Jiyong Hu

Metal and structure tuned in vitro antitumor activity of benzimidazole-based copper and zinc complexes

Four new complexes, Cu2(p-2-bmb)2Cl4 (1), Cu2(p-2-bmb)2Br4 (2), Zn2(p-3-bmb)2Cl4 (3), and [Cu3(p-3-bmb)2Cl4·(CH3OH)2] n (4), have been synthesized under solvothermal reactions based on V-shaped flexible ligands 1-((2-(pyridin-2-yl)-1H-benzoimidazol-1-yl)methyl)-1Hbenzotriazole (p-2-bmb) and 1-((2-(pyridin-3-yl)-1H-benzoimidazol-1-yl)methyl)-1Hbenzotriazole (p-3-bmb). Complexes 1–3 are binuclear, whereas 4 is an infinite chain with trimetallic units, and then these complexes are further extended into 3D supramolecular architectures by π…π interactions and hydrogen bonds. In vitro antitumor activities of these complexes on four human tumor cell lines (gastric tumor cell line, esophagus tumor cell line, liver tumor cell line, colon tumor cell line) were evaluated by MTT assay. The results exhibit that these complexes inhibit the growth of cancer cells by inducing apoptosis, and the inhibition effect shows time- and dose-effect relationship.

Metallacycle-based complexes based on a flexible pyridyl–benzimidazole derivative

Three new coordination complexes, {Cd(pbmb)(NO3)2} n (1), {Ag(pbmb)(NO3)(C3H6O)} n (2), and {Hg2(pbmb)2Cl4} n (3), have been synthesized under solvothermal or solution reactions based on a flexible N-heterocyclic ligand 1-((2-(pyridin-4-yl)-1H-benzoimidazol-1-yl)methyl)-1H-benzotriazole (pbmb) and structurally characterized by single-crystal X-ray diffraction, IR spectrum, and elemental analyses. Both 1 and 2 display a 1-D chain structure with metallacycle unit while 3 shows a binuclear cycle motif. The aromatic rings are directing groups for π ··· π stacking interactions. The π ··· π interactions and hydrogen bonds extend the simple chain structure and binuclear structure to 3-D supramolecular architectures. Complexes 1 and 3 exhibit strong luminescence in the solid state at room temperature whereas 2 shows fluorescence quenching.

Cytotoxicity towards human alimentary system carcinoma cells resulting from diverse copper(II) complexes

To investigate the potential cytotoxicity of copper(II)-based complexes, three coordination compounds with heterocyclic ligands, Cu(pbmbt)Cl2(CH3OH) (1), Cu2(ddbib)2(NO3)4·3CH3OH (2), and Cu3(ttmtmb)2Cl6·2.5H2O (3), which include mononuclear, dinuclear, and trinuclear structures, have been synthesized from reactions of corresponding copper(II) salts with 1-((2-pyrazinyl)-1H-benzoimidazol-1-yl)methyl)-1H-benzotriazole (pbmbt), 2-(2,3-dihydropyrazin-2-yl)-1-((4-((2-(2,3-dihydropyrazin-2-yl)-1H-benzo[d]imidazol-1-yl)methyl)phenyl)methyl)-1H-benzo[d]imidazole (ddbib), and 1,1′,1′′-((2,4,6-trimethylbenzene-1,3,5-triyl)tris(methylene)tris(2-methyl-1H-benzoimidazole) (ttmtmb), respectively. IC50 values revealed that 2 and 3 show strong cytotoxicity, whereas 1 is weakly cytotoxic after being tested against a panel of several human alimentary system carcinoma cell lines (SGC7901, EC109, SMMC7721, and HT29). The number of copper centers and different structures could make a tremendous difference on their cytotoxicity. Graphical Abstract Three coordination compounds with heterocyclic ligands were constructed to investigate the potential cytotoxicity of copper(II)-based complexes. IC50 values revealed that complexes 2 and 3 show strong cytotoxicity, whereas complex 1 is weakly cytotoxic after being tested by MTT assay against a panel of several human alimentary system carcinoma cell lines.

Photoluminescent and cytotoxic properties of multinuclear complexes and multinuclear-based polymers with group 12 metals and a tripodal ligand

Four novel multinuclear complexes and multinuclear-based polymers with group 12 metal centers, namely, Zn3(tpbb)Cl6 (1), {[Cd6(tpbb)2Cl12]·2CHCl3·0.5H2O}n (2), Hg4(tpbb)Br8 (3), and Hg4(tpbb)I8 (4), have been synthesized with respect to a new flexible tripodal ligand, 1,3,5-tris((2-(pyridine-2-yl)-1H-benzo[d]imidazol-1-yl)methyl)benzene (tpbb). Complex 1 is a trinuclear cluster, as determined by X-ray crystallography, while 2 features an unprecedented hexanuclear metallacycle-based 2D network with chloride ion bridges. The similar umbrella-like tetranuclear architectures of 3 and 4 with different Hg(II)-halide salts demonstrate that halides with the same tetrahedral coordination geometries of metal centers do not greatly affect the structure of the complexes. Photoluminescent studies indicate that complexes 1 and 2 reveal enhanced and red-shifted solid-state fluorescence at room temperature compared with the ligand, tpbb, while 3 and 4 show prominent phosphorescence behaviors at cryogenic temperatures with lifetimes in the microsecond range. In addition, when tested against a panel of several human carcinoma cell lines (SH-SY5Y, QBC939 and EC109) by standard MTT assay, complex 1 displayed potential cytotoxicity against SH-SY5Y and QBC939 cells and selectivity to different tumor cell lines.

