[Co(3,3-tri)(amp)Cl][ZnCl4]一对邻位差向异构体的晶体结构

The crystal structures of a pair isomers of [Co(3,3-tri)(amp)Cl][ZnCl₄] (here 3,3-tri = N-(3-Aminoprop- yl)-1,3-propanediamine; amp=2-(Aminomethyl)pyridine) have been determined by single crystal X-ray diffrac-tion. They are the epimers with the only difference of the orientation of the Sec-NH proton in 3,3-tri ligand. The crystals with the anti-epimer (m1[ZnCl₄]·CH₃OH·H₂O) are monoclinic, space group C2/c with eight molecules in a unit cell of dimensions a=30.401(5)?,b=8.0469(13)?,c=18.817(3)?,β=93.346(3)°,V=4595.3(12)?³,D_c=1.708g·cm^-3,Z=8,F₀₀₀=2416,R=0.0462,R_w=0.1304. The crystals of the syn-epimer (m2[ZnCl₄]·H₂O) are triclinic, space group P1 with two molecules in a unit cell of dimensions a=8.9752(12)?,b=9.8855(12)?,c=12.6886(16)?,α=89.228(3)°,β=76.447(2)°,γ=80.428(3)°,V=1078.8(2)nm³,D_c=1.721g·cm^-3,Z=2,F₀₀₀=568,R=0.0313,R_w=0.0929. The crystal parameters, such as bond lengths and angles, are well consistent with the data of an ab initio computational result (RHF/LANL2DZ opti-mised structure). The average error for bond length is about 1.6%, only two of them in the isomer m3 (Co-N2 and Co-N4) are over 3%, (3.09% and 4.28% respectively). The errormax for bond angle is 2.52%, the bond angles with an over 2% error are only 3.6% out of all bond angles.     

A Novel Enhancing Flow-Injection Chemiluminescence Method for the Determination of Glutathione Using the Reaction of Luminol with Hydrogen Peroxide

 A rapid flow-injection method with chemiluminescence (CL) detection is described for the determination of glutathione (GSH). The method is based on the CL reaction of luminol and hydrogen peroxide. GSH can greatly enhance the chemiluminescence intensity in 0.1 mol/L borax–sodium hydroxide buffer solution (pH = 9.7). The maximum CL intensity was directly proportional to the concentration of GSH in the range 3.0 × 10⁻⁷–2.0 × 10⁻⁵ mol/L, and the detection limit was 6.8 × 10⁻⁸ mol/L. The relative standard deviation was 3.4% for 5.0 × 10⁻⁶ mol/L of GSH (n = 11). Received October 23, 2001; accepted June 18, 2002     

Liquid-liquid-liquid microextraction of aromatic amines from water samples combined with high-performance liquid chromatography

A simple preconcentration and clean-up liquid-liquid-liquid microextraction of aromatic amines is described in this paper. The compounds were extracted from 2.0 ml aqueous samples (donor phase) into an organic phase, layered on the donor phase, and then back extracted to a microdrop of aqueous receiving phase, suspended in the organic phase. After extraction, the microdrop was injected into the HPLC system directly for analysis. Optimal conditions of the extraction were donor phase (a1): 2 ml of water sample adjusted to pH 13 with NaOH-NaCl; organic phase (o), 150 microl ethyl acetate; and receiving phase (a2) of 2 microl aqueous solution at pH 2.1. The a1-->o extraction time was 15 min and for o-->a2, 30 s. 18-Crown-6 ether, which can complex with amine, was added to the aqueous receiving phase to improve the extraction performance. Enrichment factors ranged from 218 (for 4-nitroaniline) to 378 (for 4-chloro-2-aniline). The calibration curve for these anilines was linear within the range 2.5 ng/ml-2.5 microg/ml (r2=0.998). Detection limits ranged from 0.85 to 1.80 ng/mi (at S/N=3). This procedure can be a selective preconcentration method for aromatic amines present in water samples.     

Syntheses and structural characterizations of Fe4S4 cubane-like cluster compounds containing cycloalkylthiolate ligands

In a reaction system consisting of FeCl₂, tetrathiometallate and cycloalkylthiolate, two Fe₄S₄ cubanelike cluster compounds were obtained with the following crystallographic data: (PhCH₂NMe₃)₂ [ Fe₄S₄ (SC₅H₉)₄] (I), monoclinic space groupP2₁/c,a = 1.632 7(4),b=1.122 9(3),c = 2. 802 5(10) nm, β= 94.63(2)°, Z=4, andR= 0.074; (Et₄N)₂[F₄S4(SC₆H_lI)₄] (II), tetragod space group ,a = l.167 05(9),b = 1.167 06(2),c = 2.063 26(5) nm,Z = 2, D_obs = 1. 28 g/cm³, andR = 0. 078. The participation of cycloalkylthiolate ligand does not obviously arouse the change of the Fe₄S₄ core structure. Meanwhile, the influence of the cation on the structural symmetry of the Fe₄S₄ cluster dianion is also discussed. Project supported by the National Natural Science Foundation of China and the Climbing Program Foundation of China.     

