Modular bimetallic complexes with a sulfonamido-based ligandElectronic supplementary information (ESI) available: Crystallographic, UV-vis, ESI-MS, and CV data for all complexes. CCDC 1554806-1554812. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c8dt02455c

A series of bimetallic complexes prepared with the ligands N , N , N ′, N ′-tetramethylethane-1,2-diamine (TMEDA) and N , N ′, N ′′-[2,2′,2′′-nitrilotris(ethane-2,1-diyl)]tris(2,4,6-trimethylbenzenesulfonamido) ([MST] 3− ) is described. Four diiron compounds of the formulation (TMEDA)Fe II (X)-(μ-OH)-Fe III MST were prepared, in which the X − ligands are the anions OTf − , Br − , SCN − , or N 3 − . Additionally, two heterobimetallic compounds of the formulation (TMEDA)M II (OTf)-(μ-OH)-Fe III MST (M II = Co II or Ni II ) were synthesized. All these compounds have similar spectroscopic and structural properties. The diiron compounds exhibit perpendicular-mode electron paramagnetic resonance spectra consistent with S = 1/2 spin ground states, which is expected for high-spin Fe II and Fe III centres that are antiferromagnetically coupled. The heterobimetallic (TMEDA)Ni II (OTf)-(μ-OH)-Fe III MST complex had a spin state of S = 3/2 that also resulted from antiferromagnetic coupling between the high-spin Ni II and Fe III centres. The modularity of this system is further demonstrated by the substitution of the TMEDA ligand with ethylenediamine (en); for this species two equivalents of en coordinate to the Fe II centre to form [(en) 2 Fe II -(μ-OH)-Fe III MST]OTf. These results demonstrate that a modular bimetallic system has been developed in which the key components can be modified. A series of modular unsymmetrical bimetallic complexes has been developed in which the key components can be easily substituted.