Effect of Hydrogenation on Ring C of Flavonols on Their Affinity for Bovine Serum Albumin

In this paper, the effect of hydrogenation on ring C of flavonols on the affinity for bovine serum albumin was investigated. Two differently substituted B-ring hydroxylation flavonols (myricetin and quercetin) and their dihydrides (dihydromyricetin and dihydroquercetin) were used to study their affinities for BSA by quenching the intrinsic BSA fluorescence in solution. From the spectra, the bimolecular quenching constants, the binding constants, the number of binding sites and the binding distances were calculated. The hydroxylation on ring B and hydrogenation on ring C of flavonols significantly affected the binding/quenching process; in general, the hydroxylation increased the affinity and the hydrogenation decreased the affinity. For myricetin and quercetin, the binding constants (K _a) for BSA were 1.84×10⁸ L⋅mol⁻¹ and 3.83×10⁷ L⋅mol⁻¹. For dihydromyricetin, the binding constant was 1.36×10⁴ L⋅mol⁻¹, while dihydroquercetin hardly quenched the BSA intrinsic fluorescence. These results showed that hydrogen bonding and conjugative effects may play an important role in binding of flavonols to BSA. These results also showed that the properties of flavonols are related to their chemical structure.     

CdZn2KB2O6F,a new fluoride borate crystal

During an attempt to grow crystals of the nonlinear optical material Cd₃Zn₃B₄O₁₂ using a KBF₄ flux, crystals of a new cadmium dizinc potassium borate fluoride compound, CdZn₂KB₂O₆F, were unexpectedly isolated. The structure consists of layers constructed of distorted corner‐sharing ZnO₃F tetrahedra and BO₃ triangles. Both Zn and B reside on threefold rotation axes, while the F⁻ anion is located at a site of 3.2 symmetry. The Cd^II (site symmetry ) and K⁺ (site symmetry 3.2) ions occupy six‐ and nine‐coordinate interlayer sites, respectively. The BO₃ triangles and ZnO₃ pyramids from the ZnO₃F tetrahedra share bridging O atoms with each other to form an extended [ZnBO₃] layer parallel to (001). Although these layers are similar to the [MBO₃] layers seen in other compounds, they are uniquely bridged here by the Cd centres and F⁻ anions to form a three‐dimensional framework. In so doing, a series of channels is formed along the [010] direction and the K⁺ cations are found in these channels.     

Iron-facilitated direct oxidative C-H transformation of allylarenes or alkenes to alkenyl nitriles

This paper describes the first direct approach to alkenyl nitriles from allylarenes or alkenes facilitated by an inexpensive homogeneous iron catalyst. Three C-H bond cleavages occur under the mild conditions during this process. Mechanistic studies indicate that the cleavage of the allyl C(sp(3))-H bond is involved in the rate-determining step. This observation may provide an opportunity to achieve C(sp(3))-H functionalization catalyzed by an iron catalyst.     

不同树脂对瓜果腐霉代谢产物中除草活性成分的吸附分析

利用HPD400、HPD500、HPD600、HPD700、HPD850、ADS-17、D101、DM130大孔吸附树脂对瓜果腐霉培养滤液中除草活性成分的吸附情况进行了研究,通过对树脂吸附后的流出液和洗脱液的浓缩物进行HPLC检测分析,确定了其除草活性成分。实验发现,在所选择的8种树脂中以HPD500、HPD850、HPD600、ADS-17对除草活性成分的吸附能力最强,其中以HPD500和HPD600树脂的10%的乙醇洗脱液中除草活性成分含量最高。综合结果表明,以HPD500树脂作为吸附瓜果腐霉培养滤液中除草活性成分的适宜树脂。研究发现,HPD500树脂对除草活性成分吸附和解吸附的最佳条件是:吸附最适温度为20℃,树脂吸附饱和度为33.75mL/g,较适宜吸附流速为2BV/h,较适宜脱附流速为1BV/h,洗脱剂浓度为10%乙醇,洗脱剂用量为2.5BV。     

镧(Ⅲ)系锑硒化合物[Ln(en)_4]SbSe_4·0.5en(Ln=Dy,Ho)的溶剂热合成与晶体结构(英文)

本文研究了Ln2O3/Sb/Se/en溶剂热反应体系,合成了2个镧(Ⅲ)系锑硒化合物[Ln(en)4]SbSe4·0.5en[Ln=Dy(1),Ho(2)],用元素分析和红外光谱对化合物进行了表征,并用X-射线单晶衍射测定了化合物的单晶结构,两者都属于单斜晶系,P21/n空间群。结构对比研究发现,在en溶剂中,SbSe43-离子可以与半径较大的La3+和Nd3+离子配位,而不与半径较小的Dy3+和Ho3+离子配位,可见镧系收缩效应对SbSe43-离子与镧系金属离子Ln3+的配位有重要影响。     

NO adsorption on MoS(x) clusters: a density functional theory study

The density functional theory (DFT) method has been used to investigate NO probe molecule adsorption on the stoichiometric (Mo(16)S(32)) and nonstoichiometric (Mo(16)S(34) and Mo(16)S(29)) clusters. The calculated adsorption energies indicate that the stoichiometric cluster has stronger NO affinity than the nonstoichiometric surfaces. It is also found that mononitrosyl adsorption is favored at low NO coverage, while dinitrosyl (germinal) and (NO)(2) dimer adsorption at high NO coverage are possible. Strong repulsive interaction has been found for the adsorbed dinitrosyl and (NO)(2) dimer species. In addition, the computed NO stretching frequencies for the mononitrosyl and dinitrosyl species agree well with the experimental data, while those of the dimer species are much lower than the suggested experimental data.     

A_α~2上复合算子的Hilbert-Schmidt差分

本文设A_α~2为定义在n维复空间单位多圆柱上的加权Bergman空间,L为Bergman空间上有界复合算子的全体并赋予算子范数拓扑,应用复合算子的HilbertSchmidt差分研究L的拓扑连通性.     

Dielectrical behavior of nanostructured α-Fe2O3 with different annealed temperatures

The spectra of the dielectrical constant and dielectrical loss in three nanostructured α-Fin2₃ samples at different annealed temperatures are measured by using ac LRC method. The relaxation times of polarization and the conductance are calculated by means of the Debye mechanism and the interface effects in two kinds of polarization processes with two different relaxation times are proposed. Project supported by the Natural Science Foundation of zhejiang Province and the Chinese Postdoctoral Foundation.