Reactions of cobalt clusters with deuterium

The kinetics of chemical reactions of cobalt clusters Co_n with deuterium are described. Absolute rate constants have been measured in the size range n=7–68 at 293 K. The rate constants are found to be a strong function of cluster size, varying by a factor of 400. This size dependence is most prominent for n=7 to 25: Co₁₅ is the most reactive cluster, and Co_7–9 and Co_19–20 are particularly unreactive. Abrupt changes in the rate constants from one cluster size to the next are observed. For the clusters above n=25, the rate constants show several less prominent maxima and minima superimposed on a slow, nearly monotonic increase with cluster size.     

Synthesis of oligo(p-phenylene vinylene)-porphyrin-oligo(p-phenylene vinylene) triads as antenna molecules for energy transfer

The oligo(p-phenylene vinylene)-porphyrin-oligo(p-phenylene vinylene) (P-OPVn, n=2, 4, where n is the number of phenyl rings) and the complex with Zn²⁺ based on P-OPVn were synthesized for investigating their photophysical properties via UV-vis, voltammetry, steady-state and time-resolved fluorescence spectra. In these molecules two OPV moieties as energy donors were linked to porphyrin center by virtue of Wittig reaction. The detailed studies of photophysical properties indicate that OPV group can act as an antenna unit for effective intramolecular energy transfer.     

Porous nanocomposites of zirconium dioxide and silicate

Highly porous nanocomposites of zirconium dioxide and silicate are synthesised in an aqueous system from an inorganic salt of zirconium; the nanacomposites, with tailorable pore structures, exhibit superior performance as catalyst supports.     

Primary study on the application of Serum Pharmacology in Chinese traditional medicine

In the paper, two main methods, which are Serum Pharmacology and Traditional Pharmacology, were adopted to study Chinese traditional medicine, such as Ginkgo biloba extract (GBE), ginsenosides (GS) and compound GG (GBE + GS), pharmacology in vitro. The results showed that there were evident difference between the results of Serum Pharmacology and that of Traditional Pharmacology. There was no significant difference between the drug effect of crude GS on nitric oxide (NO) production in ECV304 and that of crude GBE, and the drug effect of GG was superior to that of GS and GBE, respectively. But, compared with GBE serum, the GS serum up-regulation of NO production in ECV304 increased significantly, and the GG serum up-regulation of the NO production in ECV304 was inferior to that of GS serum and GBE serum significantly. The results suggested that Serum Pharmacological study should be adopted in the pharmacological investigation on the Chinese traditional medicine and the drug screening of the Chinese traditional medicine.     

A Highly Sensitive and Selective Assay for Cysteine Using the Chemiluminescence Reaction of Luminol and Hydrogen Peroxide

A very simple, highly sensitive and selective chemiluminescence (CL) method was established for the determination of cysteine. This method is based on the fact that the CL reaction of luminol and hydrogen peroxide can be greatly enhanced by cysteine. The CL intensities at maximum light emission were linearly correlated with the concentration of cysteine over the range of 2.0×10^–8–6.0×10^–6molL^–1 with a detection limit of 7.5×10^–9molL^–1. The relative standard deviation was 1.7% for the determination of 1.0×10^–7molL^–1 cysteine (n=9). The feasibility of utilizing the proposed method for the determination of total concentration of cysteine in human serum was examined.     

DFT study on the geometric, electronic structure and Raman spectra of 5,15-diphenylporphine

The ground state geometric, electronic structure and Raman spectra of 5,15-diphenylporphine (H(2)DPP) have been studied using B3LYP/6-31G(d) method and compared with that of well-studied free base porphine (H(2)P) and meso-tetraphenylporphine (H(2)TPP). Calculation shows that 5,15-substitution causes remarkable in-plane distortion, whereas the resulting out-of-plane distortion is negligible. The calculated electronic structure of H(2)DPP is consistent with the absorption spectra compared with H(2)P and H(2)TPP. The calculated vibrational frequencies of H(2)DPP scaled with a single factor of 0.971 agree well with experimental data (the rms error is 8.0 cm(-1)). The assignment of experimental Raman bands of H(2)DPP was discussed on the basis of theoretical calculation and the comparison with that of H(2)P and H(2)TPP. The splitting of some vibrational modes involving the motion of C(m) atom, such as nu(1), nu(8), and nu(10), was observed and was attributed to the diversification of the environment around C(m) atoms. As the shift of absorption peaks, the shift of some structure-sensitive Raman bands of H(2)DPP form that of H(2)TPP and H(2)P was attributed to the in-plane nuclear reorganization (IPNR) induced by phenyl-substitution, though the contribution of nonplanarity mechanism could not be excluded completely.