Chemical weathering of molecular single crystals to monoliths of quantum dots

In nature, nanocrystals form primarily through geological processes, such as chemical weathering of rocks and minerals. However, artificial systems that mechanistically parallel geological nanocrystal formation, particularly in the solid state, replicating the hydrolytic conditions of geological processes remain rare. Here, we report an all-solid-state strategy for the synthesis of quantum-sized semiconductor nanostructured materials under ambient conditions. The approach relies on a hydrolysable organozinc precursor, consisting of [RZn(amidate)]_n-type molecular clusters featuring reactive Zn-C and Zn-N bonds, confined within a single-crystal lattice prone to water-mediated hydrolytic processes. The initial millimetre-sized precursor crystals, when exposed to humid air, undergo hydrolytic transformations. Within hours these transformations lead to the formation of ZnO quantum dots at room temperature, reminiscent of natural chemical weathering. The crystalline network of the precursor system provides a specific environment for the formation of zinc hydroxide/oxide species, followed by nucleation and growth of quantum dots within an emerging hydrogen-bonded host organic matrix composed from the hydrolysable amidate ligands. This organic matrix, in turn, can be removed from the system under reduced pressure, yielding a nanocrystalline mesoporous scaffold consisting of quantum-sized crystals. This organometallic synthetic system provides insights into solid-state nanostructured materials formation under mild conditions and offers a pathway to sustainable synthesis of functional materials.