顺磁性聚酯金属配合物的合成及其驰豫性能的研究

本文通过二乙三胺五乙酸（ＤＴＰＡ）或乙二胺四乙酸（ＥＤＴＡ）的双酸酐与二元醇或二元酚进行聚合反应，制备了两个系列共１５种新的聚酯型大分子配体及其顺磁性金属配合物，用核磁、红外光谱以及元素分析表征了配体和配合物的结构。初步试验结果表明，与相应的小分子金属配合物相比，聚酯金属配合物具有较高的弛豫性能。     

STUDY ON SYNTHESIS AND RELAXIVITY OF PARAMAGNETIC POLYESTER METAL COMPLEXES FOR MRI

ＳＴＵＤＹＯＮＳＹＮＴＨＥＳＩＳＡＮＤＲＥＬＡＸＩＶＩＴＹＯＦＰＡＲＡＭＡＧＮＥＴＩＣＰＯＬＹＥＳＴＥＲＭＥＴＡＬＣＯＭＰＬＥＸＥＳＦＯＲＭＲＩＯｕｙａｎｇｍｉｎｇ；ＺｈｕｏＲｅｎｘｉ；ＦｕＧｏｎｇｃｈｅｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒ...     

Synthesis and relaxivity of polyamide paramagnetic metal complexes for magnetic resonance imaging

A new class of paramagnetic macromolecular magnetic resonance imaging contrast agents has been developed. Eight new polyamide ligands were synthesized by copolymerization of ethylenediaminetetraacetic acid dianhydride or diethylenetriaminepentaacetic acid dianhydride and diamine monomers. Their gadolinium(III), manganese(II) and iron(III) complexes were also synthesized. All polyamide ligands and metal complexes were characterized by ¹H nuclear magnetic resonance, infrared spectra and elemental analyses. Relaxivity studies showed that the polyamide paramagnetic metal complexes had obviously higher relaxation effectiveness as compared to corresponding simple monomeric paramagnetic metal complexes.     

聚酯型Gd(Ⅲ)配合物的合成与表征

将二乙三胺五乙酸双酐与五种分子量不同的聚乙二醇共缩聚，制得聚酯型大分子配体，配体与ＧｄＣｌ３·６Ｈ２Ｏ反应，生成相应的配合物，并测试了配合物的弛豫速率．结果表明这些配合物比现用于临床的磁共振成像造影剂Ｇｄ（ＤＴＰＡ）具有更高的弛豫速率．     

大分子聚酯配体及其钆（Ⅲ）配合物的合成和核磁弛豫性能研究

通过二乙三胺五乙酸二酐（ＤＴＰＡＡ）分别与Ｎ－正丁基、正辛基、苄基、对甲苯磺酰基、苯基和对溴苯基取代二乙醇胺共聚，制得一系列大分子配体及其钆（ＩＩＩ）配合物．对所合成的配体和钆配合物进行了表征，并测试了部分钆配合物的核磁弛豫性能．     

Ring opening reactions of pyromellitic dianhydride for the synthesis of first row transition metal dicarboxylate complexes

The ring opening reaction of pyromellitic dianhydride by methanol is an effective method to prepare first row transition metal dicarboxylate complexes. The reactions of different first row transition metal salts with pyromellitic dianhydride in the presence of nitrogen donating bidentate ligands such as 1,10-phenanthroline and 2,2′-bipyridine gives different compositions depending on the ligand and the metal salts used. For example, the reaction of nickel(II) acetate with pyromellitic dianhydride in the presence of 1,10-phenanthroline results in the formation of a carboxylato bridged nickel(II) metallacycle through the ring opening reaction of pyromellitic dianhydride (PAH) at the 1 and 3-positions, whereas a mononuclear tetra-aqua 2,2′-bipyridine nickel(II) complex is formed in a similar reaction of nickel(II) acetate through ring opening at the 1,4-position of PAH. Mononuclear cobalt(II) dicarboxylate complexes are formed from the ring opening reaction of pyromellitic dianhydride in methanol in the presence of the nitrogen donor ligands 1,10-phenanthroline or 2,2′-bipyridine. Copper(II) chloride on reaction with PAH and 2,2′-bipyridine gives a mononuclear complex via ring opening at the 1 and 4-positions; having chlorides inside and outside the coordination sphere. Whereas, the reaction of copper(II)acetate gives dinuclear copper complexes having a monodentate carboxylato bridge arising from the carboxylato groups at the 1 and 4-positions on the aromatic ring. The crystal structures of all the complexes have been determined.     

