Some Tris[(triorganophosphine)gold(I)]-oxonium and -Organoimonium Tetrafluoroborates with Bulky Substituents

Tris{[tri(2-methylphenyl)phosphine]gold(I)}-, tris{[tri(2,4,6-trimethylphenyl)phosphine]gold(I)}- and tris{[tri(cyclohexyl)phosphine]gold(I)}-oxonium tetra-fluoroborate ( 1?3 ) have been prepared from the corresponding (phosphine)gold(I) chlorides, silver oxide, and sodium tetrafluoroborate in acetone. These oxonium salts are excellent aurating agents for primary amines. Thus in the reaction with 1, t -butylamine ^tBuNH₂ and aniline PhNH₂ are readily converted into the tri nuclear imino complexes {[(2-MeC₆H₄)₃P]Au}₃N^tBu⁺BF₄^? ( 4 ) and {[(2-MeC₆H₄)₃P]Au}₃NPh⁺BF ( 5 ) in high yields. With 3 , both aniline and 8-amino-quinoline also give the tri nuclear complexes, i.e. {[(c-C₆H₁₁)₃P]Au}₃ NPh⁺BF ( 6 ) and {[(c-C₆H₁₁)₃P]Au}₃N(C₉H₆N)⁺BF ( 7 ). Auration of aniline with the most sterically hindered reagent 2 yields only the bi nuclear complex {[2,4,6-Me₃C₆H₂)₃P] · Au}₂N(Ph)H⁺BF ( 8 ). The reagents 1?3 and the Products 4 – 8 have been characterized by analytical and NMR spectroscopic data, and the crystal structures of compounds 4 and 6 have been determined by single crystal x-ray diffraction. In the cations of 4 , a triangle of gold atoms with short Au — Au contacts [3.036(1), 3.107(1), and 3.214(1) Å] forms a steep pyramid with the nitrogen atom, in which the angles Au? N? Au are all much smaller than the tetrahedral standard of 109.7°: 94.8(4), 98.1(4), and 103.0(4)°. This triangular Au₃ unit is staggered relative to the three methyl groups of the ^tBu substituent at nitrogen. The results for 6 are similar [Au — Au: 3.037(1), 3.071(1), and 3.222(1) Å; Au? N? Au: 95.3(3), 96.5(3), and 103.6(3)°]. Variable temperature NMR studies of compounds 3 and 8 show hindered rotation of the mesityl groups about the P? C bonds of the ligands originating from the steric congestion within each tertiary phosphine.     

Complexes of oxamic acid with Au(III) and Rh(III)

The preparation and some properties of the deprotonated complexes of oxamic acid with Au(III) and Rh(III) are reported. On the basis of analytical results, conductometric measurements, magnetic moments and spectral data (IR and UV-visible), a square planar structure is proposed for K[AuL(OH)₂] and octahedral for K₃[RhL ₃] 3H₂O (whereLH₂=oxamic acid).L ^2– acts as a bidentate, non-bridging ligand.

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Komplexe der Oxamidsäure mit Au(III) und Rh(III)

Zusammenfassung Es wird über die Darstellung und einige Eigenschaften von deprotonierten Komplexen der Oxamidsäure mit Au(III) und Rh(III) berichtet. Auf der Grundlage von analytischen Ergebnissen, Leitfähigkeitsmessungen, magnetischen Momenten und IR- und UV(vis)-spektroskopischen Daten wird für K[AuL(OH)₂] eine quadratisch planare und für K₃[RhL ₃] 3 H₂O eine oktaedrische Struktur vorgeschlagen (LH₂=Oxamidsäure).L ^2– reagiert als zweizähniger, nicht überbrückender Ligand.

     

Synthesis, characterization and bromination of bis(phosphinoferrocenyl) gold(I) compounds

Reaction of [(dppf)Au₂Br₂] (3) {dppf = 1,1′-bis(diphenylphosphino)ferrocene} and [(dippf)Au₂Br₂] (4) {dippf = 1,1′-bis(diisopropylphosphino)ferrocene} with excess bromine yields two new complexes [(C₅H₄Br₃)(PR₂)AuBr] (R = Ph, 5; R = i-Pr, 6). Bromination of the free diphosphinoferrocene ligands produces the expected brominated cyclopentenes (C₅H₄Br₃)(PR₂) (R = Ph, 7; R = i-Pr, 8) in good yields; however, these compounds could not be complexed to gold due to reduced basicity of 7 and 8. When the bromination is performed under wet aerobic conditions the oxidized pseudo-centrosymmetric product, [doppf][FeBr₄] (9) {doppf = 1,1′-bis(oxodiphenylphosphino)ferrocene, is formed as the major product. Solid-state structures of 1, 2, 4, 6, and 9 have been established by means of single-crystal X-ray crystallography.     

