the 
 new ligand n3pyamidesr and its feii complex 
 [ feii(n3pyamidesr)](bf4)2 ( 1 ) are described . 
 reaction of 1 with 
 phio at 40 c gives metastable [ feiv(o)(n3pyamidesr)]2 + ( 2 ) , containing a sulfide 
 ligand and a single amide h - bond donor in proximity to the terminal 
 oxo group . 
 direct evidence for h - bonding is seen in a structural analogue , 
 [ feii(cl)(n3pyamidesr)](bf4)2 ( 3 ) . 
 complex 2 exhibits rapid o - atom 
 transfer ( oat ) toward external sulfide substrates , but no intramolecular 
 oat . 
 however , direct s - oxygenation does occur in 
 the reaction of 1 with mcpba , yielding sulfoxide - ligated 
 [ feii(n3pyamides(o)r)](bf4)2 ( 4 ) . catalytic oat with 1 was also observed .