碘比醇。体外MRI和CT成像实验表明,当Gd3+的浓度为1.5 mmol/L时,T1加权MRI信号明显增强,当Yb3+的浓度为5 g/L时,可呈现清晰的CT图像。细胞毒性实验表明,ZnO∶Gd/Yb量子点的浓度低于1.5 mmol/L(Gd3+)时,量子点的毒性相对较低。     

MZn2HPO4PO4 (M=Na+, K+)的合成、表征和标准摩尔生成焓

采用低温固相法和水热法制备MZn2HPO4PO4 (M=Na+, K+) 并用XRD, FT-IR, TG and SEM对其进行表征,用等温量热计测定热化学性质。按照Hess’s定律,设计一新的热化学循环。结果表明,所合成的物质是等结构三斜晶系的目标产物,具有片层结构,分解温度分别为： 415 ℃和430 ℃。从测定的溶解焓和其他的标准热化学数据,计算出MZn2HPO4PO4 (M=Na+, K+) 的标准摩尔生成焓分别为：ΔfHm [NaZn2HPO4PO4, s]=-3042.38±0.31 kJ·mol-1; ΔfHm [KZn2HPO4PO4,s]=-3093.46 ±0.27 kJ·mol-1。     

Dioxouranium(VI)-carboxylate complexes. Speciation of UO2(2+)-1,2,3-propanetricarboxylate system in NaCl(aq) at different ionic strengths and at t=25 degrees C

The formation constants of dioxouranium(VI)-1,2,3-propanetricarboxylate [tricarballylate (3-), TCA] complexes were determined in NaCl aqueous solutions at 0 < or = I/mol L(-1) < or = 1.0 and t=25 degrees C, by potentiometry, ISE-[H+] glass electrode. The speciation model obtained at each ionic strength includes the following species: ML-, MLH0, ML2(4-) and ML2H3- (M = UO2(2+) and L = TCA). The dependence on ionic strength of protonation constants of 1,2,3-propanetricarboxylate and of the metal-ligand complexes was modeled by the SIT (Specific ion Interaction Theory) approach and by the Pitzer equations. The formation constants at infinite dilution are [for the generic equilibrium p UO22+ + q (L3-) + r H+ = (UO2(2+))p(L)qHr(2p-3q+r); betapqr]: log beta110 = 6.222 +/- 0.030, log beta111 = 11.251 +/- 0.009, log beta121 = 7.75 +/- 0.02, log beta121 = 14.33 +/- 0.06. The sequestering ability of 1,2,3-propanetricarboxylate towards UO2(2+) was quantified by using a sigmoid Boltzman type equation.     

One- and two-dimensional silver and zinc uranyl phosphates containing bipyridyl ligands

The reaction of AgCN with UO2, 4,4'-bipy, and phosphoric acid in water at 160 degrees C under autogeneously generated pressure results in the formation of [Ag(4,4'-bipy)]2[(UO2)2H3(PO4)3] (AgUP-1). Ag(2,2'-bipy)(UO2)2(HPO4)(PO4) (AgUP-2) has been prepared from the hydrothermal reaction (at 180 degrees C) of KAg(CN)2 with UO2(C2H3O2)2.2H2O and 2,2'-bipy. [Zn(2,2'-bipy)]2[UO2(HPO4)3] (ZnUP-1) was isolated from the hydrothermal reaction of UO2, 2,2'-bipyridyl, Zn(CN)2, and H3PO4. Single crystal X-ray diffraction experiments reveal that the structure of AgUP-1 consists of 2infinity[(UO2)2H3(PO4)3]2- expanded autunite-like layers in the [ac] plane, separated by 1infinity[Ag(4,4'-bipy)]+ chains of two-coordinate Ag+ bridged by 4,4'-bipy. The structure of AgUP-2 is composed of chains of edge-sharing UO7 pentagonal bipyramids that are linked by phosphate anions into 2infinity[(UO2)2(HPO4)(PO4)]1- sheets with the beta-uranophane topology that extend in the [ab] plane. Both sides of the sheets are decorated by [Ag(2,2'-bipy)]+ units, where the Ag+ cations are found in distorted trigonal planar environments. The structure of ZnUP-1 is 1D and consists of UO7 pentagonal bipyramids that are connected by phosphate anions that also bind four-coordinate zinc(II) to the periphery of the chains and five-coordinate zinc within the chains. Intense fluorescence from these compounds was observed.     

