过渡金属配合物的合成、性质及生物活性研究

金属配合物药物在疾病的治疗中起着重要的作用,过渡金属钴的配合物在药物学、配位化学和生物无机化学学科具有重要的作用。钴是组装配位聚合物时常选用的金属元素,钴离子易与含氮、氧配位原子的配体形成配合物,能与羧基以多种配位方式组成不同类型的配合物。含羧基类配体是常用的有机配体,具有良好的柔韧性,通常能形成结构新颖的配合物。其分子间的弱相互作用,如氢键和π-π堆积作用等,能进一步增强配合物结构的稳定性。因此,用水热法合成了羧酸钴类配合物,通过红外光谱、元素分析手段对配合物进行了表征并对配合物的生物活性进行研究。     

配合物[Cu（L）2][Cu’（L）2]·CH3OH·3H2O的合成和结构表征

以邻氨基苯磺酸与吡啶-2-甲醛进行缩合得到席夫碱配体(KL),然后与Cu(AcO)2.H2O进行配位反应,得到了席夫碱配合物[Cu(L)2][Cu’(L)2].CH3OH.3 H2O,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,P21/c空间群。配合物的一个独立单元由三个晶格水分子、一个晶格甲醇分子和两个不同的单核铜单元构成。有趣的是,这两个单核铜单元的组成完全相同但配位模式不同,它们均由一个铜离子和两个脱质子的席夫碱配体组成,其中一个单核铜单元中的两个磺酸基均参与了配位,另一个则只有一个磺酸基配位。     

镉配合物[Cd（2,2-bipy）（NaN3）2]n的水热合成、晶体结构及热稳定性

在水热法条件下,以N,N-二甲基甲酰胺(DMF)、无水乙醇(EtOH)和水[V(DMF)∶V(EtOH)∶V(H2O)=3∶1∶1]为溶剂,基于2,2-联吡啶(2,2-bipy)、叠氮钠(NaN3)和硝酸镉(Cd(NO3)2.4H2O)合成了一维链状超分子配合物[Cd(2,2-bipy)(NaN3)2]n(1)。晶体结构分析表明:该配合物属于三斜晶系,C2/c空间群,在不对称结构单元中一个镉原子与两个NaN3中的两个氮原子和2,2-bipy中的两个氮原子配位。同时,配合物(1)通过分子间氢键和π—π堆积作用形成三维超分子。晶胞参数:a=1.2167 5(5)nm、b=1.4631(6)nm,c=0.656 5(2)nm,V=1.168 2(8)nm3,Dc=2 005 kg/m3,Z=4,F(000)=688,GooF=1.138,R1=0.023 4,wR2=0.057 4。     

[Ni（IMI）6]（NO3）2的制备与晶体结构

咪唑(IMI)与硝酸镍反应,得到硝酸六咪唑合镍配合物,并培养出单晶。元素分析、红外光谱、X射线单晶衍射等分析表明,该晶体属于单斜晶系,空间群为P21/n,晶胞参数a=1.235 0(3)nm,b=1.235 0(3)nm,c=1.480 0(3)nm,β=90.579(2)°,V=1.955 0(7)nm3,Dc=1.491 g/cm3,Z=4,F(000)=900,R1=0.034 4,wR2=0.095 5。该化合物的分子式为[Ni(IMI)6](NO3)2,是由6个咪唑分子直接与二价镍离子配位,硝酸根离子结合形成的配合物。     

超分子化合物Mn(HPDA)(H2O)4(ClO4)的研究

以吡啶二酸作为配体,合成了分子间形成弱相互作用的锰配合物,即通过氢键连接成了超分子体系并具有新颖的梯状、格子状的三维结构.以元素分析、X-射线单晶衍射、红外光谱、紫外光谱、室温及低温ESR谱对化合物进行了表征.     

