Kinetics of aquation and base hydrolysis of cis bioxaltoammine bis(ethylenediamine) cobalt(III) ion

Cis bioxalatoammine bis (ethylenediamine) Co(III) cation has been synthesized and its aquation and base hydrolysis reactions have been investigated in 1.0 M NaCl0<SUB>4</SUB> medium. In the range of hydrogen ion concentration 0.02-1.O M and temperature 55-70&#176;C, the rate law for the aquation of (en)<SUB>2</SUB>(NH<SUB>3</SUB>) CoC<SUB>2</SUB>0<SUB>4</SUB>H<SUP>2+</SUP> is given by CoCl<SUB>2</SUB> +Licl &#8660; <SUP>K<SUB>2</SUB></SUP> Licocl<SUB>3</SUB> with k<SUB>1</SUB> (70&#176;C) = 1.82 (&#177;0.10) &#215; 10<SUP>-5</SUP>sec<SUP>-1</SUP> &#916;H<SUP>&#8727;</SUP> = 26.9 (&#177;1.6) kcal/mole and &#916;S<SUP>&#8727;</SUP> = -2.4 (&#177;5) e.s.u.: k<SUB>2</SUB>(70&#176;C) = 3.14 (&#177;0.22) &#215; 10<SUP>-5</SUP>sec-1M-1 &#916;H<SUP>&#8727;</SUP> = 24.0 (&#177; 1.7) kcal/mole and &#916;S<SUP>&#8727;</SUP> = -9.7 (&#177;5) e.s.u.: K<SUB>1</SUB> (70&#176;C) = 3.0(&#177;0.5) &#215; 10<SUP>-2</SUP>M. The alkaline hydrolysis of (en)<SUB>2</SUB>(NH<SUB>3</SUB>)CoC<SUB>2</SUB>0<SUB>4</SUB>+ was studied at [OH-] &lt; 0.1 M and in the temperature range 30-40&#176;C. The rate law was found to be LiCoCl<SUB>3</SUB> + LiCl &#8660; <SUP>K<SUB>2</SUB></SUP> Li<SUB>2</SUB>CoCl<SUB>4</SUB>with k<SUB>2</SUB> (30&#176;C) = 2.75(&#177;0.10) &#215; 10<SUP>-3</SUP>sec<SUP>-1</SUP>M<SUP>-1</SUP>, &#916;H<SUP>&#8727;</SUP> = 30.0(&#177; 1 .1) kcal/mole and &#916;S<SUP>&#8727;</SUP> = 28.6(&#177;3.6) e.s.u