Structural evolution of trimesic acid (TMA)/Zn2+ ion network on Au(111) to final structure of (10√3 x 10√3)

Presented is a scanning tunneling microscopy (STM) study of structural evolution of TMA/Zn2+ ion network on Au(111) to the final structure of (10 root 3 x 10 root 3) during solution phase post-modification of pristine trimesic acid (TMA) network of a (5 root 3 x 5 root 3) structure with Zn2+ ions. Coordination of Zn2+ ions into adsorbed TMA molecules transforms crown-like TMA hexamers in pristine TMA network to chevron pairs in TMA/Zn2+ ion network. Two ordered transient structures of TMA/Zn2+ ion network were observed. One is a (5 root 7 x 5 root 7) structure consisting of Zn2+ ion-containing chevron pairs and Zn2+ ion-free TMA dimers. The other is a (5 root 39 x 5 root 21) structure made of chevron pairs and chevron-pair-missing sites. An STM image showing domains of different stages of crystallization of chevron pairs demonstrates that the TMA/Zn2+ network before reaching to the final one is quite dynamic. The observed structural evolution of the TMA/Zn2+ ion network is discussed in terms of modification of configurations of adsorbed TMA as accommodating Zn2+ ions and re-ordering of Zn2+ ion-containing chevron pairs. (C) 2015 Elsevier B.V. All rights reserved.