基于配合共保护策略合成γ-L-谷氨酰二肽的新方法

提出了一种采用谷氨酸席夫碱Ni(II)配合物共保护L-谷氨酸的α-氨基和α-羧基合成γ-L-谷氨酰二肽的新方法. 首先由手性助剂——2-[N-(N-苄基-脯氨酰)氨基]二苯甲酮(1)、六水合氯化镍和L-谷氨酸反应, 得到谷氨酸席夫碱Ni(II)配合物2, 产率为98.2%; 进而采用二异丙基碳二亚胺(DIC)/1-羟基-苯并三唑(HOBt)复合缩合剂法分别与L-氨基酸3a～3h反应, 得到相应的γ-L-谷氨酰二肽席夫碱Ni(II)配合物4a～4h, 产率为93.1%～99.0%; 最后稀酸水解配合物, 得到γ-L-谷氨酰二肽5a～5h, 产率为73.0%～86.4%, 高收率(92.2%～97.4%)回收手性助剂. 中间产物和终产物的结构经由旋光, 1H NMR, 13C NMR和HRMS表征.     

基于季戊四胺席夫碱的Ni(Ⅱ)和Cu(Ⅱ)配合物的合成、结构及其抑菌活性

以4-甲氧基水杨醛和季戊四胺进行缩合反应得到席夫碱化合物H_4L,然后将配体H_4L分别与Ni(Cl O_4)_2·6H_2O、Cu(Cl O_4)_2在乙醇溶液中进行配位反应,得到2个席夫碱配合物[Ni_2(L)]·DMF(1)和[Cu_4(L)_2(DMSO)_3]·2DMSO(2)。并用元素分析、FT-IR和X射线单晶衍射进行了表征。配合物1和2都属于三斜晶系,P1空间群,配合物1和2都为双核配合物。初步研究了配体和配合物的体外抑菌活性,结果表明,配体及其配合物1和2对金黄色葡萄球菌具有一定的抑菌活性。     

基于季戊四胺席夫碱的Ni(Ⅱ)和Cu(Ⅱ)配合物的合成、结构及其抑菌活性

以4-甲氧基水杨醛和季戊四胺进行缩合反应得到席夫碱化合物 H₄L, 然后将配体H₄L分别与Ni(ClO₄)₂·6H₂O、Cu(ClO₄)₂在乙醇溶液中进行配位反应, 得到2个席夫碱配合物[Ni₂(L)]·DMF (1)和[Cu₄(L)₂(DMSO)₃]·2DMSO (2)。并用元素分析、FT-IR和X射线单晶衍射进行了表征。配合物1和2都属于三斜晶系, P1 空间群, 配合物1和2都为双核配合物。初步研究了配体和配合物的体外抑菌活性, 结果表明, 配体及其配合物1和2对金黄色葡萄球菌具有一定的抑菌活性。     

用密度泛函理论研究两种金属镍席夫碱配合物的电子结构和光谱性质

采用密度泛函理论(DFT),在B3LYP/6-31+G(d)-LANL2DZ水平上,研究了两种Ni(II)的席夫碱配合物1和2基态的几何结构,并在相同水平上进行了频率分析以确认稳定点的性质.基于优化的几何构型,在TDB3LYP/6-31+G(d)-LANL2DZ水平上,采用极化连续介质模型(PCM)在N,N-二甲基甲酰胺溶液中计算了配合物1和2的电子结构和紫外吸收光谱.结果显示,当配体对位上的Br原子被-NO2取代时,配合物的HOMO-LUMO能级差增大,从而导致配合物2的最大吸收波长相对于配合物1的发生蓝移.     

铂配合物与DNA碱基对间相互作用的理论研究

用量子化学方法研究一系列Pt(II)配合物作用于嘌呤碱基N7位点后对Watson-Crick碱基对AT、GC的影响. 计算结果显示铂配体与碱基对AT、GC的作用以静电作用为主，同时极化作用也是影响GC碱基对的重要因素. 静电作用极大地增强了铂化嘌呤碱基与嘧啶碱基间的相互作用，而嘌呤碱基与嘧啶碱基间作用与未铂化碱基对作用相近. Pd(II) 和 Ni(II)的相关研究得到类似的结果. 碱基对间氢键作用“二阶微扰能”分析结果与氢键强弱变化一致.     

