Tuning Coordination Environments Through Ligand Redox Chemistry: the Thiol-Disulfide Reaction

Oxidative coupling of 6-(pyridin-2-yl)pyridine-2(1H)-thione yields 1,2-bis(2,2'-bipyridin-6-yl)disulfide (4), which can act as a bis(chelate) to a single zinc(II) centre. The effects on the solid-state structure of introducing a methyl substituent into each 6-position of 4 have been examined. Ligand 4 functions as a bridging ligand in [Cu(2)(mu-4)(mu-6)](4+) in which ligand 6 is 1,2-bis(2,2':6',2 ''-terpyridin-4'-yl)disulfide; [Cu(2)(mu-4)(mu-6)](4+) self-assembles from the components according to the preference shown by copper(II) for a five-coordinate {Cu(bpy)(tpy)} environment. Reaction of 4 with [Cu(NCMe)(4)][PF(6)] leads to a product, tentatively formulated as {[Cu(4)][PF(6)]}(n), which, in air, undergoes oxidation of both copper and ligand to yield [Cu(5)(2)] (H5=2,2'-bipyridine-6-sulfonic acid), the solid state structure of which is presented.