极谱法研究金属配合物时滴汞电极表面配位剂平衡浓度的一般表达式

THE GENERALIZED EXPRESSION FOR THE EQUILIBRIUM CONCENTRATION OF COMPLEXING AGENT AT A DROPPING MERCURY ELECTRODE SURFACE IN POLAROGRAPHIC STUDIES OF METAL COMPLEXES

在金属配合物的极谱研究中,往往需要知道配位剂X-在汞滴表面的平衡浓度[X].作者曾用扩散电流理论,在配位剂X(b-)与H不配合时,导出了一个金属离子各级单核配合物在汞滴表面还原为汞齐时的[X]表达式.最近,作者又得到了一个普适性更好的[X]表达式.它不仅能把文献中更多的[X]表达式在同一理论基础上统一起来,而且还可在新的条件下得到一系列新的[X]表达式.表达式的推导设在所讨论的缓冲溶液中,加有高价金属离子M(M),低价金属离子M(M′),配位剂X(X)和足量的支持电解质.在溶液本体中和汞滴表面上,X分别与M、M、氢离

A generalized expression for[X],the equilibrium concentration of a complexing agent X at a dropping mercury electrode surface in polarographic studies of the metal complexes,has been obtained on the basis of diffusion current theory,when the electrode reactions(cathodic or anodic)take place between a series of mononuclear metal complexes in higher valence state MX(p=0,1,2…P)and a series of mononuclear metal complexes in lower valence state M’X(q=0,1,2…Q),or between a series of mononuclear metal complexes and the metal M or the amalgam M(Hg)at the dropping mercury electrode surface in a buffr solution and when the oomplexiug agent reacts with protons to form either a strong acid or a weak acid.