銅(II)-カルセイン錯体の安定度定数の測定

DOI NDLデジタルコレクション Web Site Web Site

書誌事項

タイトル別名
  • 銅（ＩＩ）‐カルセイン錯体の安定度定数の測定
  • Determination of the stability constants of copper (II)-calcein complexes
  • ドウ 2 カルセイン サクタイ ノ アンテイド テイスウ ノ ソクテイ

この論文をさがす

説明

The stability constants of copper (II)-calcein complexes were determined by spectrophotometric method at μ=0.1. Copper(II) and calcein(H6L) were found to form 1:2, 1:1 and 2:1 complexes at pH 35 by the molar ratio and the continuous variation methods. The 1:2 complex(CuI2) was analyzed by Rose-Drago method, which was applied to 0.1 M KNO3 solutions containing an excess of H6L and Cu(II) at pH 3.4. The plots of 1/K1' vs. εCuI<SUB>2</SUB> intersected at one point, indicating the formation of CuI2. Then the conditional stability constant (K1') and the molar absorptivity (εCuI<SUB>2</SUB>) for CuI2 at pH 3.4 were determined. The 2:1 complex (Cu2I) in solutions of H6L and a large excess of Cu(II) was investigated by logarithmic plot method (KingeryHume). The constant(k2') obtained was the condiditional stepwise stability constant corresponding to the formation of Cu2I from CuI. In solutions of H6L and an excess of Cu(II) at pH 3.4, CuI and Cu2I were formed simultaneously and the concentrations of CuI2 and H6L were negligibly small. Accordingly, the molar absorptivity of CuI was obtained with the solutions containing an excess of Cu(II) and H6L using the molar absorptivity of Cu2I and k2'. The conditional stability constant(K2') of CuI was obtained mathematically from the absorbance of solutions containing nearly equimolar amounts of Cu(II) and H6L. The ionic formulae of CuI2, CuI and Cu2I were assumed to be Cu(H4L) (H3L)3-, CuH2L2- and Cu2L2- at pH 35, respectively, by the absorption spectra and the potentiometric titration curves. The stability constants of these complexes were calculated as K1=2.67×1010, K2=1.87×108 and K3=K2·k2=9.23×1028, respectively, using the acid dissociation constants of H6L.

収録刊行物

  • 分析化学

    分析化学 26 (9), 615-620, 1977

    公益社団法人 日本分析化学会

キーワード

詳細情報 詳細情報について

問題の指摘

ページトップへ