用于锕系分离和三价镧系/锕系分离的水溶性配体

三价镧系（Lns（Ⅲ））与锕系（Ans（Ⅲ））分离是核工业高放废液处理过程中十分重要的环节。由于两者物理化学性质极为相近,分离难度很大,Lns（Ⅲ）与Ans（Ⅲ）的分离被公认为是最具挑战性的课题之一,迄今尚未得到满意解决。为实现两者的分离,技术上有两条途径可供选择：一是开发对Ans（Ⅲ）有高选择性的脂溶性萃取剂;二是开发对Ans（Ⅲ）有良好配位性质的水溶性配体。近年来,这两方面研究都已取得了较大进展。就后者而言,发现一些水溶性酰胺和吡啶衍生物、氨羧络合剂等配体对Ans（Ⅲ）有很好的选择性。它们已作为Ans（Ⅲ）的反萃剂或掩蔽剂用于Lns（Ⅲ）与Ans（Ⅲ）的分离。为此,本文就这些水溶性配体在对Lns（Ⅲ）和Ans（Ⅲ）萃取的影响、配合物组成与结构以及配位反应热力学性质等研究方面取得的进展进行综述,并对进一步的研究工作提出了一些建议。     

Influence of a Pre-organized N-Donor Group on the Coordination of Trivalent Actinides and Lanthanides by an Aminopolycarboxylate Complexant

The thermodynamic influence of a pre-organized N-donor group on the coordination of trivalent actinides and lanthanides by an aqueous aminopolycarboxylate complexant has been investigated. The synthesized reagent, N-2-methylpicolinate-ethylenediamine-N,N′,N′-triacetic acid (EDTA-Mpic), resembles ethylenediamine-N,N,N′,N′-tetraacetic acid (EDTA) with a single acetate pendant arm replaced by a 6-carboxypyridin-2-ylmethyl group. The rigid N-donor picolinate functionality has a profound impact on ligand protonation and trivalent f element complexation equilibria, as demonstrated by potentiometric, spectroscopic, and liquid/liquid metal-partitioning studies as well as by molecular dynamics calculations. Relative to diethylenetriamine-N,N,N′,N′′,N′′-pentaacetic acid (DTPA), the ability to preferentially bind trivalent actinides over trivalent lanthanides was moderately lowered due to the presence of the N-(6-carboxypyridin-2-ylmethyl) substituent. The structural modification substantially amplifies the total ligand acidity of EDTA-Mpic. As a result the complexant sustains the metal complexation and efficient An³⁺/Ln³⁺ differentiation in aqueous mixtures of unprecedented acidity for this class of reagents.     

（C_5H_5）_3Nd（THF）的晶体结构

报导了一种新型（Ｃ_５Ｈ_５）３Ｎｄ（ＴＨＦ）晶体结构，晶体属单斜晶系，Ｃ２／ｃ空间群，晶胞参数为ａ＝１２．８３９（７），ｂ＝１０．５２０（３），ｃ＝２６．５９９（９），β＝９８．５０°，Ｖ＝３５５３（３），Ｚ＝８，Ｄ_ｃ＝１．５４ｇ／ｃｍ￣３，Ｍ_ｒ＝４１１．６３，μ＝２９．２９ｃｍ（－１），Ｆ（０００）＝１６４０，最终偏离因子为Ｒ＝０．０６１，Ｒｗ＝０．０７３。新晶体结构在空间群、晶胞参数和Ｚ值上均明显不同于前面的报导，在Ｃｐ３Ｌｎ·ＴＨＦ系列化合物中，这是首次发现同一化合物可以用两种分子堆积方式结晶。     

Lanthanide versus Actinide Reactivity in the Formation of Sterically Crowded [(C5Me5)3MLn] Nitrile and Isocyanide Complexes