Mononuclear metal complexes of organic carboxylic acid derivatives: synthesis, spectroscopic characterization, thermal investigation and antimicrobial activity

Two Schiff base ligands bearing organic acid moiety, vis., N-(2-thienylmethylidene)-2-amino-4-chlorobenzoic acid (HL(1)) and N-(2-hydroxybenzylidene)-2-amino-4-chlorobenzoic acid (H(2)L(2)) have been synthesized by the interaction of 2-thiophenecarboxaldehyde and 2-hydroxybenzaldehyde with 2-amino-4-chlorobenzoic acid. Co(II), Ni(II), Cu(II) and Zn(II) complexes of these ligands have been prepared. They are characterized on the basis of analytical data, molar conductance, IR, (1)H NMR, UV-vis, mass spectra, magnetic measurements, thermal analysis and X-ray powder diffraction technique. The molar conductance data reveal that these complexes are non-electrolytes. The ligands are coordinated to the metal ions in a terdentate manner with ONO/ONS donor sites of the carbonyl oxygen, azomethine nitrogen and phenolic oxygen or thiophenic sulphur. An octahedral structure is proposed for the prepared metal complexes and some ligand field parameters (D(q), B and beta) in addition to CFSE were calculated. The thermal stability of the metal complexes is evaluated. The Schiff base ligands and their metal complexes have been tested against four species of bacteria as well as four species of fungi and the results have been compared with some known antibiotics.     

N-（5-氯-2-羟基苄基）氨基酸衍生物及其金属配合物的合成、表征及抑菌活性

以N-（5-氯-2-羟基苄基）氨基酸及其酯为配体,在室温下以水和甲醇为溶剂,采用分步法,以1∶1的摩尔比将配体与金属离子在弱碱性条件下混合,合成了20种未见报道的N-(5-氯-2-羟基苄基)氨基酸类金属配合物。 用核磁、红外和紫外光谱技术对其结构进行了表征。 证明在配合物中配体N-(5-氯-2-羟基苄基)氨基酸的羟基、胺基和羧基均参与了配位。 抑菌测试表明,N-(5-氯-2-羟基苄基)氨基酸类金属配合物的抑菌活性普遍高于其配体,尤其对白色念珠菌的抑菌效果更为明显,均高达100%。 对N-（5-氯-2-羟基苄基）席夫碱氨基酸酯的合成方法进行了优化,得到了较佳的合成工艺条件。     

稀土-氨基多羧酸配合物的配位结构及变化规律I氨基三乙酸(nta)、乙二胺四乙酸(edta)和反式-1,2-环己二胺四乙酸(cydta)系列

本文综述了稀土金属离子与一系列氨基多羧酸配体(如nta(=氨基三乙酸),edta(=乙二胺四乙酸),cydta(=反式-1,2-环己二胺四乙酸),dtpa(=二乙三胺五乙酸)和ttha(=三乙四胺六乙酸)等)形成配合物的分子结构和晶体结构,发现了这些配合物的配位规律和结构变化,说明了稀土金属离子象其它过渡金属离子一样,与氨基多羧酸配体形成配合物的配位数和配位结构取决于稀土金属离子的离子半径,电子结构和配体形状以及配电离子等。     

