Optical properties, bioimaging and theoretical calculation of a Zn(II) complex based on triphenylamine derivative.

A luminescent material with various optical properties based on a triphenylamine Zn(II) complex is described. The ultraviolet-visible absorption, one-photon excited fluorescence (OPEF) and two-photon excited fluorescence (TPEF) of the complex indicate that the material has good OPEF and TPEF properties. And the results of one- and two-photon HepG2 cells imaging experiments show the potential of the complex in fluorescence microscopy bioimaging. The experimental Stokes shift and the FWHM (full-width at half-maximum) in different solvents were correlated with the rMPI polarity of the solvent, and the perfect Boltzmann curves were obtained, where the Boltzmann correlation between Stokes shift and solvent polarity is reported for the second time. But the Boltzmann correlation between FWHM and solvent polarity is reported for the first time. In addition, the computational results indicate that, the covalent bond within the salt ZnBr2 is strengthened by the coordination, and the newly formed coordination bond Zn-N is stronger than the original covalent bond Zn-Br.

Diverse Lanthanide Coordination Polymers with 3,3'-Dimethylcyclopropane-1,2-dicarboxylate Ligand: Synthesis, Crystal Structure, and Properties.

In an attempt to investigate the influence of many variables on the synthesis of lanthanide coordination polymers (Ln-CPs) assembled from the ligand 3,3-dimethylcyclopropane-1,2-dicarboxylic acid, three different Ln-CPs with formulae [La9(µ4-dcd)12(µ3-O)2(H)] n (1), [Gd4(µ4-dcd)6(H2O)] n (2), and [Gd2(µ3-OH)2(µ3-dcd)(µ2-ac)2(H2O)] n (3) (dcd = 3,3-dimethylcyclopropane-1,2-dicarboxylate, ac = acetate) have been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectrum, thermal analysis, powder X-ray diffraction, and single X-ray diffraction techniques. 1 represents the first report of the three-dimensional (3D) Ln-CPs based on nonanuclear lanthanide clusters, although it shows extremely low gas uptakes. 2 exhibits one of the previously reported 3D lanthanide wheel cluster-like frameworks. 3 characterizes a novel one-dimensional ladder-like chain [Gd4(OH)4] n decorated with mixed ligand ribbons. Variable-temperature magnetic susceptibility measurement reveals that the shortest Gd···Gd distance in 3 induces the antiferromagnetic interactions between adjacent Gd3+ cations within the hydroxyl-bridged binuclear unit. Remarkably, magnetic investigation for 2 indicates a unique metamagnetic transition from the antiferromagnet to ferromagnet. Furthermore, magnetic studies for 2 also exhibit the presence of significant magnetocaloric effect with a large magnetic entropy change.

[The Latest Research Progress of Coupling between BiOX and Semiconductor Photocatalyst].

The heterojunction was formed between two kinds of coupling semiconductors , which improved the charge separation efficiency of system, widened the spectral response range of catalysts and improved photocatalytic propertirs of catalysts. The process of preparation of semiconductors coupling was easily affected by preparation methods and reaction temperature and so on, which would cause the changes in crystal structure and surface properties of coupling semiconductors, thus photocatalytic quantum efficiency of coupling semiconductors was increased. In this article, the following three aspects were mainly discussed. (1) About the coupled system of halogen bismuth oxide and oxide, because generaling BiOX with the semiconductor material compound, the efficient heterojunction structure could be formed, photocatalytic performances of the photocatalytic degradation of pollutants were improved. (2) About the coupled system of AgX and BiOX, compared with the pure AgI or BiOI, composite photocatalytic materials of AgI/BiOI had higher photocatalytic reactivity in visible light. (3) About the coupled system of halogen bismuth oxide and other compounds, after Bi2S3 coupled with BiOX, photoproduction electronic migrated in the two kinds of catalysts, the separation efficiency of electrons and holes was improved, and photocatalytic performances of coupling compound were improved. In addition, in recent years, the latest research progress of the preparation method, the influencing factors of the photocatalytic performance and improving the utilization efficiency of visible light of semiconductors coupling at home and abroad was reviewed in this paper. Finally, the main problems and the future striving direction in semiconductors coupling were presented.

[A Study on Preparation and Photocatalytic Activity of Mn-BiOCl].