The limits of steric crowding in organometallic metallocene complexes have been examined by studying the synthesis of [(C₅Me₅)₃ML_n] complexes as a function of metal in which L=Me₃CCN, Me₃CNC, and Me₃SiCN. The bis(tert‐butyl nitrile) complexes [(C₅Me₅)₃Ln(NCCMe₃)₂] (Ln=La, 1 ; Ce, 2 ; Pr, 3 ) can be isolated with the largest lanthanide metal ions, La³⁺, Ce³⁺, and Pr³⁺. The Pr³⁺ ion also forms an isolable mono‐nitrile complex, [(C₅Me₅)₃Pr(NCCMe₃)] ( 4 ), whereas for Nd³⁺ only the mono‐adduct [(C₅Me₅)₃Nd(NCCMe₃)] ( 5 ) was observed. With smaller metal ions, Sm³⁺ and Y³⁺, insertion of Me₃CCN into the M? C(C₅Me₅) bond was observed to form the cyclopentadiene‐substituted ketimide complexes [(C₅Me₅)₂Ln{NC(C₅Me₅)(CMe₃)}(NCCMe₃)] (Ln=Sm, 6 ; Y, 7 ). With tert‐butyl isocyanide ligands, a bis‐isocyanide product can be isolated with lanthanum, [(C₅Me₅)₃La(CNCMe₃)₂] ( 8 ), and a mono‐isocyanide product with neodymium, [(C₅Me₅)₃Nd(CNCMe₃)] ( 9 ). Silicon–carbon bond cleavage was observed in reactions between [(C₅Me₅)₃Ln] complexes and trimethylsilyl cyanide, Me₃SiCN, to produce the trimeric cyanide complexes [{(C₅Me₅)₂Ln(μ‐CN)(NCSiMe₃)}₃] (Ln=La, 10 ; Pr, 11 ). With uranium, a mono‐nitrile reaction product, [(C₅Me₅)₃U(NCCMe₃)] ( 12 ), which is analogous to 5 , was obtained from the reaction between [(C₅Me₅)₃U] and Me₃CCN, but [(C₅Me₅)₃U] reacts with Me₃CNC through C? N bond cleavage to form a trimeric cyanide complex, [{(C₅Me₅)₂U(μ‐CN)(CNCMe₃)}₃] ( 13 ).     

Crystallographic report: Tris(η5‐cyclopentadienyl)‐tetrahydrofuran‐praseodymium

The title compound is mononuclear with three η⁵‐cyclopentadienyl ligands and one tetrahydrofuran ligand. If the centroids of the cyclopentadienyl ligands are taken as the point of binding to praseodymium, then the environment about the metal centre is considered as a distorted tetrahedron. Copyright © 2003 John Wiley & Sons, Ltd.     

Application of Multi-step Excitation Schemes for Detection of Actinides and Lanthanides in Solutions by Luminescence/Chemiluminescence Laser Spectroscopy

The use of laser radiation with tunable wavelength allows the selective excitation of actinide/lanthanide species with subsequent registration of luminescence/chemiluminescence for their detection. This work is devoted to applications of the time-resolved laser-induced luminescence spectroscopy and time-resolved laser-induced chemiluminescence spectroscopy for the detection of lanthanides and actinides. Results of the experiments on U, Eu, and Sm detection by TRLIF method in blood plasma and urine are presented. Data on luminol chemiluminescence in solutions containing Sm(III), U(IV), and Pu(IV) are analyzed. It is shown that appropriate selectivity of lanthanide/actinide detection can be reached when chemiluminescence is initiated by transitions within 4f- or 5f-electron shell of lanthanide/actinide ions corresponding to the visible spectral range. In this case chemiluminescence of chemiluminogen (luminol) arises when the ion of f element is excited by multi-quantum absorption of visible light. The multi-photon scheme of chemiluminescence excitation makes chemiluminescence not only a highly sensitive but also a highly selective tool for the detection of lanthanide/actinide species in solutions.     

Evaluating Electron-Transfer Reactivity of Complexes of Actinides in +2 and +3 Oxidation States by using EPR Spectroscopy

The possibility that the relative reactivity of complexes of actinide metals in the +2 and +3 oxidation states could be investigated by examining reactions between An^III and An^II species of Th and U with rare-earth metal reagents that provide EPR confirmation of electron transfer reactivity has been explored. Neither Cp’’₃Th^III nor Cp’’₃U^III will reduce Cp’’₃La^III or Cp’₃Y^III (Cp’=C₅H₄SiMe₃, Cp’’=C₅H₃(SiMe₃)₂). However, both [K(2.2.2-cryptand)][Cp’’₃Th^II] and [K(2.2.2-cryptand)][Cp’’₃U^II] reduce Cp’’₃La^III and Cp’₃Y^III to form [Cp’’₃La^II]¹⁻ and [Cp’₃Y^II]¹⁻, respectively, which were identified by EPR spectroscopy. The reverse reactions also occur which indicates that the reduction potentials are similar. [Cp’’₃La^II]¹⁻ reduces Cp’₃Y^III and the reverse Y^II/La^III combination also occurs. In both cases, the reactions generate EPR spectra indicative of multiple species in the mixtures of La^II and Y^II, which is consistent with ligand exchange and demonstrates that numerous heteroleptic complexes of these Ln^II ions exist.     

