Enjun Gao

Current Development of Pd(II) Complexes as Potential Antitumor Agents

Research has proven that the most effective and widely used metal-containing chemotherapy anticancer drugs are cisplatin ([cis-PtCl(2)(NH(3))(2)]) and many platinum complexes, however, these compounds have significant disadvantages including poor water solubility and serious side effects. Thus researches in order to overcome these shortcomings have never interrupted. Many non-platinum complexes have been synthesized and tested, in which some palladium complexes show significant antitumor activity in normal tumor cells and lower resistance of tumor cells to clinical treatments as well as lower side effects. Mononuclear palladium complexes with aromatic N-containing ligands, amino acid ligands, S-donor ligands, and P-containing ligands have respective qualities and properties due to the different structures and properties of the ligands; some dinuclear palladium complexes possess interesting steric structures and good antitumor activity; a try to modify natural medicines with Pd(2+) leads the research to a new route. In this review, medicinal chemistry, the development status and interactions of palladium complexes with DNA are discussed in order to provide guidance and determine structure and antitumor activity relationships for continuing studies of these systems.

Synthesis, characterization, interaction with DNA and cytotoxicity in vitro of the complexes [M(dmphen)(CO3)]·H2O [M = Pt(II), Pd(II)]

The complexes [Pt(dmphen)CO3].H2O (1), [Pd(dmphen)CO3].H2O (2) (dmphen is 2,9-dimethyl-1,10-phenanthroline) have been synthesized and characterized. The binding of the complexes with FS-DNA was investigated by UV spectrum and fluorescence spectrum, showing that the complexes have the ability of interaction with DNA of intercalative mode. The intrinsic binding constant K of the complexes with FS-DNA is 1.8 x 10(5) M(-1) (1) and 1.6 x 10(4) M(-1) (2), respectively. Gel electrophoresis assay demonstrated the ability of the complexes to cleave the pBR 322 plasmid DNA. Evaluation of cytotoxic activity of the complexes against four different cancer cell lines proved that the complexes exhibited cytotoxic specificity and significant cancer cell inhibitory rate.

Solvothermal synthesis, crystal structure, and properties of lanthanide-organic frameworks based on thiophene-2,5-dicarboxylic acid

A series of lanthanide-organic framework coordination polymers, {[La(2)(TDC)(2)(NO(3))(H(2)O)(4)](OH)·5H(2)O}(n) (1) and [Ln(TDC)(NO(3))(H(2)O)](n) (TDC = thiophene- 2, 5- dicarboxylic acid; Ln = Nd(2), Sm(3), Eu(4), Gd(5), Tb(6), Dy(7), Ho(8), Er(9), Yb(10)) have been synthesized by solvothermal reaction and characterized by elemental analysis, FT-IR, TG analysis, single-crystal X-ray diffraction and power X-ray diffraction. The single-crystal X-ray diffraction analysis results show that 1 displays a 3-D porous framework with (3,7)-connected {4(10).6(11)}{4(3)} topology. The compounds 2-10 crystallized in the same P2(1)/c space group and exhibits a (3,6)-connected {4.6(2)}(2){4(2).6(10).8(3)} topology, Right-handed and left-handed helical chains coexist in the 2-D layer structure. The luminescence properties of 2-10 and the magnetic properties of 5,7,8,9 were investigated.

New pH-dependent complexes, from mononuclear Pd(II) monomer to heteronuclear [Pd(II),K(I)]Polymer: DNA cleavage and cytotoxicity in vitro.

Two novel complexes, namely, [Pd(pdc)(2)].(dmp).6H(2)O (1) and [Pd(pdc)(2)K(H(2)O)(5).3H(2)O]n (2) [H(2)pdc=pyridine-2,3-dicarboxylate acid, dmp=2,9-Dimethyl-1,10-phenanthroline] were synthesized and characterized as pH-dependent products. Gel electrophoresis assay demonstrated the ability of the complexes to cleave the pBR 322 plasmid DNA. Values of IC(50) calculated for complexes 1 and 2 show that the two complexes exhibit good cytotoxic activity against different cell lines tested in general, especially more effective against HL-60 and A2780(cisR) cell lines.

Hydrothermal synthesis, structure, and photoluminescence of four complexes based on 1H-imidazole-4,5-dicarboxylate or 1H-imidazole-2-carboxylate ligands

Four complexes, [Ag4(bipy)2(Himdc)2(H2O)2] n (1), [Ag(H2imdc)] n (2), [K(H3imdc)(H2imdc)(H2O)2] n (3), and [Cu(Himc)2] (4) (H3imdc = 1H-imidazole-4,5-dicarboxylic acid, H2imc = 1H-imidazole-2-carboxylic acid, and bipy = 4,4′-bipyridine), were hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis and elemental analysis. The obtained complexes exhibit different coordination structures; 1 contains a 2-D supramolecular layer based on two chains arraying uniformly in an ABAB manner. Compound 2 displays sawtooth-shaped 1-D chains extending to 2-D layers via hydrogen bond interactions. Compound 3 possesses a 3-D framework structure based on a 1-D chain via hydrogen bonding interactions. Compound 4 has a 3-D framework structure bearing a pcu-type topology. In addition, the photoluminescence for 1 has been investigated.