Crystal structures,DNA-binding ability and influence on cellular viability of gold(I) complexes of thiosemicarbazones

The present study reports the synthesis and crystal structure of four novel gold(I) complexes with di-2-pyridyl ketone N(4)-ethylthiosemicarbazone (L¹) and 2-acetylfuran-4-methyl-3-thiosemicarbazone (L²). All the gold(I) complexes were observed with monodentate thiosemicarbazones and exhibited gold(I) ions with linear geometries, bound to a sulfur atom of the ligand and a halogen ion (Br^? or Cl^?). The crystal structures of gold complexes with Br^? and thiosemicarbazone are the first examples reported. Interestingly, 2[AuBr(HL¹)]2Br was observed to have a Au?Au length of 3.155(8) Å, and this distance suggests an unusual Au?Au interaction in the solid state. The ability of the thiosemicarbazones and the corresponding gold(I) complexes to bind to DNA was studied by UV-vis and emission spectroscopy. The effect on cell viability of the compounds was evaluated against human breast cancer cell lines. The results show that the gold(I) complexes exhibit more potent inhibition of tumor growth than the free ligands.     

Crystal structure and cytotoxic activities of a bis(pyrrolyl-imine) gold(III) complex

A gold(III) complex with N,N′-ethylenebis(pyrrol-2-yl-methyleneamine) (H₂pyren) was synthesized and characterized by physicochemical and spectroscopic measurements. Density functional theory (DFT) studies and cytotoxic assays were performed. Infrared, mass spectrometry, and ¹H, ¹³C, and {¹⁵N,¹H} nuclear magnetic resonance analyses indicate that pyren is deprotonated and gold(III) is four coordinate in a square planar environment, with the pyrrole and imine nitrogens as donors. The structure was confirmed by powder X-ray diffraction and confirmed as a minimum of the potential energy surface by DFT. Cytotoxic activity of [Au(pyren)]⁺ was active against three tumorigenic cell lines with IC₅₀ values of 35 μM. Interaction studies with CT-DNA by fluorescence and competition with ethidium bromide (EB) showed a quenching of the emission band of DNA with a Stern–Volmer quenching constant value of (3.0 ± 0.1) × 10⁴ M^?1 and a decrease in fluorescence quenching of EB-DNA system, respectively, confirming that DNA is a possible target for the complex via an intercalative binding, which was confirmed by DNA conformational changes observed with circular dichroism spectroscopy.     

单核Mn(III)-Shiff碱配合物的晶体结构与性质

报导了两个Schiff碱配体的单核Mn（Ⅲ）配合物（[Mn（Ⅲ）（L1）（H2O）］4CIO。·ZH。O（1）和［Mn（ffi）（LZ）厂Ic。·ZH。O（2》的合成、晶体结构及性反X一衍射晶体结构分析证实：配合物1的晶体属于正交晶系，Pna21空间群．其晶胞参数为α＝10．932（7）A，b＝22．393（5）A，c＝8．960（3）A，V=2193（1）A3，Z＝4．2的晶体属于正交晶系，P212121空间群，α＝17．345（3）A，b＝17．905（2）A，c=7．789（1）A，V＝2418．9（6）A3，Z=4．电化学研究结果显示：配合2是稳定的电化学产物，而1在电场作用下容易歧化．由此说明配位环境是影响化合物稳定性的重要因素．     

X‐Ray Crystal Structures and Quantum Chemical Calculations of Tetraphenyl‐arsonium Tetraazidoaurate(III) and Azido(triphenylphosphine)Gold(I)