Structure and bonding of lanthanide dinitrogen complexes,Ln(N2)1-8

Lanthanide dinitrogen complexes, Ln(N₂) _x (x = 1-8), were investigated by Density Functional Theory computations using the B3LYP exchange-correlation functional in conjunction with quasirelativistic pseudopotentials for Ln. After a recent study on the lanthanum complexes (A. Kovács, Structural Chemistry 2018 , 29, 1825), the present study aimed to probe the changes upon variously filled 4f subshells of Ln on the structures, stabilities, and bonding properties in related complexes of Nd, Ho, and Lu. The bonding properties were assessed on the basis of natural atomic charges, Ln valence orbital populations, and analysis of bonding molecular orbitals.     

Bis(amido)cyclodiphosph(III)azane Complexes of Yttrium and the Lanthanides

The first cyclodiphosph(III)azane complexes of the rare‐earth elements have been synthesized. Reactions of the lithium salt cis‐[(tBuNP)₂(tBuN)₂{Li(thf)}₂] with anhydrous yttrium trichloride or the heavier lanthanide trichlorides resulted in the corresponding cyclodiphosph(III)azane complexes [Li(thf)₄][{(tBuNP)₂(tBuN)₂}LnCl₂] (Ln=Y ( 1 a ), Ho ( 1 b ), Er ( 1 c )). The single‐crystal X‐ray structures showed that compounds 1 a – c consisted of ion pairs composed of a [Li(thf)₄]⁺ cation and a C_2v symmetric [{(tBuNP)₂(tBuN)₂}LnCl₂]^? anion. By treating cis‐[(tBuNP)₂(tBuN)₂{Li(thf)}₂] with anhydrous SmCl₃ in THF, the trimetallic complex [{(tBuNP)₂(tBuN)₂}SmCl₃Li₂(thf)₄] ( 2 ) was obtained. The influence of the ionic radii of the lanthanides can be seen in the single‐crystal X‐ray structure of compound 2 , which forms a six‐membered Cl‐Li‐Cl‐Li‐Cl‐Sm metallacycle. The ring adopts a boat conformation in which one chlorine atom and the samarium atom are displaced from the Cl₂Li₂ least‐square plane. Heating of the metalate complexes in toluene resulted in the extrusion of lithium chloride and the formation of the neutral dimeric metal chloride complexes of the composition [(tBuNP)₂(tBuN)₂LnCl(thf)]₂ (Ln=Y ( 3 a ), La ( 3 b ) Nd ( 3 c ), Sm ( 3 d )). Furthermore, treating 1 a with KNPh₂ resulted in a lithium metalate complex of the composition [Li(thf)₄][{(tBuNP)₂(tBuN)₂}Y(NPh₂)₂] ( 4 ). The coordination mode of the {(tBuNP)₂(tBuN)₂}^2? ligand in 4 is different to that observed in 1 a – c , 2 , and 3 a – d ; instead of a symmetric η² coordination of the ligand, a heterocubane‐type structure is observed in the solid state. The complex [(tBuNP)₂(tBuN)₂NdCl(thf)] ( 3 c ) was used as a Ziegler–Natta catalyst for the polymerization of 1,3‐butadiene to poly‐cis‐1,4‐butadiene. The observed activities of the Ziegler–Natta catalyst strongly depended upon the nature of the cocatalyst; in some case very high turnover rates and a cis selectivity of 93–94 % were observed.     

Metal‐Porphyrin Orbital Interactions in Paramagnetic Iron Complexes Having Planar and Deformed Porphyrin Ring

¹H and ¹³C NMR chemical shifts of iron porphyrin complexes are determined mainly by the spin densities at the peripheral carbon and nitrogen atoms caused by the interaction between paramagnetic iron 3d and porphyrin molecular orbitals. This review describes how the half‐occupied iron 3d orbitals such as d_π(d_xz, d_yz), d_xy, d, and d‐ interact with a specific porphyrin molecular orbital and affect the ¹H and ¹³C NMR chemical shifts in planar, ruffled, saddled, and domed complexes. Revealing the relationship between the orbital interactions and NMR chemical shifts is quite important to determine the fine electronic structures of synthetic iron porphyrin complexes as well as naturally occurring heme proteins.     

