Effect of Nano-anatase TiO_2 on Spectral Characterization of PhotosystemⅡParticles from Spinach

The photosystem Ⅱ(PSⅡ) particles were purified by means of nano-anatase TiO_2 treatment of spinach and studied by spectroscopy. The results show that the electron transport and the oxygen-evolving rate of PSⅡ are accelerated after it has been treated with nano-anatase TiO_2; the UV-Vis absorption spectrum of PSⅡ particles is increased; the red shift of fluorescence emission peak of PSⅡ is 2 nm; the peak intensity is decreased; the PSⅡ signal Ⅱs of low temperature electron paramagnetic resonanace(EPR) spectrum is intensified under light, and the PSⅡ circular dichroism(CD) spectrum is similar to that of control. It is suggested that nano-anatase TiO_2 might bind to the PSⅡ reaction center complex and intensify the function of the PSⅡ electron donor, however, nano-anatase TiO_2 treatment does not change the configuration of the PSⅡ reaction center complex.

Preparation and Spectral Characterization of 3-Benzyl-6-aryl-1,2,4-triazolothiadiazoles

Benzyl 4 amino 5 mercapto 1,2,4 triazole reacted with aromatic acids in the presence of phosphorus oxychloride, yielding a series of new compounds, i.e. , 3 benzyl 6 aryl 1,2,4 triazolothiadiazoles, each of which has an active methylene at 3 position. The structures of all the title compounds were confirmed by elementary analysis, IR, 1H NMR and 13 C NMR spectra.

Spectral Characterizations of Veronese Surface in S^4

In this paper, we prove that the Veronese surface can be determined by the 1 spectrum of the Laplace operator.

Syntheses and Crystal Structures of 4-Amino-3-(3-hydroxypropyl)-1H-1,2,4-triazole-5(4H)-thione and 6-(4-Biphenylyl)-3-(3-hydroxypropyl)-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazine

Starting with y-butyrolactone, 4-amino-3-（3-hydroxypropyl）-1H-1,2,4-triazole-5-（4H） thione 1 was prepared, and cyclization of it with 4-phenylbromoacetophenone gave 6-（4-biphenylyl）- 3-（3-hydroxypropyl）-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazine Ⅱ. The structures of Ⅰ and Ⅱ were determined by elemental analyses, IR, ^1H NMR, ^13C NMR, and X-ray diffraction. Crystal data for 1： C5H10N4OS, Mr = 174.23, monoclinic system, space group P21/c, a =8.4568（6）, b = 22.8905（16）, c = 9.2625（6） A, β= 114.172（1）°, V= 1635.82（19） A^3, F（000） = 736, Z= 8, Dc = 1.415 g/cm^3, 2 λ=0.71073 A,μ = 0.346 mm^-1 and the final R = 0.0603 for 2870 unique reflections with 1993 observed ones （I 〉 2σ（I）. Crystal data for Ⅱ： C19H18N4OS, Mr = 350.43, monoclinic system, space group P21/c, a = 6.7481（7）, b = 8.2647（8）, c = 30.075（3） A, β= 94.445（2）°, V= 1672.3（3） A3, F（000） = 736, Z = 4, Dc = 1.392 g/cm^3, λ=0.71073 A,μ= 0.209 mm^-1 and the final R = 0.0667 for 3000 unique reflections with 2534 observed ones （I 〉 2σ（I））. In the crystal of compound Ⅱ, the five-membered triazole ring and two benzene rings are coplanar, while the six-membered thiadiazine ring is slightly distorted, with an r.m.s deviation of 0.227（1） A. Some hydrogen bonding interactions are observed and π-π stacking interactions between adjacent molecules are found in the packing diagrams of the two compounds.

