Influence of the Nature and Orientation of the Terminal Group on the Tribochemical Reaction Rates of Carboxylic Acid Monolayers on Copper
Influence of the Nature and Orientation of the Terminal Group on the Tribochemical Reaction Rates of Carboxylic Acid Monolayers on Copper
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端基性质和取向对铜上单层羧酸摩擦化学反应速率的影响
DOI：
10.1007/s11249-021-01545-4
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发表时间：
2022
影响因子：
3.2
通讯作者：
Tysoe, Wilfred T.
中科院分区：
文献类型：
--
作者：
Rana, Resham;Bavisotto, Robert;Hou, Kaiming;Hopper, Nicholas;Tysoe, Wilfred T.
在超高真空摩擦试验机和原子力显微镜(AFM)针尖上研究了改变吸附在铜表面的C7和C8羧酸盐的末端官能团对摩擦化学分解速率的影响，在这两个实验中选择了提供相似法向应力的条件。碳链由烷基、乙烯基和乙炔基团封端，其中选择不同的链长来改变末端π-轨道的取向。原子力显微镜测得的拉力与计算的分子结构相吻合，但尽管如此，所有吸附的羧酸盐的摩擦化学分解速率是相同的。然而，碳以不同的速度从表面损失，这归因于产生的碳质物种的不同反应活性，这些碳质物种是在室温下摩擦化学产生的，但在 ~ 650K时以热方式形成。这导致较低能量的势垒反应，如β-氢化物消除反应，与较高活化能的反应，如偶合反应相比，优先发生。认为这些速率受末端基团访问铜表面的能力的影响，并解释了相对反应速率和沉积在表面上的碳量。
The effect of changing the terminal functional group of C7and C8carboxylate species adsorbed on copper on the rate of tribochemical decomposition is investigated both in an ultrahigh vacuum tribometer and using an atomic force microscopy (AFM) tip, where the conditions are selected to provide similar normal stresses for both experiments. The carbon chains are terminated by alkyl, vinyl and acetylide groups, where the different chain lengths are selected to modify the orientation of the terminal π-orbitals. The pull-off forces measured by AFM are in accord with the calculated molecular structure but, despite this, the rates of tribochemical decomposition of all the adsorbed carboxylates are identical. However, the carbon is lost from the surface at different rates and this is ascribed to the different reactivities of the resulting carbonaceous species that are tribochemically produced at room temperature, but form thermally at ~ 650 K. This results in lower-energy barrier pathways, such as β-hydride elimination reactions, occurring preferentially compared to higher-activation-energy ones, such as coupling reactions. It is proposed that these rates are influenced by the ability of the terminal groups to access the copper surface and accounts for the relative reaction rates and the amount of carbon deposited onto the surface.Graphical Abstract
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DOI：
--
发表时间：
1984
期刊：
影响因子：
--
作者：
N. Canning;R. Madix
通讯作者：
R. Madix
影响因子：
4.4
作者：
Jha, Sanjiv K.;Brown, Katie;Subramanian, Gopinath
通讯作者：
Subramanian, Gopinath
影响因子：
3.2
作者：
Resham Rana;Robert Bavisotto;Nicholas C. Hopper;W. Tysoe
通讯作者：
Resham Rana;Robert Bavisotto;Nicholas C. Hopper;W. Tysoe
影响因子：
3.2
作者：
W. Tysoe
通讯作者：
W. Tysoe
奇数和偶数模型自组装单层：摩擦与结构之间的联系。
DOI：
10.1021/la052044x
发表时间：
2005
期刊：
Langmuir : the ACS journal of surfaces and colloids
影响因子：
--
作者：
P. Mikulski;Lawrence A. Herman;J. Harrison
通讯作者：
J. Harrison