Das Tris(cyclopentadienyl)methylsilan-Trianion – ein neues Ligandensystem und Komplexbildung mit Rhodium

The Tris(cyclopentadienyl)methylsilane Trianion – a New Ligand System and Complex Formation with Rhodium Starting from MeSiCl₃ the title compound was synthesized by two steps as the virtually insoluble trithallium salt ( 1 ). Reaction of 1 with [(C₂H₄)₂RhCl]₂ in pentane gives {MeSi[C₅H₄Rh(C₂H₄)₂]₃} ( 2 ). Under UV irradiation of 2 in pentane in the presence of benzene only two [C₅H₄Rh(C₂H₄)₂] units of 2 react with loss of ethene and formation of the μ-η³ : η³ benzene compound {MeSi[(C₅H₄Rh)₂(C₆H₆)][C₅H₄Rh(C₂H₄)₂]} ( 3 ). The novel complexes 2 and 3 were characterized spectroscopically and by X-ray structure analysis.     

Hydrogen‐Bonding Interactions Trigger a Spin‐Flip in Iron(III) Porphyrin Complexes

A key step in cytochrome P450 catalysis includes the spin‐state crossing from low spin to high spin upon substrate binding and subsequent reduction of the heme. Clearly, a weak perturbation in P450 enzymes triggers a spin‐state crossing. However, the origin of the process whereby enzymes reorganize their active site through external perturbations, such as hydrogen bonding, is still poorly understood. We have thus studied the impact of hydrogen‐bonding interactions on the electronic structure of a five‐coordinate iron(III) octaethyltetraarylporphyrin chloride. The spin state of the metal was found to switch reversibly between high (S=⁵/₂) and intermediate spin (S=³/₂) with hydrogen bonding. Our study highlights the possible effects and importance of hydrogen‐bonding interactions in heme proteins. This is the first example of a synthetic iron(III) complex that can reversibly change its spin state between a high and an intermediate state through weak external perturbations.     

A lutetium allyl complex that bears a pyridyl-functionalized cyclopentadienyl ligand: dual catalysis on highly syndiospecific and cis-1,4-selective (co)polymerizations of styrene and butadiene

A novel linked‐half‐sandwich lutetium–bis(allyl) complex [(C₅Me₄? C₅H₄N)Lu(η³‐C₃H₅)₂] ( 1 ) attached by a pyridyl‐functionalized cyclopentadienyl ligand was synthesized and fully characterized. Complex 1 in combination with [Ph₃C][B(C₆F₅)₄] exhibited unprecedented dual catalysis with outstanding activities in highly syndiotactic (rrrr>99 %) styrene polymerization and distinguished cis‐1,4‐selective (99 %) butadiene polymerization, respectively. Strikingly, this catalyst system exhibited remarkable activity (396 kg copolymer (mol_Lu h)^?1) for the copolymerization of butadiene and styrene. Irrespective of whether the monomers were fed in concurrent mode or sequential addition of butadiene followed by styrene, diblock copolymers were obtained exclusively, which was confirmed by a kinetics investigation of monomer conversion of copolymerization with time. In the copolymers, the styrene incorporation rate varied from 4.7 to 85.4 mol %, whereas the polybutadiene (PBD) block was highly cis‐1,4‐regulated (95 %) and the polystyrene segment remained purely syndiotactic (rrrr>99 %). Correspondingly, the copolymers exhibited glass transition temperatures (T_g) around ?107 °C and melting points (T_m) around 268 °C; typical values for diblock microstructures. Such copolymers cannot be accessed by any other methods known to date. X‐ray powder diffraction analysis of these diblock copolymers showed that the crystallizable syndiotactic polystyrene (syn‐PS) block was in the toluene δ clathrate form. The AFM micrographs of diblock copolymer showed a remarkable phase‐separation morphology of the cis‐1,4‐PBD block and syn‐PS block. This represents the first example of a lutetium‐based catalyst showing both high activity and selectivity for the (co)polymerization of styrene and butadiene.     

