聚酰胺与稀土离子相互作用的研究

用热分析和傅里叶变换红外光谱法研究了尼龙6与稀土离子之间的相互作用。实验结果表明,当将稀土离子引入尼龙6体系后,可观察到以下几种效应：1)尼龙6的熔点显著降低。2)红外光谱结果表明,尼龙6-稀土体系熔化过程中,代表N－H伸缩振动的酰胺A带发生红移。3)尼龙6的酰胺Ⅰ和Ⅱ带区段,可观察到代表与稀土配位的酰胺基团的知,随着温度升高,尼龙6的酰胺Ⅰ,Ⅱ带吸光度降低而在1600cm^-^1附近的新峰的吸光度增加。     

Fabrication and physical properties of lanthanide oxide glass wasteform for the immobilization of lanthanide oxide wastes generated from pyrochemical process

The pyrochemical process, which uses a dry method to recycle used nuclear fuel generates waste LiCl–KCl salt containing radioactive lanthanide elements. To reuse LiCl–KCl salt, the lanthanide elements are separated through a precipitation method promoted by oxygen sparging and the separated fission product of lanthanide oxide should be fabricated into durable wasteforms sustainable for several 1,000 years to store in a final geological repository. Herein, we report the fabrication of a borosilicate glass based wasteform with a glass matrix of SiO₂–Al₂O₃–B₂O₃ having a high waste loading of 50 wt% lanthanide oxide. Th physical properties of four kinds of wasteforms having a different lanthanide oxide waste composition were evaluated. To investigate the long-term physical stability of each sample having 50 wt% lanthanide oxide waste loading, time–temperature–transformation (TTT) test was conducted at 500 and 700 °C for 60 and 180 h, and the physical properties were evaluated after each TTT test.     

Controlled photophysical behaviors between dibenzo-24-crown-8 bearing terpyridine moiety and fullerene-containing ammonium salt

A novel [2]pseudorotaxane was successfully constructed by the complexation of dibenzo[24]-crown-8 (DB24C8) derivative bearing terpyridine moiety (1) with lanthanide ion (Tb(3+)) and fullerene-containing ammonium salt (2), exhibiting the controlled photophysical behaviors as a reversible luminescent lanthanide switch in the presence of K(+) or 18-crown-6 (18C6).     

GMP-quadruplex-based hydrogels stabilized by lanthanide ions

This work describes the gelation behaviors and properties of a biological molecule, guanosine 5′-monophosphate disodium salt(GMP), in the presence of trivalent lanthanide ions. Hydrogels composed of GMP-quadruplexes were prepared by adjusting p H,through which the protonation of phosphate group was controlled to tune the interactions between lanthanide ions and GMP.Within the p H region of 2–6, the electrostatic interaction between lanthanide ions and phosphate group is hindered and the cation-dipole interaction acts as the main driving force for the formation of G-quadruplexes. All the hydrogels were found consisting of three-dimensional network of the intertwining one-dimensional nanofibers formed by the stacking G-quartets induced by lanthanide ions. A significant fluorescence enhancement of thioflavin T(Th T), a fluorescent molecule, was found to be triggered by the G-quadruplex structures, for which the rotation of chromophoric groups on Th T molecules were prohibited due to the implant into the G-quadruplex structures.     

Lanthanide salts solutions: representation of osmotic coefficients within the binding mean spherical approximation

Osmotic coefficients of aqueous solutions of lanthanide salts are described using the binding mean spherical approximation (BIMSA) model based on the Wertheim formalism for association. The lanthanide(III) cation and the co-ion are allowed to form a 1-1 ion pair. Hydration is taken into account by introducing concentration-dependent cation size and solution permittivity. An expression for the osmotic coefficient, derived within the BIMSA, is used to fit data for a wide variety of lanthanide pure salt aqueous solutions at 25 degrees C. A total of 38 lanthanide salts have been treated, including perchlorates, nitrates, and chlorides. For most solutions, good fits could be obtained up to high ionic strengths. The relevance of the fitted parameters has been discussed, and a comparison with literature values has been made (especially the association constants) when available.     

