Two tri-spin complexes based on gadolinium and nitronyl nitroxide radicals: Structure and ferromagnetic interactions

Three Radical-Ln(III)-Radical complexes based on nitronyl nitroxide radicals have been synthesized, structurally and magnetically characterized: [Gd(hfac)₃(NITPhOEt)₂] (1) (hfac=hexafluoroacetylacetonate, and NITPhOEt=4′-ethoxy-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), [Gd(hfac)₃(NITPhOCH₂Ph)₂] (2) (NITPhOCH₂Ph=4′-benzyloxy-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) and [Lu(hfac)₃(NITPhOCH₂Ph)₂] (3). The X-ray crystal structure analyses show that the structures of the three compounds are similar and all consist of the isolated molecules, in which central ions Gd^III or Lu^III are coordinated by six oxygen atoms from three hfac and two oxygen atoms from nitronyl radicals. The magnetic studies show that in both of the two Gd^III complexes, there are ferromagnetic Gd^III-Rad interactions and antiferro-magnetic Rad-Rad interactions in the molecules (with J_Rad−Gd=0.27 cm⁻¹, j_Rad-Rad=−2.97 cm⁻¹ for 1: and J_Rad−Gd=0.62 cm⁻¹, j_Rad-Rad=−7.01 cm⁻¹ for 2). An analogous complex of [Lu(hfac)₃ (NITPhOCH₂Ph)₂] (3) containing diamagnetic Lu^III ions has also been introduced for further demonstrating the nature of magnetic coupling between radicals.     

InI3‐ or ZnI2‐Catalyzed Reaction of Hydroxylated 1,5‐Allenynes with Thiols: A New Access to 3,5‐Disubstituted Toluene Derivatives

Transition‐metal‐activated alkynes or allenes can accept nucleophilic attack and undergo direct addition of the nucleophiles to the unsaturated bonds or trigger subsequent rearrangement reactions. This chemistry has witnessed increasing development in recent years. In this report, we have focused on the metal‐catalyzed reactions of a variety of substituted propargyl allenic alcohols and thiophenols using indium(III) and zinc(II) catalysts, which can activate both the alcohol and alkyne. In this reaction, thio groups play the role of a nucleophile and trigger subsequent rearrangements to give benzene derivatives. The products can be further transformed into various 1,3,5‐trisubstituted aromatic compounds by nickel‐catalyzed coupling reactions through the cleavage of the C? S bonds.     

负载型镍基非晶态催化剂催化氯代硝基苯加氢合成氯代苯胺

分别以碳纳米管(CNTs), SiO_2, TiO_2, γ-Al_2O_3, TiO_2-SiO_2和活性炭(AC)为载体(M),以Ni和B为活性组分,采用浸渍-化学还原法制备了一系列负载型Ni-B非晶态合金催化剂(Ni-B/M).采用电感耦合等离子体光谱(ICP), XRD, TEM和DSC研究了Ni-B/CNTs的非晶性质,Ni的担载量及其热稳定性.将Ni-B/M用于催化三种氯代硝基苯液相加氢合成氯代苯胺的反应.结果表明,Ni-B/M在反应中表现出较高的活性和良好的选择性,其中Ni-B/CNTs可使三种氯代硝基苯的转化率均高于99.8%,加氢脱氯率小于3%.讨论了CNTs和Ni-B之间的相互作用对催化剂性能的影响.     

氧化锆布膜中硅含量的火焰原子吸收光谱分析

提出用N2O-C2H2火焰原子吸收光谱法进行镍氢蓄电池材料用氧化锆布膜中硅含量的测定.通过进行分析线、光谱通带宽度、燃烧器高度、灯电流、共存离子的影响等试验表明：该方法具有灵敏度高、选择性好、操作简便、容易掌握、分析周期短等优点.其相对标准偏差均小于1.0%（n=6）.标准加入回收率均为98.3%-100.9%（n=6）范围内.可以作为检测镍氢蓄电池材料用氧化锆布膜中硅含量的一种手段.     

Low-temperature aqueous phase oxidation of cyanide ions with the participation of nickel oxide system

The low-temperature oxidation of cyanide ions to CO₂ and N₂ in an aqueous phase in the presence of Ni-oxide system has been studied. The effect of pH, temperature and catalyst amount on the rate and selectivity of the oxidation process have been investigated. A kinetic model of the reaction studied is proposed based on the experimental results. It can be used to develop a catalytic method for purification of CN containing wastewaters.     

The Nickel‐Catalyzed Carbonylative Cycloaddition of Allyl Halides and Acetylenes: An Efficient Tool for Cyclopentane Annelation

From a practical synthetic point of view, the nickel‐mediated carbonylative cycloaddition of alkynes and allyl halides is a straightforward method for obtaining the cyclopentane skeleton in high yields and with controlled stereochemistry, especially when considering the efficiency of the intermolecular version of the reaction. The efforts to make the previously stoichiometric process catalytic in nickel, after experimental mechanistic observations, are reported herein. The unexpected intervention of iron as a reductant and the isolation of a final dimeric species that exhibits interesting tautomeric behavior are also presented. An extension of the reaction to new substrates has led to the conclusion that, although the steric and electronic effects of the alkyne substituents are generally irrelevant in relation to the adducts and their yields, those of the allylic counterpart may have a significant influence on the outcome of the reaction. However, the presence of the amine moiety in the alkyne completely inhibited the reaction. The feasibility of a multicentered reaction was verified with a triacetylene in which up to 12 bonds were created at once and in good yield.     

Practical Stannylation of Allyl Acetates Catalyzed by Nickel with Bu3SnOMe

A practical and scalable nickel‐catalyzed allylic stannylation of allyl acetates with Bu₃SnOMe is described. A variety of acyclic and cyclic allyl acetates, even with base‐sensitive moieties, undergoes the stannylation by using NiBr₂/4,4′‐di‐tert‐butylbipyridine (dtbpy)/Mn catalyst system to afford highly functionalized allyl stannanes with excellent regioselectivity and yields. Furthermore, the scope of protocol is also extended by the reaction of propargyl acetates, giving rise to propargyl or allenyl stannanes. Additionally, a unique diastereoselectivity using the nickel catalyst different from the palladium was demonstrated for the stannylation of cyclic allyl acetates. In the reaction, inexpensive and stable nickel complexes, abundant reductant (Mn), and atom‐economical stannyl source were used.