Zengchen Liu

Crystal structures, DNA-binding and cytotoxic activities studies of Cu(II) complexes with 2-oxo-quinoline-3-carbaldehyde Schiff-bases

Three novel 2-oxo-quinoline-3-carbaldehyde Schiff-bases and their Cu(II) complexes were synthesized. The molecular structures of Cu(II) complexes were determined by X-ray crystal diffraction. The DNA-binding modes of the complexes were also investigated by UV-vis absorption spectrum, fluorescence spectrum, viscosity measurement and EB-DNA displacement experiment. The experimental evidences indicated that the ligands and Cu(II) complexes could interact with CT-DNA (calf-thymus DNA) through intercalation, respectively. Comparative cytotoxic activities of ligands and Cu(II) complexes were also determined by MTT [3-(4,5-dimethyl-2-thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide] and SRB (sulforhodamine B) methods. The results showed that the three Cu(II) complexes exhibited more effective cytotoxic activity against HL60 cells and HeLa cells than corresponding ligands. Also, CuL(3) showed higher cytotoxic activity than CuL(1) and CuL(2).

An effective Cu(II) quenching fluorescence sensor in aqueous solution and 1D chain coordination polymer framework

In the article, a novel fluorescent probe for the copper cation based on fluorescence quenching mechanism was designed. It exhibited high selectivity for Cu(II) over other common metal ions in aqueous media. Furthermore the coordination between Cu(II) and the organic molecule sensor fabricated an interesting 1D chain coordination polymer framework.

Synthesis and crystal structure of a Schiff base derived from two similar pyrazolone rings and its rare earth complexes: DNA-binding and antioxidant activity

A Schiff base derived from two similar pyrazolone derivatives 4-(1′-phenyl-3′-methyl-5′-hydroxypyrazol-4′-yl)methyleneiminophenazone and its Tb(III) and Dy(III) complexes were synthesized and characterized. The molecular structures of the ligand and Dy(III) complex were determined by X-ray crystal diffraction. The DNA-binding properties of the compounds were investigated by electronic absorption spectroscopy, fluorescence spectra, and viscosity measurements. The compounds interact with DNA through intercalation. The compounds also exhibit potential antioxidant activities in vitro and the antioxidant activity of the Ln(III)-complexes was stronger than that of the ligand alone and some standard antioxidants, such as mannitol and vitamin C.

Magnetic nanoparticles modified with DTPA-AMC-rare earth for fluorescent and magnetic resonance dual mode imaging

In the present study, we report new water-soluble cell fluorescence imaging and contrast agents that are based on DTPA-AMC(7-amino-4-methyl coumarin)-Eu(3+) and DTPA-AMC(7-amino-4-methyl coumarin)-Gd(3+) compounds conjugated to Fe(3)O(4) NPs via a PEG-NH(2) linker. The novel Fe(3)O(4) NP-conjugates present two main advantages for cell fluorescence labelling: water solubility and targeting ability. The in vitro experiments demonstrate that water-soluble Fe(3)O(4) NPs-DBI-PEG-NH-DTPA-AMC(7-amino-4-methyl coumarin)-Eu(3+) has excellent cell permeating activity. Moreover, the relaxation rate test of Fe(3)O(4) NPs-DBI-PEG-NH-DTPA-AMC(7-amino-4-methyl coumarin)-Gd(3+) shows a higher T1 relaxation effect than traditional DTPA-Gd(3+) MRI agents. According to in vivo liver MRI experiments, better contrast of the liver was achieved after addition of Fe(3)O(4) NPs-DBI-PEG-NH-DTPA-AMC(7-amino-4-methyl coumarin)-Gd(3+). The results will provide a significant guide for researchers exploring the biomedical applications of superparamagnetic Fe(3)O(4) NPs.

Synthesis, Characterization, DNA Binding Properties and Antioxidant Activity of Ln(III) Complexes with Schiff Base Ligand Derived from 3-Carbaldehyde Chromone and Aminophenazone

A novel Schiff base ligand, chromone-3-carbaldehyde-aminophenazone (L) and its Ln(III) (Ln = La, Yb) complexes were synthesized and characterized by physicochemical methods. The interaction between the ligand, Ln(III) complexes and calf thymus DNA in physiological buffer (pH = 7.10) was investigated by using UV–vis spectroscopy, fluorescence spectra, ethidium bromide experiments and viscosity measurements, indicating that the studied compounds can all bind to DNA via an intercalation binding mode and the complexes have stronger binding affinity than the free ligand alone. Furthermore, antioxidant activity of the ligand and its complexes was determined by superoxide and hydroxyl radical scavenging methods in vitro, suggesting that Ln(III) complexes inhibit stronger antioxidant activity than the ligand alone and some standard antioxidants, such as mannitol and vitamin C.

A highly selective chemosensor for Al3+ based on 2-oxo-quinoline-3-carbaldehyde Schiff-base.