Syntheses, crystal structures, and luminescent properties of novel layered lanthanide sulfonate-phosphonates

Hydrothermal reactions of lanthanide metal salts with MeN(CH(2)CO(2)H)(CH(2)PO(3)H(2)) (H(3)L) and 5-sulfoisophthalic acid monosodium salt (NaH(2)BTS) lead to four isomorphous lanthanide carboxylate-phosphonate-sulfonate hybrids, namely, Ln(H(2)L)(HBTS)(H(2)O)(2).H(2)O (Ln = La (1), Pr (2), Nd (3), Gd (4)). Their structures have been established by X-ray single-crystal diffraction. The interconnection of the lanthanide(III) ions by carboxylate-phosphonate ligands results in a 1D double chain; these double chains are further bridged by bidentate bridging carboxylate-sulfonate ligands to form a <011> layer. The luminescent properties of compounds 3 and 4 have also been studied.     

Green Chemistry and Glycochemistry

With the increasing environmental concerns and the regulatory constraints faced in the chemical and pharmaceutical industries, development of environmentally benign organic reactions (also called Green Chemistry) has become a crucial and demanding research area in modem organic chemical research. Our contribution to this rapidly growing field involves use of certain lanthanide salts such as lanthanide(Ⅲ) trifluoromethanesulfonates as stable Lewis acids in protic solvent such as water or alcohols to catalyze a variety of organic transformations under nearly neutral conditions. This benign approach has the potential to replace many traditional reaction systems which are either conducted in strong acidic conditions or in environmentally less-friendly solvents. For example, aza Diels-Alder (DA) reaction in aqueous solution conveniently combines three reactant components (an aldehyde, an amine salt and a diene) in aqueous solution and generates nitrogen-containing heterocyclic products. However, this reaction is limited to either the smallest aldehyde or activated aldehydes such as glyoxylates. We have found that lanthanide(Ⅲ) triflates catalyze the aza DA reactions of a larger,inactivated aldehyde and an amine hydrochloride with a diene in aqueous solution[1]. Other examples of application of lanthanide triflates in protic solvents include Chicliibabin pyridine synthesis[2],condensation of indoles with aldehydes or ketones[3], and use of ion-exchange resin supported lanthanide catalysts[4].     

Hairpin-shaped heterometallic luminescent lanthanide complexes for DNA intercalative recognition

Luminescent Ln-Pt2 metallohairpin complexes have been developed, and their intercalative recognition with DNA has been demonstrated with linear dichroism spectroscopy. The heterotrimetallic complexes were formed in a one-step reaction, by assembly of an aminopolycarboxylate ligand, a platinum terpyridine unit, and the lanthanide salt. The metallohairpin complexes bear a neutral lanthanide moiety and two positively charged platinum-containing intercalating units. The Nd(III) analogues are luminescent in the near infrared, and this near-IR luminescence is retained upon binding to DNA. The DNA recognition was demonstrated by linear dichroism spectroscopy. The linear dichroism spectra suggested that the complexes bind perpendicular to the DNA helical axis, confirming intercalative recognition accompanied by dramatic stiffening of DNA, which suggests bis-intercalation of the complex.     

Group I cation templated formation of luminescent mono- and bis-substituted thionaphthol heterobimetallic complexes of Pr, Nd, Eu and Tb

Metathesis of lanthanide tris di-tert-butyl beta-diketonates ([Ln(thd)3] Ln=Pr, Nd, Eu, Tb) with one or two equivalents of group 1 salts of the sulfur bridged binaphtholate dianion [1,1'-S(2-OC10H4But(2)-3,6)2]2-, [M2L], M=K, Li affords luminescent mono- and bis-ligand substituted complexes ML[LnL(thd)2].L; M=K, Ln=Pr , Nd , Eu and Tb (L=thf, diethyl ether or toluene) and M(thf)2[LnL2(thd)]; M=Li, Ln=Pr , Nd , Eu , Tb . The potassium salt [K2L] affords mono-L substituted complexes most cleanly, while the lithium salt [Li2L] yields the bis-L substituted complexes most cleanly. The L ligands function as antenna for the sensitised lanthanide-centred emission in Eu3+ and Tb3+ complexes. The X-ray single-crystal structures of mono- and bis-L lanthanide complexes of Nd3+ are presented.     

