Triazole Ligands Research Articles

An investigation into the coordination chemistry of tripodal “click” triazole ligands with Mn, Ni, Co and Zn ions

The steric influences of the triazole side chains in two tripodal chelating ligands tris[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]amine (TBTA) and tris[(1-phenyl-1H-1,2,3-triazol-4-yl)methyl]amine (TPTA) are explored through structural studies of four new mononuclear d-block metal complexes. The manganese(II) complex [Mn(TPTA)2](ClO4)2·H2O 1 includes two TPTA ligands each coordinated in a tridentate fashion to give an unusual trigonal prismatic coordination geometry with two non-coordinated pendant triazole groups which engage in weak hydrogen bonding interactions. [Ni(TBTA)(OH2)Cl]Cl·3H2O·MeCN 2 contains an octahedral nickel(II) centre bound by a tetradentate TBTA ligand along with aqua and chloride ligands, where the significant degree of lattice solvation leads to an extensive hydrogen bonding network linking complexes through hexa-aqua water clusters. The mononuclear copper(II) complex [Cu(TPTA)Cl2]·MeCN 3 contains no classical hydrogen bond donors but instead intermolecular aggregation takes place through chelating CH···Cl hydrogen bonds involving the acidic triazole CH groups which leads to close association of adjacent complexes. The zinc complex [Zn(TPTA)Cl]2[ZnCl4]·MeOH 4, in which cationic [Zn(TPTA)Cl]+ species are accompanied by tetrachlorozincate anions, exhibits a tris-triazole chelating coordination geometry for the TPTA ligand and associates through tetrameric π···π stacking interactions despite the positive charge present on each species. Structural analysis of these complexes, supported by solution-state mass spectrometry, NMR spectroscopic and magnetic susceptibility measurements, where applicable, provides new insights into the breadth of coordination geometries and intermolecular packing modes available to this important class of chelating ligand.

Synthesis, crystal structure and electrochemistry properties of Cu-compound by rigid ligand

A new novel Cu(II) compound formulated as Cu(C4N6H4)2Cl2 (1) (C4N6H4 = 1H-3,4'-bi-1,2,4-triazole) is successfully synthesized by a low-temperature hydrothermal method. The single-crystal X-ray diffraction analysis shows that complex 1 was the monoclinic C2/c space group. The non-covalent intermolecular interaction formed a 3D supermolecule copper compound. It is characterized by XRD, IR spectroscopy, TG, elemental analysis and UV-visible spectrum in the solid state. In addition, triazole ligand as an active agent in compound 1 has been used to sense of H2O2.

Synthesis, Characterization, Ion-Exchange, and Catalytic Properties of Three Isostructural Copper(Ii) Coordination Polymers with a Flexible Bis(Triazole) Ligand

Synthesis, Characterization, Ion-Exchange, and Catalytic Properties of Three Isostructural Copper(Ii) Coordination Polymers with a Flexible Bis(Triazole) Ligand

Fluorinated click-derived tripodal ligands drive spin crossover in both iron(II) and cobalt(II) complexes.

Control of the spin state of metal complexes is important because it leads to a precise control over the physical properties and the chemical reactivity of the metal complexes. Currently, controlling the spin state in metal complexes is challenging because a precise control of the properties of the secondary coordination sphere is often difficult. It has been shown that non-covalent interactions in the secondary coordination sphere of transition metal complexes can enable spin state control. Here we exploit this strategy for fluorinated triazole ligands and present mononuclear CoII and FeII complexes with "click"-derived tripodal ligands that contain mono-fluorinated benzyl substituents on the backbone. Structural characterization of 1 and 2 at 100 K revealed Co-N bond lengths that are typical of high spin (HS) CoII complexes. In contrast, the Fe-N bond lengths for 3 are characteristic of a low spin (LS) FeII state. All complexes show an intramolecular face-to-face non-covalent interaction between two arms of the ligand. The influence of the substituents and of their geometric structure on the spin state of the metal center was investigated through SQUID magnetometry, which revealed spin crossover occurring in compounds 1 and 3. EPR spectroscopy sheds further light on the electronic structures of 1 and 2 in their low- and high-spin states. Quantum-chemical calculations of the fluorobenzene molecule were performed to obtain insight into the influence of fluorine-specific interactions. Interestingly, this work shows that the same fluorinated tripodal ligands induce SCO behavior in both FeII and CoII complexes.