Preparation and Crystal Structure of 3-(2-Hydroxyphenyl)-6-(4-nitrophenyl)-7H- 1,2,4-triazolo[3,4-b][1,3,4 ]thiadiazine

3-(2-Hydroxyphenyl)-6-(4-nitrophenyl)-7H-1,2,4-triazolo[3,4-b][1,3,4] thiadiazine, C 16H 11N 5O 3S, was prepared by the cyclization of 3-(2-hydroxyphenyl)-4-amino-5-mercapto-1,2,4-triazole with 2-bromo-4-nitroacetophenone. The compound was characterized by means of elemental analysis, IR, 1H NMR, 13C NMR, mass spectrometry, and X-ray diffraction. The compound crystallizes in a monoclinic system with space group C c, a=2.1853(4) nm, b=2.1192(5) nm, c=1.3526(3) nm, β=95.21(2)°, V=6.238(2) nm3 , D calcd.=1.505 Mg/m3, Z=16, F(000)=2916, R 1=0.0501, wR 2=0.0427. A comparison between the crystal structures of 1,2,4-triazolo[3,4-b] [1,3,4] thiadiazine and 1,2,4-triazolo[3,4-b][1,3,4] thiadiazole was made in the structural view. A two-dimensional network is formed by hydrogen bonds and π-π stacking interactions.

Prevention of La^(3+) on DNA Damage Caused by Hg^(2+) from Fish Intestines

The aim of this study was to investigate the effects of rare earth elements （REEs） in preventing Hg^2＋ pollution, using fish intestinal DNA in vitro and study the mechanism of the interactions between Hg^2＋ , La^3＋ , the mixture of La^3＋ and Hg^2＋ and DNA by spectroscopy. The interactions between Hg^2＋ , La^3＋ , the mixture of La^3＋ and Hg^2＋ and DNA from fish intestine in vitro was investigate by using absorption spectrum and fluorescence emission spectrum. Ultraviolet absorption spectra indicated that the addition of Hg^2＋ , La^3＋ , and the mixture of La^3＋ and Hg^2＋ to DNA generated obvious hypochromic effect. Meanwhile, the 205.2 nm peak of DNA blue and the 258.2 nm peak of DNA red shifted. The hypochromic effect and peak shift was caused by these ions in an order of Hg^2＋ 〉 Hg^2＋ ＋ La^3＋ 〉 La^3＋ . The fluorescence emission spectra showed that as the addition of Hg^2＋ , La^3＋ , and the mixture of La^3＋ and Hg^2＋ , the emission peak at about 416.2 nm of DNA did not obviously change, but the fluorescence intensity reduced gradually with the order in treatment was Hg^2＋ 〉 Hg^2＋ 〉 La^3＋ 〉 La^3＋ . Hg^2＋ , La^3＋ , and the mixture of La^3＋ and Hg^2＋ had 1.12, 0.58, and 0.81 binding sites to DNA, the fluorescence quenching of DNA caused by them all attributed to static quenching. The binding constants KA of binding sites were 3.82×10^4 and 4.22×10^2 L·mol^-1 ; 2.50×10^4 and 2.95×10^3 L·mol^-1 ; 3.05×10^4 and 1.00×10^3 L·mol^-1. The results showed that La^3＋ could relieve destruction caused by Hg^2＋ on the DNA structure.

Structure and Biological Activities of 3-Phenyl-2-[1-benzoyl-1-(1,2,4-triazol-1-yl)] Methenyl Thiazolidine

The title compound 3-phenyl-2-[1-benzoyl-1-(1,2,4-triazol-1-yl)]methenyl thiazolidine was synthesized from acetophenone,triazole,phenylthioisocyanate and 1,2-dibromo-ethane by several step reactions. Its structure was identified by means of 1H NMR,MS and IR spectrometries. The single crystal structure of \{3-phenyl\}-2-[1-benzoyl-1-(1,2,4-triazol-1-yl)]methenyl thiazolidine was determined by X-ray diffraction. The preliminary bioassays have shown that the title compound exhibits the weak activities of fungicide and plant growth regulator.

