一个计算次甲基质子NMR化学位移的经验式

本文提出了一个计算次甲基质子NMR化学位移的经验式δ_CHXYZ=δ_(CH3)2CHZ+△_xy主要用来计算那些Bell、Bowles和Senese关系式不适用的、含有无去屏蔽作用的次甲基质子体系中次甲基质子的化学位移。     

苯甲酸及其衍生物与1,10-邻菲咯啉铽的三元配合物的荧光光谱研究

分别以苯甲酸及邻、间、对甲基(甲氧基)苯甲酸为第一配体, 以邻菲咯啉(phen)为第二配体, 合成了七种Tb(Ⅲ)的三元配合物. 通过元素分析确定了各配合物的组成. 在室温下, 测定了各固体配合物的激发和发射光谱, 讨论了不同种类、不同位置的取代苯甲酸作第一配体对铽三元配合物荧光性质的影响. 结果表明, 取代苯甲酸作第一配体的Tb(Ⅲ)三元配合物的最佳发射峰5D4→7F6(489 nm), 5D4→7F5(545 nm)的强度, 均比苯甲酸作配体的配合物强. 甲基为取代基的苯甲酸的三种配合物中, 最佳发射峰的强度顺序为: Tb(o-MBA)3phen ＜Tb(m-MBA)3phen*H2O＜Tb(p-MBA)3phen(其中o-MBA为邻甲基苯甲酸根、 m-MBA为间甲基苯甲酸根、 p-MBA为对甲基苯甲酸根、 phen为邻菲咯啉);甲氧基为取代基的苯甲酸的三种配合物中, 最佳发射峰强度顺序为: Tb(o-MOBA)3phen·H2O＞ Tb(m-MOBA)3phen·H2O ＞Tb(p-MOBA)3phen(其中o-MOBA为邻甲氧基苯甲酸根、 m-MOBA为间甲氧基苯甲酸根、 p-MOBA为对甲氧基苯甲酸根).     

Syntheses and Crystal Structures of Chiral BINOL Derivatives and Their Applications in Enantioselective Lewis Acid Catalyzed Addition of Diethylzinc to Aldehydes

Two novel chiral BINOL derivatives with bis(benzylamine) groups at the 3,3- positions have been synthesized through the condensation reaction between 2,2'-bis(methoxy- methyleneoxy)-1,1'-binaphthyl-3,3'-dicarboxylic acid and benzylamine or N-phenyl benzylamine in the presence of triethylamine. Suitable single crystal of (R)-N,N'-dibenzyl-2,2'-dihydroxy-1, 1'-binaphthly-3,3'-diformamide (R)-3 for X-ray diffraction was obtained by recrystallization at room temperature from the mixture solvents. Crystallographic data of (R)-3: C40H36N2O6, Mr = 640.71, monoclinic, space group P21, a = 6.746(3), b = 21.883(9), c = 11.723(5) , β = 104.605(7)°, Z = 2, V = 1674.7(12) 3, Dc = 1.271 g/cm3, F(000) = 676, R = 0.0729, wR = 0.1687 and μ(MoKα) = 0.086 mm-1. Two chiral BINOL ligands were found to be effective in the enantioselective addition of diethylzinc to aldehydes and much different enantioselectivity was observed both in the presence and absence of Ti(OiPr)4. In the former case, (R)-3 showed moderate enantioselectivity, which was lower than that of (R)-BINOL's; and in the latter case, (R)-4 gave the highest enan- tioselectivity up to 93.3% ee.*     

Synthesis, Characterization and Structural Determination of Ferrocene Derivatives Linked with Benzo[b]pyrans ——2-Amino-7,7-dimethyl-4-ferrocenyl-5-oxo-5,6, 7,8-tetrohydro-4H-chromene-3-carbonitrile

The title compound (C22H22N2O2Fe·CH3OH) was synthesized via a one-pot proce- dure from ferrocenylaldehyde, malononitrile and 5,5-dimethyl-1,3-cyclohexanedione using room temperature ionic liquid and pyridine as the catalysts, and characterized by elemental analysis, IR and 1H NMR. The structure was determined by X-ray single-crystal diffraction. The crystal belongs to monoclinic system, space group P21/n, with a = 9.7085(15), b = 22.951(4), c = 9.987(2) A, β = 112.494(3)°, V = 2055.9(6) A3, Z = 4, Mr = 402.28, Dc = 1.403 g/cm3, μ = 0.759 mm-1, F(000) = 868, the final R = 0.0536 and wR = 0.1449 for 4202 observed reflections with I > 2σ(I). The supramolecular single-helix chain of the title compound is formed by linking the building units with the hydrogen bond between N1 and N2. The adjacent chains are connected to a 2D layer by the hydrogen bond between N1 and O1. The adjacent layers are further linked by van der waals’ force. The CH3OH molecule is trapped in the interlayer.     

可生物降解材料聚天冬氨酸的研究进展

综述了可生物降解材料聚天冬氨酸及其衍生物的特点及合成和结构表征，并介绍了聚天冬氨酸及其衍生物在水处理和药物控制释放等领域的研究进展。     

壳聚糖及其衍生物对金属离子的吸附研究(下)

壳聚糖是一种天然高分子,在其分子结构的重复单元中有-NH2和-OH,因而对金属离子有较好地吸附和配位能力。本文较全面的综述了壳聚糖及其衍生物对金属离子的吸附性能,简述了它们与金属离子形成配合物的结构及吸附机理。其中下篇主要讲述了壳聚糖及其衍生物与金属离子形成配合物后的结构以及吸附机理,并对其发展前景作了展望。     

A note on bounds for the derivatives of continued fractions

Although it is difficult to differentiate analytic functions defined by continued fractions, it is relatively easy in some cases to determine uniform bounds on such derivatives by perceiving the continued fraction as an infinite composition of linear fractional transformations and applying an infinite chain rule for differentiation.     

Identities for the Chebyshev functional involving derivatives of arbitrary order and applications

We generalize the identities of J. Pe?ari? and A.M. Fink for the Chebyshev functional. The identities are shown to be very useful in establishing various bounds for the Chebyshev functional.     

The Explicit Determination of the Logarithm of a Tensor and Its Derivatives

The logarithm of a tensor is often used in nonlinear constitutive relations of elastic materials. Here we show how the logarithm of an arbitrary tensor can be explicitly evaluated for any underlying space dimension n. We also present a method for the explicit evaluation of the derivatives of the logarithm of a tensor.      

An inclusion formula for derivatives

Often an estimate of a derivative or its range over an interval is desired rather than the derivative itself. Error terms for numerical approximations may sometimes be rigorously estimated in terms of a number of values of the derivative and a majorant. We indicate this and propose a technique for the strict estimation of the values of the derivatives in terms of central differences of the function and its majorant. We stress strictness and accept less accuracy.