Transition metal sulfito complex

Transition metal sulfito complexes are coordination compounds containing sulfite (SO32-) as a ligand.

To some extent, the sulfito ligand resembles nitrito (NO−2), which can bind through N or O. Monodentate, S-bonded sulfites are more common than O-bonded sulfito ligands.

S-Bonded sulfite is a soft ligand with a strongly trans labilizing effect as indicated by the rapid aquation of [Co(SO3)(NH3)5]+ to give [Co(SO3)(NH3)4(H2O)]+.

[3] In some cases, sulfite serves as a bridging ligand forming M-SO2-O-M’ linkages.

[4] Being dibasic, sulfito ligands are susceptible to O-alkylation and O-protonation.

The structure of [Co( ethylenediamine ) 2 (SO 3 )N 3 ]. Color code: blue = N, red = O, yellow = S. [ 1 ]
Structure of [PtCl 2 (SO 3 H)(SO 3 )] 3− [ 11 ]