过渡金属盐促进的纳米氢化钠对硝基的还原反应

研究了在过渡金属盐促进下，纳米尺寸的活性氢化钠对硝基化合物的还原反应．结果表明，过渡金属盐的存在，使纳米氢化钠（ＮａＨ＊）的还原活性进一步增强，硝基苯的转化率在较短时间内就超过９０％．镍盐对生成苯胺的选择性最好（１００％），其次是锰盐．不同纳米碱金属氢化物对硝基苯还原的活性和生成苯胺的选择性顺序为ＮａＨ＊＞ＫＨ＊＞ＬｉＨ＊．几种硝基化合物的反应结果表明，ＮａＨ＊－镍盐是硝基还原生成芳胺有效的复合还原剂     

1,1—二甲基—3—丁烯基环戊二烯基稀土二氯化物的合成

１，１－二甲基－３－丁烯基环戊二烯基稀土二氯化物的合成林进张萍王昭煜＊（河北师范大学化学系石家庄０５００１６）关键词烯基环戊二烯基，稀土二氯化物，配合物，合成１９９７－０８－０６收稿，１９９７－１２－０５修回河北省自然科学基金资助课题环戊二烯基轻稀土...     

双负载双金属催化剂催化芳香卤化物水相脱卤的研究

用PVP（聚乙烯吡咯烷酮）配合双金属Pd—Mn后,再负载于PEG400（平均分子量为400的聚乙二醇）官能化的高岭土上,制成双负载双金属催化剂PVP—PdCl2-MnCl2／GLM—PECA00,用于催化不溶于水的芳香卤化物水相脱卤,对芳香氯化物呈现出高的脱氯活性,重复使用六次转化率仍可达到62．14％,通过IR,TEM,XPS的表征对催化剂各组分在催化脱卤中的作用进行了探讨．     

碲氢化钠与苯并咪唑盐的反应和醛的合成新方法

自1975年Barton首次制备了碲氢化钠以来,由于它是一种温和的选择性还原剂和良好的亲核试剂,并具有试剂易得、后处理方便等优点,在有机合成中的应用得到了迅速发展[1-5].例如,Barton等[1]用碲氢化钠对吡啶盐和异喹啉盐的季铵化的碳氮双键在碱性乙醇溶液中还原脱卤能生成加氢衍生物.本文则首次报道碲氢化钠对苯并咪唑盐还原脱卤生成苯并咪唑烷的反应.其合成路线如图示1所示:     

官能化硅胶负载Pd—Cu催化剂的制备及催化芳香氯化物水相脱氯作用

将聚乙烯吡烷酮（PVP）与双金属Pd^2 、Cu^2 配位后,再负载于用平均分子量为600的聚乙二醇（PEG）官能化的硅胶上（SiO2-PEG600),制成一种新型双负载双金属催化剂PVP-PdCl2-CuCl2/SiO2-PEG600,将其用于催化难溶于水的芳香卤化物水相脱卤,在无需加入任何有机溶剂的情况下,对芳香氯化物呈现出高的脱氯活性和选择性,并具有良好的重复使用性能。通过IR、TEM、比表面积测定等手段,探讨了催化剂各组分在催化脱卤中的作用及可能的催化脱卤机理。     

PVP-PdCl2-SnCl4/MontK10-PEG400的制备及催化芳香卤化物水相脱卤研究

用PVP(聚乙烯吡咯烷酮)络合双金属Pd2 ,Sn4 后，再负载于PEG400(平均式量为400的聚乙二醇)官能化的蒙脱土上，制成双金属催化剂PVP-PdCl2-SnCl4/MontK10-PEG400，用于催化不溶于水的芳香卤化物水相脱卤，对芳香氯化物呈现出高的脱氯活性和选择性，并有良好的重复使用性，通过IR，TEM，XPS等手段测定对催化剂各组分在催化脱卤中的作用进行了探讨．     

中国稀土金属有机化学的进展

综述了中国稀土金属有机化学的进展。包括三环戊二烯基稀土配合物，环戊二烯基稀土氯化物，含有稀土碳σ键配合物，稀土有机氢化物，烯丙基稀土配合物，环辛四烯基稀土衍生物，中性芳烃稀土配合物，二价稀土配合物及含过渡金属，稀土异核配合物的合成和结构以及稀土有机化合物催化烯烃氢化、异构化、聚合和在脱卤、脱氧、脱硫等反应中的应用。     

有机卤化物催化脱卤研究的一些新进展

有机卤化物的脱卤反应具有重要合成价值和在治理环境污染上的巨大潜力，人们已提出了许多行之有效的脱卤方法［１］．其中，催化脱卤快速、简便，引起了人们的广泛关注，成为消除有机卤化物造成的环境污染最具吸引力的选择［２，３］．选择适当的催化剂和反应条件，可实现...     