Synthesis and Crystal Structure of 3-(4-Ethoxyphenyl)-6-(phenoxymethyl)-1,2,4-triazolo[3,4-b][1,3,4]thiadiazole

The title compound C18H16N4O2S has been synthesized by the reaction of 4-amino-3-（4-ethoxyphenyl）-5-mercapto-1,2,4-triazole with phenoxyacetic acid in phospho- rus oxychloride, and characterized by IR, NMR spectra and elemental analysis. Its structure was determined by single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 1.4903（3）, b = 1.5230（2）, c = 0.9615（16） nm, Z = 4, V = 1.7769（5） nm^3, Dc = 1.317 g/cm^3, μ = 0.201 mm^-1, F（000） = 736, R = 0.0795 and wR = 0.2233. In the title compound, all rings are essentially planar.

Synthesis and Crystal Structure of 3-Benzyl-6-trichloromethyl-[1,2,4] triazolo[3,4-b][1,3,4]thiadiazole

The title compound 3-benzyl-6-trichloromethyl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole I （C11HTC13N4S, Mr = 333.62） has been synthesized, and its structure was determined by elemental analyses, IR, ^1H NMR, ^13C NMR, and X-ray diffractions. The crystal is of triclinic, space group P1^-, with a = 5.898（3）, b = 10.510（4）, c = 11.580（5） A, α = 74.936（7）, β= 75.476（7）, γ = 79.647（7）°, V= 665.9（5）/A^3, F（000） = 336, Z= 2, Dc = 1.664 g/cm^3, 2 = 0.71073A, p = 0.834 mm^-1, the final R = 0.0605 and wR = 0.0900. The secondary bonding interactions （SBIs） S…N and π-π stacking interactions are found in the crystal structure and they link the molecules into a three-dimensional network.

Synthesis and Crystal Structure of 1,4-Dimethyl-2,5-di{[2’-(3-pyridylmethylamino-formyl)phenoxyl]methyl}benzene Perchlorate

The title compound, 1,4-dimethyl-2,5-di { [2′-（3-pyridylmethylaminoformyl）phenoxyl]- methyl}benzene perchlorate （C36H36Cl2N4O12, Mr = 787.59）, has been synthesized and structurally determined by single-crystal X-ray diffraction. The crystal crystallizes in the orthorhombic system, space group Pbca with a = 14.366（4）, b = 15.159（4）, c = 16.443（5）A, V = 3580.9（17）/A3 Z = 4, De = 1.461 g/cm^3, /t = 0.253 mm^-1, F（000） = 1640, R = 0.0618 and wR = 0.1525 for 1615 observed reflections （I 〉 2σ（I））. In the structure of the title compound, a two-dimensional supramolecular layer is formed via intermolecular hydrogen bonding interactions.

Syntheses and Crystal Structures of the First Row Transition Metals with 1,6-Bis(2＇-pyridyl)-2,5-dithiahexane

Six first row transition metal complexes with 1,6-bis（2′-pyridyl）-2,5-dithiahexane（Py;S;）, namely, MnPy;S;Cl;（1）, FePy;S;Cl;（2）, Co Py;S;Cl（3）, CoPy;S;（SCN）;（4）, NiPy;S;（SCN）;（5） and NiPy;S;（N;）;（6）, have been synthesized. A mixture of MCl;·x H;O（M = Mn, Co） in MeOH（FeCl;·4H;O in MeCN） and the stoichiometric amount of Py;S;was stirred for 4 h at room temperature, then these aiming products 1, 2 and 3 could be obtained by purification. A mixture of MPy;S;Cl;（M = Co, Ni） in MeOH and two equivalents of KSCN or NaN;was stirred for 4 h at room temperature. After that, complexes 4, 5 and 6 could be got by purifying. For 1, 2, 3, 4 and 5, the metal centers are hexa-coordinated in a similar distorted octahedral geometry and the crystal structures have the same space group Pbcn. The crystal structure of compound 6 belongs to monoclinic with space group P21/c. The coordinated atoms around M（Ⅱ） are two pyridyl N atoms(N（1） and N（2）), two thioether S atoms(S（1） and S（2）) and two chloride ions(Cl（1） and Cl（2）) in compounds 1, 2, and 3, but in 4, 5, and 6, two chloride ions(Cl（1） and Cl（2）) are replaced by another two N atoms from N;or NCS;.