Unprecedented metal-mediated in situ reactions of heterocyclic disulfide of di[4-(pyridin-2-yl)pyrimidinyl]disulfide.

By the combination of different metal salts and solvents, four unprecedented in situ reactions have been discovered for heterocyclic disulfide of 2-ppds (2-ppds = di[4-(pyridin-2-yl)pyrimidinyl]disulfide). In the CH3CN-DMF solvent, reaction of 2-ppds with AgNO3 produced a one-dimensional chain structure of {[Ag2(1L)2]·2CH3CN}n (1), wherein 2-ppds was converted into its sulfonate of 1L by means of oxidative cleavage of the S-S bond. In the CH3CN-DCM solvent, reaction between 2-ppds and Cu(ClO4)2 yielded a discrete mononuclear Cu(II) coordination structure of [Cu(2L)2H2O)](ClO4)2 (2), of which 2-ppds was turned into a totally unexpected zwitterion product of 2L via C-S bond scission followed by O substitution. In the MeOH-DCM solvent, reaction of 2-ppds with Co(ClO4)2 resulted in a mononuclear Co(III) coordination structure of [Co(3L)2]ClO4·2CH3OH·H2O (3), in which 2-ppds was transformed into its persulfide of 3L via selective single C-S bond rupture. In the CH3CN-DMF solvent, reaction between 2-ppds and CuI afforded a binuclear mixed-valence Cu(I)Cu(II) coordination structure of [Cu2I(4L)2] (4), wherein 2-ppds was converted into its thiolate of 4L through homolytic S-S bond cleavage. The reaction mechanisms of these reactions have also been discussed on the basis of these in situ generated coordination structures coupled with our previous observations on 2-ppds.