Modulating the Reduction Potential of Mononuclear Cobalt(II) Complexes via Selective Deprotonation of Tris[(2-benzimidazolyl)methyl]amine

Remote site deprotonation of the coordinated tripodal ligand, tris((2-benzimidazolyl)methyl)amine, was examined using electronic spectroscopy and electrochemistry techniques. The solid-state structures [CoH31tba(NCS)]+ and [CoH21tba(NCS)] are reported. These complexes crystallized in the triclinic space group P1̄ [a = 13.3043(2) Å, b = 13.8019(2) Å, c = 14.1322(2) Å, α = 63.6670(10)°, β = 68.0590(10)°, γ = 81.8960°; Z = 2] and the monoclinic space group P21/n [a = 15.3530(9) Å, b = 11.0645(6) Å, c = 19.1319(10) Å, β = 105.6750(10)°; Z = 4], respectively. Preliminary results suggest that selective and reversible deprotonation of coordinated benzimidazolyl ligands can tune the reduction potential of several isostructural cobalt(II) complexes.