Compositional variations in monomeric trimethylsilylated allyl lanthanide complexes

Treatment of three equivalents of the potassium salt of the bis(1,3-trimethylsilyl)allyl anion with various late lanthanide triflates (M = Dy, Ho, Er, Tm, Lu) produces the unsolvated triallyllanthanide complexes (A′ = 1,3-(SiMe₃)₂C₃H₃). The use of lanthanide halides (Cl, I) with the potassium allyl also generates neutral complexes, but when lanthanide iodides and the corresponding lithium allyl are combined, the lanthanate species are formed. Trends in the bonding of lanthanide allyl complexes with the trimethylsilylated-allyl ligand are explored and compared with those of cyclopentadienyl lanthanide complexes.     

N-Heterocyclic tridentate aromatic ligands bound to [Ln(hexafluoroacetylacetonate)3] units: thermodynamic, structural, and luminescent properties

Herein, we discuss how, why, and when cascade complexation reactions produce stable, mononuclear, luminescent ternary complexes, by considering the binding of hexafluoroacetylacetonate anions (hfac(-)) and neutral, semi-rigid, tridentate 2,6-bis(benzimidazol-2-yl)pyridine ligands (Lk) to trivalent lanthanide atoms (Ln(III)). The solid-state structures of [Ln(Lk)(hfac)(3)] (Ln=La, Eu, Lu) showed that [Ln(hfac)(3)] behaved as a neutral six-coordinate lanthanide carrier with remarkable properties: 1) the strong cohesion between the trivalent cation and the didentate hfac anions prevented salt dissociation; 2) the electron-withdrawing trifluoromethyl substituents limited charge-neutralization and favored cascade complexation with Lk; 3) nine-coordination was preserved for [Ln(Lk)(hfac)(3)] for the complete lanthanide series, whilst a counterintuitive trend showed that the complexes formed with the smaller lanthanide elements were destabilized. Thermodynamic and NMR spectroscopic studies in solution confirmed that these characteristics were retained for solvated molecules, but the operation of concerted anion/ligand transfers with the larger cations induced subtle structural variations. Combined with the strong red photoluminescence of [Eu(Lk)(hfac)(3)], the ternary system Ln(III)/hfac(-)/Lk is a promising candidate for the planned metal-loading of preformed multi-tridentate polymers.     

Self-assembled microspheres from f-block elements and nucleoamphiphiles

Hollow microspheres featuring a hybrid lipid-cation multilamellar shell are prepared by hydration of a nucleoside based amphiphile with an aqueous solution containing either actinide or lanthanide salts. The physico-chemical data collected clearly indicate that the formation of these microspheres is a consequence of the following concomitant stabilizing factors: (i) hydrophobic interactions, (ii) nucleobase dimer formation and (iii) phosphate/f-block element salt binding.     

Metal—-Metal “Communication” of Rh or Pd with Nd in Novel Heterobinuclear Complexes

The reaction of a neodymium “ate” complex and an electron-rich transition metal chloride by salt elimination is an efficient method for synthesizing heterobinuclear compounds which contain a lanthanide and a Group 9 or 10 metal [Eq. (1), H₂Ap=2-amino-4-methylpyridine]. The use of bisaminopyridinato ligands allows extremely short distances between Rh or Pd and Nd.     

Metallotricycle of Lanthanide Supported by a Bridging Diamide: Syntheses and Molecular Structures of {Li(THF)3[LnCl(μ2-trans-1,2-(NSiMe3)2C6H10)(μ2-Cl)]}2•2THF (Ln＝Yb, Nd)

The reactions of dilithium salt of trans-1,2-bis（trimethylsilylamino）cyclohexane with anhydrous lanthanide trichlorides LnCl3 （Ln = Yb, Nd） in THF afforded the dianionic binuclear tricycles of lanthanide chlorides {Li（THF）3[LnCl（μ2-trans-1,2-（NSiMe3）2C6H10）（μ2-Cl）]}2·2THF （Ln=Yb 1, Nd 2） in moderate yields. Both of the bridged complexes were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Crystal structural analysis shows that the two complexes are the analogues which have a tricyclic framework built by two bridged lanthanide metals, four nitrogens and four carbons from two diamide ligands. Each lanthanide metal coordinates to three nitrogen atoms and two chlorines to form a distorted trigonal bipyramid and connects with a lithium by a bridging chlorine.     

