Layered inorganic–organic frameworks based on the 2,2-dimethylsuccinate ligand: structural diversity and its effect on nanosheet exfoliation and magnetic properties

Abstract

The structures of four new 2,2-dimethylsuccinate frameworks suitable for exfoliation into nanosheets using ultrasonication are reported. These hybrid compounds contain either monovalent (Li⁺) or divalent (Co²⁺ and Zn²⁺) cations, and they all feature hydrophobically capped covalently bonded layers that only interact with each other via weak van der Waals forces. Critically this shows that the use of this dicarboxylate ligand generally yields two dimensional compounds suitable for simple and affordable nanosheet exfoliation. This extends the range of frameworks that can be exfoliated and highlights the 2,2-dimethylsuccinate ligand as an excellent versatile platform for the production of nanosheets. The topologies of the layers in each framework were found to vary significantly and this appears to have a significant effect on the relative size of the nanosheets produced; increased space between methyl groups and more extensive inorganic connectivity appears to favour the formation of thin nanosheets with larger lateral dimensions. Additionally the magnetic properties of two of these frameworks were examined, and it was found that both exhibit strong low dimensional antiferromagnetic coupling despite their well-separated layers preventing three dimensional magnetic order.