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1.
本文用氯化稀土(RECl_3)与二茂铁丙烯酸钠盐(LNa)在无水乙醇中反应,合成了13种新的稀土配合物。由元素分析、红外光谱和热谱分析确定配合物的组成为:(C_5H_5FeC_5H_4CH=CHCOO)_3RE·H_O(RE=La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb),配体羧基以双齿对称螯合方式与稀土离子配位。经X射线粉末衍射分析,对其晶体结构进行了初步探讨。  相似文献   

2.
Two series of new dinuclear rare‐earth metal alkyl complexes supported by indolyl ligands in novel μ‐η211 hapticities are synthesized and characterized. Treatment of [RE(CH2SiMe3)3(thf)2] with 1 equivalent of 3‐(tBuN?CH)C8H5NH ( L1 ) in THF gives the dinuclear rare‐earth metal alkyl complexes trans‐[(μη211‐3‐{tBuNCH(CH2SiMe3)}Ind)RE(thf)(CH2SiMe3)]2 (Ind=indolyl, RE=Y, Dy, or Yb) in good yields. In the process, the indole unit of L1 is deprotonated by the metal alkyl species and the imino C?N group is transferred to the amido group by alkyl CH2SiMe3 insertion, affording a new dianionic ligand that bridges two metal alkyl units in μη211 bonding modes, forming the dinuclear rare‐earth metal alkyl complexes. When L1 is reduced to 3‐(tBuNHCH2)C8H5NH ( L2 ), the reaction of [Yb(CH2SiMe3)3(thf)2] with 1 equivalent of L2 in THF, interestingly, generated the trans‐[(μη211‐3‐{tBuNCH2}Ind)Yb(thf)(CH2SiMe3)]2 (major) and cis‐[(μη211‐3‐{tBuNCH2}Ind)Yb(thf)(CH2SiMe3)]2 (minor) complexes. The catalytic activities of these dinuclear rare‐earth metal alkyl complexes for isoprene polymerization were investigated; the yttrium and dysprosium complexes exhibited high catalytic activities and high regio‐ and stereoselectivities for isoprene 1,4‐cis‐polymerization.  相似文献   

3.
A series of cationic rare‐earth aryloxide complexes, i.e., [LREOAr']+[B(C6F5)4] (L = CH3C(NAr)CHC(CH3)(NCH(R)CH2PPh2); RE = Y, Lu; Ar' =2,6‐tBu2‐C6H3, 2,6‐(PhCMe2)2‐4‐Me‐C6H2; Ar = 2,6‐iPr2‐C6H3, 2,6‐(Ph2CH)2‐4‐iPr‐C6H2; R = H, CH3, iPr, Ph), were prepared and applied to the Lewis pair polymerization of methyl methacrylate (MMA). The stereoregularity of the resulting PMMA was significantly affected by the R substituent on the pendant arm of the tridentate NNP ligand, and was found to increase with increase in the steric hindrance of R. When using a Ph group as R, the Y complex produced a highly isotactic polymer with an mm value of 95% and a Tg of 54.6 oC. In contrast, the steric hindrance of the Ar and Ar' groups had no effect on the tacticity of the resulting polymer, presumably because these two substituents were situated such that they pointed outward from the cyclic intermediates. Kinetics studies demonstrated that the polymerization was a first‐order process with regard to the monomer concentration prior to catalyst deactivation. End group analysis indicated that the polymerization was accompanied by two possibly competing chain‐termination side reactions that proceeded via intramolecular backbiting cyclization.  相似文献   

4.
Six new rare‐earth metal tetracyanidoborates were prepared and characterized by single‐crystal X‐ray diffraction. Crystals of these salts contain co‐crystallized solvent molecules, such as water, acetone, ethanol, or diethyl ether. In [La(EtOH)3(H2O)2{B(CN)4}3] ( 1 ), [La(EtOH)(H2O)4{B(CN)4}3] · Et2O ( 2 ), and [Y(EtOH)(H2O)4{B(CN)4}3] · EtOH ( 6 ) the tetracyanidoborate anions are all or in part bonded to the RE3+ ions, whereas in [Pr(H2O)9][B(CN)4]3 · (CH3)2CO ( 3 ), [Er(H2O)8][B(CN)4]3 · (CH3)2CO ( 4 ), and [Lu(EtOH)(H2O)7][B(CN)4]3 · EtOH · 0.5H2O ( 5 ) the [B(CN)4] anions are not coordinated to the central metal atoms. Only in 1 , one of the three crystallographically independent [B(CN)4] anions acts as a bridging ligand.  相似文献   