稀土-氨基多羧酸配合物的配位结构及变化规律的研究 II.二乙三胺五乙酸(dtpa)和三乙四胺六乙酸(ttha)系列

在前文的基础上,本文继续综述了氨基多羧酸类-dtpa和ttha配体与一系列稀土金属离子形成配合物的分子结构和配位结构。发现了dtpa和ttha配体与稀土金属离子的配位规律和结构变化规律。研究结果表明,稀土金属离子与dtpa和ttha配体形成配合物的配位数和配位结构明显地取决于稀土金属离子的离子半径,电子结构和氧化态以及配体的形状。     

Gas-phase ion-molecule reactions of transition metal complexes: the effect of different coordination spheres on complex reactivity

Using a modified quadrupole ion trap mass spectrometer, a series of metal complex ions have been reacted with acetonitrile in the gas phase. Careful control of the coordination number and the type of coordinating functionality in diethylenetriamine-substituted ligands enable the effects of the coordination sphere on metal complex reactivity to be examined. The association reaction kinetics of acetonitrile with these pentacoordinate complexes are followed in order to obtain information about the starting complexes and the reaction dynamics. The kinetics and thermodynamics of acetonitrile addition to the metal complex ions are strongly affected by the chemical environment around the metal center such that significant differences in reactivity are observed for Co(II) and Cu(II) complexes with various coordination spheres. When thiophene, furan, or benzene moieties are present in the coordination sphere of the complex, addition of two acetonitrile molecules is readily observed. In contrast, ligands with better sigma donors react mainly to add one acetonitrile molecule. Among the ligands with good sigma donors, a clear trend in reactivity is observed in which complexes with nitrogen-containing ligands are the least reactive, sulfur-containing complexes are more reactive, and oxygen-containing complexes are the most reactive. In general, equilibrium and reaction rate constants seem to be consistent with the hard and soft acid and base (HSAB) principle. Interestingly, the presence of certain groups (e.g., pyridine and imidazole) in the coordination sphere clearly can change the acid character of the metal as seen by their effect on the binding properties of other functional groups in the same ligand. Finally, we conclude that because complexes with different coordination spheres react to noticeably different extents, ion-molecule (I-M) reactions may be potentially useful for obtaining coordination structure information for transition metal complexes.     

Coordination polymers from polycondensates and metal oxides. II. Effect of water molecules on the reactions of polyesters with Mgo and Zno

Polyester molecules containing free carboxyl end-groups react with MgO and ZnO as polydendate ligands to form donor–acceptor complexes, followed by the increase in molecular weight of the original polyester. The role of water in these coordination reactions was studied. It was demonstrated that the water can catalyze the reactions by promoting an ionization effect. In some case it can coordinate to the metal compound and effectively compete with the other ligands present.     

Simultaneous spectrophotometric determination of atrazine and cyanazine by chemometric methods

Three novel ligands containing pyridine-2,6-dicarboxylic acid unit, trans-4 -(4'-methoxystyryl) pyridine-2,6-dicarboxylic acid, trans-4-(4'-(dimethylamino)styryl)pyridine-2,6-dicarboxylic acid, and trans-4-(4'-(diphenylamino)styryl)pyridine-2,6-dicarboxylic acid were synthesized and their complexes with Eu(III), Tb(III) ions were successfully prepared. The ligands and the corresponding metal complexes were characterized by means of MS, elemental analysis, IR, (1)H NMR and TG-DTA. The luminescence spectra of Eu(III) and Tb(III) complexes in solid state were studied. The strong luminescence emitting peaks at 615 nm for Eu(III) and 545 nm for Tb(III) can be observed. The applications in cell imaging of the europium and terbium complexes were investigated.     

Mass spectrometric studies on pyridine-piperazine-containing ligands and their complexes with transition metals formed in solution

Electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) methods were used to study open-chain piperazine-containing ligands (L) and their complexes formed with transition-metal salts. ESI and MALDI measurements were performed with a Fourier transform ion cyclotron resonance (FT-ICR) and a time-of-flight (TOF) mass spectrometer, respectively. Only singly charged complexes, between one ligand and one or several metal ions, were formed in the ESI measurements. Because the net charge was always one, one or several counterions were attached to the complex. Under ESI conditions, the complexes formed between the ligands and metal (Co, Ni, Cu, and Cd) salts were [L + M + X](+), [L + H + M + X(2)](+) and [L + M(2) + X(3)](+) (M = metal ion, X = counterion). In collision induced dissociation reactions the [L + H + M + X(2)](+) complexes easily eliminated one proton and one counterion. Fragmentation pathways were more dependent on the metal ion than the ligand, and elimination of the second counterion occurred with one proton from copper and nickel complexes and with one proton and one hydrogen from cobalt complexes. Differences in the fragmentation of the complexes could be due to electronic configuration of the metal ion. In the MALDI measurements the ratio between the [L + H](+) and [L - H](+) ions varied with the matrix. Fragmentation of the ligands through elimination of 2-methylpyridine end groups occurred with the aromatic matrices containing carboxylic acid and hydroxyl substituents. Ionization of the complexes was not successful with MALDI as the matrix molecules were also attached to the complexes.     

The effect of ligand donor atoms on ternary complex stability

Formation constants of mixed ligand complexes of Cu²⁺, Zn²⁺, Ni²⁺, Co²⁺, and Mn²⁺,with cyadine-5′-monophosphoric acid (CMP) and various primary ligands such as 1,10-phenanthroline(phen), glycylglycine(glygly) and salicylic acid (sal) have been determined in aqueous solution at 35°C and 0.1 M (KNO₃) by potentiomeric measurements. The acid dissociation constants of all the above mentioned ligands together with their 1 : 1 binary metal complex formation constants were also measured at 35°C. In general all the 1 : 1 binary complexes follow the Irving-Williams order of stability. Further the binary metal complexes of primary ligands are more stable than their ternary complexes with CMP. For ternary complexes, Δ(log K) values seem to change from positive to highly negative as the coordinating atoms of the primary ligands were varied from N,N to N,O^? to O^?O^?. The higher stability of ternary complexes involving phen is due to its Π-bonding interaction with the above metal ions and the relative decrease in the stability of other ternary systems is due to the coulombic repulsion of donor oxygen atoms of primary and secondary ligands. Thus for ternary complexes the stabilities follow a decreasing order of M-phen-CMP > M-glygly-CMP > M-sal-CMP.     

Spectroscopic validation and biological screening of new iron(III) complexes with N,O donor ligands

Monometallic trivalent complexes of iron were synthesized by reaction between N, O type donor ligands (L) or (L′) and metal salt in a 1:2 (metal:ligand) molar ratio. Structure and composition of metal complexes were evaluated by elemental analysis, conductance measurements, magnetic moment measurements, and various spectroscopic studies viz. FTIR, UV–visible, and ESI–MS. Analytical and molar conductance data are consistent with the formulation of complexes as [Fe(L)₂X₂]·X and [Fe(L′)₂X₂]·X (where; L = Hydrazine carboxylic acid ethyl ester, L′ = Hydrazine carboxylic acid tert-butyl ester and X = Cl^?, Br^? or NO₃ ^?) due to their 1:1 electrolytic nature. IR spectral data revealed bi-dentate coordination behavior of ligands. An octahedral geometry may be assigned for metal complexes on the basis of electronic absorption data and magnetic moment parameters. The compounds were evaluated for their biological activity by in vitro antimicrobial screening against bacteria Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Salmonella typhi and fungi Candida parapsilosis and Saccharomyces cerevisiae. The results indicate that metal complexes exhibit more activity than free ligands against studied microbes.     

Metal Complexes Bearing Terminal Borylene Ligands

More and more metal complexes with terminal borylene ligands will be synthesized. Although these ligands in metal complexes must be stabilized either by integration of the boron atom into a polyhedral skeleton ( 1 ) or by B–N π interactions with a bulky amino group ( 2 ), the route to new complexes with terminal RB ligands (R=alkyl, aryl) is clearly indicated.     

Interplay and Competition Between Two Different Types of Redox-Active Ligands in Cobalt Complexes: How to Allocate the Electrons?

