Schiff碱H_2TTAen，H_2TTAdien，H_2TTApn的合成和螯合性能的研究

SYNTHESIS,CHARACTERIGE AND ACID DISSOCIATION CONS-TANT OF TWO SCHIFF BASE-MUETIDENTATE CHELTES

以ＨＴＴＡ为端基与乙二胺、二乙三胺及丙二胺缩合制得Ｈ２ＴＴＡｅｎ，Ｈ２ＴＴＡｄｉｅｎ，Ｈ２ＴＴＡＰｎ３种Ｓｃｈｉｆｆ碱．它们既类似于聚酸可作多齿螯合配体，又与ｐ－二酮类似，其羰其可以异构成烯醇式，为一个二元酸．用多种近代分析测试方法对其组成和基本性质进行了表征，用ＰＨ电位法和光度法测定了酸离解常数．

Three schiff base-acyclic crown ethers breviated as H2TTAen,H2TTAdien and H2TTApn Were synthesiged by means of the condensation reaction from HTTA and ethylenediamine(en),1,3-propylenediamine(pn),diethgleneiriamine(dien)in ether or etlcylacetate at room temperature respectively.These cumpounds were chareactreized on the basis of their imtrared spectra,elemental analysis,differential thermal analysis and thermogravimetry.The meating point is 116℃, 139℃ 153℃respectively,They are insolulle in water and practically stable with wate. The ionijation constants pKa pKa for H2TTAen and H2TTAdien have been determind by potentiometry in a mixing solvent and by spectrophotometry respecen. The results obtained by these two methods are in agreement with each other.