The single crystal X‐ray structure determinations are reported for [Ph₄As][Au(N₃)₄] ( 1 ) and Ph₃PAuN₃ ( 2 ). Compound 1 is an ionic species with a “windmill” shaped anion. It crystallizes in the monoclinic space group C2/c, a = 18.396(2), b = 6.2492(4), c = 23.555(2) Å; β = 107.98(1)°, Z = 4, R1_{(all data)} = 0.0227, wR2 = 0.0374. The lattice parameters of compound 2 , which crystallizes in the orthorhombic space group P2₁2₁2₁, are a = 10.9252(1), b = 11.5642(1), c = 13.0993(1) Å; Z = 4, R1_{(all data)} = 0.0176, wR = 0.0334. The experimentally obtained X‐ray data and vibrational frequencies of both compounds were compared with those calculated at B3LYP/LANL2DZ and B3LYP/SDD level of theory and for 1 also at the MP2/SDD level.     

Unveiling the Potential of Innovative Gold(I) and Silver(I) Selenourea Complexes as Anticancer Agents Targeting TrxR and Cellular Redox Homeostasis

A series of NHC-based selenourea Ag(I) and Au(I) complexes were evaluated for their anticancer potential in vitro, on 2D and 3D human cancer cell systems. All NHC-based selenourea complexes possess an outstanding cytotoxic potency, which was comparable or even better than that of the reference metallodrug auranofin, and were also able to overcome both platinum-based and multi-drug resistances. Intriguingly, their cytotoxic potency did not correlate with solution stability, partition coefficient or cellular uptake. On the other hand, mechanistic studies in cancer cells revealed their ability to strongly and selectively inhibit the redox-regulating enzyme Thioredoxin Reductase (TrxR), being even more effective than auranofin, a well-known TrxR inhibitor, without affecting other redox enzymes such as Glutathione Reductase (GR). The inhibition of TrxR in H157 human cancer cells caused, in turn, the disruption of cellular thiol-redox homeostasis and of mitochondria pathophysiology, ultimately leading to cancer cell death through apoptosis.     

Copper(I) and silver(I) complexes of bridging bis(quinaldinyl)phenylphosphine oxide ligand

Abstract

A novel tertiary phosphine oxide containing two quinaldinyl substituents has been synthesized according to adapted literature procedures. Its coordination properties toward Cu(I) and Ag(I) were investigated and the resulting complexes were analyzed by single crystal X-ray diffraction. Multinuclear complexes are formed, wherein the ligand is bridging across two metal centers. Though for the silver complex, no argentophilic interactions are present. The copper complex was characterized further by multinuclear NMR spectroscopy at variable temperatures.     

Über Tris[(trialkylphosphan)gold(I)]oxonium-tetrafluoroborate und Tris[(triphenylphosphan)gold(I)]sulfonium-tetrafluoroborat

On Tris[(trialkylphosphine)gold(I)]oxonium Tetrafluoroborates and Tris[(triphenylphosphine)gold(I)]sulfonium Tetrafluoroborate [Et₃PAu]⁺BF, obtained from Et₃PAuCl and AgBF₄ in tetrahydrofuran, reacts with KOH (molar ratio 3:1) to give the oxonium salt [(Et₃P)Au]₃O⁺BF ( 1 ). The homologous [^t(Bu₃P)Au]₃O⁺BF ( 2 ) is generated similarly from ^tBu₃PAuCl and Ag₂O in the presence of NaBF₄ in THF. The composition and identity of these two first tris[(tri alkyl phosphine)gold(I)]oxonium salts have been confirmed by analytical and spectroscopic data. The compounds are useful aurating agents. From the corresponding triphenylphosphine complex and (Me₃Si)₂S quantitative yields of the sulfonium salt [(Ph₃P)Au]₃S⁺BF ( 3 ) are obtained. Its crystal structure features monomeric cations, and in these small Au? S? Au angles indicate significant metal-metal bonding.     

Preparation of Palladium(II) and Platinum(II) Phosphine Complexes Promoted by Phase-Transfer Catalysts

The synthesis of M(PR₃)₂Cl₂ (M = Pd and Pt, R = alkyl or aryl) front K₂MCl₄ (in H₂O) and PR₃ (in CH₂Cl₂) was promoted by the addition of phase-transfer catalysts (PTC). The greater the amount of PTC used, the more quickly the reaction completed. ³¹P NMR spectra of some M(PR₃)₂Cl₂ in the presence of free PR₃ were measured; these NMR resulls were used to explain problems encountered during the preparations.     