The field of molecular transition metal complexes with redox-active ligands is dominated by compounds with one or two units of the same redox-active ligand; complexes in which different redox-active ligands are bound to the same metal are uncommon. This work reports the first molecular coordination compounds in which redox-active bisguanidine or urea azine (biguanidine) ligands as well as oxolene ligands are bound to the same cobalt atom. The combination of two different redox-active ligands leads to mono- as well as unprecedented dinuclear cobalt complexes, being multiple (four or six) center redox systems with intriguing electronic structures, all exhibiting radical ligands. By changing the redox potential of the ligands through derivatisation, the electronic structure of the complexes could be altered in a rational way.     

Complexation of metal ions with TRAP (1,4,7-triazacyclononane phosphinic acid) ligands and 1,4,7-triazacyclononane-1,4,7-triacetic acid: phosphinate-containing ligands as unique chelators for trivalent gallium

Three phosphinic acid 1,4,7-triazacyclononane (TACN) derivatives bearing methylphosphinic (TRAP-H), methyl(phenyl)phosphinic (TRAP-Ph), or methyl(hydroxymethyl)phosphinic acid (TRAP-OH) pendant arms were investigated as members of a new family of efficient Ga(3+) chelators, TRAP ligands (triazacyclononane phosphinic acids). Stepwise protonation constants of ligands and stability constants of their complexes with Ga(3+), selected divalent metal, and Ln(3+) ions were determined by potentiometry. For comparison, equilibrium data for the metal ion-NOTA (1,4,7-triazacyclononane-1,4,7-triacetic acid) systems were redetermined. These ligands exhibit high thermodynamic selectivity for Ga(3+) over the other metal ions (log K(GaL) - log K(ML) = 7-9) and a selective complexation of smaller Mg(2+) over Ca(2+). Stabilities of the Ga(3+) complexes are dependent on the basicity of the donor atoms: [Ga(NOTA)] (log K(GaL) = 29.6) > [Ga(TRAP-OH)] (log K(GaL) = 23.3) > [Ga(TRAP-H)] (log K(GaL) = 21.9). The [Ga(TRAP-OH)] complex exhibits unusual reversible rearrangement of the "in-cage" N(3)O(3) complex to the "out-of-cage" O(6) complex. The in-cage complex is present in acidic solutions, and at neutral pH, Ga(3+) ion binds hydroxide anion, induces deprotonation and coordination of the P-hydroxymethyl group(s), and moves out of the macrocyclic cavity; the hypothesis is supported by a combination of results from potentiometry, multinuclear nuclear magnetic resonance spectrometry, and density functional theory calculations. Isomerism of the phosphinate Ga(3+) complexes caused by a combination of the chelate ring conformation, the helicity of coordinated pendant arms, and the chirality of the coordinated phosphinate groups was observed. All Ga(3+) complexes are kinetically inert in both acidic and alkaline solutions. Complex formation studies in acidic solutions indicate that Ga(3+) complexes of the phosphinate ligands are formed quickly (minutes) and quantitatively even at pH <2. Compared to common Ga(3+) chelators (e.g., 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) derivatives), these novel ligands show fast complexation of Ga(3+) over a broad pH range. The discussed TRAP ligands are suitable alternatives for the development of (68)Ga radiopharmaceuticals.     

1-乙酰胺基丙叉-1,1-二膦酸和1-丙酰胺基乙叉-1,1-二膦酸与碱土金属离子的螯合作用

用pH电位法研究了1-乙酰胺基丙叉-1,1-二膦酸(S-186)和1-丙酰胺基乙叉-1,1-二膦酸(S-106)与碱土金属的螯合作用(30±O.1℃).当金属离子与配体的摩尔浓度比为10∶1、1∶1和1∶2时,在水溶液中形成了MHL、ML、ML_2和M_2L等几种类型的配合物.分别测定了它们的稳定常数,其中S-186配合物稍高于S-106,说明配合物稳定性与螯合剂的碱度有平行关系.值得注意的是,这两种螯合剂与Sr~(2 )形成的双核配合物的稳定性均较其它碱土金属离子的为高.