1,2,3-Triazole based ligands with phosphine and pyridine functionalities: synthesis, PdII and PtII chemistry and catalytic studies.

This manuscript describes the syntheses of pyridine appended triazole-based mono- and bisphosphines, [o-Ph2P(C6H4){1,2,3-N3C(Py)C(H)}] (2), [o-Br(C6H4){1,2,3-N3C(Py)C(PPh2)}] (3), [C6H5{1,2,3-N3C(Py)C(PPh2)}] (4), [Ph2P(C6H4){1,2,3-N3C(Py)C(PPh2)}] (5) and [3-Ph2P-2-{1,2,3-N3C(Ph)C(PPh2)}C5H3N] (6), their palladium and platinum chemistry and catalytic applications. These ligands upon treatment with [M(COD)Cl2] (M = Pd or Pt) yielded complexes with different coordination modes, depending on the reaction conditions. Both κ2-P,N and κ2-P,P coordination modes were observed in many of the complexes indicating the ambidentate nature of these ligands. Monophosphine 2 in the presence of a base afforded rare fused-5,6-membered PCN pincer complexes [MCl{o-Ph2P(C6H4){1,2,3-N3C(Py)C(H)}}-κ3-P,C,N] (7, M = Pd; 8, M = Pt), whereas the reactions of 4 with [M(COD)Cl2] (M = Pd, Pt) produced κ2-P,N chelate complexes [MCl2{C6H5{1,2,3-N3C(Py)C(PPh2)}-κ2-P,N}] (9, M = Pd; 10, M = Pt). Similar reactions of 5 and 6 resulted in κ2-P,P chelate complexes [MCl2{{3-Ph2P-2-{1,2,3-N3C(Ph)C(PPh2)}C5H3N}-κ2-P,P}] (11, M = Pd; 12, M = Pt) and [MCl2{3-Ph2P-2-{1,2,3-N3C(Ph)C(PPh2)}C5H3N}-κ2-P,P}] (13, M = Pd; 14, M = Pt), respectively. The palladium(II) complexes have shown excellent catalytic activity in the α-alkylation reaction of acetophenone derivatives.

Glycosyl Triazole Ligand for Temperature-Dependent Competitive Reactions of Cu-Catalyzed Sonogashira Coupling and Glaser Coupling

Glycosyl triazoles have been introduced as efficient ligands for the Cu-catalyzed Sonogashira reaction to overcome the challenges of sideways homocoupling reactions in Cu catalysis in this reaction. The atmospheric oxygen in a sealed tube did not affect the coupling, and no need of complete exclusion of oxygen was experienced in the presence of glycohybrid triazole ligand L3. High product yields were obtained at 130 °C for a variety of substrates including aliphatic and aromatic terminal alkynes and differently substituted aromatic halides including 9-bromo noscapine. In contrast, at room temperature, a very low loading of the L3-Cu catalytic system could produce excellent yields in Glaser coupling including homocoupling and heterocoupling of a variety of aliphatic and aromatic alkynes.

New insights into potential estrogen agonistic activity of triazole fungicides and coupled metabolic disturbance

Triazole fungicides are highly effective pesticides widely used in plant protection, which has caused potential hazards to human health and ecological safety. To fully understand their potential hepatotoxicity, we first analyzed the transcriptome profiles in HepG2 cells treated with five triazole fungicides (hexiconazole (HEX), tebuconazole (TEB), propiconazole (PRO), cyproconazole (CYP), and difenoconazole (DIF)), and found that these pesticides remarkably affected estrogen signaling pathways, especially estrogen synthesis. Furthermore, we found that TEB, CYP, PRO and DIF had agonistic activity towards estrogen receptor alpha (ERα) and elucidated the binding mode of triazole ligands with ERα using the reporter gene assay and molecular docking. Four triazole fungicides regulated eight major genes involved in estrogen synthesis (StAR, CYP11A1, 3βHSD2, CYP17, CYP19, CYP3A4, CYP1A2 and SCP2) and stimulated the secretion of 17β-estradiol (E2). Finally, we assessed possible metabolic outcomes caused by abnormal estrogen synthesis, and found that triazole fungicides affected the metabolism of various macromolecules (such as lipid, amino acid, and carbohydrate) and signal transduction. These findings will provide new insights into endocrine-disrupting effects of triazole fungicides and highlight their potential ecological and health risks.

