Ferrocenyl-derived face-capping ligands: syntheses and molecular structures of [(FcTt)Cu] 4 and [FcTt] 2M (M = Fe, Co, Ni; FcTt − = ferrocenyltris((methylthio)methyl)borate)

Abstract

The synthesis and characterization of a ferrocenyl-derived tridentate ligand, ferrocenyltris((methylthio)methyl)borate (FcTtP −), and its representative metal complexes, [(FcTt)Cu] 4 and [FcTt] 2M (M = Fe, Co and Ni), are reported. The M = Fe complex exhibits spin-crossover behavior with a μ eff = 1.19 μ B at 25°C. The low-spin Co(II) derivative (1.88 μ B) exhibits a characteristic axial electron paramagnetic resonance (EPR) spectrum, g av = 2.13, A ⊥ = 53 G and A ¦ = 43 G. The [FcTt] 2M complexes display reversible two-electron redox processes assigned to ligand-centered events about 200 mV negative of the ferrocene-ferrocenium couple. [(FcTt)Cu] 4 and [FcTt] 2Ni have been characterized by X-ray diffraction. X-ray data for [(FcTt)Cu] 4: monoclinic space group C2/ c, with a = 24.3747(3) Å, b = 20.0857(2) Å, c = 17.2747(4) Å, β = 95.843(1)°, V = 8413.5(3) Å 3, and Z = 4; [FcTt] 2Ni: monoclinic space group C2/ c, with a = 12.6220(3) Å, b = 11.6002(3) Å, c = 25.0125(7) Å, β = 94.067(1)°, V = 3653.1(2) Å 3, and Z = 4.