η~3-2-甲基烯丙基稀土配合物的合成及其催化性质的研究

1975年CouPs和Wailes首次合成了第一个η~3-烯丙基稀士配合物——Cp_2Sc(η~3-C_3H_5)。由于该类配合物稳定性差难于合成,目前为止文献上仅有几篇报道。其中代表性的例子是1991年吴文玲等人合成的(η~3-cC_3H_5)_2CeCl_5Mg_2(tmed)_2,并测定了其晶

A MASS-SPECTROMETRIC STUDY OF ORGANIC PHOSPHORUS-COMPOUNDS .5. EI SPECTRA OF 1, 3, 2-OXAZAPHOSPHOLIDINE 2-SULFIDES DERIVATES

The mass spectral behaviour of 15 new type of organic phosphorus compounds with a considerable insecticidal activity, 1, 3,2-oxazaphospholidine 2-sulfides derivatives, under 70 eV electron impact has been studied by means of high and low resolution mass spectrometry as well as by B/E linked scan and MIKES/CID analysis. Discussion is focused into the isomerization between oxygen and sulphur in molecules and some rearrangement reactions.

有机磷化合物的质谱研究——Ⅴ.2-硫-1,3,2-氧氮磷杂环戊烷衍生物

本文报道15种新合成的2-硫-1,3,2-氧氮磷杂环戊烷衍生物的 EI 谱.在质量分析离子动能谱、碰撞诱导分解谱、B/E 联动扫描及高分辨精确质量测量的基础上,讨论了这类化合物的质谱裂解机理及特征.着重讨论上述化合物的氧硫异构现象及几种重排反应.

汉语四声的数学奥秘——频率变比3∶2

本论文采用音乐物理和数学方法揭示了汉语四声的奥秘——频率变比3∶2,这个比例被命名为“宝石配比”.这一发现为语音研究、语音教学以及计算机语音识别提供了一条重要的科学依据.

Bifunctional AgOAc-catalyzed asymmetric [3+2] cycloaddition of azomethine ylides

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A 3/2 algorithm for two-machine open shop with route-dependent processing times

This paper considers the problem of minimizing the schedule length of a two-machine shop in which not only can a job be assigned any of the two possible routes, but also the processing times depend on the chosen route. This problem is known to be NP-hard. We describe a simple approximation algorithm that guarantees a worst-case performance ratio of 2. We also present some modifications to this algorithm that improve its performance and guarantee a worst-case performance ratio of 3=2.

DFT calculations of the structures and vibrational spectra of the [Fe(bpy)(3)](2+) and [Ru(bpy)(3)](2+) complexes

Structures of the [M(bpy)(3)](2+) complexes (M = Fe and Ru) have been calculated at the B3-LYP/DZVP level. IR and Raman spectra were calculated using the optimised geometries, employing a scaled quantum chemical force field, and compared with an earlier normal coordinate analysis of [Ru(bpy)(3) ](2+) which was based upon experimental data alone, and the use of a simplified model. The results of the calculations provide a highly satisfactory fit to the experimental data and the normal coordinate analyses, in terms of potential energy distributions, allow a detailed understanding of the vibrational spectra of both complexes. Evidence is presented for Jahn-Teller distortion in the E-1 MLCT excited state. (C) 2008 Elsevier B.V. All rights reserved.