不对称二亚胺席夫碱的合成、表征和抗菌活性

用两步法合成了3种不对称二亚胺L,LMe和LCl。起始原料席夫碱2-羟基-N-(5-硝基糠叉)苯胺(SB-NO2)用5-硝基糠醛和2-羟基苯胺反应制得。SB-NO2然后在溶液中被还原为其氨基衍生物SB-NH2。在SB-NH2溶液中分别加入2-羟基苯甲醛,2-羟基-5-甲基苯甲醛和2-羟基-5-氯苯甲醛制得二亚胺化合物L,LMeand LCl。同时还合成了这些配体的Fe(Ⅲ)and Ni(Ⅱ)的二聚和双核配合物。用元素分析、LC-MS、IR、UV-Vis、1H and13C-NMR、TGA、电导率和磁性测量等对二亚胺及其配合物进行了表征,还研究了席夫碱配体及其配合物对5种细菌的抗菌活性。所有化合物对大肠埃布氏菌、枯草芽孢杆菌、小肠结肠炎耶尔森氏菌均有中等强度的活性。Fe(Ⅲ)配合物对绿脓假单胞菌(绿脓杆菌)具有最高活性。     

新型双核镍（Ⅱ）配合物Ni2L2（phen）2的合成及其晶体结构与热稳定性

以邻香草醛缩氨基甲磺酸席夫碱(H2L)和1,10-邻菲啰啉(phen)为配体合成了一种新型双核镍配合物Ni2L2(phen)2(1),其结构经IR,XRD和元素分析表征。1属三斜晶系,P-1空间群,晶胞参数a=14.466(16),b=16.302(17),c=20.335(2),α=67.557 0(10)°,β=87.662(2)°,γ=89.658(2)°,V=4.432 7(8)nm3,Mr=1 000.32,Z=4,Dc=1.499 g.cm-3,μ=1.01 mm-1,R1=0.146 8,ωR2=0.327 9和F(000)=206 4。1中每个Ni(Ⅱ)分别与phen的两个氮原子、L的一个酚羟基氧原子和另一个L的一个氮及两个氧原子配位,形成扭曲的八面体配位构型。1分子间通过氢键及其形成的水簇和π-π堆积形成三维网状结构。1在217.8℃以下比较稳定。     

一种含噻吩基Ni(Ⅱ)配合物的合成及其与DNA的相互作用

以1,10-菲咯啉为原料,经氧化、缩合和络合反应,合成了一种含噻吩基的Ni(Ⅱ)配合物[Ni(phen)2TIP]2+,总收率为38.2%,并用MS和元素分析进行了结构表征。用电子吸收光谱和荧光光谱法研究了该配合物与小牛胸腺DNA的相互作用,其电子吸收光谱的最大吸收峰红移2nm,减色率为15.3%,同时配合物的荧光增强幅度为1.73。这些结果表明,配合物与DNA存在明显的插入结合作用。     

铜(II)蛋氨酸席夫碱配合物EPR波谱研究

Two kinds of new copper(Ⅱ) complexes with methionine Schiff bases have been synthesized respectively. EPR spectra of these complexes in polycrystalline powder and in three organic solvents were investigated at different temperatures. The bonding characterization of these complexes were discussed .The result shows that the in -place bond and the in -place bond in these complexes all play an important role.     

