Multi-electron reactivity of a cofacial di-tin(ii) cryptand: partial reduction of sulfur and selenium and reversible generation of S˙.

Cofacial bimetallic tin(ii) ([Sn(BDCA-5t)], ) and lead(ii) ([Pb(BDCA-5t)], ) complexes have been prepared by hexadeprotonation of hexacarboxamide cryptand BDCA-5t-H together with double Sn(ii) or Pb(ii) insertion. Reaction of with elemental sulfur or selenium generates di-tin polychalcogenide complexes containing μ-E and bridging μ-E ligands where E = S or Se, and the Sn(ii) centers have both been oxidized to Sn(iv). Solution and solid-state UV-Vis spectra of [(μ-S)Sn(μ-S)(BDCA-5t)] () indicate that the complex acts reversibly as a source of S˙ in DMF solution with a = 0.012 ± 0.002. Reductive removal of all six chalcogen atoms is achieved through treatment of [(μ-E)Sn(μ-E)(BDCA-5t)] with PR (R = Bu, Ph, OPr) to produce six equiv. of the corresponding EPR compound with regeneration of di-tin(ii) cryptand complex .