Redox state switching of transition metals by deprotonation of the tridentate ligand 2,6-bis(imidazol-2-yl)pyridineElectronic supplementary information (ESI) available: Fig. S1: ORTEP view of the [Mn(1)2]2+ solvated complex. Fig. S2: ORTEP view of the [Mn(1)2]2+ non-solvated complex. Fig. S3: ORTEP view of the [Co(1 ? 2H)2]? complex. See http://www.rsc.org/suppdata/dt/b3/b313440g/