Using Bi2O3 and MnC2 x 4H2O as raw materials, with HCl as solvent, photocatalysts of Mn-BiOCl with different molar ratio of Mn and Bi were prepared by a hydrolysis method. The obtained samples were characterized by XRD, HRTEM, TEM, UV-Vis DRS and SPS. The UV light photocatalytic activity of Mn-BiOCl was evaluated by using methyl orange as model compounds of photocatalytic reaction. The active species in the degradation process of methyl orange were studied. The results show that the Mn content of Mn-BiOCl photocatalysts has an important effect on the catalytic activity. When the molar ratio of Mn and Bi is 0.25%, the as-prepared Mn-BiOCl photocatalyst has the highest catalytic activity toward the degradation of methyl orange. Photocatalytic degradation rate of methyl orange can reach 95.1%.

Hg(II)-activated emission "turn-on" chemosensors excited by up-conversion nanocrystals: synthesis, characterization and sensing performance.

In this paper, two emission "turn-on" chemosensors for Hg(II) sensing were designed and synthesized. Up-conversion NaYF4 nanocrystals were prepared and used as the excitation host for both chemosensors. Spectral analysis suggested that there should be an efficient energy transfer between the host and the chemosensors, which was then confirmed by excited state lifetime analysis. Then two sensing systems using this up-conversion host and the two chemosensors were constructed, their sensing performance for Hg(II) ions was then studied. It was found that the probe emission intensity increased with increasing Hg(II) concentrations, showing an emission "turn-on" effect. Good selectivity and linear response were observed from both sensing systems.

[Study on synthesis and matching degree of energy level of terbium complexes using o-fluoro-benzoic acid as ligand].

Tb(2-FBA)3 x 2H2O and Tb(2-FBA)3 phen were synthesized using o-fluoro-benzoic acid (2-FBA) as the first ligand, and 1,10-phenanthroline (phen) as the second ligand. Elemental analysis and IR spectra were employed to characterize the molecular composition of the two kinds of lanthanide complexes. The UV absorption spectra with same concentration show that the second ligand phen of Tb(2-FBA)3 phen absorbs the portion of the UV light instead of the first ligand 2-FBA. Liquid fluorescence spectra with same concentration show that the fluorescence intensity of Tb(2-FBA)3 x 2H2O is higher than that of Tb (2-FBA)3 phen. The analytical results show that the energy level of 2-FBA matches the lowest excited state energy level of Tb3+ (5D4) better than that of phen. The O-H oscillation of the crystal water in Tb(2-FBA)3 x 2H2O will greatly consume the absorbed energy by ligands, and cause the fluorescence intensity of Tb(2-FBA)3 x 2H2O significantly decline. The energy level of triplet state of the first ligand 2-FBA corresponding to the absorption peak 273 nm has poor matching degree with the 5D4 energy level of Tb3+. In this case, the emission intensity of Tb(2-FBA)3 x 2H2O is still stronger than that of Tb(2-FBA)3 phen. It illustrates that the energy level of the triplet state of the first ligand 2-FBA corresponding to 252 nm has much better matching degree with the lowest excited state of 5D4 energy level of Tb3+ than that of phen. It is the only way to compensate for energy loss by thermal vibration of water molecules and low energy transfer efficiency for poor matching degree between the energy level of corresponding to 273 nm of the first ligand 2-FBA and 5D4 energy level of Tb3+. By combining UV absorption spectra with fluorescence spectra of lanthanide complexes to qualitatively analyze energy level of ligands, the contribution of different types of ligands to the fluorescence properties can be preliminarily understood.

Dipole-dipole interactions in solution mixtures probed by two-dimensional synchronous spectroscopy based on orthogonal sample design scheme.

Two-dimensional (2D) synchronous spectroscopy together with a new approach called "Orthogonal Sample Design Scheme" was used to study the dipole-dipole interactions in two representative ternary chemical systems (N,N-dimethyllformamide (DMF)/CH3COOC2H5/CCl4 and C60/CH3COOC2H5/CCl4). For the first system, dipole-dipole interactions among carbonyl groups from DMF and CH3COOC2H5 are characterized by using the cross peak in 2D Fourier Transform Infrared Radiation (FT-IR) spectroscopy. For the second system, intermolecular interaction among π-π transition from C60 and vibration transition from the carbonyl band of ethyl acetate is probed by using 2D spectra. The experimental results demonstrate that "Orthogonal Sample Design Scheme" can effectively remove interfering part that is not relevant to intermolecular interaction. Additional procedures are carried out to preclude the possibilities of producing interfering cross peaks by other reasons, such as experimental errors. Dipole-dipole interactions that manifest in the form of deviation from the Beer-Lambert law generate distinct cross peaks visualized in the resultant 2D synchronous spectra of the two chemical systems. This work demonstrates that 2D synchronous spectra coupled with orthogonal sample design scheme provide us an applicable experimental approach to probing and characterizing dipole-dipole interactions in complex molecular systems.

