Construction of nanodevices has been a driving force in synthetic coordination chemistry in recent years. By building devices from the bottom-up using molecules, devices can be tailored to have specific properties. 

Molecular shape is an important consideration because in order for these molecular building blocks to be attached to a surface the flatter the molecule the better. Therefore, flat 2D polymetallic grids represent an ideal structure for these nanodevices. However, making square grids is easier said than done.

In their Dalton Transactions Perspective, Louise Dawe, Tareque Abedin and Laurence Thompson discuss their contributions to the area of square grid synthesis. They concentrate on using hydrazone based ligands to develop rational routes to polymetallic grids.

Thompson and his team also take a look at the non-square structures which result in some cases, in order to elucidate the mechanisms involved. While regular square [n x n] grids are the target, it should be borne in mind that alternative construction routes are possible as the ligands and metal ions react. The non-grid structures which result can be used to throw some light on the mechanism of grid construction, says Thompson.