Chiral Fluorescent Metal-Organic Framework with a Pentanuclear Copper Cluster as an Efficient Luminescent Probe for Dy3+ Ion and Cyano Compounds.

Luminescent probes have been used for the detection of various heavy metals and toxic compounds. A novel sensor with excellent sensitivity and selectivity is in high demand. Herein, we designed and synthesized a three-dimensional copper-organic framework of "pcu" α-Po primitive cubic topology with a Schläfli symbol of {4.4.4.4.4.4.4.4.4.4.4.4.*.*.*}. By taking advantage of metal clusters and a triazole ligand as the metal-organic framework (MOF) components, the newly obtained MOF is stable in various environments and can be potentially used as the sensor. Remarkably, this MOF-based sensor shows high sensitivity and selectivity toward a dysprosium ion (Dy3+) in a multiple-lanthanide mixed solution. Besides, it exhibits luminescent quenching toward various cyano compounds. This chiral cluster-based network provides a potential luminescent probe for various inorganic and organic compounds with high sensitivity and selectivity.

Synthesis, structure, spectral, redox properties and anti-cancer activity of Ruthenium(II) Arene complexes with substituted Triazole Ligands

Three versatile half-sandwich ruthenium(II) p-cymene complexes bearing substituted triazole ligands exhibit promising cancer cell growth inhibition activity towards A549 lung adenocarcinoma and MDA-MB-231 breast adenocarcinoma cells. In this context, the triazole based phthalimide protected new ligand (2-(3, 5-di(pyridin-2-yl)-4H-1,2,4-triazol-4-yl) isoindoline-1,3-dione) (L1) was prepared. Three ruthenium(II) p-cymene complexes [Ru(η6-p-cymene)(L1)Cl]Cl: [1]Cl, L1: (2-(3,5-di(pyridin-2-yl)-4H-1,2,4-triazol-4-yl)isoindoline-1,3-dione), [Ru(η6-p-cymene)(L2)Cl]Cl: [2]Cl and [Ru(η6-p-cymene)(L2)Cl](PF6): [2](PF6), L2 (2,2′-(4-(1H-pyrrol-1-yl)-4H-1,2,4-triazole-3,5-diyl) dipyridine) have been successfully synthesized and characterized by different spectral and analytical tools. Pyrrole protected substituted ruthenium complexes [2]Cl and [2](PF6) have been successfully identified structurally by single-crystal X-ray diffraction studies and confirmed the successful anion exchange. The redox properties of the ligands and the targeted metal complexes have been carefully examined. Cellular staining, live-cell imaging and MTT assay have been performed for all the complexes. We have demonstrated that our synthesized ruthenium(II) p-cymene complexes are capable of inducing significant cytotoxicity in A549 lung cancer cell lines, with an IC50 values of 6.56 ± 0.31 µM, 4.74 ± 0.2 µM and 13.67 ± 0.64 µM and in MDA-MB-231 breast cancer cell lines with an IC50 values of 1.13 ± 0.046 µM, 0.36 ± 0.016 µM and 11.32 ± 0.49 µM for [1]Cl, [2]Cl and [2](PF6) respectively.

Synthesis and Characterization of New Triazole Ligand with Some Transition Metals

The work includes synthesis and characterization of new ligand and its complexes with divalent metal ions such as cobalt, nickel, copper and zinc. This project includes firstly, the synthesis of Schiff base by reacting P-aminoacetophenone with 2-amino-6-methylpyridine by the reflux reaction for 6 hr. and at 70 ° C. The second step involves the synthesis azo-Schiff base containing ligand which was prepared by the reaction of the Schiff base with the heterocyclic 1,2,4-triazole. The prepared ligand was characterized using spectroscopic methods such as Infrared spectrum, UV-visible spectrum, 1HNMR and 13CNMR spectrum. In the third step, the ligand complexes were prepared by the reaction between the ligand and the metal ion salts to obtain the related metal complex. Some properties of the prepared compounds were studied such as the solubility. The prepared complexes were characterized using IR spectroscopy, UV-Visible, conductivity, magnetic sensitivity, and the atomic absorption technique was used to determine the percentage of each metal in its complex.

Stabilization of an elusive tautomer by metal coordination.

