两个含N-皮考林酰肼铁配合物的合成和结构表征

合成了含N-乙酰皮考林酰肼(简写为Haphz)的铁配合物[Fe₂(aphz)₂(μ-CH₃O)₂Cl₂]·CH₃OH(1,C₁₉H₂₆Cl₂Fe₂N₆O₇,Mr=633.06)和含N-苯甲酰皮考林酰肼(简写为Hphphz)的铁配合物Fe(phphz)Cl₂(2,C₁₃H₁₀Cl₂FeN₃O₂,Mr=366.99).2个配合物均属三斜晶系,空间群为P     

三元体系LaCl3-Am(Am=Gly,Glu,Ser)-H2O(25℃)的研究

测定了3个三元体系LaCl₃-Am-H₂O(Am=Gly,Glu,Ser)在25℃时的溶度和饱和溶液的折光指数。报道了三元体系中生成的三元配合物La(Gly)Cl₃·2H₂O(A₁)、La(Gly)₃Cl₃·3H₂O(A₂)、La₂(Glu)₃Cl₆·8H₂O(C)、La(Ser)Cl₃·3H₂O(E)。用摩尔电导、红外光谱、X射线衍射、热分析及偏光显微镜鉴测定了各配合物的一些物理化学性质。     

利用碳氢键活化合成钴的钳式配合物及其性质研究

利用CoMe(PMe₃)₄或者CoMe₃(PMe₃)₃与[PCP]-钳式配体,[Ph₂P(ortho-C₆H₄)]₂CH₂(1),室温下反应,在实现碳氢键活化的同时,合成了钴的钳式配合物[PCP]Co(I)(PMe₃)(2).配合物2与卤代烃C₆Cl₆, EtBr, n-BuBr以及CH₃I反应,分别生成了单电子氧化加成产物3~5,[PCP]Co(II)X(PMe₃)[X=Cl(3), Br(4), I(5)]. X射线衍射分析测定了配合物2~6的结构.     

用二维核磁共振研究[Co(phen)2(HNAIP)]Cl3配合物与错配及正常寡聚核苷酸的作用

为了开发能识别正常与错配核酸的探针, 首次合成了[Co(phen)₂(HNAIP)]Cl₃金属配合物, 并利用二维核磁研究了此配合物与错配d(CCGAATGAGG)₂及正常d(CCTAATTAGG)₂寡聚核苷酸的相互作用, 首次发现, [Co(phen)₂(HNAIP)]Cl₃是从“大沟”插入到错配碱基对G₃A₄和G₇A₈之间, 能够很好地识别G:A错配; 而[Co(phen)₂(HNAIP)]Cl₃与正常的寡聚核苷酸的作用, 则是从小沟插入, 即[Co(phen)₂(HNAIP)]Cl₃与错配和正常寡聚核苷酸在不同位置及不同沟槽存在明显的插入式结合、并且有明显的差异, 这就有可能被用来作为识别正常与错配寡聚核苷酸的探针.     

聚苯撑乙炔-苯并噻二唑共聚物的合成及光谱性能

利用钯催化剂[Pd(PPh₃)₂Cl₂]和相转移催化剂(PTC), 采用Heck交叉偶联缩聚反应合成了聚(苯撑乙炔撑-苯并噻二唑)系列交替共聚物(PPE-BT), 比较了聚合物的紫外吸收光谱和荧光光谱特征.     

顺-[Pt(NH3)2Cl2]与核苷的作用

用分光光度法研究了37℃、pH=5.5、0.1M NaClO₄介质中cis[Pt(NH₃)₂Cl₂]和DNA组成物--鸟嘌呤核苷、腺嘌呤核苷、胞嘧啶核苷及胸腺嘧啶核苷的作用。发现顺-[Pt^Ⅱ(NH₃)₂]与前三种核苷能生成组成为1:1、1:2二种络合物,与胸腺嘧啶核苷不作用。所测得一级和二级表观生成常数,以及作用初速分别有如下大小次序:Guo>Ado>Cyt》Thy;Guo>Ado>Cyt》Thy.在所得结果基础上讨论了顺-[Pt(NH₃)₂Cl₂]和癌细胞中DNA作用的可能方式。     