配合物Zn(5-硝基-8-羟基喹啉)_2的合成、结构及荧光性质

以4-[(8-羟基-5-喹啉)偶氮]苯磺酸与氯化锌为原料,采用溶剂热法通过原位反应合成标题配合物,并通过X-射线单晶衍射、红外光谱、元素分析和粉末X-射线衍射等方法对其进行了表征。标题配合物中两个5-硝基-8-羟基喹啉与Zn离子配位形成离散结构,通过两种C—H…O氢键将标题配合物连接形成二维层状结构,相邻层之间借助喹啉环间的两种π…π堆积相互作用将二维超分子层状结构沿c轴连接形成了三维超分子网络结构。荧光光谱表明,标题配合物为配体到配体的跃迁,跃迁过程中伴随有分子内电荷转移。     

一维梯状配位聚合物[ZnL（bbi）0.5（H2O）]n的结构及性质研究

一种新的配位聚合物[ZnL(bbi)0.5(H2O)]n(1)(L=3-羧甲基苯甲酸,bbi=1,4-二咪唑丁烷)被合成出来。结构分析表明化合物1结晶于单斜晶系,P21/n空间群,a=0.9674(3)nm,b=0.6294(2)nm,c=2.4918(7)nm,β=96.91(1)°。两种配体与金属离子连接形成一维梯状链,链间通过分子间相互作用形成二维网络结构。化合物1的元素分析,红外光谱,热重分析和荧光性质被表征。     

Eu（ClO4）3-C12H8N2·H2O-C4H8O3N2配合物的制备与表征

在95%乙醇体系中,以高氯酸铕、N-甘氨酰甘氨酸、邻菲啰啉为原料合成了三元晶相配合物,并运用IR光谱法、TG-DSC、紫外光谱法、荧光分析法以及电导法等手段对配合物进行了表征,推测出配合物的分子组成。     

二聚物[Ni2（phen）2（BTC）（H2O）6]·2H2O的水热合成和晶体结构

在水热条件下,成功合成出一例新型镍配位聚合物(CPs),[Ni2(phen)2(BTC)(H2O)6]·2H2O(化合物1,phen=1,10-菲罗啉,BTC=1,2,4,5-均苯四甲酸)。X-射线单晶衍射分析表明,化合物1属于三斜晶系,P1空间群,晶胞参数为ɑ=7.3604(5),b=10.9871(7),c=12.1984(8),α=66.787(6)°,β=76.531(6)°,γ=70.716(6)°,Z=2。结构分析显示化合物1是一个二聚物,并且通过配位水分子和均苯四甲酸配体上的配位原子形成的氢键进一步形成3D的超分子结构。     

[Cu（bpy）（H2O）（mal）]·H2O配合物的拓扑结构及磁性研究

应用溶液法合成标题配合物[Cu(bpy)(H2O)(mal)].H2O(bpy=2,2’-联吡啶,mal=丙二酸)。通过X射线衍射法测定配合物的晶体结构,其晶体学数据如下:三斜,P-1,a=7.132(1),b=10.404(2),c=10.694(2);α=105.85(3)°,β=104.53(3)°,γ=105.28(3)°,V=690.4(2)(3),Dc=1.721 g.cm-3,Z=2。在标题化合物中,中心Cu(Ⅱ)离子配位数为5,构成CuN2O3四方锥配位模式。并对其进行红外光谱、元素分析、粉末X射线衍射、差热、磁性等表征。配合物的3D拓扑分析可简化含有(4,6)-双节点fsc拓扑网络,配合物在2～300 K区间遵循韦斯定理χm(T-0.27)=0.85cm3.K.mol-1,磁性测试结果表明Cu2+离子之间存在铁磁作用。     

Two novel Cd(II)-based coordination polymers constructed from isomeric double betaine ligands: Syntheses,structures and fluorescent properties

Two novel Cd^2 + based coordination compounds based on two isomeric double betaine ligands (1,4-Bis(4-carboxylatopyridinium-1-methylene)benzene (H₂L₁Cl₂) and 1,4-Bis(3-carboxylatopyridinium-1-methylene)benzene (H₂L₂Cl₂)) were synthesized, structurally and optically characterized. Both compounds show two dimensional sheet architectures with different features depending on structural motifs that ranging from helical chain to linear chain, and the spatial arrangements of coordinated ligands as well as their unlike coordination modes. They further exhibit the way how three dimensional supramolecular isomers form via weak interactions. Meanwhile, two compounds exhibit intense fluorescence attributing to the ligands' emissions with stokes shift.     