(CH~3OCH~2CH~2C~5H~4)~2Ln(C~5H~5)的合成和反应性能

本文通过双(2-甲氧乙基环戊二烯基)稀土氯化物与环戊二烯基钠在室温下反应, 经升华得新配合物,(CH~3OCH~2CH~2C~5H~4)~2Ln(C~5H~5) (Ln=La,Pr,Nd), 这些配合物都经红外、光电子能谱、质谱、核磁共振谱和元素分析鉴定；并且比较了具有不同配位环境的三茂稀土配合物－氢化钠体系还原1－己烯的活性。     

RExOy.nH2O对氟离子的吸附性能

La、Ce等稀土水含氧化物对阴离子的吸附性早有研究「‘－‘1，但从混合轻稀土氯化物制得的水合氧化物吸附F一的研究报道较少．为探讨难溶金属水合氧化物的除氟性能，本文以混合轻稀土氯化物为原料，制得其水含氧化物（RExOy·nH。O），采用高聚物造粒，研究了粒状RExOy·nH。O对F一的吸附性能及吸附机理．所用混合轻稀土氯化物由包头钢铁稀土公司提供，其主要组成（以氧化物计）为：CeO。（50％）、Nd。O3（25％）、La。O。（15％）、P36Oll（8％）．聚丙烯睛分子量为（2．5～5）X10‘．其它试剂为分析纯．RExO．·nH。O参照文…     

Synthesis of Ln(III) chloride tetraphenylporphyrin complexes

The isolation and identification of the first examples of anhydrous lanthanide chloride tetraphenylporphyrin complexes have been described. The purple complexes were generated by the reaction of dilithiotetraphenylporphyrin bis(dimethoxyethane) with lanthanide trichloride tris(tetrahydrofuran) salts to yield the products in up to 85% yield. The crystal structures for the holmium and ytterbium complexes are also presented.     

How Lanthanide Ions Affect the Addition–Elimination Step of Methanol Dehydrogenases

The recently discovered methanol dehydrogenase, XoxF, is a widespread enzyme used by methylotrophic bacteria to oxidize methanol for carbon and energy, and requires lanthanide ions for its activity. This enzyme represents an essential component of methanol utilization by both methanol- and methane-utilizing bacteria. The present investigation looks on the electronic, energetic and geometrical behavior of the methanol dehydrogenase from Methylacidiphilum fumariolicum SolV, which is strictly dependent on early lanthanide metals with +3 oxidation states, by examining enzyme-substrate complexes of all the lanthanides. We focus on the catalytic reaction mechanism of two methanol dehydrogenases having as cofactor europium and ytterbium belonging to the mid- and later- series of lanthanides, in comparison with the methanol dehydrogenase containing the cerium, one early lanthanide. Our results provide evidence for the influence of the lanthanide contraction effect in all the elementary steps of the catalytic reaction mechanism. This indication may prove useful for developing new catalytic machineries of enzymes that adopt new-to-nature transformations.     

Efficient Synthesis of Functionalized Benzimidazoles and Perimidines: Ytterbium Chloride Catalyzed C?C Bond Cleavage

An efficient method is developed for the synthesis of functionalized benzimidazoles and perimidines by the condensation of aryl diamines with β‐carbonyl compounds catalyzed by ytterbium chloride. The reactions give good yields under mild conditions. A mechanism involving a lanthanide activated C C bond cleavage is proposed.     

Synthesis and structural characterization of a series of lanthanide(II) amides: steric effect of amido ligand

The synthesis and structures of a series of lanthanide(II) and lanthanide(III) complexes supported by the amido ligand N(SiMe3)Ar were described. Several lanthanide(III) amide chlorides were synthesized by a metathesis reaction of LnCl3 with lithium amide, including {[(C6H5)(Me3Si)N]2YbCl(THF)}2.PhCH3 (1), [(C6H3-iPr2-2,6)(SiMe3)N]2YbCl(mu-Cl)Li(THF)3.PhCH3 (4), [(C6H3-iPr2-2,6)(SiMe3)N]YbCl2(THF)3 (6), and [(C6H3-iPr2-2,6)(SiMe3)N]2SmCl3Li2(THF)4 (7). The reduction reaction of 1 with Na-K alloy afforded bisamide ytterbium(II) complex [(C6H5)(Me3Si)N]2Yb(DME)2 (2). The same reaction for Sm gave an insoluble black powder. An analogous samarium(II) complex [(C6H5)(Me3Si)N]2Sm(DME)2 (3) was prepared by the metathesis reaction of SmI2 with NaN(C6H5)(SiMe3). The reduction reaction of ytterbium chloride 4 with Na-K alloy afforded monoamide chloride {[(C6H3-iPr2-2,6)(SiMe3)N]Yb(mu-Cl)(THF)2}2 (5), which is the first example of ytterbium(II) amide chloride, formed via the cleavage of the Yb-N bond. The same reduction reaction of 7 gave a normal bisamide complex [(C6H3-iPr2-2,6)(SiMe3)N]2Sm(THF)2 (8) via Sm-Cl bond cleavage. This is the first example for the steric effect on the outcome of the reduction reaction in lanthanide(II) chemistry. 5 can also be synthesized by the Na/K alloy reduction reaction of 6. All of the complexes were fully characterized including X-ray diffraction for 1-7.     