5.
The reactivity of homoleptic rare‐earth metal aryloxide based Lewis pairs toward organic azide substrates has been investigated herein. Treatment of RE(OAr)3 (RE = La, Sm, Y, and Sc, Ar = 2,6‐tBu2‐C6H3), PEt3 and Me3SiN3 in 2 : 1 : 1 molar ratio resulted in formation of separated ion pair complexes [Me3Si‐PEt3]+[(ArO)3RE‐N=N=N‐RE(OAr)3] under mild conditions. Replacement of phosphine with the nitrogen‐containing Lewis base 1,4‐diazabicyclo[2.2.2]octane (DABCO) produced analogous rare‐earth azide complexes with [Me3Si‐DABCO]+ counterions. In contrast, reaction of the La(OAr)3/PEt3 Lewis pair with 1‐adamantyl azide (AdN3) afforded the typical frustrated Lewis pair‐type 1,1‐addition product. A tetrahydrofuran ring‐opening reaction was also observed for the resulting rare‐earth azide complex with the [Me3Si‐PEt3]+ cation, with cleavage of the C—O bond by Si/P cooperation.  相似文献   

6.
以稀土硝酸盐作为模板,用1,6-己二胺、乙二胺和姜黄素为原料,在乙醇溶液中合成了8种稀土姜黄素大环配合物REL1L2(NO3),·4H2O(RE;Eu、By、Sm、Ce),并由元素分析、1H NMR、摩尔电导、热重-热差分析、红外光谱、紫外-可见吸收光谱等对其进行了结构表征,分析了配合物的热稳定性,研究了配合物在室温下的荧光性质,结果表明配合物表现出相应姜黄素的特征发射.姜黄素和配合物的生物活性测试表明,合成的8种稀土配合物具有抑菌生物活性功能.  相似文献   

7.
An earlier reported series of the [Ln(Ur)4(H2O)4]I3 (Ln = Y, La, Nd, Eu, Gd, Dy, Ho, Er; Ur = urea) complexes was completed with seven new compounds (Ln = Ce, Pr, Sm, Tb, Tm, Yb, Lu); one of them, [Ce(Ur)4(H2O)4]I3, was studied by X‐ray diffraction. The most striking feature of the [Ln(Ur)4(H2O)4]I3 structures is the presence of two types of coordinated urea molecules. There are two planar symmetric and two non‐planar asymmetric urea molecules. The Ln–O–C bond angles vary in the ranges 163.06–165.71° and 148.42–152.42° for symmetric and asymmetric urea ligands, respectively, correlating with the ionic mode of urea coordination. To elucidate the role of aqua ligands for the urea coordination mode, two water‐free perchlorate complexes, [La(Ur)8](ClO4)3 · 2Ur and [La(Ur)7(OClO3)](ClO4)2 were synthesized and structurally characterized. In these complexes, all urea molecules are planar symmetric; however, both covalent and ionic types of urea coordination with the La–O–C bond angles varying in the 132.4–142.3° and 145.5–159.1° ranges, respectively can be observed.  相似文献   

8.
9.
10.
用紫外分光光度法和荧光光谱法研究了多柔比星( Adriamycin,ADM)稀土金属离子配合物(ADM-M)与DNA的相互作用.结果发现,在pH=7.0时,ADM与Eu3+、yb3+能形成稳定配合物,该配合物可使DNA的最大吸收产生明显的减色效应及红移,并能够竞争置换溴化乙锭(EB)与DNA的结合点.KI猝灭试验发现D...  相似文献   

11.
开链冠醚不仅保留了冠醚选择性配合金屆离子的能力,而且具有易合成、产率高、成本低、低毒或无毒等特点,故近年来得到较为广泛的研究,但文献中有关酰胺型开链冠醚及其稀土配合物的报道甚少,本工作是在合成文献中未见报道的三甘双酰-N-甲基苯胺的基础上,制备出它与15种稀土硝酸盐的配合物,并对配合物的组成和性质进行了研究。  相似文献   

