Ruthenium(IV) and Osmium(II) Tetraphenylporpohine Complexes: Synthesis and Oxidation Reactions

摘要

The Ru(IV) and Os(II) complexes (PhO)_2RuTPP and OsTPP were synthesized from tetraphe-nylporphine (H_2TPP) and K_2PuO_4 or K_2OsO_4 (taken in the molar ratio of 1:30) in boiling phenol. The kinetics of oxidation reactions of these complexes in solutions of HOAc (acetic), H_2SO, and HOAc-H_2SO acids was studied. It was foound that in the aerated HOAc-H_2SO_4 mixture heated above 340 K, these complexes are oxidized with participation of different reaction sites: the Ru(IV) complex is oxidized at macrocycle to give the pi-radical-cation (PhO)_2RuTPP~centre dot +, while in the Os(II) complex, the metal atom is oxidized to form the Os(III) complex. In the first case, the reaction follows the activation mechanism, whereas in the second case, the activation energy of the reaction is zero.