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

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