A novel coordination polymer with double chains structure: hydrothermal syntheses,structures and magnetic properties of [Cu(phen)(H2O)2SO4]n (phen=1,10-phenanthroline)

A coordination polymer [Cu(phen)(H₂O)₂(SO₄)]_n (1) has been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectrum, thermogravimetric analysis, and single crystal X-ray diffraction. This compound displays a novel double chains structure, in which each one-dimensional chain is constituted by the distorted octahedral complex of copper(II) bridged through bidentate sulfate ligands. Magnetic susceptibility measurement of 1 has been performed down to 2 K. Although paramagnetic behavior is dominantly manifested, compound 1 shows a weak antiferromagnetic interaction on cooling from room temperature to 2 K.     

A Novel Approach to the Discovery of Small-Molecule Ligands of CDK2

In an attempt to identify novel small-molecule ligands of cyclin-dependent kinase 2 (CDK2) with potential as allosteric inhibitors, we have devised a robust and cost-effective fluorescence-based high-throughput screening assay. The assay is based on the specific interaction of CDK2 with the extrinsic fluorophore 8-anilino-1-naphthalene sulfonate (ANS), which binds to a large allosteric pocket adjacent to the ATP site. Hit compounds that displace ANS directly or indirectly from CDK2 are readily classified as ATP site binders or allosteric ligands through the use of staurosporine, which blocks the ATP site without displacing ANS. Pilot screening of 1453 compounds led to the discovery of 12 compounds with displacement activities (EC(50) values) ranging from 6 to 44 μM, all of which were classified as ATP-site-directed ligands. Four new type I inhibitor scaffolds were confirmed by X-ray crystallography. Although this small compound library contained only ATP-site-directed ligands, the application of this assay to large compound libraries has the potential to reveal previously unrecognized chemical scaffolds suitable for structure-based design of CDK2 inhibitors with new mechanisms of action.     

XAFS study of Ti-silicalite: structure of framework Ti(IV) in presence and in absence of reactive molecules (H2O,NH3)

X-ray absorption at the Ti K edge (both XANES and EXAFS) of a very pure Ti-silicalite containing a small fraction of Ti(IV) substituting Si(IV), has been performed in order to study the effect of the presence or absence of ligands such as H₂O and NH₃ on the Ti(IV) coordination sphere. In particular, the effect of an outgassing treatment at 400 K and of the interaction with NH₃ has been studied and described in detail. It has been found that the Ti(FV) is fourfold coordinated in the samples outgassed at 400 K and expands its coordination sphere number under the action of adsorbates.     

A rod-spacer mixed ligands MOF [Mn3(HCOO)2(D-cam)2(DMF)2]n as coating material for gas chromatography capillary column

The interest in metal-organic frameworks (MOFs) is rapidly expanding because of their fascinating architectures and intriguing topologies which allowed for potential applications in gas storage, separation, heterogeneous catalysis, and several other areas. As suitable chromatographic separation media, several MOFs have been employed as stationary phase for gas chromatography and high-performance liquid chromatography. In this work we report the use of a mixed ligands rod-spacer MOF [Mn₃(HCOO)₂(D-cam)₂(DMF)₂]_n as coating material for capillary column of gas chromatographic separation of a series of biochemical important compounds having linear alkyl hydrocarbon (aldehyde, alcohol and ester), aromatic hydrocarbon with two phenyls (ether, ester and ester with alcohol) and aromatic hydrocarbon (ester, ester with amino and two esters). The mixture of functional ligands, good thermal and chemical stabilities and host-guest interaction sites of the MOF are attributes to the good efficiency in gas chromatographic separation.     

