Computer-Chemistry-Center and Interdisciplinary Center for Molecular Materials, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
ACS Appl Mater Interfaces. 2013 Jul 10;5(13):6073-80. doi: 10.1021/am4008374. Epub 2013 Jun 18.
We report a computational study on the chemical bonding of phosphonates and carboxylates to aluminum oxide surfaces and how the binding properties are related to the amount of water in the experimental environment. Two different surface structures were used in the calculations in order to model representative adsorption sites for the phosphonates and carboxylates and to account for the amorphous nature of the hydroxylated AlOx films in experiment. For the phosphonates, we find that the thermodynamically preferred binding mode changes between mono-, bi-, and tridentate depending on the surface structure and the amount of residual water. For the carboxylates, on the other hand, monodentate adsorption is always lower in energy at all experimental conditions. Phosphonates are more strongly bound to aluminum oxide than carboxylates, so that carboxylates can be replaced easily by phosphonates. The theoretical findings are consistent with those obtained in adsorption, desorption, and exchange reactions of n-alkyl phosphonic and carboxylic acids on AlOx surfaces. The results provide an atomistic understanding of the adsorption and help to optimize experimental conditions for self-assembly of organic films on aluminum oxide surfaces.
我们报告了一项关于膦酸酯和羧酸根与氧化铝表面的化学键合的计算研究，以及结合性质如何与实验环境中的水量有关。为了模拟膦酸酯和羧酸根的代表性吸附位点，并考虑到实验中氧化铟锡膜的非晶态性质，在计算中使用了两种不同的表面结构。对于膦酸酯，我们发现，根据表面结构和残留水量的不同，热力学上优先的结合模式在单齿、双齿和三齿之间发生变化。另一方面，对于羧酸根，在所有实验条件下，单齿吸附的能量始终较低。膦酸酯与氧化铝的结合比羧酸根强，因此羧酸根很容易被膦酸酯取代。理论发现与在 AlOx 表面上 n-烷基膦酸和羧酸的吸附、解吸和交换反应中获得的结果一致。这些结果提供了对吸附的原子理解，并有助于优化在氧化铝表面上自组装有机膜的实验条件。