Comparative study of uranyl(VI) and -(V) carbonato complexes in an aqueous solution

Electrochemical, complexation, and electronic properties of uranyl(VI) and -(V) carbonato complexes in an aqueous Na2CO3 solution have been investigated to define the appropriate conditions for preparing pure uranyl(V) samples and to understand the difference in coordination character between UO22+ and UO2+. Cyclic voltammetry using three different working electrodes of platinum, gold, and glassy carbon has suggested that the electrochemical reaction of uranyl(VI) carbonate species proceeds quasi-reversibly. Electrolysis of UO22+ has been performed in Na2CO3 solutions of more than 0.8 M with a limited pH range of 11.7 < pH < 12.0 using a platinum mesh electrode. It produces a high purity of the uranyl(V) carbonate solution, which has been confirmed to be stable for at least 2 weeks in a sealed glass cuvette. Extended X-ray absorption fine structure (EXAFS) measurements revealed the structural arrangement of uranyl(VI) and -(V) tricarbonato complexes, [UO2(CO3)3]n- [n = 4 for uranyl(VI), 5 for uranyl(V)]. The bond distances of U-Oax, U-Oeq, U-C, and U-Odist are determined to be 1.81, 2.44, 2.92, and 4.17 A for the uranyl(VI) complex and 1.91, 2.50, 2.93, and 4.23 A for the uranyl(V) complex, respectively. The validity of the structural parameters obtained from EXAFS has been supported by quantum chemical calculations for the uranyl(VI) complex. The uranium LI- and LIII-edge X-ray absorption near-edge structure spectra have been interpreted in terms of electron transitions and multiple-scattering features.     

Theoretical study of the oxygen exchange in uranyl hydroxide. An old riddle solved?

A multistep mechanism for the experimentally observed oxygen exchange [Inorg. Chem. 1999, 38, 1456] of UO2(2+) cations in highly alkaline solutions is suggested and probed computationally. It involves an equilibrium between [UO2(OH)4](2-) and [UO2(OH)5](3-), followed by formation of the stable [UO3(OH)3 x H2O](3-) intermediate that forms from [UO2(OH)5](3-) through intramolecular water elimination. The [UO3(OH)3 x H2O](3-) intermediate facilitates oxygen exchange through proton shuttling, retaining trans-uranyl structures throughout, without formation of the cis-uranyl intermediates proposed earliar. Alternative cis-uranyl pathways have been explored but were found to have activation energies that are too high. Relativistic density functional theory (DFT) has been applied to obtain geometries and vibrational frequencies of the different species (reactants, intermediates, transition states, products) and to calculate reaction paths. Two different relativistic methods were used: a scalar four-component all-electron relativistic method and the zeroeth-order regular approximation. Calculations were conducted for both gas phase and condensed phase, the latter treated using the COSMO continuum model. An activation energy of 12.5 kcal/mol is found in solution for the rate-determining step, the reaction of changing the four-coordinated uranyl hydroxide to the five-coordinated one. This compares favorably to the experimental value of 9.8 +/- 0.7 kcal/mol. Activation energies of 7.8 and 5.1 kcal/mol are found for the hydrogen transfer between equatorial and axial oxygens through a water molecule in [UO3(OH)3 x H2O](3-) in the gas phase and condensed phase, respectively. Contrary to previously proposed mechanisms that resulted in high activation barriers, we find energies that are low enough to facilitate the reaction at room temperature. For the activation energies, two approximate DFT methods, B3LYP and PBE, are compared. The differences in activation energies are only about 1-2 kcal/mol for these methods.     

Synthesis, characterization, and reactivity of a uranyl beta-diketiminate complex

Addition of 1 equiv of Li(Ar2nacnac) (Ar2nacnac = (2,6-(i)Pr2C6H3)NC(Me)CHC(Me)N(2,6-(i)Pr2C6H3)) to an Et2O suspension of UO2Cl2(THF)3 generates the uranyl dimer [UO2(Ar2nacnac)Cl]2 (1) in good yield. A second species can be isolated in low yield from the reaction mixtures of 1, namely [Li(OEt2)2][UO2(Ar2nacnac)Cl2] (2). The structures of both 1 and 2 have been confirmed by X-ray crystallography. Complex 1 reacts with Ph3PO to generate UO2(Ar2nacnac)Cl(Ph3PO) (3). In addition, 1 reacts with AgOTf and either 1 equiv of DPPMO2 or 2 equiv of Ph2MePO to provide [UO2(Ar2nacnac)(DPPMO2)][OTf] (4) and [UO2(Ar2nacnac)(Ph2MePO)2][OTf] (5), respectively. Both 4 and 5 have been fully characterized, including analysis by X-ray crystallography and cyclic voltammetry. Reduction of 4 with Cp2Co provides UO2(Ar2nacnac)(CH{Ph2PO}2) (6), a uranyl(VI) complex that is generated by the formal loss of H* from the DPPMO2 ligand. Labeling studies have been performed in an attempt to elucidate the mechanism of hydrogen loss. In contrast, reduction of 5 with Cp2Co provides UO2(Ar2nacnac)(Ph2MePO)2 (7), a rare example of a uranyl(V) complex. As expected, the solid-state molecular structure of 7 reveals slightly longer U-O(oxo) bond lengths relative to 5. Furthermore, complex 7 can be converted back into 5 by oxidation with AgOTf in toluene.     

Coordination environment of aqueous uranyl(VI) ion

Water dissociation from [UO2(OH2)5]2+ is studied with Car-Parrinello molecular dynamics simulations (using the BLYP density functional) in the gas phase and in aqueous solution. Free energies, DeltaA, are estimated from pointwise thermodynamic integration using one U-O(H2) distance as a reaction coordinate. While an isomeric, four-coordinate complex, [UO2(OH2)4]2+.H2O, is more stable than the five-coordinate reactant in the gas phase (DeltaA = -2.2 kcal/mol), the former is strongly disfavored in water (DeltaA = +8.7 kcal/mol).     

