酚氧基修饰的AlPS-PVPA固载手性Salen Mn(III)催化剂的合成及催化烯烃不对称环氧化研究

以有机共聚物-无机杂化材料聚（苯乙烯-苯乙烯基膦酸）-磷酸铝（AlPS-PVPA）为载体,酚氧基为连接基团,轴向配位手性salen Mn（Ⅲ）制备了新型固载手性salen Mn（Ⅲ）催化剂,并运用FT-IR,UV-vis,XPS,SEM,TG,元素分析等手段对其进行了表征.以m-CPBA为氧化剂,茚和α-甲基苯乙烯为底物,考察了催化剂对非功能化烯烃不对称环氧化反应的催化性能.结果表明,在相同的条件下,固载催化剂3a~3d在不加助催化剂NMO时显示出了优良的催化活性,其转化率和ee值均比添加了轴向配体NMO时有很大的提高（ee%,99.2 vs.45.9; conv%,98.6 vs.64.6）,这种现象与大多数文献报道相反.此外,催化剂容易分离,且回收使用9次仍能保持较好的催化活性.     

Kinetics and mechanism of (salen)MnIII–catalysed hydrogen peroxide oxidation of alkyl aryl sulphides

The kinetics of (salen)Mn^III complexes catalysed oxidation of aryl methyl and alkyl phenyl sulphides with hydrogen peroxide have been investigated at 25°C in 80% acetonitrile – 20% water spectrophotometrically. The reaction follows first‐order kinetics in (salen)Mn^III complex and zero‐order kinetics in hydrogen peroxide. The order of the reaction with respect to sulphide is fractional and saturation in reaction rate occurs at higher sulphide concentrations. The pseudo first‐order rate constants have been analysed as per Michaelis–Menten kinetics to obtain the values of k₂, the oxidant‐substrate complex decomposition rate constant, and K, the oxidant‐substrate complex formation constant. The effects of nitrogenous bases, free radical inhibitor and changes in solvent composition have also been studied. A suitable mechanism, supported by electronic‐oxidant and electronic‐substrate effect studies, involving a manganese(III)‐hydroperoxide complex as reactive species has been proposed. Copyright © 2007 John Wiley & Sons, Ltd.     

大位阻手性吡咯烷(salen)Mn(III)配合物在烯烃不对称环氧化反应中的应用

设计合成了具有大位阻的手性吡咯烷(salen)Mn(III)配合物Mn3,并研究了其在NaClO水/有机两相氧化体系中催化烯烃的不对称环氧化反应性能。 具有叔胺基团的配合物Mn3具有比Jacobsen催化剂更高的反应活性、以及近似的产率和略高的对映选择性。 尤其是过量CH₃I的加入可以极大地缩短环氧化反应的时间,而高产率和高对映选择性依然保持。     

Salen impregnated silica gel as a new sorbent for on-line preconcentration of cadmium(II)

A new sorbent – salen impregnated silica gel – was prepared and characterised for application as a minicolumn packing for flow-injection on-line preconcentration of cadmium(II). The system was coupled with flame atomic absorption spectrometer (FI-FAAS). The optimal pH for Cd(II) sorption was in the range of 7.4–8.8 and nitric acid (1%, v/v) was efficient as eluent. Sorption was most effective within the sample flow rate up to 7?mL?min^?1. Sorption capacity of the sorbent found in a batch procedure was 26.3?µmol?g^?1 (2.95?mg?g^?1). Enrichment factor (EF) and limit of detection (LOD) obtained for 120-second loading time were 113 and 0.26?µg?L^?1, respectively. The sorbent stability in the working conditions was proved for at least 100 preconcentration cycles. The evaluated method was applied to Cd(II) determination in various water samples.     

A DFT Study on the Mechanism of the Cycloaddition Reaction of CO2 to Epoxides Catalyzed by Zn(Salphen) Complexes

The reaction mechanism for the Zn(salphen)/NBu₄X (X=Br, I) mediated cycloaddition of CO₂ to a series of epoxides, affording five‐membered cyclic carbonate products has been investigated in detail by using DFT methods. The ring‐opening step of the process was examined and the preference for opening at the methylene (C_β) or methine carbon (C_α) was established. Furthermore, calculations were performed to clarify the reasons for the lethargic behavior of internal epoxides in the presence of the binary catalyst. Also, the CO₂ insertion and the ring‐closing steps have been explored for six differently substituted epoxides and proved to be significantly more challenging compared with the ring‐opening step. The computational findings should allow the design and application of more efficient catalysts for organic carbonate formation.     

Convenient Preparation of Chiral trans-9,10-Dihydrophenanthrene-9,10-diamine

Chiral trans-9,10-dihydrophenanthrene-9,10-diamine was conveniently prepared from biphenyl-2,2′-dialdehyde using intramolecular imino pinacol coupling and oxidative cleavage of aminoalcohol as key steps.     