Mononuclear Fe(III) and tetranuclear [Fe(III)Gd(III)]2 complexes with a Schiff-base ligand derived from the o-vanillin: Synthesis, crystal structures and magnetic properties

The mononuclear high-spin iron(III) complexes [Fe(3-MeOsalpn)Cl(H₂O)] (1) and [Fe(3-MeOsalpn)(NCS)(H₂O)]·0.5CH₃CN (2) and the tetranuclear oxo-bridged compound [{Fe(3-MeOsalpn)Gd(NO₃)₃}₂(μ-O)]·CH₃CN (3) [3-MeOsalpn²⁻ = N,N′-propylenebis(3-methoxysalicylideneiminate)] have been prepared and magneto-structurally characterised. The iron(III) ion in 1 and 2 is six-coordinated in a somewhat distorted octahedral surrounding with the two phenolate-oxygens and two imine-nitrogens from the Schiff-base building the equatorial plane and a water (1 and 2) and a chloro (1)/thiocyanate-nitrogen (2) in the axial positions. The neutral mononuclear units of 1 and 2 are assembled into centrosymmetric dinuclear motifs through hydrogen bonds between the axially coordinated water molecule of one iron centre and methoxy-oxygen atoms from the Schiff-base of the adjacent iron atom. The values of the intradimer metal-metal distance within the supramolecular dimers are 4.930 (1) and 4.878 Å (2). The tetranuclear of 3 can be described as two {Fe^III(3-MeOsalpn)} units connected through an oxo-bridge, each one hosting a [Gd^III(NO₃)₃] entity in the outer cavity defined by the two phenolate- and two methoxy-oxygen atoms. The values of the intramolecular Fe?Fe and Fe?Gd distances in 3 are 3.502 and 3.606 Å, respectively. The analysis of the magnetic data of 1-3 in the temperature range 1.9-300 K shows the occurrence of weak intermolecular antiferromagnetic interactions in 1 and 2 [J = −0.76 (1) and −0.75 cm⁻¹ (2) with the Hamiltonian defined as H = −JS_Fe1·S_Fe1] whereas two intramolecular antiferromagnetic interactions coexist in 3, one very strong between the two iron(III) ions (J₁) through the oxo bridge and the other much weaker between the iron(III) and the Gd(III) ions (J₂) across the double phenoxo oxygens [J₁ = −275 cm⁻¹ and J₂ = −3.25 cm⁻¹, the Hamiltonian being defined as H=-J₁S_Fe1·S_Fe1^′-J₂(S_Fe1·S_Gd1+S_Fe1^′·S_Gd1^′)]. These values are analysed in the light of the structural data and compared with those of related systems.     

Syntheses and Crystal Structures of Silver(I) Complexes by Depolymerizing [Ag(C(CPh)]n with a NP3 Ligand

Two silver(I) complexes were prepared by the reaction of [Ag(C(CPh)]n with NP3 [NP3 = N(CH2CH2PPh2)3] or with NP3 and [Cu(CH3CN)4]ClO4. Complex 1 [(Ag2Cl(NP3)2)(Ag5(C(CPh)6)] contains both NP3 and PhC(C- ligands. The complex cation is (Ag2Cl(NP3)2)+, in which two Ag(NP3)+ cations were bridged by a Cl- donor. The anion is (Ag5(C(CPh)6)-, where five Ag+ ions are linked by six C(CPh- to form a pentanuclear cluster. Complex 2 only contains NP3 ligand, where the silver center adopts a trigonal-bipyramidal geometry. Crystal data for 1: C133H116Ag7Cl3N2P6, Mr = 2789.54, triclinic, space group P, a = 13.0780(2), b = 15.3678(2), c = 31.2041(3) (A), α = 91.3928(7), β = 90.9328(8), γ = 96.0244(4)o, V = 6233.8(1) (A)3, T = 293(2) K, Z = 2, Dc = 1.486 g/cm3, F(000) = 2796, μ = 1.266 mm-1, the final R = 0.0746 and wR = 0.1953 for 16475 observed reflections with I > 2σ(I). Crystal data for 2: C42H42AgClNO4P3, Mr = 861.00, trigonal, space group R3, a = 17.451(1), b = 17.451(1), c = 11.3985(7) (A), V = 3006.0(3) (A)3, T = 293(2) K, Z = 3, Dc = 1.427 g/cm3, F(000) = 1326, μ = 0.731 mm-1, the final R = 0.0251 and wR = 0.0663 for 1499 observed reflections with I > 2σ(I).     

