DTO体系分子反应动力学

基于DTO分子( 1A1)的氢同位素效应,得到修正的Born-Oppenheimer(B-O)理论下多体展式分析势能函数.用准经典的Monte-Carlo轨迹法研究了D+ TO(0 ,0)和T+ DO(0 ,0)的分子反应动力学过程.结果表明:在碰撞能量较低时( < 209.2 kJ. mol - 1 ),D+ TO(0 ,0)和T+DO(0,0)反应主要生成O+ DT,并且该反应是无阈能的;有少量的交换反应产物DO (TO)生成,并伴有极少量的络合物产生.碰撞能大于209.2kJ . mol - 1后,逐渐出现分子被完全碰散成D,T ,O 原子的情形.反应 D+TO(0 ,0) →OD + T和 T +DO(0 ,0) →OT + D是无热反应但是有阈能存在.由于D和T原子的同位素效应,置换产物轨线存在非一致性.     

Nonadiabatic transitions in chemical reactions. A comparison between exact and approximate collinear calculations

The quantum mechanical study of nonadiabatic transitions during a reactive collision of an atom and a diatomic molecule is extended. The constant coupling term used in our previous work is replaced by a gaussian-type function to simulate the fact that the interaction becomes stronger as the two interacting surfaces become closer. the two surfaces are assumed to be one above the other but shifted along the vibrational coordinate. It is found that when the coupling is not too strong, the nuclear process taking place on the original adiabatic surface can be decoupled from the electronic process which is responsible for the transitions between the two surfaces. It is established that the strength of the coupling is defined in terms of the area under the coupling function and its width. Dependence on the latter is in general expected to be much stronger than on the former.     

Stereoselective nucleophilic attacks on carbenium ions generated from (1-indanol)- and (1-tetralol)Cr(CO)3 as synthetic intermediates.

Temporary complexation of an arene ring by the Cr(CO)₃ unit bringing about both a considerably enhanced stabilization of adjacent carbenium ions and a total control of nucleophilic attack in an “exo” fashion allows important applications in organic synthesis.     

Pseudoasymetrie dans la serie du benchrotrene II. Structure cristalline de la forme pseudoasymetrique F 144° des glycols ortho-substitutes (OC)3CrC6H4(CHOHCH3)2

The crystalline structure of one of the pseudoasymmetric forms of the benchrotrenic glycols 1,2-(CHOHCH₃)₂C₆H₄Cr(CO)₃ (m.p. 144° C) has been determined by X-ray diffraction to provide a complete identification of these isomeric glycols.     

Study on particle removal efficiency of an impinging jet by an image-processing method

 An image-processing method is proposed to obtain the distribution of the removal efficiency of particles on a plate by an air jet. This method can be used to measure particle removal from a flat surface by processing the image of the reflected light from the surface. Factors affecting the particle removal efficiency such as air pressure, distance between the nozzle and the impinging surface and the impinging angle are discussed. Optimal conditions are determined to obtain the most effective particle removal by the air jet. Received: 10 April 2001 / Accepted: 2 August 2001     

Isolation of fatty acids and aromatics from cell suspension cultures of Lavandula angustifolia

Cell suspension cultures of Lavandula angustifolia Mill. ssp. angustifolia (syn.: L. officinalis Chaix.) afforded a fatty acid composition, cis and trans p-coumaric acids (=p-hydroxy cinnamic acids), and beta-sitosterol. The fatty acid composition was analyzed by GC-MS, and the structures of the isolated three compounds were determined by 1H- and 13C-NMR, and MS spectroscopic techniques.     

Intracellular Localization of an Osmocenyl‐Tamoxifen Derivative in Breast Cancer Cells Revealed by Synchrotron Radiation X‐ray Fluorescence Nanoimaging

A series of tamoxifen‐like metallocifens of the group‐8 metals (Fe, Ru, and Os) has strong antiproliferative activity on the triple‐negative breast cancer cells (MDA‐MB‐231). To shed light on the mechanism of action of these molecules, synchrotron radiation X‐ray fluorescence nanoimaging studies were performed on cells exposed to osmocenyl‐tamoxifen (Oc‐OH‐Tam) to disclose its intracellular distribution. High‐resolution mapping of the lipophilic Oc‐OH‐Tam in cells revealed its preferential accumulation in the endomembrane system. This is consistent with the ability of the amino nitrogen chain of the compounds to be protonated at physiological pH and responsible for electrostatic interactions between Oc‐OH‐Tam and membranes. A comprehensive scenario is proposed that provides new insight into the cellular behavior and activation of Oc‐OH‐Tam and advances the understanding of its mechanism of action.     

Ferrocenyl catechols: synthesis, oxidation chemistry and anti-proliferative effects on MDA-MB-231 breast cancer cells

The synthesis and anti-tumoral properties of a series of compounds possessing a ferrocenyl group tethered to a catechol via a conjugated system is presented. On MDA-MB-231 breast cancer cell lines, the catechol compounds display a similar or greater anti-proliferative potency (IC(50) values ranging from 0.48-1.21 μM) than their corresponding phenolic analogues (0.57-12.7 μM), with the highest activity found for species incorporating the [3]ferrocenophane motif. On the electrochemical timescale, phenolic compounds appear to oxidize to the quinone methide, while catechol moieties form the o-quinone by a similar mechanism. Chemical oxidation of selected compounds with Ag(2)O confirms this interpretation and demonstrates the probable involvement of such oxidative metabolites in the in vitro activity of these species.     

Synthesis and antiproliferative activity of (Z + E)‐1‐[4‐(2‐(cyclopentadienyltricarbonylmanganese)‐2‐oxo‐ethoxy)phenyl]‐1,2‐di(p‐hydroxyphenyl)‐but‐1‐ene against breast cancer cells

This paper describes the synthesis of (Z + E)‐1‐[4‐(2‐(cyclopentadienyltricarbonylmanganese)‐2‐oxo‐ethoxy)phenyl]‐1,2‐di(p‐hydroxyphenyl)‐but‐1‐ene. Two synthetic pathways were explored. The best pathway consisted of the alkylation of 1,2‐bis‐[4‐(tert‐butyl‐dimethylsilyloxy)phenyl]‐1‐(4‐hydroxyphenyl)but‐1‐ene with BrCH₂COOEt. The ester obtained was transformed into the Weinreb amide by reaction with HN(OMe)Me–HCl. The reaction of lithium manganese tricarbonylcyclopentadienide with the Weinreb amide produced 1‐[4‐(2‐(cyclopentadienyltricarbonylmanganese)‐2‐oxo‐ethoxy)phenyl]‐1,2‐di(p‐tert‐butyldimethylsiloxyphenyl)‐but‐1‐ene. The deprotection of phenolic functions of the latter compound led to the formation of the final compound. The Z and E isomers could be separated but the isomerization of these isomers from one to another is an easy process. The Z + E compound 2 was tested against the hormone‐dependent MCF‐7 and hormone‐independent MDA‐MB‐231 breast cancer cell lines. The IC₅₀ values of compound 2 were 4.80 ± 2.00 µm and 4.79 ± 0.70 µm for MCF‐7 cells and MDA‐MB‐231 cells, respectively, which was three times better than the ferrocenyl analogue. Copyright © 2012 John Wiley & Sons, Ltd.