Heterometallic Ru2Co2 [2 × 2] Grid with Localized Single Molecule Magnet Behavior

Metal complexes with a [n × n] gridlike structure are discussed as attractive building blocks for various materials chemistry applications in molecular nanotechnology and electronics, which often rely on the grids’ magnetic and redox properties. Most of the known metallogrids are homometallic, though heterometallic systems that comprise two or more different metals promise higher level functionalities. However, heterometallic [n × n] grids are relatively rare, mostly because of the more challenging synthetic strategies. To that end a new heterometallic [2 × 2] grid complex [L4Ru2Co2](BF4)4 (2) based on a known pyrazolate-bridged bis(tridentate) compartmental N-donor ligand [L]− is presented in this work, along with its doubly oxidized congener [L4Ru2Co2](BF4)6 (3). In order to prevent scrambling of the different metal ions, a stepwise synthetic approach was implemented in which an inert RuII “corner complex” [(HL)2Ru](BF4)2 (1) was isolated first, followed by addition of the more labile CoII. This exclusi...