Publications by authors named "Dongcai Guo"

Four novel coumarin fluorescence small-molecules were successfully prepared and validated by proton nuclear magnetic resonance ( H-NMR), carbon-13 ( C)-NMR, and mass spectrometry (MS). Their corresponding europium(III) complexes were synthesized and characterized. The ligand can emit green fluorescence in solutions, and the best concentration was 40 μmol/L.

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Two novel coumarin derivatives and the corresponding europium complexes were prepared using a simple procedure. The pH response of the ligand and the aggregation-induced emission (AIE) properties of the target europium complex were studied. The ligand had an intramolecular charge transfer (ICT) effect and was linearly and sharply responsive under acidic conditions.

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Four novel salicyloylhydrazone derivatives and their terbium(III) complexes were synthesized and characterized. The thermal analysis results showed that the terbium(III) complexes possessed good thermal stability. The fluorescence research results showed that the terbium(III) complex substituted by phenyl possessed the best fluorescence intensity among them, and its fluorescence quantum yield was also the highest.

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Six novel 8-hydroxyquinoline derivatives were synthesized using 2-methyl-8-hydroxyquinoline and para-substituted phenol as the main starting materials, and were characterized by H nuclear magnetic resonance (NMR), mass spectrometry (MS), ultraviolet (UV) light analysis and infra-red (IR) light analysis. Their complexes with Eu(III) were also prepared and characterized by elemental analysis, molar conductivity, UV light analysis, IR light analysis, and thermogravimetric-differential thermal analysis (TG-DTA). The results showed that the ligand coordinated well with Eu(III) ions and had excellent thermal stability.

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Gd(3+)-ion-doped upconversion nanoparticles (UCNPs), integrating the advantages of upconversion luminescence and magnetic resonance imaging (MRI) modalities, are capturing increasing attention because they are promising to improve the accuracy of diagnosis. The embedded Gd(3+) ions in UCNPs, however, have an indistinct MRI enhancement owing to the inefficient exchange of magnetic fields with the surrounding water protons. In this study, a novel approach is developed to improve the MR imaging sensitivity of Gd(3+)-ion-doped UCNPs.

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Novel Schiff base ligands derived from N'-benzylidene-benzohydrazide (substituted by -H, -CH3, -OCH3, -Cl) and 2-chloro-N-phenylacetamide were synthesized. The solid complexes of rare earth (Eu, Tb) nitrate with these Schiff base ligands were synthesized and characterized by elemental analysis, EDTA titrimetric analysis, thermal analysis, infrared spectra and UV-Vis spectra analysis. The fluorescence properties of rare earth (Eu, Tb) complexes in solid were studied.

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A series of terbium complexes with salicylhydrazide-salicylacylhydrazone derivatives were synthesized and characterized by elemental analysis, IR spectra, UV/vis spectra and thermal analysis. The luminescence and electrochemical properties of the terbium complexes were investigated. The results show that all the target complexes exhibited characteristic emissions of terbium ions and the complex substituted by the chlorine has the strongest luminescence intensity with the highest quantum yield at 0.

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Seven novel coumarin derivatives derived from salicylaldehyde and phenol were synthesized and characterized by (1)H NMR and (13)C NMR spectra, mass spectra, infrared spectra and elemental analysis. Their corresponding Eu(III) complexes having general formula EuL(1-7)(NO3)3[Symbol: see text]2H2O were successfully prepared and characterized by elemental analysis, EDTA titrimetric, molar conductivity, UV-Vis, FT-IR and thermal performance studies. The luminescence properties, fluorescence quantum yields and the electrochemical properties of the title complexes were investigated.

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Four novel salicylaldehyde isonicotinoyl hydrazone derivatives and their corresponding europium ion complexes were synthesized and characterized, while the luminescence properties and the fluorescence quantum yields of the target complexes were investigated. The results indicated that the ligands favored energy transfers to the emitting energy level of europium ion, and four target europium complexes showed the characteristic luminescence of central europium ion. Besides the luminescence intensity of the complex with methoxy group, which possessed the highest fluorescence quantum yield (0.

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Seven novel pyrazolone derivatives were synthesized and characterized by (1) H NMR and (13) C NMR spectra, mass spectra, infrared spectra and elemental analysis. Their terbium complexes were prepared and characterized by elemental analysis, EDTA titrimetric analysis, UV/vis spectra, infrared spectra and molar conductivity, as well as thermal analysis. The fluorescence properties and fluorescence quantum yields of the complexes were investigated at room temperature.