The solid-state isolation of the different tautomers of a chemical compound can be a challenging problem. In many cases, tautomers with an energy very close to the most stable one cannot be isolated (elusive tautomers). In this article, with reference to the 4-methyl-7-(pyrazin-2-yl)-2H-[1,2,4]triazolo[3,2-c][1,2,4]triazole ligand, for which the elusive 3H-tautomer has an energy only 1.4 kcal mol-1 greater than the most stable 2H form, we show that metal complexation is a successful and reliable way for stabilizing the elusive tautomer. We have prepared two complexes of the neutral ligand with CuBr2 and ZnBr2, namely, aquabromidobis[4-methyl-7-(pyrazin-2-yl)-3H-[1,2,4]triazolo[3,2-c][1,2,4]triazole]copper(II) bromide trihydrate, [CuBr(C8H7N7)2(H2O)]Br·3H2O, and dibromido[4-methyl-7-(pyrazin-2-yl)-2H-[1,2,4]triazolo[3,2-c][1,2,4]triazole][4-methyl-7-(pyrazin-2-yl)-3H-[1,2,4]triazolo[3,2-c][1,2,4]triazole]zinc(II) monohydrate, [ZnBr2(C8H7N7)2]·H2O. The X-ray analysis shows that, in both cases, the elusive 3H-tautomer is present. The results of the crystallographic analysis of the two complexes reflect the different coordination preferences of CuII and ZnII. The copper(II) complex is homotautomeric as it only contains the elusive 3H-tautomer of the ligand. The complex can be described as octahedral with tetragonal distortion. Two 3H-triazolotriazole ligands are bis-chelated in the equatorial plane, while a water molecule and a bromide ion in elongated axial positions complete the coordination environment. The zinc(II) complex, on the other hand, is heterotautomeric and contains two bromide ions and two monodentate ligand molecules, one in the 2H-tautomeric form and the other in the 3H-tautomeric form, both coordinated to the metal in tetrahedral geometry. The observation of mixed-tautomer complexes is unprecedented for neutral ligands. The analysis of the X-ray molecular structures of the two complexes allows the deduction of possible rules for a rational design of mixed-tautomer complexes.

Ligand Engineered Metal−Organic Frameworks for Electrochemical Reduction of Carbon Dioxide to Carbon Monoxide

The economic feasibility of electrocatalytic carbon dioxide reduction reaction (CO2RR) relies on the development of highly selective and efficient catalysts operating at a high current density. Herein, we explore a ligand engineering strategy involving the use of metal-organic frameworks (MOFs) and combining the desirable features of homogeneous and heterogeneous catalysts for boosting the activity of CO2RR. Zn-based MOFs involving two different azolate functional ligands i.e., 1,2,4-triazole (Calgary Framework-20, CALF-20) and 2-methylimidazole (zeolitic imidazolate framework-8, ZIF-8) were investigated for CO2RR in an alkaline flow cell electrolyzer. The highest CO partial current density of 53.2 mA/cm2 was observed for a Zn-based MOF (CALF-20). CALF-20 showed the highest reported Faradaic efficiency of Zn-based MOFs for CO production (ca. 94% at -0.969 V vs. reversible hydrogen electrode, RHE), with a TOF of 1360.8 h-1 and a partial current density -32.8 mA/cm2. Experimental and density functional theory (DFT) results indicate that the sp2 carbon atoms in azole ligands coordinated with the metal center in the MOFs are the active sites for CO2RR, due to the fully occupied 3d orbital of Zn(II) centers. Ab initio investigation shows that both azolate frameworks in CALF-20 and ZIF-8 have most favorable adsorption sites at the N−sp2 C. Adopting the triazole ligand in CALF-20 enhances the charge transfer (as compared with diazole group in ZIF-8), which induces more electrons in the adjacent active sites at the azole ligand and facilitates *COOH formation, boosting the current density and Faradaic efficiency towards CO production. This study suggests that ligand engineering in MOFs could be a viable approach to design highly efficient CO2RR catalyst.