Redistribution and fluxionality in heteropolyoxoperoxo complexes: [PO4[M2O2(mu-O2)2(O2)2]2]3- with M = Mo and/or W

When peroxotetramolybdophosphate, [(n-C4H9)4N]3[PO4[Mo2O2(mu-O2)2(O2)2]2], denoted (NBu4)3PMo4, and its tungsten(VI) analogue, (NBu4)3PW4, are mixed in acetonitrile at room temperature, redistribution occurs with the formation of three mixed-addenda species [PO4[Mo4-xWxO20]]3- (x = 1-3). The temperature dependence of the phosphorus-31 NMR spectra of a 1 1 mixture and of the pure salts, (NBu4)3PMo4 or (NBu4)3PW4, shows that [MO(O2)2] species are in chemical exchange, as are the [MOp] units of certain heteropolyacids (e.g. H3[PMo12O40] x aq and H3[PW12O40] x aq). However, there is no chemical exchange between free phosphate and [MO(O2)2] species in these systems; but there is fluxional behaviour involving PMo2W2, PMo4 and PW4. This is attributed to the rapid equilibrium between isomers (PMo2W2) and to equilibrium between anionic structures with tridentate (mu-eta2:eta1-O22-) and bidentate (eta2-O22-) modes of coordination for the two peroxo groups of the [M2O2(mu-O2)2(O2)2] moieties.     

Stoichiometry and structure of uranylVI hydroxo dimer and trimer complexes in aqueous solution

We studied the structure and stoichiometry of aqueous uranylVI hydroxo dimers and trimers by spectroscopic (EXAFS, FTIR, UV-vis) and quantum chemical (DFT) methods. FTIR and UV-vis spectroscopy were used for the speciation of uranyl complexes in aqueous solution. DFT calculations show that (UO2)2(OH)22+ has two bridging hydroxo groups with a U-U distance of 3.875 A. This result is in good agreement with EXAFS, where a U-U distance of 3.88 A was found. For the hydroxo trimer complex, DFT calculations show that the species (UO2)3(O)(OH)3+ with oxo bridging in the center is energetically favored in comparison to its stoichiometric equivalent (UO2)3(OH)5+. This is again in line with the EXAFS result, where a shorter U-U distance of 3.81-3.82 A and evidence for oxo bridging in the center were found. Several stable intermediates which lie several tens of kJ/mol above that of (UO2)3(O)(OH)3+ were identified, and their structures, energies, and intramolecular proton-transfer reaction are discussed.     

Linear alkyl diamine-uranium-phosphate systems: U(VI) to U(IV) reduction with ethylenediamine

Mild-hydrothermal reactions in acidic medium using 1,3-diaminopropane, 1,4-diaminobutane, and 1,5-diaminopentane as structure directing agents led to three-dimensional (3D) uranyl phosphates (CH?)?(NH?)?{[(UO?)(H?O)][(UO?)(PO?)]?} (C3U5P4), (CH?)?(NH?)?{[(UO?)(H?O)][(UO?)(PO?)]?} (C4U5P4) and (CH?)5(NH?)?{[(UO?)(H?O)][(UO?)(PO?)]?} (C5U5P4). The structures of (C4U5P4) and (C5U5P4) were solved in the space group Cmc2? using single-crystal X-ray diffraction data. The compounds are isostructural to the corresponding uranyl vanadates and contain the same 3D inorganic framework built from uranyl-phosphate layers of uranophane-type anion topology pillared by [UO?(H?O)] pentagonal bipyramids. In neutral or basic medium the alkyl diamines decompose to give ammonium uranyl phosphate trihydrate. In the same conditions by using ethylenediamine, unexpected reduction of uranium(VI) to uranium(IV) occurs leading to the formation of (CH?)?(NH?)?[U(PO?)?] (C2UP2) single crystals. C2UP2 undergoes a reversible phase transition from triclinic to monoclinic symmetry at about 230 °C. The structure of the two forms results from the stacking of inorganic layers (∞)1[U(PO?)?]2?, and organic layers containing ethylene diammonium ions, the two layers being linked by hydrogen bonds. Single crystals of (CH?)?(NH?)?[PO?OH] (C2HP) are formed by evaporation of the solution after filtering of C2UP2 single crystals. The structure of C2HP contains infinite (∞)1[PO?OH]2? chains connected by (CH?)?(NH?)?2? ions through hydrogen bonds.     

Synthesis and Characterization of Two New Organically Templated Open-framework Uranium Phosphites

1 INTRODUCTION Uranium-based open-framework materials are the subject of significant investigation because of their relevance to radioactive waste management, ura- nium geochemistry and possible applications in ion exchange, catalysis, etc[1]. The crystal chemistry of hexavalent uranium is rich in structure style due to the high coordination numbers (six, seven, or eight) accessible to U6 and the polarized distribution of bond strengths within uranyl polyhedra. The area of metal phospho…