아세톤-물혼합용매에서 trans-[Co(en)_2Cl_2]^+ 및 trans-[Co(1,3-pn)_2Cl_2]^+ 이온의 가용매 분해 반응에 미치는 압력과 용매조성의 영향 = The Effects of Solvent Composition and Pressure on the Rate of Solvolysis of trans-[Co(en)_2Cl_2]^+ and trans-[Co(1,3-pn)_2Cl_2]^+ in Acetone-Water Mixtur

다국어 초록 (Multilingual Abstract)

The rates of solvolysis of trans-[Co(en)_2CL_2]^+ and trans- [Co(1,3-pn)_2CL_2]^+, in which en and 1,3-pn are ethylenediamine and 1,3-propylenediamine resepectively, have been investigated using conductometric and spectrophotometric methods at various pressures up to 2,000 bar in aceton-water mixture. The activation volumes obtained from the pressure effect on rate constants were small and positive values in both complexes of trans- [Co(en)_2Cl_2]^+ and trans- [Co(1,3-pn)_2CL_2]^+. These results are discussed in terms of dissociative mechanism (S_NI) for the solvolysis of both complexes.
The importance of solvent composition on the reaction is further confirmed by application of a free energy cycle. It is concluded from the free energy cycle that the effect of solvation of transition state in the solvolysis of both complexes is more dominant than that of initial state. In addition to that, it is shown that the character of S_NI is further increased with increasing the content of acetone.