利用结构相关性方法研究碳氢键活化反应C-H+M■的机理

本文利用结构相关(?)方法对碳氢键活化反应的氧化加成反应机理进行了研究.建立了反应的过渡态,并对反应途径进行了描述.根据所得到的反应途径对碳氢键活化研究中的一些问题进行了解释.     

降香黄檀和印度紫檀中微量元素的研究

运用ＩＣＰ－ＡＥＳ法测定了呀约降香的基源植物降香黄檀和印度檀心材中１４种无机元素含量，发现它们之间含量相近的元素为Ｃｒ，Ｍｎ，Ｔｉ，Ｆｅ，含量差别较大的元素有Ｓｒ，Ｃｏ，Ｃａ等。     

Reducing the complexity of photoreaction pathway of pyrazoles: photochemistry of 4,5-cycloalkanopyrazoles

Products from photoirradiation of 4,5-cycloalkanopyrazoles have been isolated and characterized. The simpler product mixtures relative to the parent systems are in agreement with the hypothesis that the extra carbocyclic ring could reduce the possible number of reaction pathways. Relative reactivities and secondary photoreaction pathways have also been determined.     

Remarkable axial ligand effect on regioselectivity towards terminal alkenes in epoxidation of dienes by a robust manganese porphyrin

With a highly encumbered manganese porphyrin as catalyst, significant improvements in regioselectivity towards less substituted C-C double bond in diene epoxidation were attained by simply adding organic bases as axial ligand.     

Alternating conjugated and transannular chromophores: tunable property of fluorene-paracyclophane copolymers via transannular pi-pi interaction

[structure-see text]A series of fluorene-dithia[3.3]paracyclophane copolymers was synthesized by Suzuki coupling reactions of suitable precursors. Transannular pi-pi interactions altered the electronic and optical properties of the polymer backbone significantly. A large red shift in the emission spectrum of the unsubstituted polymer was accompanied by enhanced photoluminescence (PL) efficiency. Substitution in the cyclophane unit resulted in PL quenching.     

Limit theorems for sums of dependent random variables

Summary In Lai and Stout [7] the upper half of the law of the iterated logarithm (LIL) is established for sums of strongly dependent stationary Gaussian random variables. Herein, the upper half of the LIL is established for strongly dependent random variables {X _i} which are however not necessarily Gaussian. Applications are made to multiplicative random variables and to f(Z _i ) where the Z _i are strongly dependent Gaussian. A maximal inequality and a Marcinkiewicz-Zygmund type strong law are established for sums of strongly dependent random variables X _i satisfying a moment condition of the form E¦S _a,n ¦^pg(n), where , generalizing the work of Serfling [13, 14].Research supported by the National Science Foundation under grant NSF-MCS-78-09179Research supported by the National Science Foundation under grant NSF-MCS-78-04014     

Doeblin's big limit theorem

Doeblin regarded his paper(²) as his hardest work. The big limit is that ofP(ⁿ)(x, E) asn tends to infinity, in a measurable non-topologized space. An exposition of part one of this paper was published in Ref. 1. This is the exposition of part two, which contains some reparation as well as clarification.Doeblin's great contributions to probability theory were remembered at a conference 50 Years after Doeblin: Developments in the Theory of Markov Chains, Markov Processes and Sums of Random Variables held at Blaubeuren. Germany November 2–7, 1991. Professor Chung contributed this article to further celebrate this occasion. The editor thanks him.     

有机质谱学在中药鱼腥草研究中的应用

研究了中药鱼腥草的挥发性物质和鱼腥草注射液的有效成分。用CC／MS方法鉴定了鱼腥草挥发性物质和鱼腥草注射液有效成分的化学组成，从二者中共鉴定出48个化合物。研究结果表明：二者中的化学组成基本相同。主要成分有：2-十一烷酮(甲基正壬酮)、癸酰乙醛(鱼腥草素)、苯甲醛、薄荷醇、冰片乙酸酯、2-十一烯醛、正十一烷醇、葵酸、δ-瑟林烯、肉豆蔻醚、斯巴醇、石竹烯氧化物、二苯胺及十六酸。占优势的化合物为甲基正壬酮，它在鱼腥草的挥发性物质中和鱼腥草注射液的有效成分中分别占9．8％和9．2％。作为鱼腥草中的特有物质癸酰乙醛(鱼腥草素)，在鱼腥草的挥发性物质中和鱼腥草注射液的有效成分中分别占5．1％和2．6％。本文还讨论了甲基正壬酮和癸酰乙醛结构的确定。     