金属串配合物(n,m)[Cr3(PhPyF)4Cl2](n=2, 3, 4; m=2, 1, 0)的配位结构及其与电场的关系

应用密度泛函理论BP86 方法研究具有分子导线潜在应用的金属串配合物(n, m)[Cr₃(PhPyF)₄Cl₂](HPhPyF=N, N'-苯基吡啶基甲脒; n=2, 3, 4; m=2, 1, 0)的配位结构及其受电场作用的影响, n、m分别表示PhPyF-的苯环在左侧和在右侧的配体个数. 结果表明: (1) 零电场下, 四个PhPyF-的(2, 2)、(3, 1)和(4, 0)三种配位方式能量差别很小, 为竞争态, (2, 2)最稳定. (4, 0)结构中两端轴向配体Cl 均可与Cr 配位, 且Cl₄―Cr1 键比Cl5―Cr3键更强, 若作为分子器件可与电极结合, 这与(4, 0)[CuCuM(npa)₄Cl][PF₆](M=Pd, Pt; Hnpa=2-萘啶苯胺)靠近苯环一端的轴向配体无法与M配位不同. (2) 在(2, 2)、(3, 1)和(4, 0)中, Cr₃⁶⁺链均具有三中心三电子离域σ键, 但离域性逐渐减弱. 随四个PhPyF-配位方式趋于一致, 分子极性逐渐增大, 由Cl₄指向Cl5(Z)方向, Cr1的α自旋密度增大, Cr2 的β和Cr3 的α自旋密度减小. (3) 分子的几何结构和电子结构在电场下发生规律性变化, 在-Z方向电场作用下, (3, 1)、(4, 0)电子移动方向与极性方向相同, 使分子的键长、自旋密度、电荷和能隙变化显著性均大于Z方向电场, 且极性越大变化越显著, 有利于提高分子导电性.     

铬酸根桥联Cu(Ⅱ)/Ni(Ⅱ)链状配位聚合物的合成及性质

设计合成了2个一维链状铬酸根桥连的配位聚合物(NH₄)₂[Cu(NH₃)₂(CrO₄)₂](1)和(NH₄)₂·[Ni(NH₃)₂(CrO₄)₂](2), 并对其进行了X射线单晶结构分析、 热重-差热分析和多种磁学测试. 晶体结构分析表明, 2个配合物的晶体均属于三斜晶系, 空间群均为P1. 配合物1的晶胞参数为: a=0.59090(12)nm, b=0.6929(3) nm, c=0.73740(15) nm, α=107.03(4)°, β=92.79(3)°, γ=112.44(2)°; 配合物2的晶胞参数为: a=0.56987(7)nm, b=0.69972(9) nm, c=0.73335(8)nm, α=104.929(3)°, β=96.121(3)°, γ=112.325(4)°. 热重分析结果表明, 配合物1和2均在150 ℃左右开始分解, 生成H₂Cr₂CuO₅和H₂Cr₂NiO₅, 在410 ℃以上继续分解, 脱水得到相应的氧化物. 配合物的变温磁化率测试结果表明, 相邻Cu(Ⅱ)离子(配合物1)或Ni(Ⅱ)离子(配合物2)之间存在较弱的反铁磁相互作用; 低温变场和交流磁化率测试结果表明, 2个配合物均为反铁磁体.     

双二苯基-1-甲基咪唑膦氯化镍的制备及其电催化还原CO2的研究

以二苯基-1-甲基咪唑膦（dpim）为配体制备了一种新型的配合物催化剂Ni(dpim)₂Cl₂. 循环伏安研究表明,Ni(dpim)₂Cl₂配合物在氮气气氛下表现出两步还原的电化学行为,在-0.7 V下为两电子的不可逆还原,在-1.3 V下为单电子准可逆还原. 向电解液中通入CO₂后,在-1.3 V下的还原峰变得不可逆,且其峰电流从0.48 mA·cm^-2增大到0.55 mA·cm^-2. 在质子源（CH₃OH）存在的条件下,该还原峰电流可继续增大到0.72 mA·cm^-2. 该研究结果表明,Ni(dpim)₂Cl₂配合物对CO₂还原具有良好的电催化性能,且其电催化还原过程符合ECE机理. 在-1.3 V下恒电位电解得到的还原产物主要为CO,催化转换频率（Turnover of Frenquency, TOF）为0.17 s^-1.     

