title: Redox state switching of transition metals by deprotonation of the tridentate ligand 2,6-bis(imidazol-2-yl)pyridine.
abstract: The chemistry of the ligand 1, 2,6-bis(imidazol-2-yl)pyridine with manganese, cobalt, nickel and ruthenium has been investigated. The ligand binds as a meridional tridentate ligand as shown by the crystal structures of [Mn(1)2](CF3SO3)2 x Et2O and [Ru(1)2](PF6)2 x 2CH3CN x H2O. The coordinated ligand is deprotonated in mildly basic solution, and this leads to a drop in the metal M(III)/M(II) reduction potential for cobalt and ruthenium of roughly 1.3 V. The crystal structure of Na2(PPN)[Co(1 - 2H)2]2(OH) x MeOH x 2H2O confirms the deprotonation and shows sodium to bind to the deprotonated nitrogen atoms. No stabilisation of the M(III) oxidation state was observed for nickel and manganese.
authors.affiliation: Department of Inorganic, Analytical and Applied Chemistry, University of Geneva, 30 quai Ernest Ansermet, CH 1211 Geneva 4, Switzerland.
authors.forename: Gilles
authors.initials: G
authors.lastname: Stupka
authors.forename: Ludovic
authors.initials: L
authors.lastname: Gremaud
authors.forename: Gérald
authors.initials: G
authors.lastname: Bernardinelli
authors.forename: Alan F
authors.initials: AF
authors.lastname: Williams
mesh_terms: D018360:Crystallography, X-Ray; D007093:Imidazoles / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D010084:Oxidation-Reduction; D011725:Pyridines / Q000737:chemistry*; D028561:Transition Elements / Q000737:chemistry*
chemical_list: C500568:2,6-bis(imidazol-2-yl)pyridine; D007093:Imidazoles; D008024:Ligands; D009942:Organometallic Compounds; D011725:Pyridines; D028561:Transition Elements