Journal of the Korean Chemical Society (대한화학회지)

Korean Chemical Society (대한화학회)
권호 표지

Pressure Effects on the Ionic Dissociation of $[Co(en)]_3Cl_3\;and\;[Co(NH_3)_6Cl_3$ in Aqueous Solutions

수용액에서 $[Co(en)_3]Cl_3$ 및 $[Co(NH_3)_6]Cl_3$착물의 이온 해리에 미치는 압력의 영향

  • Jong Jae Chung (Department of Chemistry, College of Natural Sciences, Kyungpook National University) ;
  • Rho Byung Gill (Department of Chemistry, College of Natural Sciences, Kyungpook National University)
  • 정종재 (경북대학교 자연과학대학 화학과) ;
  • 노병길 (경북대학교 자연과학대학 화학과)
  • Published : 1986.08.20
Download PDF
⟨ Previous Next ⟩

Abstract

The thermodynamic dissociation constants of $[Co(en)]_3Cl_3\;and\;[Co(NH_3)_6Cl_3$ in aqueous solutions at $25{\circ}$ and at the pressure from 1 bar to 2000 bars were measured by conductometric method. The dissociation constants were increased with pressure elevation because of volume decreasing by the formation of charged ions during dissociation reaction. That is, the $pK^T$ values of $[Co(en)]_3Cl_3$ were 2.16 for I bar, 2.08 for 500 bars, 2,08 for 1000 bars, 2.05 for 1500 bars and 2.03 for 2000 bars, respectively and those of $[Co(NH_3)_6Cl_3$ were 2.02 for 1 bar 1.96 for 500 bars, 1.90 for 1000 bars, 1. 88 for 1500 bars and 1. 87 for 2000 bars, respectively. Comparing and analyzing the values of Stokes' radii and $K^T$, the formation of ion pair compound was affected by not only the electrostatic interaction, but also the Interal Conjugate Base(ICB), which was increased by the elevation of the pressure.

$25{\circ}$에서 $[Co(en)]_3Cl_3,\;[Co(NH_3)_6Cl_3$수용액의 열역학적 해리상수를 1~2000bar의 압력범위에서 전도도법으로 측정하였다. 착물이 해리할 때 하전을 띤 이온이 생성하여 부피가 감소하므로 압력이 증가함에 따라 해리상수($K^T$)는 커졌다. 즉 $[Co(en)]_3Cl_3$에 대한 $pK^T$값은 1bar에서 2.16, 500bar에서 2.08, 1000bar에서 2.08, 1500bar에서 2.05, 2000bar에서 2.03이었고, $[Co(NH_3)_6Cl_3$의 $P^K^T$는 1bar에서 2.02, 500bar에서 1.96, 1000bar에서 1.90, 1500bar에서 1.88, 2000bar에서는 1.87이었다. 각 압력에서 Stokes반경과 해리상수($K^T$)값을 비교 분석하여 착물의 이온쌍 형성에는 정전기적 인력 이외에 Internal Conjugate Base(ICB)효과도 영향을 미쳤으며 이효과는 압력이 증가할 수록 커졌다.

Keywords

References

  1. J. Chem. Soc. I.L. Jenkins;C.B. Monk
  2. J. Chem. Soc. S.H. Laurie;C.B. Monk
  3. Bull. Chem. Soc. Jpn. v.39 N. Tanaka;K. Ogino;G. Sato
  4. Bull. Chem. Soc. Japan. v.40 R. Tamamushi;T. Isono;S. Katayama
  5. Z. Anal. Chem. v.224 N. Tanaka;A. Yamada
  6. Bull. Chem. Soc. Japan. v.41 S. Katayama;R. Tamamushi
  7. Nippon Kagaku Zasshi v.92 N. Tanaka;H. Kaneko;T. Shirakashi
  8. Bull. Chem. Soc. Jpn. v.46 S. Katayama
  9. Chem. Lett H. Yokoyama;H.Yamatera
  10. Bull. Chem. Soc. Jpn. v.49 T. Takahashi;T. Koiso
  11. Bull. Chem. Soc. Jpn. v.51 T. Takahashi;T. Koiso
  12. Inorg. Chem. v.5 D.B. Rorabacher
  13. Inorg. Chem. Purcell;Kotz
  14. J. Chem. Soc. I.L. Jenkins;C.B. Monk
  15. Inorganic Synthesis v.14 J.K. Ruff;A. Word
  16. Daehan Hwahak Hwoejee v.28 J.U. Hwang;J.J. Chung;S.O. Bek
  17. Principles and Applications of Electrochemistry D.R. Crow
  18. Physik, Z. v.28 L. Onsager
  19. Bull. Chem. Soc. Japan. v.46 K. Tamura;Y. Oga;T. Imoto
  20. Annual Rev. Phy. Chem. v.23 C.A. Echert
  21. Bull. Chem. Soc., Japan. v.40 N. Tanaka;Y. Kobayashi;M. Kamada