Hydrothermal synthesis, crystal structure and properties of Ni(II)–4f complexes based on 1H-benzimidazole-5,6-dicarboxylic acid

Nine novel heterometallic coordination polymers [Ln(2)Ni(Hbidc)(2)(SO(4))(2)(H(2)O)(8)](n) (Ln = Pr (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6), Ho (7), Er (8), Yb (9), H(3)bidc = 1H-benzimidazole-5,6-dicarboxylic acid) have been synthesized under hydrothermal conditions and characterized by elemental analysis, FT-IR, TG analysis and single crystal X-ray diffraction. X-ray analysis revealed that all complexes present almost identical three-dimensional (3D) structures with PtS-type topology. Complexes 1-7 are all isomorphous, and the structure variation of polymers 8 and 9 is induced by the lanthanide contraction effect. In additional, the luminescence properties of complexes 2, 3 and 5-7, and the magnetic properties of complexes 4 and 6-8 were investigated.

Synthesis, interaction with double-helical DNA and biological activity of new Pt(II) and Pd(II) complexes with phenylglycine

The mononuclear palladium(II) (1) and platinum(II) (2) complexes containing phenylglycine have been synthesized and characterized by elemental analysis, IR spectra, and 1H NMR spectra. The structure of 1 was determined by X-ray diffractometry. The interaction between the complexes and fish sperm DNA (FS-DNA), adenosine-5′-triphosphate (ATP), and adenine (Ade) were investigated by UV absorption spectra, the interaction mode of the complex binding to DNA was studied by fluorescence spectra and viscometry. The results indicate that the two complexes have different binding affinities to DNA, complex 2 > complex 1. Gel electrophoresis assay demonstrates that the two complexes have the ability to cleave pBR322 plasmid DNA. Cytotoxicity experiments were carried out toward four different cancer cell lines, and 1 shows lower inhibitory efficiency than 2, consistent with the binding affinities towards DNA.

Synthesis, characterization, and study on HeLa cells activity of a dinuclear complex [Cu4(phen)4(H2O)2]·(pyri)·3H2O

The complex [Cu4(phen)4(H2O)2]·(pyri)·3H2O(where phen=1,10-phenanthroline and pyri=3,5-pyridine dicarboxylic acid)has been synthesized and characterized. IR spectra, elemental analysis and X-ray single-crystal diffraction were carried out to determine the composition and crystal structure of the complex. The binding of the complex with HC-DNA (HeLa cells DNA, which was extracted by ourselves) was investigated by fluorescence spectrum. Gel electrophoresis assay demonstrates the ability of the complex to cleave the extracted HC-DNA. Additionally, the complex exhibited a significant cytotoxic specificity and cancer cell inhibitory rate. The apoptotic tests indicate that the complex have an apoptotic effect on HeLa cells.

Synthesis, crystal structure, and characterization of two three-fold interpenetrating Co(II) coordination polymers based on 1,4-benzenedicarboxylic acid and length modulated bisimidazole ligands

Two Co(II) coordination polymers, {[Co(bdc)(bib)(H2O)]·H2O}n (1) and {[Co(bdc)(bibp)]}n (2), where H2bdc = 1,4-benzenedicarboxylic acid, bib = 1,4-bis(1-imidazolyl)benzene, and bibp = 4,4′-bis(imidazolyl)biphenyl, have been synthesized by solvothermal methods and characterized by IR spectra, element analyses, thermal analysis, powder X-ray diffraction, and single crystal X-ray diffraction. Complex 1 exhibits a 3-D pillared-layer framework, the ligands of bib and bdc link Co ions to generate a 2-D layer structure, which is further pillared by the bib, giving the final 3-D pillared-layer networks. The void in 1 induces the three-fold interpenetrating structure. Complex 2 features three-fold interpenetrating 3-D architecture, bdc and bibp both adopt a bidentate bridging coordination to link Co ions to afford right- and left-handed helical chains; these helices fuse together and form the 3-D framework. Graphical Abstract

Synthesis, characterization, and DNA interaction of novel Pt(II) complexes and their cytotoxicity, apoptosis and molecular docking

The complexes [Pt{Ar(COOH)2}(OH)2] (1), [Pt{Ar(COOH)2}(OH)2]·H2O (2) have been synthesized and characterized by IR, 1H NMR, element analysis and single-crystal X-ray diffractometry. The interaction of the Pt(II) complexes with fish sperm DNA was explored by UV absorption, fluorescence spectroscopy and viscosity measurements. The results indicated that the complexes bind to FS-DNA in an intercalative mode with different binding affinities. The reaction of the complexes with N7, N3/N9 from guanine and adenine were investigated by 1H NMR. A gel electrophoretic assay demonstrated the ability of the Pt(II) complexes to cleave the pBR322 plasmid DNA. The docking methods were used to predict the DNA binding affinity of Pt(II) complexes by the resulting relative binding energy with DNA with −6.74 kcal mol−1 (complex 1) and −6.21 kcal mol−1 (complex 2). The cytotoxic activity of the complexes was tested against Hela cancer cell lines. The two complexes showed cytotoxic specificity and a significant cancer cell inhibitory rate. Complex 1 possessed the highest inhibition on viability of tested cells. Furthermore, the apoptotic tests indicated that the complexes had an apoptotic effect on HeLa cells.