[Study on preparations and fluorescent properties of rare earth complex with property of fluorescence sensor].

Europium chloride, 2-thienylformyltrifluoroacetone and sodium silicate were used to synthesize new-style rare earth complex (Eu-TNS). By adding into dichloromethane solution containing Eu-TNS, the fluorescent intensities were enhanced gradually and regularly. High-resolution mass spectrometry was used to detect the formula of Eu-TNS, which belongs to multi-core rare-earth complex. Polarity of solution increasing by adding absolute ethanol will cause Eu-TNS to dissociate, which enhances the fluoresceot intensities of Eu-TNS solution. This rare earth complex Eu-TNS can be employed as fluorescence sensor to detect the content of ethanol in organic solvent.

[Synthesis of SiO2 coated Eu(TTA)3phen and study on its fluorescent property].

New-style fluorescent material of SiO2/Eu(TTA)3 phen was synthesized by the method of dispersing Eu(TTA)3 phen in isopropanol and hydrolyzing TEOS. Fluorescence spectra showed that the emission intensities of SiO2/Eu(TTA)3 phen were much more stronger than that of Eu(TTA)3 phen by more than two times. At the same time, the peak at 617.4 nm became very sharp, which could not be observed for Eu(TTA)3 phen. This indicated that the structure of Eu(TTA)3 phen became more rigid after coated by SiO2. Thus, the emission intensity was enhanced largely. Life-time of SiOz/Eu(TTA)3 phen decreasing just confirmed the rigidity of SiO2/Eu(TTA)3 phen.

[Synthesis and characterization of new lanthanide complexes using pipemidic acid (PPA) and dioxane as ligands].

Eu(PPA)3 dioxane and Tb(PPA)3 dioxane were synthesized by firstly adopting dioxane as second ligand and using pipemidic acid (PPA) as first ligand. In contrast with two kinds of binary lanthanide complexes Eu(PPA)3 and Tb(PPA)3, the photoluminescent intensities of Eu (PPA)3 dioxane and Tb (PPA)3 dioxane are much stronger, especially for that of Tb(PPA)3 dioxane. The enhancement of photoluminescent intensities of Eu(PPA)3 dioxane and Tb(PPA)3 dioxane is because of the replacement of dioxane for water bonded to Eu3+ and Tb3+, by which the energy loss through heat oscillation will be inhibited. The as-synthesized lanthanide complexes were characterized by FT-IR, photoluminescence spectra and photoluminescence lifetime. The lifetime of Eu(PPA)3 dioxane and Tb(PPA) dioxane remarkably changed compared with those of Eu(PPA)3 and Tb(PPA)3. However, there is much difference for the lifetime change of as-synthesized lanthanide complexes formed by Eu3+ and Tb3+, which shows that there is different energy transfer process for the lanthanide complexes formed by Eu3+ and Tb3+. The synthesis of lanthanide complexes using dioxane as second ligand will provide a new method to detect the existence of dioxane.

[Study on the effect of C-terminal acidic protein on the prokaryotic expression of alpha-thionin by FTIR microspectroscopy].

Fourier transform infrared (FTIR) microspectroscopy was used to investigate the effects of C-terminal acidic protein on the secondary structure of wheat alpha-thionin in the absence of signal peptide during the prokaryotic expression process. SDS-PAGE analysis revealed that the presence of acidic protein gave rise to the formation of inclusion body, however, the absence of acidic protein greatly enhanced the solubility of the heterogenous protein expressed in E. coli BL21(DE3) with the induction of 1 mmol x L(-1) IPTG at 37 degrees C. Difference spectra in amide I region were obtained by subtraction between the spectra of intact cells containing S and Sc, which corresponds to the absence and presence of C-terminal acidic proteins, respectively. The second derivative of the difference spectra measured 2 h after induction showed one principal component at approximately 1 630 cm(-1), while no significant peak appeared at the same peak position when the spectra before induction were compared. Combined with SDS-PAGE of recombinant protein, the authors presumed that the peak absorption at approximately 1 630 cm(-1) is most likey to be assigned to protein aggregate within inclusion body. Gaussian curve-fitting was done on the Fourier self-deconvolution spectra within amide I region of intact cells containing S and Sc. The experimental data revealed that the relative content of aggregate absorption at (1 629 +/- 1) cm(-1) gradually increased with induction time, which is consistent with the results of SDS-PAGE. Simutaneously, the formation of aggregate gave rise to the increase of alpha-helix, as well as the decrease of beta-turn and random coil in the case of Sc. It was not the case for S, however, where random coil experienced the increase in the relative average fractions, while beta-turn and beta-sheet at (1 629 +/- 1) cm(-1) behaved in different ways. The above mentioned phenomenon indicated that beta-sheet and random coil are most likely to transform into aggregate and alpha-helix with the introduction of C-terminal acidic protein.

