Dissociative and Reactive Hyperthermal Ion−Surface Collisions with Langmuir−Blodgett Films Terminated by CF3(CH2)n−, n-Perfluoroalkyl, or n-Alkyl Groups
摘要:
Langmuir-Blodgett (L-B) films prepared from 18,18,18-trifluorooctadecanoic acid [CF3(CH2)(16)-COOH], perfluorotetradecanoic acid [n-C13F27COOH], or octadecanoic acid [n-C17H35COOH] were used as target surfaces for hyperthermal ion-surface collisions. The synthesis of 18,18,18-trifluorooctadecanoic acid and the preparation of the L-B film from this compound using a subphase containing Al3+ are reported in this paper. The Ion-surface collision results show that the outermost surface group, namely CF3 vs CH3, is the main determinant for the efficiency of both energy transfer and electron transfer during low-energy(e.g., 10-100 eV) polyatomic ion-surface collisions. For atomic projectile ions, there is evidence of penetration into a depth of the films.
Dissociative and Reactive Hyperthermal Ion−Surface Collisions with Langmuir−Blodgett Films Terminated by CF3(CH2)n−, n-Perfluoroalkyl, or n-Alkyl Groups
摘要:
Langmuir-Blodgett (L-B) films prepared from 18,18,18-trifluorooctadecanoic acid [CF3(CH2)(16)-COOH], perfluorotetradecanoic acid [n-C13F27COOH], or octadecanoic acid [n-C17H35COOH] were used as target surfaces for hyperthermal ion-surface collisions. The synthesis of 18,18,18-trifluorooctadecanoic acid and the preparation of the L-B film from this compound using a subphase containing Al3+ are reported in this paper. The Ion-surface collision results show that the outermost surface group, namely CF3 vs CH3, is the main determinant for the efficiency of both energy transfer and electron transfer during low-energy(e.g., 10-100 eV) polyatomic ion-surface collisions. For atomic projectile ions, there is evidence of penetration into a depth of the films.
efficient rhodium-catalyzed β-dehydroborylation of aldehyde-derived silyl enol ethers (SEEs) with bis(pinacolato)diboron (B2pin2) is disclosed. The borylation reactions proceeded well with alkyl- and aryl-substituted SEEs, affording a wide array of valuable functionalized β-boryl silyl enolates with high efficiency and excellent stereoselectivity. Moreover, the borylated products, through versatile
公开了醛衍生的甲硅烷基烯醇醚(SEE)与双(频哪醇)二硼(B 2 pin 2 )的有效铑催化的β-脱硼氢化。硼基化反应与烷基和芳基取代的 SEE 进行得很好,提供了一系列有价值的功能化 β-硼基甲硅烷基烯醇化物,具有高效率和优异的立体选择性。此外,borylated产品,通过通用的碳-硼键的变换,被容易地转化为合成多样有用分子,包括α羟基酮,官能看到,和宝石-difunctionalized醛。
Leaving Group Assisted Strategy for Photoinduced Fluoroalkylations Using <i>N</i>
-Hydroxybenzimidoyl Chloride Esters
作者:Weigang Zhang、Zhenlei Zou、Yuanheng Wang、Yi Wang、Yong Liang、Zhengguang Wu、Youxuan Zheng、Yi Pan
DOI:10.1002/anie.201812192
日期:2019.1.8
(RAEs) as alkylradical precursors have been extensively developed for C−C bond formations. However, the analogous transformations of fluoroalkyl radicalsfrom the corresponding acid or ester precursors remain challenging because of the high oxidation potential of the fluoroalkyl carboxylate anions. The newly developed N‐hydroxybenzimidoylchloride (NHBC) ester provides a general leavinggroup assisted
Csuk, Rene; Tamba, Maria Gabriela; Kluge, Ralph, Zeitschrift fur Naturforschung, B: Chemical Sciences, 2011, vol. 66, # 10, p. 1069 - 1075
作者:Csuk, Rene、Tamba, Maria Gabriela、Kluge, Ralph
DOI:——
日期:——
Source of Image Contrast in STM Images of Functionalized Alkanes on Graphite: A Systematic Functional Group Approach
作者:Christopher L. Claypool、Francesco Faglioni、William A. Goddard、Harry B. Gray、Nathan S. Lewis、R. A. Marcus
DOI:10.1021/jp9701799
日期:1997.7.1
A series of functionalized alkanes and/or alkyl alcohols have been prepared and imaged by scanning tunneling microscopy (STM) methods on graphite surfaces. The stability of these ordered overlayers has facilitated reproducible collection of STM images at room temperature with submolecular resolution, in most cases allowing identification of individual hydrogen atoms in the alkane chains, but in all cases allowing identification of molecular length features and other aspects of the image that can be unequivocally related to the presence of functional groups in the various molecules of concern. Functional groups imaged in this study include halides (X = F, Cl, Br, I), amines, alcohols, nitriles, alkenes, alkynes, ethers, thioethers, and disulfides. Except for -Cl and -OH, all of the other functional groups could be distinguished from each other and from -Cl or -OH through an analysis of their STM metrics and image contrast behavior. The dominance of molecular topography in producing the STM images of alkanes and alkanols was established experimentally and also was consistent with quantum chemistry calculations. Unlike the contrast of the methylene regions of the alkyl chains, the STM contrast produced by the various functional groups was not dominated by topographic effects, indicating that variations in local electronic coupling were important in producing the observed STM images of these regions of the molecules. For molecules in which electronic effects overwhelmed topographic effects in determining the image contrast, a simple model is presented to explain the variation in the electronic coupling component that produces the contrast between the various functional groups observed in the STM images. Additionally, the bias dependence of these STM images has been investigated and the contrast vs bias behavior is related to factors involving electron transfer and hole transfer that have been identified as potentially being important in dominating the electronic coupling in molecular electron transfer processes.
ANDRIEU, ANNIE HUGUETTE;BLANCOU, HUBERT;COMMEYRAS, AUGUSTE
作者:ANDRIEU, ANNIE HUGUETTE、BLANCOU, HUBERT、COMMEYRAS, AUGUSTE