Pathway-dependent quantitative self-assembly of a metastable Pd6L4 square-based pyramid promoted by template and assist anions

Precise control of molecular self-assembly process is one of ultimate goals in molecular self-assembly because this enables us to make a rational design of self-assembly pathway to selectively obtain even metastable assemblies, which is impossible under thermodynamic control. Toward this goal, modulation of the energy landscape of molecular self-assembly is demanded. Here, we report that a metastable Pd6L4 square-based pyramid (SP) was almost quantitatively assembled by a pathway-dependent process with the aid of template and assist anions, which properly modulate the energy landscape, while usual heating a mixture of building blocks without modulation of the energy landscape gave a mixture of Pd6L4 SP and uncharacterized species in equilibrium. These results indicate that synergy of template and assist effects is powerful approach for pathway selection in metal-organic assembly resulting in a metastable product selectively.