Parallel disulfido bridges in bi- and poly-nuclear transition metal compounds: Bonding flexibility induced by redox chemistry

The 2S22-/S42- dichotomy in bimetallic MS4M cores having triple-decker (TD) or chair-like structures is theoretically analyzed in terms of the known experimental compounds. The extent of the disulfide coupling (or formation of a S42- ring) is on one side correlated with the electron configuration of the metals and their electronegativity, on the other side, with the physical separation between the two S2 units.