[Study on X-ray powder diffraction of various structured zinc titanate prepared by the method of direct precipitation].

Zinc titanate powders were prepared from Ti(SO4)2, Zn(NO3)2 x (6)H2O and (NH4)2CO3 by the method of direct precipitation. The effects of reaction conditions on the structure of zinc titanate were studied. The sample was analyzed by means of XRD and TG-DTA. The structure of zinc titanate was affected by the reaction subsequence of the formation of titanic acid and zinc carbonate. In the reaction system where titanic acid was generated earlier, collision reaction occurred between the generated zinc carbonate molecule and the surrounding titanic acid molecule. When titanic acid was generated earlier and precipitant (NH4)2CO3 was sufficient, Zn2Ti3O8 was obtained because of the sufficient collision reaction and superfluous titanic acid. In the reaction system where zinc carbonate was generated earlier, collision reaction occurred between the generated titanic acid molecule and the surrounding zinc carbonate molecule. When zinc carbonate was generated earlier and precipitant (NH4)2CO3 was sufficient, Zn2TiO4 was obtained because of the sufficient collision reaction and superfluous zinc carbonate. In addition, the kinds and structure of the production were affected by the dosage of precipitant and the reaction temperature. Zn2Ti3O8 or Zn2TiO4 could be obtained easier when using more precipitant or higher reaction temperature which could cause more sufficient collision reaction. ZnTiO3 could be obtained under the conditions of less precipitant and lower reaction temperature.

[The study on the growth process of ZnO nanorods].

Albstract The authors synthesized ZnO nanorods by calcining the precursor composed of PVP and Zn(CH3COO)2.2H2O at 300 degrees C. In order to investigate the growth process of ZnO nanorods, the precursor was calcined for different time (0.5, 3, 12, 24 h) and the corresponding products were measured by TEM, HR-TEM (high-resolution transmission electron microscopic), SAED (selected-area electron diffraction pattern) and XRD. The result showed that there were ZnO crystallites in the precursor of PVP and Zn(CH3COO)2.2H2O, which was dried at 110 degrees C. When the precursor was calcined at 300 degrees C for 0.5 h, ZnO nanorods could be observed with diameter of 50 nm and the nanorods consisted of two parts. One was compact nanorod with diameter of about 30 nm and the other part was ZnO crystallites attaching around the nanorod. This phenomenon indicated that there might be a transverse growth direction of ZnO nanorods at early time of crystal growth. When the precursor was calcined for 3 h, the products were direct and smooth single crystal ZnO nanorods. Further increasing the calcining time at 300 degrees C could improve the length of the ZnO nanorods in a certain extent while the diameter changed a little. The HR-TEM results showed that the growth direction of ZnO nanorods was along c axis.

[The synthesis and characteristic of Co3O4 nanocrystals].

The authors found a new method to synthesize Co3O4 nanocrystals, which were synthesized using Co(CH3COO)2 x4H2O and PVP as precursor. The as-prepared products were measured by SEM, TEM and XRD. Co(CH3COO)2 x 4H2O and PVP were dissolved together in a kind of solvent. Then, the solution was vaporized in water bath at 60 degrees C till the solution became viscid. The viscid solution was transferred into a ceramic boat and was dried in a oven at 110 degrees C for 12 hours. Finally, the dried sample was calcined in tube-like stove at 400 degrees C for 2 hours in air to produce the Co3O4 nanocrystals. To prepare the precursor composed of PVP and Co (CH3COO)2 x 4H2O, the authors employed two different solvent (ethanol and H2O). It was found that different appearance of Co3O4 nanocrystals was achieved by using different solvent. When ethanol is used as solvent, the prepared spherical particles with diameter of about 1 microm were consisted of Co3O4 nanocrystals with diameter of 20-50 nm. However, only Co3O4 nanocrystals with diameter of 20 nm were synthesized when H2O is used as solvent. This indicated that the solvent played a big role for the final appearance of Co3O4 nanocrystals.

