Ligand-directed synthesis of {MnIII5} twisted bow-ties

Two isostructural polymetallic complexes [Mn(μ3-O)2(CH3COO)4(L1)4]- and [Mn(μ3-O)2(CH3COO)4(L2)4]- have been synthesised by using two Schiff base ligands derived from 3,5-diamino-1,2,4-triazole, following two different preparative routes, either using the pre-formed ligand (for L1) or via a metal-mediated template synthesis (for L2). The {Mn} structure is unusual, being based on two corner-sharing perpendicular {Mn3} triangles forming a twisted bow-tie. The magnetic studies reveal antiferromagnetic coupling between Mn(iii) ions while electrochemical experiments are consistent with a quasi-reversible Mn(iii)↔Mn(iv) redox process at the central manganese ion.