A new Schiff-base ligand (1) with good fluorescence response to Al(3+), derived from 2-oxo-quinoline-3-carbaldehyde and nicotinic hydrazide, had been synthesized and investigated in this paper. Spectroscopic investigation revealed that the compound 1 exhibited a high selectivity and sensitivity toward Al(III) ions over other commonly coexisting metal ions in ethanol, and the detection limit of Al(3+) ions is at the parts per billion level. The mass spectra and Jobs plot confirmed the 1:1 stoichiometry between 1 and Al(3+). Potential utilization of 1 as intracellular sensors of Al(3+) ions in human cancer (HeLa) cells was also examined by confocal fluorescence microscopy.

Lanthanide Complexes of 1-phenyl-3-methyl-5-hydroxypyrazole-4-carbaldehyde-(4′-hydroxybenzoyl) Hydrazone: Crystal Structure and Interaction Studies With Biomacromolecules

1-phenyl-3-methyl-5-hydroxypyrazole-4-carbaldehyde-(4′-hyd roxybenzoyl) hydrazone and Ln(III) complexes have been synthesized and characterized. The interaction between these compounds and biomacromolecules was investigated by fluorescence and UV/vis absorption spectroscopy. The results suggested that the compounds caused fluorescence quenching of BSA through a static quenching procedure. Hydrophobic interaction force also played a major role in stabilizing the compounds. Moreover, interactions between calf thymus DNA and compound H3L and its Ln(III) complexes were studied by spectroscopy and viscosity measurements. These studies showed that these compounds bind to DNA via an intercalation mode. Furthermore, antioxidant activities of compounds were determined by hydroxyl radical scavenging methods in detail. Supplemental materials are available for this article. Go to the publishers online edition of Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry to view the supplemental file.

A facile synthesis of a highly water-soluble and selective fluorescent sensor towards zinc ions derived from β-cyclodextrin based on an unexpected sensing process

A highly water-soluble and sensitive fluorescent sensor derived from β-cyclodextrin with relatively lower toxicity was synthesized. The fluorescent sensor exhibited spherical morphology under SEM observation. By the fluorescence behavior towards several metal ions, the sensor showed high selectivity and sensitivity for Zn2+ over other commonly co-existent metal ions in a pure water environment (pH = 7.2). Moreover, the large binding constant (2.55 × 1013 M−1) between Zn2+ and the fluorescent sensor was calculated in a pure water media. The fluorescent microscope images of onion epidermal cells proved that the water-soluble sensor showed a high ability for cell permeability. In addition, a chelating induced fluorescence enhancement (CIFE) and photoinduced electron transfer (PET) sensing mechanism was concluded according to the fluorescence behavior. The fluorescent sensor in a pure water media effectively enhanced the application value of the fluorescent sensor for the tracking and detection of Zn2+.

A supramolecular self-assembly host–guest system from cyclodextrin as an absolute water-soluble fluorescence sensor for aluminium ions: synthesis, characterization and sensing activity

In the study, an organic molecule derived from paeonol and anthraniloyl hydrazine (L) was synthesized via a Schiff-base reaction. Moreover, a host–guest system composed of TEPA-β-CD and L was self-assembled via supramolecular interactions. The organic molecule and host–guest system were characterized via NMR, HRMS, IR, and SEM. In addition, the internal structure of the system was clearly observed via HRTEM. The host–guest system exhibited absolute water-solubility. Via the fluorescence behavior toward several metal ions in aqueous media without organic solvents (pH = 7.2), the host–guest system showed high selectivity toward Al3+ over other commonly coexistent metal ions. Therefore, this host–guest system can be used as a fluorescence sensor for aluminium ions in aqueous media. Moreover, a large binding constant (5.84 × 104 M−1) between the sensor and Al3+ was calculated via a fluorescent titration experiment. Additionally, the absolute water-solubility activity effectively enhanced the application value of the host–guest system for tracking and detection of Al3+.

Fabrication of a self-assembled supramolecular fluorescent nanosensor from functional graphene oxide and its application for the detection of Al3+

In this paper, an excellent water-soluble platform derived from a β-cyclodextrin derivative and graphene oxide was synthesized and characterized. Moreover, by a supramolecular host–guest self-assembly interaction between the organic molecule and the water-soluble platform, an interesting supramolecular system was fabricated successfully. By fluorescence experiments toward several metal ions, a higher response toward Al3+ than other commonly coexistent metal ions in absolute water media (pH = 7.2) was shown. Meanwhile, a large binding constant (3.89 × 1012 M−1) between them was calculated by fluorescence titration experiments. In addition, fluorescence imaging in living cells was studied systemically, which exhibited a high fluorescence sensing activity toward Al3+. This study provides the first detailed supramolecular host–guest self-assembled nanosensor from graphene oxide and β-cyclodextrin derivatives. Its water-solubility and excellent sensing activity effectively enhanced the application value of the fluorescent nanosensor for tracking and detecting Al3+ in the environment and in organisms.