Cu(Ⅱ) 및 Ni(Ⅱ)과 2-pyridinealdehyde-4, 4'-diphenylsemicarbazone의 착물형성에 관한 분광광도법적 연구

Abstract

In order to examine the usefulness of the 2-pyridinealdehyde-4, 4'-diphenylsemicarbazone (PDC) which one of the Schiff base, as a quantitative analytical reagent for the spectrophotometry, the PDC has been synthesized, the complex formation reaction has been studied, the best condition for pH and wavelength has been chosen, and at the condition the composition of complexes, stability constant, and molar absortivity has been determined. And quantitative analytical method has been investigated for Cu(Ⅱ) or Ni(Ⅱ) mixture solution by using PDC. The complex formation reaction has been completed within 20 minutes and the effect of the reaction temperature can be ignored. Cu(Ⅱ)-PDC complex has shown its maximum absorbance at pH range 4.5-5.0 and the molar ratio of the Cu(Ⅱ) to PDC is estimated to be 1:1 by the continuous variation method and molar ratio method, similary showed 1:2 complex at pH range 6.0-6.2 for Ni(Ⅱ). Cu(Ⅱ)-PDC complex has shown its maximum absorption wavelength at 375 nm, and Ni(Ⅱ)-PDC complex at 365 nm. Stability constant has been calculated 2.15×10^(5) for Cu(Ⅱ)-PDC and 5.40×10^(10) for Ni(Ⅱ)-PDC in the best condition. The molar absorptivies for Cu(Ⅱ) and Ni(Ⅱ) were investigated to be 2.04×10^(4)/mol·cm·dm^(3) and 1.68×10^(4)/mol·cm·dm^(3), respectively. Taking the large stability constant and molar absorptivity of Cu(Ⅱ) complex and Ni(Ⅱ) complex at the best condition into consideration, therefore it has been realized that PDC which one of the pyridinealdehyde derivative is a useful quantitative analytical reagent of spectrophotometry for Cu(Ⅱ) and Ni(Ⅱ). The interference of various ions have been examined and estimated for Cu(Ⅱ) and Ni(Ⅱ) in synthetic mixture solution respectively.;Schiff base^(l-4))의 하나인 2-pyridinealdehyde-4,4＇-diphenylsemicarbazone(PDC)의 Cu(Ⅱ) 및 Ni(Ⅱ)에 대한 분광광도법 시약으로서의 유용성을 검토하기 위하여 PDC를 합성한 후 착물을 형성하는 최적 pH와 극대흡수파장을 찾아 그 최적조건에서의 착물의 조성과 안정도 상수 및 몰흡광계수를 결정하였다. 또한 PDC를 이용하여 Cu(Ⅱ) 및 Ni(Ⅱ) 혼합물에서 각각을 분리·정량하는 방법에 대해 조사하였다. 착물형성 반응은 20분이내에 완결되며 온도변화에 따른 영향은 보이지 않았다. Cu(Ⅱ)와 PDC는 pH 4.5∼5.0의 영역에서 조성비가 1 : 1인 안정한 착물을 형성하였고, Ni(Ⅱ)와 PDC는 pH 6.0∼6.2의 범위에서 조성비가 1 : 2인 착물을 형성하였다. 최대흡수파장은 Cu(Ⅱ)-complex가 375㎚, Ni(Ⅱ)-complex는 365㎚에 나타났으며, 최적조건에서의 Cu(Ⅱ)-complex는 2.15×10^(5) 의 안정도 상수와 2.04×10^(4)/㏖·㎝·dm^(3)의 몰흡광계수를, Ni(Ⅱ)-complex는 5.40×10^(10)의 안정도 상수와 1.68×10^(4)/㏖·㎝·dm^(3)의 몰흡광계수를 나타냈다. 이로써 pyridinealdehyde의 유도체^(5,6)) 인 PDC가 Cu(Ⅱ), Ni(Ⅱ)에 대한 분광광도법 시약으로써 유용함을 알 수 있었으며 이때 Cu(Ⅱ)와 Ni(Ⅱ)의 정량에서 방해를 나타내는 여러 가지 공존 이온들을 조사하여 혼합시료에서 Cu(Ⅱ)와 Ni(Ⅱ)를 각각 정량하는 방법을 검토하였다.