Self-Assembly of (S)-Glutamic Acid on Ag(100): A Combined LT-STM and Ab Initio Investigation

• Published in: Langmuir 2010-05, Vol.26 (10), p.7208-7215
• Main Authors: Smerieri, M, Vattuone, L, Costa, D, Tielens, F, Savio, L
• Format: Article
• Language: English
• Subjects: Adsorption; Catalysis; Chemical Sciences; Chemistry; Colloidal state and disperse state; Computer Simulation; Exact sciences and technology; General and physical chemistry; Glutamic Acid - chemical synthesis; Glutamic Acid - chemistry; Interfaces: Adsorption, Reactions, Films, Forces; Microscopy, Scanning Tunneling; Models, Chemical; Quantum Theory; Silver - chemistry; Stereoisomerism; Surface physical chemistry; Surface Properties; Temperature
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la904331d

Self-assembly of organic molecules at metal surfaces is of greatest importance in nanoscience; in fact, it opens new perspectives in the field of molecular electronics and in the study of biocompatible materials. Combining an experimental low-temperature scanning tunneling microscopy investigation with ab initio calculations, we succeeded to describe in detail (S)-glutamic acid adsorption on Ag(100) at T = 350 K. We find that (S)-glutamic acid organizes in a squared structure and, at variance with the majority of cases reported in literature, it adsorbs in the neutral form, 4.6 Å above the surface plane. The interaction with the poorly reactive Ag substrate is only due to weak van der Waals forces, while H-bonds between carboxyl groups and the formation of a OCOH−OCOH−OCOH−OCOH cycle at the vertex of the squares are the main responsible for the self-assembly.