Novel Lanthanide (III) Complexes Derived from an Imidazole–Biphenyl–Carboxylate Ligand: Synthesis,Structure and Luminescence Properties

A series of neutral mononuclear lanthanide complexes [Ln(HL)₂(NO₃)₃] (Ln = La, Ce, Nd, Eu, Gd, Dy, Ho) with rigid bidentate ligand, HL (4′-(1H-imidazol-1-yl)biphenyl-4-carboxylic acid) were synthesized under solvothermal conditions. The coordination compounds have been characterized by infrared spectroscopy, thermogravimetry, powder X-ray diffraction and elemental analysis. According to X-ray diffraction, all the complexes are a series of isostructural compounds crystallized in the P2/n monoclinic space group. Additionally, solid-state luminescence measurements of all complexes show that [Eu(HL)₂(NO₃)₃] complex displays the characteristic emission peaks of Eu(III) ion at 593, 597, 615, and 651 nm.     

2-巯基苯并噻唑稀土金属有机配合物的合成及表征

用2－巯基苯并噻唑和三环戊二烯基稀土化合物或三（甲基－环戊二基）稀土化合物反应,合成了未见文献报道的5种稀土金属有机配合物,其结构经元素分析,IR和MS鉴定,推测它们是配体以S,N与Ln(Ln=La,Eu,Tb,Y,Yb)二齿配位的配合物,并且以二倍体形式存在。     

A Systemic Insight into Exohedral Actinides and Endohedral Borospherenes: An&Bm and An@Bn (An=U,Np, Pu; m = 28, 32, 34, 36, 38, 40; n = 36, 38, 40)

A series of exohedral actinide borospherenes, An&B_m, and endohedral borospherenes, An@B_n (An=U, Np, Pu; m = 28, 32, 34, 36, 38, 40; n = 36, 38, 40), have been characterized by density functional theory calculations. The electronic structures, chemical bond topological properties and spectra have been systematically investigated. It was found that An@B_n is more stable than An&B_n in terms of structure and energy, and UB₃₆ in an aqueous solution is the most stable molecular in this research. The IR and UV-vis spectra of An&B_m and An@B_n are computationally predicted to facilitate further experimental investigations. Charge-transfer spectroscopy decomposes the total UV-Vis absorption curve into the contributions of different excitation features, allowing insight into what form of electronic excitation the UV–Vis absorption peak is from the perspective of charge transfer between the An atoms and borospherenes.     

Synthesis,Reactivity, and Structural Characterization of Dioxovanadium(V) Complexes with Tridentate Schiff Base Ligand: Vanadium Complexes in Supramolecular Networks

The synthesis, characterization and crystal structure analysis of the ammonium salt of the dioxovanadium(V) complex NH₄[VO₂(salhyph)] with the tridentate Schiff base ligand derived from salicylaldehyde and benzoic acid hydrazide (H₂salhyph) is reported. NH₄[VO₂(salhyph)] crystallizes in the monoclinic space group Pn with a = 708.8(2), b = 1444.3(3), c = 717.1(2) pm and β = 101.09(2)°. The vanadium atom of the dioxovanadium(V) moiety has a distorted square‐pyramidal coordination geometry. Extensive hydrogen bonding is observed between the ammonium cation and the oxygen atoms coordinated to the vanadium atom yielding to a two‐dimensional network, where the complex anions are arranged in a bilayer. Additional crystal packing within the bilayer appears to be controlled mostly by π stacking between the aromatic rings of the ligand. The reactions of NH₄[VO₂(salhyph)] with several proton acidic compounds including water, methanol, and proton acids lead to neutral monooxovanadium(V) and dioxovanadium(V) complexes ([VO₂(Hsalhyph)], [V₂O₃(salhyph)₂] and [VO(OMe)(salhyph)(HOMe)]).     

两个半夹心型聚吡唑硼酸盐羧酸钴配合物的合成、结构及催化活性

设计合成了2个结构新颖的半夹心单核聚吡唑硼酸盐羧酸配合物Tp^*Co(Hglu)(CH₃OH)(1)和Tp^*Co(Hsub)(H₂O)(2)[Tp^*=三聚(3,5-二甲基吡唑)硼酸根, H₂glu=戊二酸, H₂sub=辛二酸], 并通过元素分析、 红外光谱、 紫外-可见光谱和X射线单晶结构分析对标题配合物进行了表征. 结构分析表明, 在配合物1和2中, 配体Tp^*都是三齿配位, 配位模式相同; 戊二酸和辛二酸都以μ₁-η¹-η¹的端基配位模式与金属相连. 此外, 还对配合物的热稳定性进行了详细分析, 并初步探讨了配合物催化氧化环己烷的催化活性.