Metallorganische Verbindungen der Lanthanoide. 88. Monomere Lanthanoid(III)-amide: Synthese und Röntgenstrukturanalyse von [Nd{N(C6H5)(SiMe3)}3(THF)], [Li(THF)2(μ-Cl)2Nd{N(C6H3Me2-2,6)(SiMe3)}2(THF)] und [ClNd{N(C6H3-iso-Pr2-2,6)(SiMe3)}2(THF)]

Organometallic Compounds of the Lanthanides. 88. Monomeric Lanthanide(III) Amides: Synthesis and X-Ray Crystal Structure of [Nd{N(C₆H₅)(SiMe₃)}₃(THF)], [Li(THF)₂(μ-Cl)₂Nd{N(C₆H₃Me₂-2,6)(SiMe₃)}₂(THF)], and [ClNd{N(C₆H₃-iso-Pr₂-2,6)(SiMe₃)} ₂(THF)] A series of lanthanide(III) amides [Ln{N(C₆H₅) · (SiMe₃)}₃(THF)_x] [Ln = Y ( 1 ), La ( 2 ), Nd ( 3 ), Sm ( 4 ), Eu ( 5 ), Tb ( 6 ), Er ( 8 ), Yb ( 9 ), Lu ( 10 )] could be prepared by the reaction of lanthanide trichlorides, LnCl₃, with LiN(C₆H₅)(SiMe₃). Treatment of NdCl₃(THF)₂ and LuCl₃(THF)₃ with the lithium salts of the bulky amides [N(C₆H₃R₂-2,6)(SiMe₃)]^? (R = Me, iso-Pr) results in the formation of the lanthanide diamides [Li(THF)₂(μ-Cl)₂Nd{N(C₆H₃Me₂-2, 6)(SiMe₃)}₂(THF)] ( 11 ) and [ClLn{N(C₆H₃-iso-Pr₂-2,6)(SiMe₃)} ₂(THF)] [Ln = Nd ( 12 ), Lu ( 13 )], respectively. The ¹H- and ¹³C-NMR and mass spectra of the new compounds as well as the X-ray crystal structures of the neodymium derivatives 3 , 11 and 12 are discussed.     

Synthesis and cytotoxicity study of gold(III) porphyrin complexes and their derivative in breast cancer cells

Gold(III) [Au(III)] complexes exhibit potential anticancer activities. A series of Au(III) porphyrin complexes containing different meso-substituent groups (phenyl, methoxyphenyl, butyloxyphenyl, octyloxyphenyl, and decyloxyphenyl) was synthesized. The synthesized compounds were characterized using mass spectrometry, infrared spectroscopy, UV–visible and fluorescence spectroscopy, and electron paramagnetic resonance spectroscopy. Moreover, the in vitro cytotoxicity of these Au(III) porphyrin complexes was investigated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide surrogate viability assay on an MCF7 human breast cancer cell line. The Au(III) complexes with 5,10,15,20-tetraphenylporphyrin (AuTPP) and 5,10,15,20-tetrakis(4-methyloxyphenyl)porphyrin (AuTOMPP) demonstrated high anticancer activity with IC₅₀ values against MCF7 cells at 4.30 and 25.35 µM, respectively. The toxicity of the Au(III) porphyrin complexes against the LLC-MK2 rhesus monkey kidney epithelial cell line, a representative normal cell line, was investigated. All the tested Au(III) porphyrin complexes were non-cytotoxic in LLC-MK2 cells. For AuTPP, more than 80% LLC-MK2 cell viability was observed at concentrations lower than 5 μM.     