Lanthanide-sensitized lanthanide luminescence: terbium-sensitized ytterbium luminescence in a trinuclear complex

A heterotrinuclear lanthanide complex has been prepared which contains two terbium ions in DO3A-derived binding sites and a single ytterbium ion in a DTPA-like site. The luminescence properties of the system have been investigated, showing that the terbium remains in a seven-coordinate binding site throughout the synthesis, while the ytterbium occupies the eight-coordinate site. Pumping the 488 nm absorption band of the terbium ion results in energy transfer to ytterbium with emission at 980 nm.     

镧系金属有机配合物研究LX: 含碳、氮稀土金属σ键的稀土金属有机配合物的合成和表征

双(2-甲氧乙基环戊二烯基)氯化镧或氯化镱, 在四氢呋喃中, -20℃下,分别与苯乙炔基钠发生交换反应, 生成双(2-甲氧乙基环戊二烯基)苯乙炔基镧或镱, 产率分别为77%和66%。直接将无水三氯化镱或三氯化钇, 在四氢呋喃中, 冰水冷却下, 与两摩尔的双(三甲基甲硅烷基)氨基锂和2-甲氧乙基环戊二烯基钠进行一锅煮反应, 可得2-甲氧乙基环戊二烯基双(双三甲基甲硅烷基氨基)镱或钇, 产率分别为56%和72%。配合物经元素分析, 红外光谱, 核磁共振氢谱和质谱的鉴定, 它们可能是非溶剂化的, 含分子内配位键的中性单体配合物。     

A high-throughput approach to lanthanide complexes and their rapid screening in the ring opening polymerisation of caprolactone

Libraries of lanthanide complexes supported by nitrogen and oxygen containing ligands have been synthesised using a high-throughput approach. The complexes were employed in the ring-opening polymerisation of epsilon-caprolactone, in some cases giving polycaprolactone of controlled molecular weight and narrow polydispersity. The libraries, based on twenty-one ligands and eight lanthanide reagents, were developed in order to determine the best combination of lanthanide metal and ligand. They were prepared via transamination reactions of [Ln[N(SiMe(3))(2)](3)] complexes with tetradentate dianionic ligands containing oxygen and nitrogen donors. 1H NMR spectroscopy was used to screen polymerisation activity. The steric demand of the ligand has a significant effect on the polymerisation process, as do the type of nitrogen donor and the size of the central Ln(3+) ion. Ligands containing aryl rings with bulky substituents such as tert-pentyl groups afforded species capable of performing controlled polymerisation of caprolactone, whereas less bulky groups such as methyl were not effective. Yttrium and mid-sized lanthanides such as samarium showed increased activity compared with the larger lanthanides, lanthanum and praseodymium, and the smaller lanthanides like ytterbium. X-ray crystal structures of a sterically demanding chelating amine-bis((2-hydroxyaryl)methyl) ligand and a chloride bridged dinuclear gadolinium complex are reported. The centrosymmetric molecule contains gadolinium in distorted capped trigonal prismatic environments bonded to two amine, two phenolate, one THF and two chloride donors.     

Reductive Amination of Carbonyl Compounds over a Ni2P/SiO2 Catalyst in a Flow Mode

Kinetics and Catalysis - The catalytic properties of a nickel phosphide catalyst supported on silica gel in the reductive amination of carbonyl compounds were studied in a flow reactor using...     

Lanthanide reagents in solid phase synthesis

From solid-supported ytterbium(III) catalysts to linkers cleaved by electron transfer from samarium(II) species, lanthanide reagents are beginning to find widespread application in solid phase organic synthesis. This tutorial review introduces the use of lanthanide(III) Lewis acids and lanthanide(IV) oxidants in solid phase chemistry before concentrating on the growing use of lanthanide(II) reagents in the area.     

Synthesis, Reactivity and Crystal Structure of β—Diketiminate Ytterbium Chlorides

Reaction of anhydrous YbCl3 with 1 equiv, of LLi [L=p-ClPhNC(Me)CH(Me)N(C6H3-2,6-i-Pr2)] in THF at room temperature gave the β-diketiminate lanthanide dichloride LYbCl2(THF)2 (1) in good isolated yield. Similarly reaction of anhydrous YbCl3 with 1 equiv, of LLi, then with 1 equiv, of t-BuCpNa in THF yielded the expected mixed-ligand β-diketiminate ytterbium chloride (t-BuCp)YbL(μ-Cl)2Li(THF)2 (2). Both 1 and 2 were well characterized by elemental analysis, IR spectra, ^1H NMR spectra, and X-ray diffraction analysis.