Towards the rational design of platinum(II) and gold(III) complexes as antitumour agents

Metal complexes afford an opportunity for the discovery of new antitumour drugs with truly novel mechanisms of action. Various tactics and some new concepts have been employed to improve the physico-chemical and biological properties of metal complexes. Recent advances in this area demonstrate a bright prospect for the utilization of metal complexes in cancer chemotherapy. The theme of this article focuses on the approaches towards the rational design of platinum(II) and gold(III) complexes with antitumour properties based on the updated understanding of the mechanism of action of these compounds. The complexes summarized in this work include monofunctional platinum(II) complexes, multinuclear platinum(II) complexes, hybrid and targeted platinum(II) complexes, and gold(III) complexes. Most of them violate the established structure-activity relationships and demonstrate different reactivities from cisplatin and thereby show some potential for the prevention of detoxification.     

Thermal Analysis in Structural Characterization of Hydrazone Ligands and Their Complexes

Results of our research on synthesis and characterization of complexes with acylhydrazone derivatives are described in this review paper. Structural characterization of newly synthesized complexes by thermal analysis (TG, DTA, DSC) is particularly emphasized in this paper. Thermal analysis enabled us to study not only structural changes of substances during thermal treatment, but also the mode of coordination and degree of deprotonation of acylhydrazones, as well as geometry of the coordination sphere of complexes, the structure of which had not been determined by X-ray analysis. Topics in this paper are as follows: complexes of dioxomolybdenum(VI) with tridentate hydrazones, usnic acid derivatives and their Cu(II) complexes, as well as transition metal complexes with 2,6-diacetylpyridine bis(hydrazones). This revised version was published online in July 2006 with corrections to the Cover Date.     

Investigation of the first shot phenomenon in MALDI mass spectrometry of protein complexes

Matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) of noncovalent protein complexes is difficult, due to the disruptive nature of processes occurring during MALDI sample preparation and ion formation. Sometimes the observation of intact noncovalent protein complexes with MALDI is only possible if data are acquired from the first laser shot fired at a fresh sample; this is called the 'first shot phenomenon'. To study the origin of the first shot phenomenon, we used MALDI-MS and confocal laser scanning microscopy (CLSM) to examine typical MALDI sample preparations with embedded protein complexes, labeled with fluorophores. Fluorescence energy transfer techniques allowed the differentiation between intact and dissociated protein complexes with CLSM. In cases where a first shot behavior was observed by MALDI-MS, it was found to be accompanied by localization of protein complexes at the exterior of the sample crystals. Segregation of the large protein complexes to the exterior and dissociation of the complexes in the crystal interior during sample crystallization can rationalize this observation.     

Mechanistic study of beta-hydrogen elimination from organoplatinum(II) enolate complexes

A detailed mechanistic investigation of the thermal reactions of a series of bisphosphine alkylplatinum(II) enolate complexes is reported. The reactions of methylplatinum enolate complexes in the presence of added phosphine form methane and either free or coordinated enone, depending on the steric properties of the enone. Kinetic studies were conducted to determine the relationship between the rates and mechanism of beta-hydrogen elimination from enolate complexes and the rates and mechanism of beta-hydrogen elimination from alkyl complexes. The rates of reactions of the enolate complexes were inversely dependent on the concentration of added phosphine, indicating that beta-hydrogen elimination from the enolate complexes occurs after reversible dissociation of a phosphine. A normal, primary kinetic isotope effect was measured, and this effect was consistent with rate-limiting beta-hydrogen elimination or C-H bond-forming reductive elimination to form methane. Reactions of substituted enolate complexes were also studied to determine the effect of the steric and electronic properties of the enolate complexes on the rates of beta-hydrogen elimination. These studies showed that reactions of the alkylplatinum enolate complexes were retarded by electron-withdrawing substituents on the enolate and that reactions of enolate complexes possessing alkyl substituents at the beta-position occurred at rates that were similar to those of complexes lacking alkyl substituents at this position. Despite the trend in electronic effects on the rates of reactions of enolate complexes and the substantial electronic differences between an enolate and an alkyl ligand, the rates of decomposition of the enolate complexes were similar to those of the analogous alkyl complexes. To the extent that the rates of reaction of the two types of complexes are different, those involving beta-hydrogen elimination from the enolate ligand were faster. A difference between the rate-determining steps for decomposition of the two classes of complexes and an effect of stereochemistry on the selectivity for beta-hydrogen elimination are possible origins of the observed phenomena.     