[The emission of rare earth complex Eu(asprin)3phen].

Two kinds of electroluminescent devices were fabricated by doping the rare earth complex Eu(asprin)3phen into polymer PVK: (1) ITO/PVK:RE/LiF/Al; (2) ITO/PVK:RE/PBD/LiF/Al. A great difference in the EL spectrum was found between the two kinds of devices. In device (2) the intensity of 594 nm was rather weak compared with that of 614 nm. The spectrum was consistent with the photoluminescence (PL) spectrum under the state of thin film. But in device (1), the peak emission of 594 nm was comparable to that of 614 nm. Preliminary discuss on this phenomenon was made; in device (1), the recombination region was close to the metal cathode, effect of metal cathode on the electroluminescence of the rare earth complex caused the changes of the EL emission which was quite different from the TL emission. The phenomenon was not observed in device (2) whose recombination region was far from the cathode because an electron-transport layer was inserted.

[Interaction between polyamide and zinc salt].

X-ray diffraction and FTIR spectroscopic method have been used to investigate the interaction between the amide group of nylon 6 and zinc chloride. The nylon sample obtained by adding formic acid solution of nylon into aqueous solution saturated by zinc chloride is significantly different from the nylon precipitated after mixing formic acid solution of nylon and water. X-ray diffraction results demonstrate that nylon precipitated from water has crystallization while the sample acquired from saturated solution of ZnCl2 remains amorphous. FTIR spectroscopic study shows that the interaction between zinc ion and the amide group of nylon 6 brings about significant variation of amide I and II bands and prevents the crystallization of nylon. The interaction between nylon and zinc ions may be helpful in the development of a new method of manufacturing new nylon material with superior performance.

Synthesis, characterization, and antibacterial activities of some rare Earth metal complexes of pipemidic acid.

Eight new solid complexes of pipemidic acid (PPA) with trichlorizated rare earth metals LaCl(3), CeCl(3), PrCl(3), NdCl(3), SmCl(3), TbCl(3), DyCl(3), and YCl(3) have been synthesized. The complexes were characterized by elemental analyses, IR, NMR, and molar conductance measurements. The general formulas of the complexes are [M(PPA)(4)]Cl(3) (M=Ce(III), Pr(III), Nd(III), Sm(III), Tb(III), Dy(III), Y(III)), and [La(PPA)(4)Cl]Cl(2). At the same time, the antibacterial activities of PPA and four of its complexes were tested. The results show that PPA and its complexes all have inhibitory action against bacteria of Escherichia coli, Bacillus subtilis, Streptococcus pneumoniae, and Pseudomonas aeruginosa but not Staphylococcus aureus. We compared their antibacterial activities and found that the antibacterial activity of [La(PPA)(4)Cl]Cl(2) against S. pneumoniae is much stronger than that of PPA and the other complexes.

A new mechanism of Raman enhancement and its application.

Strong electronic Raman bands corresponding to the transition between 4I9/2 and 4I11/2 manifolds of Nd3+, caused by a Raman-enhancement effect, are observed in the FT-Raman spectrum of Nd2O3. Neither resonance enhancement (RR) nor surface enhancement (SERS) accounts for the Raman enhancement observed here. We propose a new mechanism of Raman enhancement called the "feed-back" mechanism. A YAG laser excites the final state of the Raman transition (4I11/2 of Nd3+) to the 4F3/2 state and causes a significant decrease in the population of Nd3+ at the 4I11/2 state. This causes the population ratio of Nd3+ at 4I9/2 and 4I11/2 to deviate from the value required by Boltzmann's law. To restore equilibrium, Raman scattering is enhanced so that more Nd3+ ions are brought from the 4I9/2 state to the 4I11/2 state. This hypothesis gets support from the temperature-variable FT-Raman spectroscopic results. Additionally, obvious differences between the Stokes and anti-Stokes Raman spectrum of Nd3+ provide further evidence to support the feed-back mechanism. The Raman-enhancement effect confers on the electronic Raman bands a special ability to reflect the variation of coordinated structure around metal ions. The structural variations in polymer-metal ion composites and biomineralization systems have been investigated by using the electronic Raman bands.