Syntheses and Crystal Structures of Silver(I) Complexes by Depolymerizing [Ag(C≡CPh)]_n with a NP_3 Ligand

1 INTRODUCTION Great attention has currently been paid to com-pounds formed by the reaction between phosphineand metal alkynyl building blocks[1]. The ligand NP3contains one tertiary nitrogen atom as well as threephosphorous atoms and bonds to the metal ions as atetradentate ligand, affording tetrahedral[2] or triangle-bipyrimidal geometry[3, . In other coordination ca- 4]ses, one[5, , two[7], three P donors[8, 6] …     

Computational Studies of Au(I) and Au(III) Anticancer MetalLodrugs: A Survey

Owing to the growing hardware capabilities and the enhancing efficacy of computational methodologies, computational chemistry approaches have constantly become more important in the development of novel anticancer metallodrugs. Besides traditional Pt-based drugs, inorganic and organometallic complexes of other transition metals are showing increasing potential in the treatment of cancer. Among them, Au(I)- and Au(III)-based compounds are promising candidates due to the strong affinity of Au(I) cations to cysteine and selenocysteine side chains of the protein residues and to Au(III) complexes being more labile and prone to the reduction to either Au(I) or Au(0) in the physiological milieu. A correct prediction of metal complexes’ properties and of their bonding interactions with potential ligands requires QM computations, usually at the ab initio or DFT level. However, MM, MD, and docking approaches can also give useful information on their binding site on large biomolecular targets, such as proteins or DNA, provided a careful parametrization of the metal force field is employed. In this review, we provide an overview of the recent computational studies of Au(I) and Au(III) antitumor compounds and of their interactions with biomolecular targets, such as sulfur- and selenium-containing enzymes, like glutathione reductases, glutathione peroxidase, glutathione-S-transferase, cysteine protease, thioredoxin reductase and poly (ADP-ribose) polymerase 1.     

Complexes of Oxamic Acid with La(III), Gd(III), Tb(III), Er(III), Tm(III) and Lu(III)

The preparation, for the first time, of the deprotonated complexes of oxamic acid with La(III), Gd(III), Tb(III), Er(III), Tm(III) and Lu(III) is reported. Analytical results, conductometric measurements, magnetic moments and spectral data (IR and diffuse reflectance spectra) are discussed in terms of possible structural types. The oxamate anion acts as a N, O bidentate non-bridging ligand.     

The preparation, properties and X-ray structures of gold(I) trithiophosphite complexes

The first gold(I) trithiophosphite complexes were synthesised and fully characterised. Reaction of (tht)AuX (X = Cl, C₆F₅; tht = tetrahydrothiophene) with trithiophosphites (RS)₃P (R = Me, Ph) and the bicyclic [(SCH₂CH₂S)PSCH₂]₂ (²L) afforded the corresponding molecular complexes (RS)₃PAuX [R = Me, X = Cl (1); R = Me, X = C₆F₅ (2); R = Ph, X = Cl (3); R = Ph, X = C₆F₅ (4)], and ²L(AuX)₂ [X = Cl (5), X = C₆F₅ (6)]. Reacting (tht)AuCl consecutively with two mole equivalents of (MeS)₃P and then AgOTf, gave the ionic compound {[(MeS)₃P]₂Au}OTf (7). The compounds were characterised by multinuclear NMR spectroscopy, IR measurements and mass spectrometry, and the crystal and molecular structures of 1, 3, 6, two polymorphs of 2 as well as the known (MeO)₃PAuCl (8) were determined by X-ray diffraction. The halide complexes 1 and 8 are isostructural and exhibit infinite chains of “crossed-sword”-type aurophilic interactions with Au?Au contact distances of 3.2942(3) and 3.1635(4) Å, respectively. Complex 6 exhibits a long Au?Au contact of 3.4671(9) Å. Au?S interactions between 3.3455(7) and 3.520(2) Å are present in the structures of 1 and one polymorph of 2.     

三价金配合物抗肿瘤活性研究*

三价金配合物具有潜在的抗肿瘤活性,是目前金属药物领域的研究热点。本文按配位原子的不同总结了稳定三价金配合物的结构特征,按其生物活性的构效关系、生物靶点和作用机制综述了三价金配合物抗肿瘤活性研究的最新成果：配体的结构特点以及离去基团对三价金配合物的体外细胞毒性影响较大;介绍了用于检测三价金配合物与可能的生物靶分子之间的相互作用的多种物理和生物学方法,重点关注了相互作用的模式,如嵌入/静电吸引/共价结合等,并解释了三价金配合物抗肿瘤活性的原因。最后提出了一些研究新思路,以期有助于设计得到靶标明确的具有良好药理活性的抗肿瘤药物。