A complexomic study of Escherichia coli using two-dimensional blue native/SDS polyacrylamide gel electrophoresis

Study of the complexome - all the protein complexes of the cell - is essential for a better understanding and more global vision of cell function. Using two-dimensional blue native/SDS-PAGE (2-D BN/SDS-PAGE) technology, the cytosolic and membrane protein complexes of Escherichia coli were separated. Then, the different partners of each protein complex were identified by LC-MS/MS. In this report, 306 protein complexes were separated and identified. Among these protein complexes, 50 heteromultimeric and 256 homomultimeric protein complexes were found. Among the 50 heteromultimeric protein complexes, 18 previously described protein complexes validate the technology. In this study, 109 new protein complexes were found, providing insight into the function of previously uncharacterized bacterial proteins.     

Chemistry of λ-2H-azaphosphirene metal complexes

In this review, important aspects of λ³-2H-azaphosphirene metal complexes are discussed in relation to synthesis, physical properties and synthetic applications; ab-initio calculations on relative energies of CH₂NP isomers and of λ³-2H-azaphosphirene metal complexes (Cr, Mo, W) are also presented. Currently, there are three routes to this unsaturated three-membered ring system, which are discussed in detail: two of them use a rearrangement of metal carbene complexes, whereas the other relies on [2+1] cycloaddition reactions of electrophilic terminal phosphanediyl complexes and carbonitriles. The structural data show characteristics of a very strained heterocyclic ring system, which partially helps to understand the reactivity of this heterocycle complex in solution. The synthetic potential of λ³-2H-azaphosphirene metal complexes is illustrated by selected examples, which demonstrate their ability to serve, under very mild conditions as precursor for various new building blocks, i.e. nitrilium phosphanylide complexes, electrophilic terminal phosphanediyl complexes and phosphavinyl-nitrene complexes.     

氢键复合物自组装性质的研究

超分子复合物体系因近年来发展较快及应用范围广而颇具吸引力。作为形成超分子复合物的主要手段,氢键自组装对于高分子聚合材料以及生命科学等领域有着重要的意义。本文根据氢键的多重性及不同氢键的缔合方式对氢键复合物进行分类,并对氢键自组装复合物的性质和研究状况作了综述,同时介绍了本研究组在此方面的理论研究工作。     

On the π coordination of organometallic fullerene complexes

Novel organometallic complexes of fullerene C?? and aryl ligands were simulated. The nature and characteristics of this family of complexes involving π coordination between the fullerene and a metal centre have been studied from a theoretical point of view. We are particularly interested in complexes where η? coordination is present, this being the strangest manifestation of known coordinations, and thus we have studied several known and simulated compounds of this kind in order to understand the lack of examples. The presence of other η? or η? ligands on the opposite side seems to be an important element aiding the stabilization of these complexes, also inducing the conductive and semiconductive behaviour of the studied species.     

Qualitative comparison between the quantum calculations and electrospray mass spectra o complexes of polyammonium macrotricyclic ligands with dicarboxylic acids

The host-guest interactions play a very important role in chemical and biological processes. It is therefore important to be able to characterize these complexes. Electrospray mass spectrometry can be used to characterize the complex formation. It provides information on the mass and the charge of these ionic complexes. In this article, we show that the use of ab initio and semiempirical calculations, in addition to the results obtained by electrospray mass spectrometry, reveal to be a promising tool for the study of these noncovalent complexes. In this article, host-guest complexes formed by macropolycyclic polyammonium host molecules and dicarboxylic acids are studied.     