酚羟基席夫碱钯配合物的合成、表征及其催化性能

以Na₂PdCl₄与(2-NC₅H₄)C(H)=N(C₆H₄OH-2)在不同溶剂中合成了两个钯配合物 Pd{2-(NC₅H₄)C(H)=N[2-（OH）C₆H₄]}Cl₂（Complexe 1）和 Pd{2-(NC₅H₄)C(H)=N[2-(O)C₆H₄]}Cl（Complexe 2）。X射线单晶衍射确定了配合物的分子结构,在配合物1和2中,氯离子的配位个数对所形成的配合物的四边形结构产生一定的影响。两种钯配合物的催化活性通过空气中在醇溶剂体系下4-碘甲苯和苯硼酸的Suzuki-Miyaura反应进行评价。结果显示：催化产物4-甲基联苯的产率可达98.72%和92.31%,副产物联苯的产率小于1.15%,进一步通过配合物的单晶结构数据分析了不同配位模式对催化活性的影响。      

Solution behavior and structural diversity of bis(dialkylphosphino)methane complexes of palladium

The preparation of dipalladium complexes containing sterically nondemanding diphosphine (P-P) ligands of the type R(2)PCH(2)PR(2) where R = Me (dmpm) or Et (depm) is reported. Variable-temperature (1)H NMR spectra of the Pd(I)(2) complexes Pd(2)X(2)(dmpm)(2) (X = Cl, Br, or I; the P-P ligands in the Pd(2) complexes are always bridged, but for convenience, the micro -symbol is omitted) show the complexes to be fluxional in solution, the barriers to a ring-flipping process being DeltaG( double dagger ) = 37.9, 39.0, and 43.2 +/- 0.9 kJ mol(-)(1) for the chloro, bromo, and iodo complexes, respectively. Treatment of Pd(2)X(2)(P-P)(2) (X = Cl or Br) with X(2) generates the stable, face-to-face Pd(II)(2) derivatives trans-Pd(2)X(4)(P-P)(2), while oxidation of Pd(2)I(2)(P-P)(2) complexes with I(2) generates a new type of symmetrically di-iodo-bridged, five-coordinate complexes Pd(2)I(2)(micro -I)(2)(dmpm)(2) and Pd(2)I(2)(micro -I)(2)(depm)(2). The molecular crystal structures of four dipalladium(II) complexes are described: trans-Pd(2)Cl(4)(dmpm)(2).2CHCl(3), trans-Pd(2)Br(4)(dmpm)(2), trans-Pd(2)Cl(4)(depm)(2), and Pd(2)I(2)(micro -I)(2)(dmpm)(2). Solution NMR and UV-vis absorption spectra are consistent with the solid-state structures determined by X-ray diffraction. The stability of the dimeric Pd(II) complexes is attributed primarily to ligand steric factors.     

Synthesis, structural characterization, antimicrobial and cytotoxic effects of aziridine, 2-aminoethylaziridine and azirine complexes of copper(II) and palladium(II)

The synthesis, spectroscopic and X-ray structural characterization of copper(II) and palladium(II) complexes with aziridine ligands as 2-dimethylaziridine HNCH(2)CMe(2) (a), the bidentate N-(2-aminoethyl)aziridines C(2)H(4)NC(2)H(4)NH(2) (b) or CH(2)CMe(2)NCH(2)CMe(2)NH(2) (c) as well as the unsaturated azirine NCH(2)CPh (d) are reported. Cleavage of the cyclometallated Pd(II) dimer [μ-Cl(C(6)H(4)CHMeNMe(2)-C,N)Pd](2) with ligand a yielded compound [Cl(NHCH(2)CMe(2))(C(6)H(4)CHMe(2)NMe(2)-C,N)Pd] (1a). The reaction of the aziridine complex trans-[Cl(2)Pd(HNC(2)H(4))(2)] with an excess of aziridine in the presence of AgOTf gave the ionic chelate complex trans-[(C(2)H(4)NC(2)H(4)NH(2)-N,N')(2)Pd](OTf)(2) (2b) which contains the new ligand b formed by an unexpected insertion and ring opening reaction of two aziridines ("aziridine dimerization"). CuCl(2) reacted in pure HNC(2)H(4) or HNCH(2)CMe(2) (b) again by "dimerization" to give the tris-chelated ionic complex [Cu(C(2)H(4)NC(2)H(4)NH(2)-N,N')(3)]Cl(2) (3b) or the bis-chelated complex [CuCl(C(2)H(2)Me(2)NC(2)H(2)Me(2)NH(2)-N,N')(2)]Cl (4c). By addition of 2H-3-phenylazirine (d) to PdCl(2), trans-[Cl(2)Pd(NCH(2)CPh)(2)] (5d) was formed. All new compounds were characterized by NMR, IR and mass spectra and also by X-ray structure analyses (except 3b). Additionally the cytotoxic effects of these complexes were examined on HL-60 and NALM-6 human leukemia cells and melanoma WM-115 cells. The antimicrobial activity was also determined. The growth of Gram-positive bacterial strains (S. aureus, S. epidermidis, E. faecalis) was inhibited by almost all tested complexes at the concentrations of 37.5-300.0 μg mL(-1). However, MIC values of complexes obtained for Gram-negative E. coli and P. aeruginosa, as well as for C. albicans yeast, mostly exceeded 300 μg mL(-1). The highest antibacterial activity was achieved by complexes 1a and 2b. Complex 2b also inhibited the growth of Gram-negative bacteria.     

