Synthesis of Prussian Blue Metal Coordination Polymer Nanocubes via Cyanoferrate Monomer Design

The effect of cyanoferrate monomers on the metal coordination polymerization of Fe 3+ and [Fe(CN) 5 L] 3− , where L = CN, NH 3 , pyrazine (Pz), pyridine (Py) and 4-(dimethylamino)-pyridine (DMAP), for the synthesis of Prussian blue (PB) polymers was investigated. The polymerizations were performed in water at ambient temperature in the absence of templates and/or surfactants. The morphology and crystallinity of the resulting polymers are influenced by the nature of the ligands L associated with the monomers. When L = CN or NH 3 , crystalline polymers with irregular structures were produced. The polymerization employing [Fe(CN) 5 L] 3− with L = Pz, Py and DMAP led to amorphous polymers with a tendency to form individual nanoparticles depending on the choice of L. Notably, in the case of [Fe(CN) 5 DMAP] 3− , amorphous PB nanocubes with a regular size distribution were produced. Based on this study, the binding forces of L to Fe(II)(CN) 5 is highlighted as an important parameter for PB metal coordination polymer nanostructure control and design.