Reversible and Site-Specific Reduction of the Ligand Sides in a Molecular Rectangle with up to Eight Electrons

The molecular rectangle [(bp)2(bpym)2(OC)12Re4]4+ (bp = 4,4‘-bipyridine and bpym = 2,2‘-bipyrimidine) undergoes several reversible reduction processes in DMF solution. UV/vis and IR spectroelectrochemistry shows that the two bpym ligands are reduced twice by one electron each before the bp components pick up additional electrons in one-electron steps at more negative potentials.