环钯化合物合成及其在催化中的应用

环钯化合物由于丰富的结构、高度的稳定性和卓越的催化性能,已成为钯化学研究的热点之一。迄今已开发出了C-H键活化、氧化加成、转金属化、亲核加成和配体交换等多种方法,可制备出从三元环到十一元环的CY型环钯化合物和多种YCY型环钯化合物。环钯化合物目前已应用于偶联、烯烃氢化和不对称催化等反应中。本文简单介绍了环钯化合物的种类,重点介绍了环钯化合物的合成方法和催化应用情况,最后提出了环钯化合物在今后合成研究和催化应用中的发展建议。     

用于抑制海洋微生物附着的过渡金属配合物研究进展

许多金属配合物具有杀菌、抗病毒和抗癌的活性,在医疗卫生等领域占有重要地位,其生物活性机理也得到了较深入系统的研究.虽然一些过渡金属配合物也在防止海洋微生物附着方面得到应用,但是专门从配位化学和生物无机化学的角度对其进行总结分析的研究还未见报道.以配体的不同类型对这类过渡金属配合物进行分类,简介了其用于防海洋微生物附着的实验室研究和实际应用情况,并对未来研究前景进行了展望.     

The chemistry of tri- and high-nuclearity palladium(II) and platinum(II) complexes

This review gives an overview of the progress on tri- and high-nuclearity palladium(II) platinum(II) complexes and discusses recent developments in the chemistry of these complexes. Three or more square-planar metal atoms can be assembled in several ways resulting into myriad geometric forms of the resulting complexes. These square planes may be sharing a corner, an edge and two edges or even separated by ligands having their donor atoms incapable of forming chelates yielding dendrimers and self-assembled molecules. A variety of ligands have been used to stabilize these complexes. The chemistry of these complexes has been dealt based on nuclearity of the complexes. Synthetic, spectroscopic, structural aspects and applications of these complexes are described in this review.     

Ruthenium-indenylidene complexes: powerful tools for metathesis transformations

Ruthenium-indenylidene complexes represent a class of robust and efficient pre-catalysts for olefin metathesis reactions. In this feature article, we provide an overview of the various complexes belonging to this family and summarise their use in various applications. The relation between the nature of ancillary ligands around the metal coordination sphere of these complexes and their catalytic activity is also discussed.     

A highly active palladium catalyst for intermolecular hydroamination. Factors that control reactivity and additions of functionalized anilines to dienes and vinylarenes

We report a catalyst for intermolecular hydroamination of vinylarenes that is substantially more active for this process than catalysts published previously. With this more reactive catalyst, we demonstrate that additions of amines to vinylarenes and dienes occur in the presence of potentially reactive functional groups, such as ketones with enolizable hydrogens, free alcohols, free carboxylic acids, free amides, nitriles, and esters. The catalyst for these reactions is generated from [Pd(eta(3)-allyl)Cl](2) (with or without added AgOTf) or [Pd(CH(3)CN)(4)](BF(4))(2) and Xantphos (9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene), which generates complexes with large P-Pd-P bite angles. Studies on the rate of the C-N bond-forming step that occurs by attack of amine on an eta(3)-phenethyl and an eta(3)-allyl complex were conducted to determine the effect of the bite angle on the rate of this nucleophilic attack. Studies on model eta(3)-benzyl complexes containing various bisphosphines showed that the nucleophilic attack was faster for complexes containing larger P-Pd-P bite angles. Studies of substituted unsymmetrical and unsubstituted symmetrical model eta(3)-allyl complexes showed that nucleophilic attack on complexes ligated by Xantphos was faster than on complexes bearing ligands with smaller bite angles and that nucleophilic attack on unsymmetrical allyl complexes with larger bite angle ligands was faster than on unsymmetrical allyl complexes with smaller bite angle ligands. However, monitoring of catalytic reactions of dienes by (31)P NMR spectroscopy showed that the concentration of active catalyst was the major factor that controlled rates for reactions of symmetrical dienes catalyzed by complexes of phosphines with smaller bite angles. The identity of the counterion also affected the rate of attack: reactions of allylpalladium complexes with chloride counterion occurred faster than reactions of allylpalladium complexes with triflate or tetrafluoroborate counterion. As is often observed, the dynamics of the allyl and benzyl complexes also depended on the identity of the counterion.     