Two functional hybrids based on polyoxometalate coordination polymers: Synthesis, electrochemical and photocatalytic properties

Two isostructural polyoxometalate (POM)-based supramolecules were obtained under hydrothermal conditions by the self-assembly of wells–dawson polyoxometalates, transition metal ions and flexible bi(triazole) ligands, namely, [M(H2O)2(btp)(Hbtp)2][H2P2W18O62] (M = Cd for 1, Zn for 2), where the btp represents 1,3-bis(1,2,4-triazol-1-y1)propane). 1 and 2 exhibit three-dimensional supramolecular structures through the hydrogen-bonding reactions. Otherwise, the crystal structures were characterized by single X-ray diffractions, powder X-ray diffraction (PXRD), Thermal Gravimetric curves (TG), Ultraviolet–visible (UV–vis) spectroscopy and Infrared Radiation (IR) spectra. Meantime, the photocatalytic and electrochemical properties were also investigated. 1 and 2 exhibit selectively degredation for cationic dyes of methylene blue (MB) and rhodamine B (RhB). The corresponding degradation efficiency can reach 98% and 34% in an hour. Whereas, no remarkably degradation phenomenon was observed for anionic dye of alphazurine A (ATBA), which may be the electrostatic repulsion between P2W18 and ATBA.

Triazole-assisted trinuclear oxidovanadium(IV) complexes for gas adsorptions

Two novel microporous trinuclear oxidovanadium(IV) triazole frameworks, K2Na[V3O3(μ3-O)(ox)3(H-4-trz)2(4-trz)]·3H2O (1) and [V3O3(μ3-O)(H-3-trz)2(3-trz)4]·5H2O (2) (ox = oxalate, H-4-trz = 1H-1,2,4-triazole, H-3-trz = 1-H-1,2,3-triazole) have been obtained from alkaline solution respectively. Three vanadium atoms are closely connected together by deprotonated/protonated triazole ligands and bridging oxygen, leading to an equilateral triangular structure. Both 1 and 2 were well characterized by X-ray structural analyses, IR and UV–vis spectra, power XRD patterns, theoretical bond valence calculations (BVS) and EPR spectra. Moreover, 1 exists an inner channel diameter of 12.0 Å, showing selective O2 and CO2 adsorption of 23.91 and 14.22 mg/g under 29.9 bar respectively, which has potential application in O2/N2 and CO2/H2 separation.

Synthesis, Molecular Docking, MEP and SAR Analysis, ADME-Tox Predictions, and Antimicrobial Evaluation of Novel Mono- and Tetra-Alkylated Pyrazole and Triazole Ligands

Newly synthesized compounds of N-alkylated heterocyclic compounds were prepared by condensation of amine with alcohol which undergoes a reaction of SN2. These newly synthesized derivatives were characterized by spectral analysis. The objective is to prepare new potent nontoxic antimicrobial agents which are easy to synthesize and could be scaled up in pharmaceutical industries. Thirteen new heterocyclic compounds containing a pyrazole moiety were synthesized with good yields (29.79 to 99.6%) and were characterized by FTIR, 1H NMR, 13C NMR, and CG-MS techniques. The compounds were divided into two series—monoalkylated compounds (1–11) and tetra-alkylated compounds (12 and 13)—and then evaluated for their in vitro antifungal and antibacterial activities against several fungal and bacterial strains. None of the monoalkylated compounds had antibacterial or antifungal activity. However, the two tetra-alkylated pyrazole ligands displayed strong antibacterial potential. Moreover, compound 12 was more potent against all tested bacterial strains than compound 13. Interestingly, compounds 12 and 13 acted as weak antifungal agents against Saccharomyces cerevisiae. ADME-Tox studies suggested that compounds 12 and 13 exhibit better toxicity profiles than the commercial antibiotic streptomycin. MEP studies suggested that compounds 12 and 13 have the same charge locations but differ in their values which are due to the condensed geometry of compound 13 that make it more polarizable than compound 12. Of particular interest, these different MEPs were evident in ligand protein docking, suggesting that compound 12 has better affinity with MGL enzyme than compound 13. All these findings suggested that these novel compounds represent promising antibacterial lead compounds.

Integrated High Water Affinity and Size Exclusion Effect on Robust Cu-Based Metal–Organic Framework for Efficient Ethanol–Water Separation

Purification of ethanol from ethanol/water mixtures is important in industrial separation processes, especially for bioethanol fuel purification. In this work, a robust Cu-triazole metal–organic framework (Cu-Tria) with interconnected 3D supermicroporous channels containing tridentate bridging triazole ligands and rich open Cu2+ sites was identified to separate ethanol/water mixtures. By virtue of the size exclusion effect for ethanol and excellent water affinity, this MOF exhibits an ideal molecular sieving effect for ethanol/water separation. The DFT calculation results reveal that a water molecule can form coordination bonds with Cu2+ open metal sites, and the subsequent water molecules can form multiple hydrogen bonds with the coordinated water. Breakthrough experiments of water/ethanol mixtures (v/v = 5/95) show that complete water/ethanol separation can be achieved, and online mass spectrometry results reveal that the purity of the collected ethanol from the outlet is up to 99.99%. More importantly, this MOF displays excellent water, alkali, and acid stability, as well as outstanding recyclability for water/ethanol separation. Consequently, the Cu-Tria can be deemed as a potential porous adsorbent for the purification of bioethanol fuel.