Palladium complexes affect the aggregation of human prion protein PrP106-126

Many neurodegenerative disorders are induced by protein conformational change. Prion diseases are characterized by protein conformational conversion from a normal cellular form (PrP(C)) to an abnormal scrapie isoform (PrP(Sc)). PrP106-126 is an accepted model for studying the characteristics of PrP(Sc) because they share many biological and physiochemical properties. To understand how metal complexes affect the property of the prion peptide, the present work investigated interactions between Pd complexes and PrP106-126 based on our previous research using Pt and Au complexes to target the peptide. The selected compounds (Pd(phen)Cl(2), Pd(bipy)Cl(2), and Pd(en)Cl(2)) showed strong binding affinity to PrP106-126 and affected the conformation and aggregation of this active peptide in a different binding mode. Our results indicate that it may be the metal ligand-induced spatial effect rather the binding affinity that contributes to better inhibition on peptide aggregation. This finding would prove valuable in helping design and develop novel metallodrugs against prion diseases.     

Structures and interaction with DNA of ternary palladium(II) complexes: [Pd(Gly)(X)] (Gly=glycine; X=2,2'-bipyridine, 1,10-phenanthroline and 2,2'-bi-pyridylamine)

The structures of the ternary palladium(II) complexes of the formulations [Pd(Gly)(bpy)](+)Cl(-).4H(2)O (Gly=glycine; bpy=2,2'-bipyridine) (1), [Pd(Gly)(phen)](+)Cl(-).4H(2)O (2) (phen=1,10-phenanthroline) and {[Pd(Gly)(bpa)](+)Cl(-)}(2).6H(2)O (3) (bpa=2,2'-bipyridylamine) were determined. All complexes are positively charged and neutralized by the chloride anion located nearby the complexes. The central Pd(II) atoms of the complexes 1, 2 and 3 have a similar distorted square planar coordination geometry, in which each Pd(II) atom is coordinated to two N atoms of the bidentate heterocyclic ligand, and N and O atoms of the bidentate glycine ligand. The interaction of the complexes with calf thymus (CT) DNA was also studied using the fluorescence method. All complexes showed the inhibition of ethidium bromide binding to CT DNA, and the DNA-binding strengths were reflected as the relative order 2>1>3. The remarkable reduction of UV absorption intensity of 2 caused in the presence of DNA suggests the presence of pi-pi stacking interaction between the heterocyclic ring of the phen ligand and nucleobases. The intercalative DNA-binding of 2 is suggested by UV and CD measurements. DNA cleavage studies indicated that the cleavage of the plasmid supercoiled pBR322 DNA in the presence of H(2)O(2) and ascorbic acid could be enhanced by the complexes.     

