氨基膦酸树脂对镱的吸附及机理

氨基膦酸树脂 ( APAR)对镱 ( )的吸附在 p H=5 .1时最佳。静态饱和吸附容量为 2 75 mg/g千树脂 ;用 3.0～ 4.0 mol· L- 1HCl能还原洗脱。测得吸附速率常数k2 98=9.5 7× 1 0 - 6 s- 1,等温吸附服从 Freundlich经验式 ,吸附热力学函数△ H0 =1 7.6k J· mol- 1。吸附机理表明 ,APAR功能基上的 N、O与 Yb3+发生配位键合 ,配位摩尔比为 2∶ 1     

Crystal Structure of Di[(μ‐benzoato‐O,O′)bis(η5‐methylcylopentadienyl)ytterbium(III)]

Transparent orange‐red crystals of [Yb(MeCp)₂(O₂CPh)]₂ obtained by oxidation of Yb(MeCp)₂ with Tl(O₂CPh) in tetrahydrofuran have a dimeric structure with bridging bidentate (O,O′)‐benzoate groups and eight‐coordinate ytterbium.     

Lanthanide(II) Complexes of the Dihydrotriazinido Ligand [N{C(Ph)=N}2C(tBu)Ph]−

The potassium dihydrotriazinide K(L^Ph,tBu) ( 1 ) was obtained by a metal exchange route from [Li(L^Ph,tBu)(THF)₃] and KOtBu (L^Ph,tBu = [N{C(Ph)=N}₂C(tBu)Ph]). Reaction of 1 with 1 or 0.5 equivalents of SmI₂(thf)₂ yielded the monosubstituted Sm^II complex [Sm(L^Ph,tBu)I(THF)₄] ( 2 ) or the disubstituted [Sm(L^Ph,tBu)₂(THF)₂] ( 3 ), respectively. Attempted synthesis of a heteroleptic Sm^II amido‐alkyl complex by the reaction of 2 with KCH₂Ph produced compound 3 due to ligand redistribution. The Yb^II bis(dihydrotriazinide) [Yb(L^Ph,tBu)₂(THF)₂] ( 4 ) was isolated from the 1:1 reaction of YbI₂(THF)₂ and 1 . Molecular structures of the crystalline compounds 2 , 3· 2C₆H₆ and 4· PhMe were determined by X‐ray crystallography.     

Reactivity of Lanthanoid Aryloxide Complexes: Isolation of a 1,2‐Dimethoxyethane Cleavage Product

[Yb(OAr)₂(μ‐OMe)(DME)]₂ ( 1 ) (OAr = 2,6‐di‐iso‐propylphenolate) was synthesised via a redox transmetallation ligand exchange reaction between ytterbium metal, diphenylmercury and 2,6‐di‐isopropylphenol in DME. The source of the methoxy groups is from cleavage of DME, and the C‐O bond activation is unexpected given that the reaction was undertaken at ambient temperature. Each Yb³⁺ metal ion in 1 is six coordinate, and the coordination arrangement around each metal ion is distorted trigonal antiprismatic with Yb‐O(OMe) bond lengths (2.191(2) and 2.258(2) Å) shorter than the Yb‐O(aryloxide) bond distances (2.094(2) and 2.074(2) Å).     

Efficient synthesis of pyrimidinone derivatives by ytterbium chloride catalyzed Biginelli-type reaction under solvent-free conditions

An efficient and clean method was developed for the one-pot synthesis of pyrimidinones by ytterbium chloride catalyzed Biginelli-type reaction of aromatic aldehyde, cyclopentanone, and urea or thiourea under solvent-free conditions.     

Infrared Luminescence of Ytterbium Ion in Complexes with Calix[4]resorcinarenes

New ytterbium complexes with seven calix[4]resorcinarenes containing methoxycarbonyl, methyldiethylamino groups, and bromine as the substituents in the resorcinol ring and methyl or phenyl substituents in the macro ring were synthesized. The absorption, excitation, phosphorescence, and luminescence spectra of these complexes were studied. The positions of triplet levels of the ligands were measured and the values of relative quantum yields for the complexes were calculated. The paths of ligand–lanthanide energy transfer are discussed.     

Yb（OTf）3 Catalyzed Nucleophilic Conjugate Addition of Pyrrole to α，β-Unsaturated Ketones and Nitro-compounds

Under the catalysis of Yb(OTf)3, nucleophilic conjugate addition of pyrrole to electron deficient olefins in CH2Cl2 at ambient temperature gives corresponding 2-alkylated pyrrole derivatives in good yields with high selectivity.     

Efficient synthesis of alkyl 2,3-unsaturated glucopyranosides from glycals mediated by ytterbium(III) triflate-trialkyl aluminum

Treatment of glycals with trialkylaluminum in the presence of a catalytic amount of Yb(OTf)₃ leads to the corresponding alkyl 2,3-unsaturated glycosides in good to excellent yields. Reactions of protected glycals are achieved under very mild conditions.     

Solution structure of chiral lanthanide complexes

The determination of solution structure of small to medium size chiral lanthanide complexes through paramagnetic NMR and circular dichroism is briefly reviewed. The main focus is on ytterbium as the rare earth, because of its negligible contact contribution to the hyperfine shift and of its intense CD spectrum in the near IR. The structures discussed contain various stereogenic elements: classical chiral centres, atropisomeric axes, slowly interconverting conformations, which gives rise to a manifold of situations to be identified, classified, and characterised through spectroscopic tools. The fallout of these structural properties are in enantioselective catalysis, in molecular recognition, or even in biomedicine, on account of the role of Gd³⁺ complexes as MRI contrast agents. Moreover, the information encoded in the NMR and CD spectra of Ln³⁺ complexes may be used to extract original data on the solution stereochemistry of organic molecules used as ligands. The first part summarises some basic theoretical aspects, with special emphasis onto those which have practical consequences in the experimental design. A discussion of selected applications can be found in the second part.     

OH-对磷酸盐铒玻璃光谱性质的影响

本文系统研究了Yb³⁺、Er³⁺共掺磷酸盐铒玻璃中OH^-含量与铒玻璃荧光寿命和光谱性质的关系.结果表明OH^-基团的存在使得Er³⁺离子的荧光强度显著降低,荧光寿命大大缩短.比较了三种不同Al₂O₃含量(5mol%,8mol%和13mol%)的铒玻璃在2.9μm波长处的红外吸收系数与铒离子荧光寿命的关系,发现玻璃中OH^-在2.9μm的吸收系数和Er³⁺的⁴Ⅰ_13/2能级离子衰减速率成线性关系,不同Al₂O₃含量的玻璃具有不同Er³⁺和OH^-基团的相互作用参量和不同的荧光寿命值及量子效率.并从玻璃结构上解释了Al₂O₃含量对除水机制和光谱性质的影响.经过充分除水后的铒玻璃荧光寿命可达到9.1ms.