Osmium trifluoromethanesulfonato

The total time required for this procedure is 3-4 hr. Pentaammine(trifluoromethanesulfonato-0)osmium(lII) trifluoromethanesul-fonate, [0s(NH3)5(0S02CF,)](CF3S03)2 (0.30 g, 0.42 mmol), is added to a 0.1 M aqueous solution of CF3SO3H (1 mL) contained in a 15-mL beaker. The solution is boiled for 5 min. After being cooled to room temperature, the solution is cooled further to <5° in an ice bath. Neat CF3SO3H (1 mL) is added slowly in dropwise fashion, while the solution is stirred rapidly. 

The total time required for the synthesis and recrystallization is 1 day. Pentaammine(trifluoromethanesulfonato-0)osmium(III) trifluoromethanesul-fonate, [0s(NH3)s(0S02CF3)KCF3S03)2 (0.10 g, 0.14 mmol), is placed in a 100-mL two-necked round-bottomed flask, and the flask and solid are heated in a vacuum oven at 110°. A second 100-mL two-necked round-bottomed flask is connected to a KOH drying tower and placed in a dish containing Dry Ice. Liquid ammonia (—40 mL) is transferred to this flask, and the flask is stoppered. 

This procedure requires 1 day. Pentaammine(trifluoromethanesulfonato-O)osmium(III) trifluoromethanesulfonate, [0s(NH3)5(0S02CF3)](CF3S03)2 (0.5 g, 0.69 mmol), is added to spectrophotometric grade acetonitrile [Aldrich Chemical] (2 mL) containing several drops of trifluoromethanesulfonic anhydride (triflic anhydride) all contained in a 10-mL test tube. 

Osmium and ruthenium polypyridine complexes initially received much attention from Dwyer and coworkers because the M(II), M(III), and M(IV) oxidation states are substitution inert.Interest in them has been renewed because of their photochemical reactions and the role they play in the study of reactions of coordinated ligands " and of mixed valence ions and in the preparation of electroactive polymer films. The aqua complexes " also have important potential applications in the selective oxidation of organic molecules and water. We found that trifluoromethanesulfonato (triflato) complexes are convenient synthetic intermediates in the preparation of aqua and oxo species, " and we describe the syntheses of the cii-bis(2,2 -bipyridine) complexes here. 

The (2,2 -bipyridine-A(,A( )(2,2 6 2"-terpyridine-A(,yV, yV"),(bpy)(trpy) complexes of ruthenium and osmium, like the bis(2,2 -bipyridine-A(,N ) series, were first studied by Dwyer and coworkers " and are interesting because more than one oxidation state is substitution inert. More recently, these (bpy)(trpy) species have generated interest because the M(IV) oxo complexes are useful oxidants of organic molecules. " The (bpy)(trpy) series of complexes have also proved useful in the study of the redox chemistry of coordinated ligands. The (bpy)(trpy) and bis(bpy) complexes containing the coordinated trifluoromethanesulfonato (triflato) ligands are useful precursors to a variety of complexes. The syntheses of these species and the aqua complexes derived from them are reported here. 

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