The Coordination Chemistry of f-Block Elements in Molten Salts

The coordination chemistry of f-block elements (lanthanide and actinide) in molten salts has become a resounding topic in view of its great importance to the research and development (R&D) of molten salt reactors and pyroprocessing. In this Review article, a general overview of the coordination chemistry of f-block elements in molten salts is provided including past achievements and recent advances. Particular emphases are placed on the oxidation state, speciation, and solution structure of f-block metal ions in molten salts, as well as their relationships with the salt composition. Furthermore, this review briefly discusses the spectroscopic and theoretical methods that complement each other in revealing the coordination properties.     

新型柱-层结构的金属有机配位聚合物的合成与性质

利用5-磺基间苯二甲酸单钠盐（NaH₂L）和La(NO₃)₃在水热条件下成功合成了一种新型配位聚合物[La(L)(H₂O)₃]_n·nH₂O（1, CCDC: 1422966）,其结构和性质经IR, X-射线单晶衍射,元素分析,热重分析和FL表征。结果表明：La³⁺为九配位,呈三帽三棱柱配位构型。化合物1基于La³⁺和L^3-配体的两种拓扑非等价节点,呈现出五连接3D柱层状金属有机骨架结构,Schlafli符号为(4⁵, 6⁵)。化合物¹的荧光发射峰位于410 nm,归属于配体到金属的电荷转移。     

A tunable full-color lanthanide noncovalent polymer based on cucurbituril-mediated supramolecular dimerization

The construction of lanthanide multicolor luminescent materials with tunable photoluminescence properties has been developed as one of the increasingly significant topics and shown inventive applications in miscellaneous fields. However, fabricating such materials based on synergistically assembly-induced emission rather than simple blending of different fluorescent dyes together still remains a challenge. Herein, we report a europium-based noncovalent polymer with tunable full-color emission, which is constructed from the 2,6-pyridinedicarboxylic acid-bearing bromophenylpyridinium salt. This rationally designed bifunctional component can concurrently serve as a guest molecule and a chelating ligand to associate with cucurbit[8]uril and europium ions, thus leading to the formation of a trichromatic (red–green–blue, RGB) photoluminescent polypseudorotaxane-type noncovalent polymer in aqueous solution. Meanwhile, the full-color emission enclosed within the RGB color triangle could be readily produced by simply tuning the molar ratio of cucurbit[8]uril and europium ions. The lanthanide supramolecular polymer featuring tricolor emission, long lifetime, high photoluminescence efficiency and low cytotoxicity could be further applied in multicolor imaging in a cellular environment. These results provide a new and feasible strategy for the construction of full-color single lanthanide self-assembled nanoconstructs.

A lanthanide noncovalent polymer is constructed by integrating host–guest complexation and metal–ligand coordination, and can exhibit tunable trichromatic emission and multiple excited-state lifetimes under single wavelength excitation.     

Thermal behaviour of fumaric acid, sodium fumarate and its compounds with light trivalent lanthanides in air atmosphere

Characterization, thermal stability and thermal decomposition of light trivalent lanthanide fumarates, as well as, the thermal behaviour of fumaric acid and its sodium salt were investigated employing simultaneous thermogravimetry and differential thermal analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy (FTIR), TG?CFTIR techniques, elemental analysis and complexometry. On heating, sublimation of fumaric acid is observed, while the thermal decomposition of the sodium fumarate occurs with the formation of a mixture of sodium carbonate and carbonaceous residue. The thermal decomposition of light trivalent lanthanide fumarates occurs in consecutive and/or overlapping steps with the formation of the respective oxides: CeO₂, Pr₆O₁₁, and Ln₂O₃ (Ln?=?La, Nd, Sm, Eu, Gd).     

(R)-bis-Binaphthoxy iodo lanthanides as catalysts for Diels–Alder reactions

[(R)-1,1′bi-2,2′-Naphthoxy]LnI(THF)₂ (Ln: Yb, Sm, La) 5 have been prepared by reaction of the bispotassium salt of (R)-binaphthol with lanthanide triiodides, and characterized. They are active catalysts for Diels–Alder reactions although with low asymmetric inductions. The lanthanum iodo bisbinaphthoxide gives a slightly higher enantiomeric excess than the two other complexes.