席夫碱锰(Ⅱ)配合物的合成及结构表征

由乙酰丙酮和1R,2R-环己二胺缩合得到N,N’-双(乙酰丙酮)-1R,2R-环己二胺的席夫碱配体L,然后与MnCl2.4H2O进行配位反应,得到了配合物[Mn(L)Cl2]n.nH2O,并用元素分析、FT-IR和X-射线单晶衍射进行了表征。结果表明,配合物属于单斜晶系,空间群P21,晶体学参数:a=9.2719(14),b=18.871(3),c=24.767(4),β=98.346(4),Z=2,Dc=0.854g.cm-3,F(000)=1164,R1=0.1201,wR2=0.2968[Ⅰ>2σ(Ⅰ)]。在配合物中,每个Mn(Ⅱ)的配位环境都是三角双锥,每个Mn(Ⅱ)离子同时与3个配体配位,每个配体L通过其两臂乙酰丙酮亚胺单元的端基氧原子同2个金属离子配位桥连形成二维网状结构。     

Synthesis,Spectroscopic and Electrochemical Studies of Novel Transition Metal Complexes with Quadridentate Schiff Base

A novel quadridentate, N₂O₂ type Schiff base, synthesized from 1,4‐bis‐(o‐aminophenoxy)butane and 2‐hydroxynaphthalin‐1‐carbaldehyde, forms stable complexes with transition metal ions such as Co(II), Cu(II) and Ni(II) in DMF. Microanalytical data, elemental analysis, magnetic measurements, UV‐visible and IR‐spectra as well as conductance measurements were used to confirm the structures. Electrochemical measurements show that metal complexes undergo quasi‐reversible one‐electron redox processes. The voltammetric results also revealed that the CuL complex has the highest electron transfer rate indicating that both the Cu(II) and Cu(I) forms appear in a similar planar configuration, so the electron transfer does not require larger reorganization of the complex.     

Synthesis and characterization of Co(II), Ni(II), Zn(II) and Cu(II) complexes with a new tetraazamacrocyclic Schiff base ligand containing a piperazine moiety: X-ray crystal structure determination of the Co(II) complex

Two macrocyclic Schiff base ligands, L¹ [1+1] and L² [2+2], have been obtained in a one-pot cyclocondensation of 1,4-bis(2-formylphenyl)piperazine and 1,3-diaminopropane. Unfortunately, because of the low solubility of both ligands, their separation was unsuccessful. In the direct reaction of these mixed ligands (L¹ and L²) and the appropriate metal ions only [CoL¹(NO₃)]ClO₄, [NiL¹](ClO₄)₂, [CuL¹](ClO₄)₂ and [ZnL¹(NO₃)]ClO₄ complexes have been isolated. All the complexes were characterized by elemental analyses, IR, FAB-MS, conductivity measurements and in the case of the [ZnL¹(NO₃)]ClO₄ complex with NMR spectroscopy.     

Synthesis and Crystal Structure of a Co(II) Complex with Schiff Base and Imidazole Ligand

1 INTRODUCTION The chemical behavior of metal complexes with Schiff base ligand has attracted much attention be- cause of their catalytic activity in some industrial[1, 2] and biochemical processes[3~5]. As some metal com- plexes have shown the catalytic activity in some polymerization reactions[2, 6], we are recently inte- rested in polymerizartion of organo-silicon com- pounds catalyzed by Schiff base complexes of tran- sition metals. A series of Schiff base complexes have been prepare…     

Synthesis and structural characterization of Ni(II) complexes containing a heterocyclic NO donor ligand

Five novel nickel(II) complexes have been successfully synthesized with a heterocyclic ligand, Opdac, [Ni(Opdac)₂]Cl₂ (1), [Ni(Opdac)₂(CH₃OH)₂]Br₂(CH₃OH)₂ (2), [Ni(Opdac)₂]I₂ (3), [Ni(Opdac)₂NO₃]NO₃ (4) and [Ni(Opdac)₂ClO₄]ClO₄ (5) where Opdac = 4-(1-H-1,3-benzimidazole-2-yl)-1,5-dimethyl-2-phenyl-1-2-dihydro-3-H-pyrazol-3-one. All the complexes were characterized by elemental analysis, molar conductivity, CHN analysis, magnetic susceptibility measurements, spectroscopic studies and TG/DTA methods. In all the complexes, Opdac acts as a bidentate ligand coordinating to Ni(II) ion via the benzimidazole imine nitrogen and the pyrazolone oxygen atoms. The complexes 1 and 3 have a tetrahedral geometry while 2, 4 and 5 have an octahedral geometry around the Ni(II) center.     

