Thermodynamic versus kinetic control in self-assembly of zero-, one-, quasitwo-, and two-dimensional metal-organic coordination structures

Tao Lin, Qi Wu, Jun Liu, Ziliang Shi, Pei Nian Liu, and Nian Lin

The Journal of Chemical Physics, 2015

Figure 1. Left: Representative STM images of the four bi-component systems following a series of thermal annealing treatments. (a)-(c) 1-5. (d)-(f) 2-5. (g)-(i) 3-5. (j)-(l) 4-5. The annealing temperature is indicated in each image. All images are 100 x 100 nm2. Right: MC simulated structures of the four bi-component systems formed at different temperatures. (a)-(d) 1-5. (e)-(h) 2-5. (i)-(l) 3-5. (m)-(p) 4-5.

Abstract

Four types of metal-organic structures exhibiting specific dimensionality were studied using scanning tunneling microscopy and Monte Carlo simulations. The four structures were self-assembled out of specifically designed molecular building blocks via the same coordination motif on an Au(111) surface. We found that the four structures behaved differently in response to thermal annealing treatments: The two-dimensional structure was under thermodynamic control while the structures of lower dimension were under kinetic control. Monte Carlo simulations revealed that the self-assembly pathways of the four structures are associated with the characteristic features of their specific heat. These findings provide insights into how the dimensionality of supramolecular coordination structures affects their thermodynamic properties.