
TY  - JOUR
A1  - Ellis, A 
A1  - Fultz, A 
A1  - Hicks, R 
A1  - Morgan, T 
A1  - Parsons, L 
A1  - Saderholm, MJ 
A1  - Smith, LA 
A1  - Stabb, M 
A1  - Starnes, JK 
A1  - Sun, LJ 
A1  - Roecker, L 
T1  - Synthesis and Base Hydrolysis of the Pentaammine(dimethyl sulfide)cobalt(III) Ion
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1992
VL  - 45
IS  - 12
SP  - 2049
EP  - 2055
KW  - 
UR  - https://doi.org/10.1071/CH9922049 
N2  - The synthesis of the trifluoromethanesulfonate salt of the pentaarnmine (dimethy1 sulfide)-cobalt(III) ion, [NH3)5Co-S(CH3)2]3+, is described along with the kinetics of its hydrolysis in basic and acidic solutions. The synthesis proceeds in 44% yield from the reaction of [(NH3)5Co-OSO2CF3] (CF3SO3)2 with CH3SCH3 in tetramethylene  sulfone at 80ºC. The salt has been characterized by elemental analysis, visible-U.V. spectroscopy, and 1H n.m.r. In basic solution the complex decomposes by Co-S cleavage to yield [(NH3)5CO-OH]2+ and non-coordinated CH3SCH3. The kinetics of this reaction were studied in phosphate buffers ranging from pH 8.50 to 11.67 ( µ= 1.0 M); a linear dependence of the reaction rate on [OH-] was observed. At 25ºC, kOH = 8.8 ± 0.2 dm3 mol-1 s-1. Activation parameters, determined over a temperature range from 15 to 44ºC, were &#916;H&#8225; = 152 ± 3 kJ mol-1 and &#916; S&#8225; = 286 ± 9 J K-1 mol-1. In 0.01 M HClO4 ( µ = 1.0 M, 25ºC), the cobaltsulfur bond is cleaved at a rate of 1.6&#215;10-6 s-l. Activation parameters, determined over a temperature range from 25 to 60ºC, were &#916;H&#8225; = 106 ± 5 kJ mol-1 and &#916;S&#8225;= -2 ± 16 J K-1 mol-1. 
ER  -