Synthesis and Characterization of a New Dioxime and Its Heterotrinuclear BF2 + Capped Complexes

ω‐Isonitrosoacetophenone 1 Uçan, H. ? and Mirzao?lu, R. 1990. Synth. React. Inorg. Met.‐Org. Chem., 20: 437[Taylor & Francis Online], [Web of Science ®] , [Google Scholar], phenylglyoxime 2 Burakevich, J. V., Lore, A. M. and Volpp, G. P. 1971. J. Org. Chem., 36: 1[Crossref], [Web of Science ®] , [Google Scholar], chlorophenylglyoxime 1 Uçan, H. ? and Mirzao?lu, R. 1990. Synth. React. Inorg. Met.‐Org. Chem., 20: 437[Taylor & Francis Online], [Web of Science ®] , [Google Scholar], dopaminophenylglyoxime 3 Uysal, ?., Co?kun, A., Koç, Z. E., Uçan, M. and Uçan, H. ?. 2007. R. J. Coord. Chem., 33: 351–357. [Crossref] , [Google Scholar] and [(salen/saloph)Fe]₂O 4 Kopel, P., Sindelar, Z. and Klicka, R. 1998. Trans. Met. Chem., 23: 139[Web of Science ®] , [Google Scholar] have been synthesized as described in the literature procedure. [Fe(III)(salen/saloph)dopaminophenylglyoxime)] (starting complexes) have been synthesized from dopaminophenylglyoxime and tetradentate schiff bases which contain dinuclear Fe(III) oxygen‐bridges N,N′‐bis(salicylidene)ethylenediamine (salenH₂) and bis(salicylidene)‐o‐phenylenediamine (salophH₂). The new heterotrinuclear complexes have been obtained from starting complexes and Co(II), Ni(II), Cu(II) salts. Then, heterotrinuclear vic‐dioxime complexes containing BF₂ ⁺ capped have been synthesized. The complexes have been characterized as low‐spin distorted octahedral Fe(III) bridged by o‐hydroxyphenolic groups. The o‐hydroxyphenolic groups play a role as bridges for weak antiferromagnetic intramolecular exchange. The structure of dioxime and its complexes were identified by using elemental analysis, ICP‐AES, ¹H‐NMR and IR spectral data.     

Enantioselective O-acetylcyanation/cyanoformylation of aldehydes using catalysts with built-in crown ether-like motif in chiral macrocyclic V(V) salen complexes

Chiral macrocyclic V(V) salen complexes 1a-f derived from macrocyclic ligands obtained by the reaction of 1R,2R-(−) diaminocyclohexane/(1R,2R)-(+)-1,2-diphenylethylenediamine with bis-aldehydes 2 and 3 were synthesized and used as efficient catalysts in asymmetric cyanation reactions. The V(V) catalysts demonstrated excellent performance (product yields and ees up to 99%) with potassium cyanide (KCN) and sodium cyanide (NaCN). The catalytic system also performed very well with a safer source of cyanide-ethyl cyanoformate to give cyanohydrin carbonates in excellent yield and ee (up to 97%). The V(V) macrocyclic salen complex 1b retained its performance at multi-gram level and was conveniently recycled for a number of times.     

一种有机电致发光材料水杨醛缩乙二胺锌的光电性能表征

合成了一种新型的有机电致发光材料水杨醛缩乙二胺锌[Zn(salen)],并对其结构与性能进行了表征。Zn(salen)具有较高的热稳定性,利用真空热蒸镀的方法很容易制备高质量、无定型薄膜。Zn(salen)的HOMO、LUMO能级及电化学带隙分别为-5.87,-3.41,2.46 eV。在365 nm紫外光的照射下,Zn(salen)粉体具有强的蓝光发射,但其薄膜具有黄光发射。在正向电压的驱动下,器件ITO/CuPc/NPD/Zn(salen)/Al的EL发光峰位于552 nm,是色坐标为x=0.504,y=0.316的黄光发射,器件的启动电压7.5 V,最大亮度301cd/m²,电流效率1.6 cd/A。无论是Zn(salen)薄膜的光致发光还是器件的电致发光,与Zn(salen)粉体相比,都发生了很大的红移现象,这归因于薄膜中Zn(salen)聚集态的形成。     

Post-Modification of Copolymers Obtained by ATRP for an Application in Heterogeneous Asymmetric Salen Catalysis

Copolymers are valuable supports for obtaining heterogeneous catalysts that allow their recycling and therefore substantial savings, particularly in the field of asymmetric catalysis. This contribution reports the use of two comonomers: Azido-3-propylmethacrylate (AZMA) bearing a reactive azide function was associated with 2-methoxyethyl methacrylate (MEMA), used as a spacer, for the ATRP synthesis of copolymers, and then post-functionalized with a propargyl chromium salen complex. The controlled homopolymerization of MEMA by ATRP was firstly described and proved to be more controlled in molar mass than that of AZMA for conversions up to 63%. The ATRP copolymerization of both monomers made it possible to control the molar masses and the composition, with nevertheless a slight increase in the dispersity (from 1.05 to 1.3) when the incorporation ratio of AZMA increased from 10 to 50 mol%. These copolymers were post-functionalized with chromium salen units by click chemistry and their activity was evaluated in the asymmetric ring opening of cyclohexene oxide with trimethylsilyl azide. At an equal catalytic ratio, a significant increase in enantioselectivity was obtained by using the copolymer containing the largest part of salen units, probably allowing, in this case, the more favorable bimetallic activation of both the engaged nucleophile and electrophile. Moreover, the catalytic polymer was recovered by simple filtration and re-engaged in subsequent catalytic runs, up to seven times, without loss of activity or selectivity.