Synthesis, characterization, structures, and catalytic property of oxovanadium(V) complexes with hydrazone ligands

The reaction of [VO(Acac)2] with 4-methyl-N′-[(2-hydroxy-1-naphthyl)methylidene]benzohydrazide (H2L1) and 4-methyl-N′-[1-(2-hydroxynaphthyl)ethyiidene]benzohydrazide (H2L2), respectively, in methanol, affords two new oxovanadium(V) complexes [VO(OMe)L1]2 (I) and [VO(OMe)L2] (II). Both complexes have been characterized by elemental analysis, IR, and single crystal X-ray diffraction methods. Complex I is a methoxide-bridged dinuclear oxovanadium(V) compound, while complex II is a mononuclear oxovanadium(V) compound. The dinegative hydrazone ligands coordinate to the metal atoms through phenolate, imine, and deprotonated amide donor atoms. The geometry around vanadium atom in I is a distorted VNO5 octahedron, while that in II is a VNO4 square pyramid. Both complexes have effective catalytic property for the sulfoxidation reaction.

Three Cu(II) complexes based on mixed ligands: their structures and catalytic behaviour

The Cu(II) complexes, [Cu(2,5-pydc)(bmi)(H2O)]n, [Cu2(H2O)2(2,6-pydc)2(btx)]·2H2O and [Cu(btc)2(bmi)2]·1.5H2O, (bmi = 1-[(benzotriazol-yl)methyl)-1H-1,3-imidazole; 2,5-H2pydc = pyridine-2,5-dicarboxylic acid; btx = 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene; H3btc = 1,3,5-benzenetricarboxylate) have been synthesised and their X-ray structures show that hydrogen bonds and π···π stacking interactions are employed in their construction. The complexes can effectively catalyse the oxidative coupling reaction of 2,6-di-tert-butylphenol in good yield and unique selectivity.

Synthesis, crystal structure, DNA/BSA interaction and in vitro antitumor activity of N-heterocycle Cu(II) and Co(II) complexes

Abstract Investigation of N-heterocycle transition metal complexes has led to the discovery of metal-based antitumor agents. Herein, two binuclear complexes, [Cu(p-4-bmb)(Ac)2]2 (1) and [Co(p-4-bmp)Cl2]2 (2), were prepared and characterized. The interactions of 1 and 2 with calf thymus (CT)-DNA and bovine serum albumin (BSA) were detected by absorbance and emission spectroscopy. The complexes bind to CT-DNA via an intercalative mode and show moderate affinity to BSA. Both complexes exhibited remarkable DNA cleavage activity. The MTT assay demonstrated that 1 exhibited higher cytotoxicity against three human alimentary system carcinoma cell lines compared to 2. Further, a cellular uptake assay demonstrated that 1 can accumulate in the nucleus and mitochondria of SMMC7721 cells to induce DNA damage and mitochondrial dysfunction. Fluorescence staining and flow cytometry analyses revealed that 1 can induce cell death by apoptosis. These findings should promote the development of benzimidazole-based transition metal complexes as novel chemotherapy agents with fewer side effects than conventional antitumor drugs.

Two cyclohexane-type octadecanuclear metalla-macrocycle-based metal organic frameworks and adsorption properties

Two novel porous metal–organic frameworks (MOFs) with {M18(Hbtib)36} (M = Ni(II), Zn(II)) as the basic building unit, namely, [Ni(Hbtib)2]n (1) and [Zn(Hbtib)2·H2O]n (2) [H2btib = 4-((2-butyl-5-(2-carboxy-3-(thiophen-2-yl)prop-1-enyl)-1H-imidazol-1-yl)methyl)] were synthesized using solvothermal reactions. Gas adsorption (N2, H2, CO2 and CH4) studies show that the desolvated solid 1 is a highly effective absorbent for CO2 over CH4 at 273 and 298 K. The results suggest that 1 has potential application in gas separation or purification. In addition, the photoluminescence properties of 2 were also investigated.

Group IIB metal directed complexes with flexible benzimidazole-based connector

Four group IIB metal complexes, namely [ZnCl2(Mbibix)]n (I), [Cd2(Ac)4(Mbibix)2] · (H2O) (II), [HgCl2(DMF)(Mbibix)]2 (III) and [HgI2(Mbibix)]2 (IV), have been achieved via the reaction of corresponding metal salts and organic spacer Mbibix (Mbibix = 1-(3-((2-methyl-1H-benzimidazol-1-yl)methyl)benzyl)-2-methyl-1Hbenzimidazole). Crystal structure analyses reveal that complex I is one-dimensional (1D) zigzag chain, whereas II, III and IV are binuclear motifs (CIF files CCDC nos. 1006224 (I), 1006225 (II), 1006226 (III), 1006227 (IV)). These structures are further stacked into 3D supramolecular architectures via hydrogen bonding and π ⋯ π interactions. The result indicates that the metal centers imparted their influences on the structures and fluorescence behaviors.

Oxovanadium(V) Complexes With Schiff Base Ligands: Synthesis, Structure, and Catalytic Property

The reaction of [VO(acac)2] with N,N′-ethylenebis(3-ethoxysali- cylideneimine) (H2L1) and N,N′-ethylenebis(3-methylsalicyli- deneimine) (H2L2), respectively, in methanol, affords two new oxovanadium(V) complexes, [VOL1]·H2O (1) and [VOL2] (2). Both complexes have been characterized by elemental analysis, IR, and single-crystal X-ray diffraction methods. The V atoms in the complexes are in distorted square pyramidal coordination. The dinegative Schiff base ligands coordinate to the metal atoms through phenolate and imine donor atoms. Both complexes have effective catalytic property for the sulfoxidation reaction.