12.
A series of isotypic rare‐earth metal pentagermanides including the new compound TbGe5 were prepared by high‐pressure synthesis. They crystallize in the orthorhombic space group Immm [No. 71; a = 395.70(9) pm; b = 611.1(2) pm, and c = 983.6(3) pm for TbGe5]. The crystal structure is isotypic to LaGe5 and consists of puckered germanium slabs, which sandwich a second germanium species and the rare‐earth metal atoms. At ambient pressure, the thermal decomposition of the phases REGe5 (RE = La, Nd, Sm, Gd, and Tb) proceeds via discrete intermediate steps into Ge(cF8) and thermodynamically stable germanium‐poorer phases. The investigated compounds REGe5 are paramagnetic metallic conductors, which order antiferromagnetically at low temperatures. Specific heat measurements reveal that the superconducting state of LaGe5 below Tc = 7.1(1) K is characterized by a critical field of μ0Hc2 = 0.2 T and weak electron‐phonon coupling. Density‐functional based band‐structure calculations yield a very similar electronic structure for all the isotypic REGe5 compounds. Besides a slight increase in the width of the valence band for smaller RE atoms, only minor differences are found for the two different germanium environments.  相似文献   

13.
Junwei Xi  Zhenhua Gu 《中国化学》2020,38(10):1081-1085
Isoplagiochin D is a ring‐strained macrocyclic bisbibenzylis, which showed stable axial chirality in one biaryl structure, and semistable axial chirality in the other biaryl moiety. We reported here an unprecedented example for the catalytically asymmetric synthesis of ring‐strained atropisomers via Pd‐catalyzed macrocyclization between benzyl halides and carbenes. This newly developed Pd‐catalyzed asymmetric macrocyclization protocol enabled us a quick synthesis of isoplagiochin D in a highly enantioselective manner.  相似文献   

14.
首次合成出稀土元素11一钨锌合铝杂多配合物,用元素分析、红外光谱、紫外光谱、X射线光电子能谱和热分析等对合成产物进行了表征。其分子通式为:LnH4[Al(H2O)ZnW11O39]·xH2O(Ln=La,Pr,Nd,Sm)。在此基础上,对其在合成己二酸二(2-乙基己)酯(DOA)中的催化性能进行了研究。结果表明,稀土元素11-钨锌合铝杂多配合物具有较高的催化活性和选择性,且可以重复使用。DOA产品质量高,达到食品包装级。  相似文献   

15.
聚合物稀土配合物兼具稀土离子独特的发光特性和聚合物易加工成型等优点,在平面显示和信息通讯等领域具有巨大的应用潜力,研究开发新型大分子配体以及稀土含量高且荧光强的聚合物稀土配合物材料具有重要意义。本文重点对聚合物稀土配合物发光材料结构设计和合成方法的研究进展进行了综述,并从大分子配体和高分子稀土配合物的结构与发光性能关系...  相似文献   

16.
张武  蔡跃鹏 《合成化学》1999,7(2):112-114
由双乙酰丙酮缩乙二胺与三茂稀土在四氢呋喃溶液中室温下反应,合成了具有通式为(acen)LnCp(Cp=η^5-C5H5,Ln=Y,Nd,Tb,Dy,Er,Yb)的6个新稀土金属有机配合物,这些配合物均经元素分析,IR,MS和^1H NMR表征。  相似文献   

17.
Monocationic bis‐allyl complexes [Ln(η3‐C3H5)2(thf)3]+[B(C6X5)4]? (Ln=Y, La, Nd; X=H, F) and dicationic mono‐allyl complexes of yttrium and the early lanthanides [Ln(η3‐C3H5)(thf)6]2+[BPh4]2? (Ln=La, Nd) were prepared by protonolysis of the tris‐allyl complexes [Ln(η3‐C3H5)3(diox)] (Ln=Y, La, Ce, Pr, Nd, Sm; diox=1,4‐dioxane) isolated as a 1,4‐dioxane‐bridged dimer (Ln=Ce) or THF adducts [Ln(η3‐C3H5)3(thf)2] (Ln=Ce, Pr). Allyl abstraction from the neutral tris‐allyl complex by a Lewis acid, ER3 (Al(CH2SiMe3)3, BPh3) gave the ion pair [Ln(η3‐C3H5)2(thf)3]+[ER31‐CH2CH?CH2)]? (Ln=Y, La; ER3=Al(CH2SiMe3)3, BPh3). Benzophenone inserts into the La? Callyl bond of [La(η3‐C3H5)2(thf)3]+[BPh4]? to form the alkoxy complex [La{OCPh2(CH2CH?CH2)}2(thf)3]+[BPh4]?. The monocationic half‐sandwich complexes [Ln(η5‐C5Me4SiMe3)(η3‐C3H5)(thf)2]+[B(C6X5)4]? (Ln=Y, La; X=H, F) were synthesized from the neutral precursors [Ln(η5‐C5Me4SiMe3)(η3‐C3H5)2(thf)] by protonolysis. For 1,3‐butadiene polymerization catalysis, the yttrium‐based systems were more active than the corresponding lanthanum or neodymium homologues, giving polybutadiene with approximately 90 % 1,4‐cis stereoselectivity.  相似文献   

