Toluenesulfonyl -l,4,7-triazacyclononane

Cobalt complexes have been also extensively studied as artificial hydrogenases for the reductive side of water splitting.It has been recently demonstrated that the cobalt(ii) complex of the pentadentate ligand l,4-di(picolyl)-7-(p-toluenesulfonyl)-l,4,7-triazacyclononane (iy2T stacn) displays excellent H2 photoproduction catalytic activity, in the presence of [Ir(ppy)2(bpy)]PF6 as photosensitiser, and EtgN as electron donor. Under the same conditions, the corresponding complex of nick-el(ii) presents low photochemical activity, while the iron(n) analogue is inactive. 

---