Aguilar-Sánchez R, Fu Yongchun, Homberger M, Simon U
Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, 72570 Puebla, Mexico.
Institute of Inorganic Chemistry, RWTH Aachen University, 52074 Aachen, Germany.
Langmuir. 2025 Aug 12;41(31):20648-20656. doi: 10.1021/acs.langmuir.5c02088. Epub 2025 Jul 29.
Scanning Tunneling Microscopy (STM) and electrochemical studies were conducted on a series of 4-methyl-4'-(-mercaptoalkyl) biphenyls CH(CH)(CH)SH (BP, where = 1-6) self-assembled on the unreconstructed Au(100)-(1 × 1) surface. The study investigated the role of substrate crystallography in the electrochemical and surface properties of BP adlayers. Notably, unlike BP on Au(111)-(1 × 1), short alkane chain BP (1 to 4) does not induce gold surface vacancies when adsorbed on the Au(100)-(1 × 1) indicating distinct surface chemistry. The adlayers exhibit two coexisting phases (α and β), the presence of which evolves with the number of methylene units. The electrochemical properties of the BP adlayers are characterized by higher thermodynamic stability during reductive desorption with charge values alternating with the number of methylene units. The molecule adsorption modifies an important parameter such as the work function of the underlying Au(100)-(1 × 1) metal substrate. The reciprocal capacitance exhibits a linear dependence on the length of the alkane spacer. Its change per CH group agrees well with the values of -alkanethiols on Au(111).
对一系列在未重构的Au(100)-(1×1)表面自组装的4-甲基-4'-(-巯基烷基)联苯CH(CH)(CH)SH（BP，其中 = 1 - 6）进行了扫描隧道显微镜（STM）和电化学研究。该研究调查了基底晶体学在BP吸附层的电化学和表面性质中的作用。值得注意的是，与在Au(111)-(1×1)上的BP不同，短烷烃链的BP（1至4）吸附在Au(100)-(1×1)上时不会诱导金表面空位，这表明表面化学性质不同。吸附层呈现出两个共存相（α和β），其存在随着亚甲基单元数量的变化而演变。BP吸附层的电化学性质的特征在于在还原解吸过程中具有更高的热力学稳定性，电荷值随亚甲基单元数量交替变化。分子吸附改变了诸如底层Au(100)-(1×1)金属基底的功函数等重要参数。倒数电容对烷烃间隔基的长度呈线性依赖关系。其每个CH基团的变化与在Au(111)上的 -烷硫醇的值非常吻合。
