1-乙酰胺基丙叉-1,1-二膦酸和1-丙酰胺基乙叉-1,1-二膦酸与碱土金属离子的螯合作用

用pH电位法研究了1-乙酰胺基丙叉-1,1-二膦酸(S-186)和1-丙酰胺基乙叉-1,1-二膦酸(S-106)与碱土金属的螯合作用(30±O.1℃).当金属离子与配体的摩尔浓度比为10∶1、1∶1和1∶2时,在水溶液中形成了MHL、ML、ML_2和M_2L等几种类型的配合物.分别测定了它们的稳定常数,其中S-186配合物稍高于S-106,说明配合物稳定性与螯合剂的碱度有平行关系.值得注意的是,这两种螯合剂与Sr~(2 )形成的双核配合物的稳定性均较其它碱土金属离子的为高.

The chelation of 1-acetamido-propylidene-1, 1-diphosphonic acid and 1-propionamido-ethylidene-1, 1-diphosphonic acid with alkaline earth metalions

1-Acetamido-propylidene-1, 1-diphosphonic acid (S-186) and 1-propionamido-ethylidene-1, 1-diphosphonic acid (S-106) were synthesized and their chelation with alkaline earth metal ions was studied by pH method at 30+/-0.1 C. The complexes MHL, ML, ML2 and M2L were formed in aqueous solutions, when the molar proportion of metal to ligand varied from 10:1 to 1:2. Their stability constants were determined and it was found that the complexes of S-186 were more stable than those of S-106 and that there was a close relationship between the stability of the complexes and basicity of the ligands. It was also noticed that their binuclear complexes with Sr(II) were more stable than those with other alkaline earth metal ions.