[K_2(TNR)(H_2O)]_n的制备、分子结构和热分解机理

2,4,6-三硝基间苯二酚(斯蒂芬酸)及其盐类,如斯蒂芬酸铅、斯蒂芬酸钡等是常用的含能材料犤1犦,但斯蒂芬酸铅盐及钡盐在爆炸后产生重金属污染,对使用人员的健康及环境都产生危害。同时,斯蒂芬酸铅盐和钡盐存在一些缺陷,如斯蒂芬酸铅对静电敏感、生产不安全等,这就要求人们寻求新的产品来代替它们。近年来钾含能配合物以其低毒性、良好的安定性引起了火工药剂专家和研究人员的重视犤2～9犦,成为了含能材料行业一个重要研究方向。因此,我们选择了斯蒂芬酸与氢氧化钾反应制备了斯蒂芬酸钾,并就其晶体结构及热分解机理进行了研究。1实验部分1.1仪…     

Electronic spectroscopy, photophysical properties, and emission quenching studies of an oxidatively robust perfluorinated platinum porphyrin

The highly electron-deficient, beta-octafluorinated meso-tetrakis(pentafluorophenyl)-porphyrin (H(2)F(28)TPP) was metalated with platinum to afford the oxidatively robust luminophore [PtF(28)TPP], and its X-ray structure shows that the porphyrin core exists in a slightly saddle-shaped conformation. The absorption spectrum of [PtF(28)TPP] in CH(2)Cl(2) displays a near-UV Soret band (B) at 383 nm (epsilon = 2.85 x 10(5) dm(3) mol(-1) cm(-1)) and two visible Q(1,0) and Q(0,0) bands at 501 (epsilon = 1.45 x 10(4) dm(3) mol(-1) cm(-1)) and 533 (epsilon = 1.36 x 10(4) dm(3) mol(-1) cm(-1)) nm, respectively. These absorption bands of [PtF(28)TPP] are blue-shifted from those in [PtF(20)TPP] (390, 504, and 538 nm, respectively) and [PtTPP] (401, 509, and 539 nm, respectively). Excitation of [PtF(28)TPP] (complex concentration = 1.5 x 10(-6) mol dm(-3)) in dichloromethane at the Soret or Q(1,0) or Q(0,0) band gave a phosphorescence with peak maximum at 650 nm (lifetime = 5.8 micros) and a weak shoulder at 712 nm. Both the emission lifetime and quantum yield vary with solvent polarity, and plots of tau versus E(K) and Phi versus E(K) (where E(K) is the empirical solvent polarity parameter based on the hypsochromic shift of the longest wavelength absorption of the [Mo(CO)(4)[(C(5)H(4)N)HC[double bond]NCH(2)C(6)H(5)]] complex with increasing solvent polarity; see: Kamlet, M. J.; Abboud, J. L. M.; Taft, R. W. Prog. Phys. Org. Chem. 1981, 13, pp 485-630) show linear correlation, indicating that the emission is sensitive to the local environment/medium. Electrochemical studies on [PtF(28)TPP] by cyclic voltammetry showed no porphyrin-centered oxidation at potential < or = 1.5 V versus Ag/AgNO(3), demonstrating that [PtF(28)TPP] is more resistant toward oxidation than [PtF(20)TPP] (E(1/2) = 1.33 V) and [PtTPP] (E(1/2) = 0.97 V). The porphyrin-centered reduction of [PtF(28)TPP] occurs at -0.75 and -1.18 V, which is anodically shifted from those at -1.06 and -1.55 V in [PtF(20)TPP], and -1.51 V in [PtTPP], respectively. The excited-state reduction potential of [PtF(28)TPP] is estimated to be 1.49 V versus Ag/AgNO(3). Over 97% of the emission intensity of [PtF(28)TPP] was retained after irradiation with a high power mercury arc lamp (500 W) for 14 h, compared to 90% and 12% for [PtF(20)TPP] and [PtTPP], respectively; hence, [PtF(28)TPP] exhibits superior photostability. Quenching of the emission of [PtF(28)TPP] by oxygen, alcohol, catechol, and butylamine reveals that [PtF(28)TPP] is an oxidatively robust material with medium-sensitive photoluminescence properties.