铱(Ir~Ⅲ)-稀土(Ln~Ⅲ)异核配合物发光性能研究

稀土离子(LnⅢ)丰富的4f电子跃迁能级,使稀土发光材料获得重要而广泛的应用.稀土配合物中天线基团的引入,弥补了稀土离子f-f跃迁禁阻而导致吸收较低的不足.而具有三重态吸收的过渡金属配合物作为天线基团,更使稀土离子的激发窗口红移.相关研究具有重要的理论意义和实际应用价值.本文主要综述近年来有关铱(IrⅢ)-稀土(LnⅢ)异核发光配合物方面的研究进展.     

Elongated dihydrogen complexes: what remains of the H-H bond?

Of the several hundred examples of transition metal dihydrogen complexes that have been reported to date, the vast majority have H-H distances of less than 1.0 Angstrom. A small number of complexes have been reported with distances in the range of 1.1 to 1.5 Angstrom. These complexes have been termed elongated dihydrogen complexes. In this review, experimental methods for structure determination of such complexes are summarized, along with computational approaches which have proven useful in understanding the structures of these molecules.     

Research Progress on the Biological Activities of Metal Complexes Bearing Polycyclic Aromatic Hydrazones

Due to the abundant and promising biological activities of aromatic hydrazones, it is of great significance to study the biological activities of their metal complexes for the research and development of metal-based drugs. In this review, we focus on the metal complexes of polycyclic aromatic hydrazones, which still do not receive much attention, and summarize the studies related to their biological activities. Although the large number of metal complexes in phenylhydrazone prevent them all from being summarized, the significant value of polycyclic aromatic hydrocarbons themselves (such as naphthalene and anthracene) as pharmacophores are also considered. Therefore, the bioactivities of the metal complexes of naphthylhydrazone and anthrahydrazone are focused on, and the recent research progress on the metal complexes of anthrahydrazone by the authors is also included. In terms of biological activities, these complexes mainly show antibacterial and anticancer activities, along with less bioactivities. The present review demonstrates that the structural design and bioactivities of these complexes are fundamental, which also indicates a certain structure—activity relationship (SAR) in some substructural areas. However, a systematic and comprehensive conclusion of the SAR is still not available, which suggests that more attention should be paid to the bioactivities of the metal complexes of polycyclic aromatic hydrazones since their potential in structural design and biological activity remains to be explored. We hope that this review will attract more researchers to devote their interest and energy into this promising area.     

共价双金属配合物在分子导线方面的研究进展

共价双金属配合物因其结构的优越性,在分子器件特别是分子导线的研究方面有广阔的应用前景。分子内电子耦合作用的研究是揭示这类配合物构成的分子导线性能的关键之一。本文介绍了共价双金属配合物的分子内电子耦合作用及此类配合物的结构特点,总结了近年来共价双金属配合物在分子导线领域的研究进展,并对共价双金属配合物的发展前景进行了展望。     

含铋（Ⅲ）配合物的合成及其铋的配位性质

由于金属铋的绿色安全性，其配合物的应用领域不断扩大。因此，从分子水平探索配合物结构具有十分重要的意义。本文主要根据有机配体的不同，对三价铋离子配合物的合成及相应的结构进行分类概括，并针对固态铋配合物，对铋(Ⅲ)离子在各配合物中所处的配位环境以及与配体的配位方式等进行了综述。     

Advances in the coordination chemistry of nitrogen ligand complexes of coinage metals

Coinage metals nitrogen chemistry has not been studied extensively until recently. The focus of this review is the base- and halide-free complexes of the monoanionic nitrogen ligands. This review describes how minor ligand modifications can result in a drastic change in the metal–metal interactions in multinuclear compounds. Crystal structures of these complexes show individual complexes, dimers, supramolecular columnar packing or more complex supramolecular aggregates. Bulky substituents on the ligands can prevent intermolecular metal–metal interactions or the formation of supramolecular architectures. The nuclearity and metal–metal interactions in these complexes are controlled by ligand steric and electronic factors and solvent of crystallization. Many classes of nitrogen ligand coordination compounds have given rise to advances in several fundamental and applied research aspects. Recent potential applications of nitrogen ligand complexes are highlighted particularly for those complexes included in this review.