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Four novel salicyladehyde salicyhydrazone derivatives and their corresponding europium (Eu(3+)) complexes were synthesized and characterized. The formulas of the complexes were [EuL(a-d)(NO3)2](NO3) · H2O. The investigatoin of fluoresence properties of the Eu(3+) complexes showed that the salicyladehyde salicyhydrazone derivatives were efficient sensitizers for the fluoresence of Eu(3+) ions.

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Eight novel 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazol derivatives have been designed and synthesized, and their corresponding Tb(3+) complexes were also prepared successfully. The fluorescence properties and fluorescence quantum yields of the target complexes were investigated, the results showed that the ligands were an efficient sensitizer for Tb(3+) luminescence, and the target complexes exhibited characteristic fluorescence emissions of Tb(3+) ion. The fluorescence intensity of the complex substituted by chlorine was stronger than that of other complexes.

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The reaction of 5,5'-(pyridine-2,6-diyl)bis(4-amino-3-mercapto-1,2,4-triazole) with various aromatic aldehydes in acetic acid yielded the corresponding 5,5'-(pyridine-2,6-diyl)bis(4-arylideneamino-3-mercapto-1,2,4-triazole) derivatives. The structures of the synthesized compounds as well as their intermediates were confirmed by elemental analysis, infrared spectra, (1)H NMR spectra and mass spectra studies. All the synthesized title compounds were screened for their antibacterial activities, and the preliminary results revealed that some of them showed good activities against Escherichia coli and Pseudomonas aeruginosa.

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Six novel 2-(benzylcarbamoyl)phenyl derivatives were synthesized and characterized by (1) H-NMR, mass spectrometry, infrared spectra and elemental analysis. Their europium complexes were prepared and characterized by elemental analysis, EDTA titrimetric analysis, IR and UV spectra as well as molar conductivity measurements. The luminescence properties of these complexes were investigated and results show that 2-(benzylcarbamoyl)phenyl derivatives possess high selectivity and good coordination with the europium ion.

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This paper reports the synthesis of a new bioactive complex, 8-hydroxyquinolinato-bis-(salicylato) yttrium (III) (HSAY), whose composition and structure were characterized by elemental analysis, IR spectra, thermogravimetric analysis, and X-ray diffraction. The power-time curves of the compounds HSAY, C(7)H(6)O(3), C(9)H(7)NO, and YCl(3)·6H(2)O on the growth metabolism of Schizosaccharomyces pombe (S. pombe) were determined at 32.

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Five ternary complexes were synthesized from europium with aromatic carboxylic acid (p-methylbenzoic acid, methoxybenzoic acid, m-chlorobenzoic acid and benzoic acid, p-hydroxylbenzoic acid) and acrylonitrile, and characterized by means of elemental analysis, thermal analysis, FTIR spectra and UV spectra. The fluorescence spectra show that five ternary complexes have good luminescence properties, and the sequence of the ability of the aromatic carboxylic acids to transfer light energy to europium ion is as follows: p-methylbenzoic acid>benzoic acid>m-chlorobenzoic acid>p-hydroxylbenzoic acid>methoxybenzoic acid. Meanwhile, the ternary europium complexes containing a reactive ligand acrylonitrile will possibly have a potential application to the fabrication of bonding-type europium polymer luminescent materials.

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In this paper, five new reactive ternary europium complexes were synthesized with the first ligand of 1,10-phenanthroline and the reactive second ligands of maleic anhydride, acrylonitrile, undecenoic acid, oleic acid and linoleic acid, and also characterized by means of elemental analysis, EDTA titrimetric method, FTIR spectra and UV spectra. The fluorescence spectra show that the five new ternary complexes have much higher luminescence intensity than their corresponding binary complexes, and the synergy ability sequence of the five reactive ligands is as follows: linoleic acid > oleic acid > acrylonitrile > maleic anhydride > undecenoic acid. At the same time, the reactive ternary europium complexes coordinated with the reactive ligands, which can be copolymerized with other monomers, will provide a new way for the synthesis of bonding-type rare earth polymer functional materials with excellent luminescence properties.

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