Synthesis,crystal structure and electrocatalytic activity of discrete and polymeric copper(II) complexes with bitopic bis(pyrazol-1-yl)methane ligands

New coordination copper(II) compounds containing bitopic bis(pyrazol-1-yl)methane ligands, namely 1,1,2,2-tetrakis(pyrazol-1-yl)ethane, 1,4-bis[bis(pyrazol-1-yl)methyl]benzene and 1,4-bis[bis(3,5-dimethylpyrazol-1-yl)methyl]benzene were prepared. Reactions of ligands with Cu^2 + ions in 1:2 ratio gave discrete homodinuclear complexes, while 1:1 ligand-to-metal ratio lead to the formation of coordination polymers. Electrocatalytic activity of compounds in oxygen electroreduction reaction on the surface of modified carbon paste electrode was evaluated.     

Structural diversity in oligonuclear nickel(II) complexes of unsymmetrical compartmental ligands

Coordination chemistry has been used to provide model compounds to simulate the first coordination sphere present at metallobiosites. There is also a synergistic relationship between coordination chemistry and bioinorganic chemistry in that knowledge retrieved from crystallographic studies on metallobiosites can be used to inspire the generation of new chemistry based on the coordination environments at these sites. It is in this aspect that urea has served as a muse for the coordination chemist and some of the resulting bio-inspired chemistry concerning the generation of dinuclear, trinuclear and tetranuclear nickel(II) complexes of unsymmetrical compartmental Schiff base ligands is the subject of this mini-review.     

Cationic Peptides and Their Cu(II) and Ni(II) Complexes: Coordination and Biological Characteristics

Antimicrobial peptides are a promising group of compounds used for the treatment of infections. In some cases, metal ions are essential to activate these molecules. Examples of metalloantibiotics are, for instance, bleomycin and dermcidin. This study is focused on three new pseudopeptides with potential biological activity. The coordination behavior of all ligands with Cu(II) and Ni(II) ions has been examined. Various analytical methods such as potentiometric titration, UV-Vis and CD spectroscopies, and mass spectrometry were used. All compounds are convenient chelators for metal ion-binding. Two of the ligands tested have histidine residues. Surprisingly, imidazole nitrogen is not involved in the coordination of the metal ion. The N-terminal amino group, Dab side chains, and amide nitrogen atoms of the peptide bonds coordinated Cu(II) and Ni(II) in all the complexes formed. The cytotoxicity of three pseudopeptides and their complexes was evaluated. Moreover, their other model allowed for assessing the attenuation of LPS-induced cytotoxicity and anti-inflammatory activities were also evaluated, the results of which revealed to be very promising.     

Supramolecular Coordination Assemblies Using 2-Aminodiacetic Terephthalic Acid Ligands: K[NiII(Hadta)(H2O)2]·H2O and K[Cu 1.5 II (adta)(H2O)1.5]·H2O

Two new network structures, K[Ni^II(Hadta)(H₂O)₂]·H₂O (1) and K[Cu_1.5^II(adta)(H₂O)_1.5]·H₂O (2) which are stabilized by 2-aminodiacetic terephthalic acid ligands have been synthesized and structurally characterized. Supplemental analyses include infrared spectroscopy and CHN analysis. 1 contains mononuclear secondary building units that are linked through potassium counterions and H-bonds to form a 3D network structure. 2 contains a 1D coordination polymer containing Cu^II ions with two different coordination environments. Potassium counterions further network these 1D chain structures.     

Synthesis and crystal structure of scandium(III) and cadmium(II) thiocyanato complexes with dimethylsulfoxide

Two novel complex compounds, molecular fac-[Sc(NCS)₃(DMSO)₃] and polymeric chain [Cd(NCS)_4/2(DMSO)₂]_∞ (DMSO = dimethylsulfoxide), were synthesized and structurally characterized. In both complexes, the metal atoms have octahedral coordination with the NCS⁻ ion serving two different functions: as a terminal ion with the coordination via N in Sc complex and as a bridge ligand with the coordination via N and S in the case of Cd compound, respectively. The DMSO ligands are coordinated by oxygen atoms.