Control of the coordination structure of organometallic palladium complexes in an apo-ferritin cage

We report the preparation of organometallic Pd(allyl) dinuclear complexes in protein cages of apo-Fr by reactions with [Pd(allyl)Cl]2 (allyl = eta3-C3H5). One of the dinuclear complexes is converted to a trinuclear complex by replacing a Pd-coordinated His residue to an Ala residue. These results suggest that multinuclear metal complexes with various coordination structures could be prepared by the deletion or introduction of His, Cys, and Glu at appropriate positions on protein surface.     

pK(a) coupling at the intein active site: implications for the coordination mechanism of protein splicing with a conserved aspartate

Protein splicing is a robust multistep posttranslational process catalyzed by inteins. In the Mtu RecA intein, a conserved block-F aspartate (D422) coordinates different steps in protein splicing, but the precise mechanism is unclear. Solution NMR shows that D422 has a strikingly high pK(a) of 6.1, two units above the normal pK(a) of aspartate. The elevated pK(a) of D422 is coupled to the depressed pK(a) of another active-site residue, the block-A cysteine (C1). A C1A mutation lowers the D422 pK(a) to normal, while a D422G mutation increases the C1 pK(a) from 7.5 to 8.5. The pK(a) coupling and NMR structure determination demonstrate that protonated D422 serves as a hydrogen bond donor to stabilize the C1 thiolate and promote the N-S acyl shift, the first step of protein splicing. Additionally, in vivo splicing assays with mutations of D422 to Glu, Cys, and Ser show that the deprotonated aspartate is essential for splicing, most likely by deprotonating and activating the downstream nucleophile in transesterification, the second step of protein splicing. We propose that the sequential protonation and deprotonation of the D422 side chain is the coordination mechanism for the first two steps of protein splicing.     

NMR studies of transformations of aminoacid complexes of Pt(II) and Pd(II) in solution. 2. Bisalaninates

Synthetic procedures are suggested for diastereomers of Pt(II) and Pd(II) bischelates with alanine: cis- and trans-Pt(l-Ala)₂ , trans-Pt(l-Ala)fd-Ala), trans-Pd(l-Ala)₂ , and trans-Pd(l-Ala)(d-AIa). Methods of their isolation in individual solid state are proposed.¹H,¹³C, and¹⁹⁵Pt NMR spectral investigations are reported for the individual diastereomers and for M(Ala)₂ racemates in DMSO solution. The trans-isomers of Pd(II) bisalaninates in DMSO solution are transformed into an equilibrium mixture of cis- and trans-isomers. For Pt(II) complexes, the cis ↔ trans equilibrium was also found but the equilibration rate is much lower than that for Pd(II) bischelates for both cis- and trans-isomer. An equilibrium 2M(l-Ala)(d-Ala) ⇌ M(l-Ala)₂+M(d-Ala)₂ is also shown to exist. Translated fromZhurnal Strukturnoi Khimii, Vol. 41, No. 2, pp. 312–323, March–April, 2000.     

Pd(II) complexes of N(4)‐substituted phenylaminoacetohydrazone and biacetylmonooxime: synthesis,characterization, structures and catalytic behaviour towards Suzuki–Miyaura coupling reactions

The reaction of [PdCl₂(CH₃CN)₂] and N(4)‐substituted phenylaminoacetohydrazone ligands (LH) in methanol at room temperature afforded air‐ and moisture‐stable palladium(II) complexes of two types with general formulae [Pd(LH)Cl] and [Pd₂(LH)(L)]Cl. An unusual coordination mode of ligand LH is observed, in which the ligand coordinates through N(4)H nitrogen and without enolization of the carbonyl group of the hydrazone moiety in both mono‐ and bimetallic complexes. The crystal structure of the complexes reveals that the oxime LH reacts with [PdCl₂(CH₃CN)₂] presumably via the elimination of HCl from hydrazine NH. All the synthesized Pd(II) complexes were evaluated as catalysts in the Suzuki cross‐coupling reaction of aryl halides, activated 4‐bromoacetophenone and non‐activated bromobenzene, with phenylboronic acid in aqueous medium. In both cases, i.e. with activated and non‐activated aryl halides, all the complexes show moderate conversion leading to biaryls with yields in the range 50–65%. Copyright © 2016 John Wiley & Sons, Ltd.     

Palladium-catalyzed hydrogenation: detection of palladium hydrides. A joint study using para-hydrogen-enhanced NMR spectroscopy and density functional theory

Pd(PEt3)2(OTf)2, acting as an in situ source of Pd(PEt3)2, reacts with an alkyne and hydrogen via phosphine loss to form the detectable hydride-containing species Pd(PEt3)2(H)(CHPhCH2Ph), cis- and trans-Pd(PEt3)2(H)(CPh=CHPh), and Pd2(PEt3)3(H)(CHPhCH2Ph)2+, which map onto the reaction scheme predicted by density functional theory.