Synthesis and Crystal Structure of a Copper(II) Complex with 2,4-Dihydroxybenzylidene Benzoylhydrazone Ligand

1 INTRODUCTION The chemical properties of acylhydrazones Schiff bases and their complexes with some transition metal ions have been intensively investigated in several re- search areas because of their chelating capability and pharmacological applications[1～10]. Intriguingly, the copper(II) complexes are shown to be signifycantly more potent than the metal free chelate, suggesting that the metal complex is the biologically active species. Owing to the biological interest in these types …     

Synthesis and Crystal Structure of Zn(II) Complex with Tridentate Ligand N-(2-Hydroxy-1-naphthylidene)-L-serine

1 INTRODUCTION As the basic building blocks of proteins or enzy- mes, amino acids are versatile ligands showing flexi- ble coordination modes[1]. Recently, researchers have synthesized some metal complexes with amino acids and their derivatives[2～6]. Considerable efforts have been devoted to the preparation and structure of amino acid Schiff base complexes with transition metals[6～11]. In such cases, some Zn(II) complexes have been reported. However, most of them have been carried out…     

Synthesis and spectroscopic studies of novel transition metal complexes with schiff base synthesized from 1,4-bis-(<Emphasis Type="Italic">o</Emphasis>-aminophenoxy)butane and salicyldehyde

The new Co(II), Cu(II), Ni(II) and Zn(II) complexes of potentially N₂O₂ Schiff base ligand [N,N’-bis(salicyldehydene)-1,4-bis-(o-aminophenoxy)butane] (H₂L) prepared from 1,4-bis-(o-aminophenoxy)butane and salicyldehyde in DMF. Microanalytical data, elemental analysis, magnetic measurements, ^lH NMR, ¹³C NMR, UV-visible and IR spectra as well as conductance measurements were used to confirm the structures. In all complexes, H₂L behaves as a tetradentate. The article is published in the original.     

Synthesis,Characterization and Crystal Structures of Four Dinuclear Schiff Base Nickel(II) and Copper(II) Complexes with Versatile Bridging Groups

Four novel Schiff base nickel(II) and copper(II) complexes, derived from the end‐on (μ_1,1‐N₃) azide, end‐to‐end (μ_1,3‐NCS) thiocyanate, or phenolate oxygen bridges, have been synthesized and their crystal structures determined by X‐ray diffraction methods. They are the dinuclear double end‐on azide‐bridged [Ni₂(L1)₂(MeCN)₂(μ_1,1‐N₃)₂]·MeOH ( 1 ), the dinuclear double end‐on azide‐bridged [Ni₂(L2)₂(MeOH)₂(μ_1,1‐N₃)₂][Ni₂(L2)₂(OH₂)₂(μ_1,1‐N₃)₂]·MeOH ( 2 ), the dinuclear double end‐to‐end thiocyanate‐bridged [Cu₂(L3)₂(μ_1,3‐NCS)₂] ( 3 ), and the dinuclear double phenolate O‐bridged [Cu₂(L4)₂(NCS)₂] ( 4 ), where HL1, HL2, HL3 and HL4 are four tridentate Schiff bases obtained by the condensation of 3,5‐dibromosalicylaldehyde with N‐ethylethane‐1,2‐diamine, of 3,5‐dichlorosalicylaldehyde with N‐methylpropane‐1,3‐diamine, of 3‐bromo‐5‐chlorosalicylaldehyde with 2‐aminomethylpyridine, and of 5‐nitrosalicylaldehyde with 2‐aminomethylpyridine, respectively. Each nickel(II) atom in 1 and 2 is in an octahedral coordination, while each copper(II) atom in 3 and 4 is in a square pyramidal coordination. There exists crystallographic inversion centre symmetry in each of the complexes.