18.
The reaction of 3‐benzoylcyanomethylidine‐1(H)‐indole‐2‐one ( 1 ) with a variety of active methylene compounds, thioglycolic acid, glycine, hydrazine hydrate and phenyl hydrazine led to the formation of compounds 4a‐d‐10 . 3‐Thiosemicarbazide‐1(H)‐indole‐2‐one 2 on reaction with α‐halocarbonyl compounds gave compounds 11a‐c, 12a‐c . The latter compounds on heating with phosphoryl chloride, cyclization takes place via losing water to give the angular tetracyclic compounds 13a,b and 14a‐c . Cyanoacetic hydrazone derivative 3 readily cyclized upon heating in triethyl orthoformate to give the tricyclic system, oxopyridazino indole 15 . On the other hand, the reaction of 3 with benzylidine malononitrile and benzylidene ethylcyanoactate gave the pyranyl hydrazone derivatives 16a,b .  相似文献   

19.
A series of NCO/NCS pincer precursors, 3‐(Ar2OCH2)‐2‐Br‐(Ar1N?CH)C6H3 ((Ar1NCOAr2)Br, 3a , 3b , 3c , 3d ) and 3‐(2,6‐Me2C6H3SCH2)‐2‐Br‐(Ar1N?CH)C6H3 ((Ar1NCSMe)Br, 4a and 4b ) were synthesized and characterized. The reactions of [Ar1NCOAr2]Br/ [Ar1NCSMe]Br with nBuLi and the subsequent addition of the rare‐earth‐metal chlorides afforded their corresponding rare‐earth‐metal–pincer complexes, that is, [(Ar1NCOAr2)YCl2(thf)2] ( 5a , 5b , 5c , 5d ), [(Ar1NCOAr2)LuCl2(thf)2] ( 6a , 6d ), [(Ar1NCOAr2)GdCl2(thf)2] ( 7 ), [{(Ar1NCSMe)Y(μ‐Cl)}2{(μ‐Cl)Li(thf)2(μ‐Cl)}2] ( 8 , 9 ), and [{(Ar1NCSMe)Gd(μ‐Cl)}2{(μ‐Cl)Li(thf)2(μ‐Cl)}2] ( 10 , 11 ). These diamagnetic complexes were characterized by 1H and 13C NMR spectroscopy and the molecular structures of compounds 5a , 6a , 7 , and 10 were well‐established by X‐ray diffraction analysis. In compounds 5a , 6a , and 7 , all of the metal centers adopted distorted pentagonal bipyramidal geometries with the NCO donors and two oxygen atoms from the coordinated THF molecules in equatorial positions and the two chlorine atoms in apical positions. Complex 10 is a dimer in which the two equal moieties are linked by two chlorine atoms and two Cl? Li? Cl bridges. In each part, the gadolinium atom adopts a distorted pentagonal bipyramidal geometry. Activated with alkylaluminum and borate, the gadolinium and yttrium complexes showed various activities towards the polymerization of isoprene, thereby affording highly cis‐1,4‐selective polyisoprene, whilst the NCO? lutetium complexes were inert under the same conditions.  相似文献   

20.
Four Ln(III) complexes based on a new nitronyl nitroxide radical have been synthesized and structurally characterized: {Ln(hfac)3[NITPh(MeO)2]2} (Ln = Eu( 1 ), Gd( 2 ), Tb( 3 ), Dy( 4 ); NITPh(MeO)2 = 2‐(3′,4′‐dimethoxyphenyl)‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide; hfac = hexafluoroacetylacetonate). The single‐crystal X‐ray diffraction analysis shows that these complexes have similar mononuclear trispin structures, in which central Ln(III) ion is eight‐coordinated by two O‐atoms from two nitroxide groups and six O‐atoms from three hfac anions. The variable temperature magnetic susceptibility study reveals that there exist ferromagnetic interactions between Gd(III) and the radicals, and antiferromagnetic interactions between two radicals (JGd‐Rad = 3.40 cm?1, JRad‐Rad = ?9.99 cm?1) in complex 2 . Meanwhile, antiferromagnetic interactions are estimated between Eu(III) (or Dy(III)) and radicals in complexes 1 and 4 , and ferromagnetic interaction between Tb(III) and radicals in complex 3 , respectively.  相似文献   

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