Discovery of a novel family of FKBP12 "reshapers" and their use as calcium modulators in skeletal muscle under nitro-oxidative stress.

The hypothesis of rescuing FKBP12/RyR1 interaction and intracellular calcium homeostasis through molecular "reshaping" of FKBP12 was investigated. To this end, novel 4-arylthioalkyl-1-carboxyalkyl-1,2,3-triazoles were designed and synthesized, and their efficacy was tested in human myotubes. A library of 17 compounds (10a-n) designed to dock the FKBP12/RyR1 hot-spot interface contact residues, was readily prepared from free α-amino acids and arylthioalkynes using CuAAC "click" protocols amenable to one-pot transformations in high overall yields and total configurational integrity. To model nitro-oxidative stress, human myotubes were treated with the peroxynitrite donor SIN1, and evidence was found that some triazoles 10 were able to normalize calcium levels, as well as FKBP12/RyR1 interaction. For example, compound 10bat 150nM rescued 46% of FKBP12/RyR1 interaction and up to 70% of resting cytosolic calcium levels in human myotubes under nitro-oxidative stress. All compounds 10 analyzed showed target engagement to FKBP12 and low levels of cytotoxicity invitro. Compounds 10b, 10c, 10h, and 10iR were identified as potential therapeutic candidates to protect myotubes in muscle disorders with underlying nitro-oxidative stress, FKBP12/RyR1 dysfunction and calcium dysregulation.

SC-SC Anion-Assisted Linker Exchange within a Three-Dimensional Cu(II)-Triazole Framework: A Luminescent Probe for S2.

A three-dimensional (3D) binodal 3,5-connected net, {[Cu(MTP)(H2O)](NO3)}n (1) with the Schläfli symbol of {3·72}{32·75·83} can be transformed into a two-dimensional (2D) kagóme network with the Schlafli symbol of {32·62·72} in an irreversible single crystal–single crystal (SC–SC) guest-assisted linker exchange process. The product of this SC–SC represents the first luminescent probe for S2– based on triazole ligand.

Energetic metal–organic frameworks achieved from furazan and triazole ligands: synthesis, crystal structure, thermal stability and energetic performance

Energetic metal–organic frameworks (EMOFs) have witnessed increasing development and been proved as promising candidates for new high energy density materials (HEDMs).

Syntheses, crystal structures, and biological evaluations of new dinuclear platinum(ii) complexes with 1,2,4-triazole derivatives as bridging ligands.

A series of new dinuclear platinum(ii) complexes with the general formula [Pt2(μ-HL)4] (1-4), where H2L is 4-[(5-chloro-2-hydroxy-benzylidene)-amino]-3-R-1,2,4-triazole-5-thione: R = H (1), methyl (2), ethyl (3) and propyl (4), were synthesized and characterized. The X-ray crystal structures of 2, 3 and 4 reveal that the two platinum atoms form a paddlewheel core with four chelating triazole ligands as bridges, revealing a radically different structure than those of the traditional anticancer platinum(ii) complexes. These complexes show higher in vitro antiproliferative activity against human liver hepatocellular carcinoma (HepG2) and human breast adenocarcinoma (MCF7) than human lung cancer (A549) and human normal hepatocyte (HL-7702) cell lines. In particular, 3 exhibits antiproliferative activity (IC50 = 5.5 μM) against HepG2 cells comparable to that of cisplatin. Different from the traditional anticancer platinum(ii) complexes with high DNA affinity, 3 binds very weakly to DNA. Upon comparison, it exhibits potent inhibiting activity against protein tyrosine phosphatases 1B (PTP1B, IC50 = 16 μM) through possible binding to its active sites and its binding constant is 5.28 × 104 M-1. The results suggest that the antiproliferative mechanism of 3 against HepG2 cells may be different from that of cisplatin.