Sequential photooxidation of a Pt(II) (diimine)cysteamine complex: intermolecular oxygen atom transfer versus sulfinate formation

Inorg Chem. 2013 Feb 18;52(4):1676-8. doi: 10.1021/ic3020578. Epub 2013 Jan 28.


The thiolato complex [platinum(II) (bipyridine)(N,S-aminoethanethiolate)](+)Ch(-) (1) undergoes sequential reactions with singlet oxygen to initially form the corresponding sulfenato complex [platinum(II) (bipyridine)(N,S(═O)-aminoethansulfenate)](+) (2) followed by a much slower reaction to the corresponding sulfinato complex. In contrast with many platinum dithiolato complexes, 1 does not produce any singlet oxygen, but its rate constant for singlet oxygen removal (k(T)) is quite large (3.2 × 10(7) M(-1) s(-1)) and chemical reaction accounts for ca. 25% of the value of k(T). The behavior of 1 is strikingly different from that of the complex platinum(II) (bipyridine)(1,2-benzenditholate) (4). The latter complex reacts with (1)O(2) (either from an external sensitizer or via a self-sensitized pathway) to form a sulfinato complex. These two very different reactivity pathways imply different mechanistic pathways: The reaction of 1 with (1)O(2) must involve O-O bond cleavage and intermolecular oxygen atom transfer, while the reactive intermediate in complex 4 collapses intramolecularly to the sulfinato moiety.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Crystallography, X-Ray
  • Cysteamine / chemistry*
  • Imines / chemistry*
  • Models, Molecular
  • Molecular Structure
  • Organoplatinum Compounds / chemical synthesis
  • Organoplatinum Compounds / chemistry*
  • Oxidation-Reduction
  • Oxygen / chemistry*
  • Photochemical Processes
  • Platinum / chemistry*
  • Sulfinic Acids / chemical synthesis*
  • Sulfinic Acids / chemistry


  • Imines
  • Organoplatinum Compounds
  • Sulfinic Acids
  • Platinum
  • Cysteamine
  • Oxygen