三乙烯四胺基双(二硫代甲酸钠)及其重金属配合物的光谱研究

Spectra Study of a Sodion Triethylenetetramine-bisDithiocarbamate and Its Complexes with Heavy Metal Ions

采用红外光谱、紫外光谱、原子吸收光谱及元素分析研究了三乙烯四胺基双（二硫代甲酸钠）（DTC-TETA）的结构及其重金属配合物的配位行为。在DTC-TETA的红外光谱图中，在1461～1388cm^-1处和1174-996cm^-1。处分别出现含有部分双键性质的C—N键和C—S键的特征吸收峰；在紫外光谱图中，分别在265和290nm处出现两个最大吸收峰，分别对应于N…C…S基团的π-π’跃迁和S…C…S基团中硫原子上非键电子向共轭体系的，π-π＇跃迁；元素分析结果表明该化合物中碳、氢、氮、硫的摩尔比近似为2：4：1：1。在Cu（Ⅱ），CA（Ⅱ），Zn（Ⅱ），Ni（Ⅱ）配合物的紫外光谱图中分别在紫外区的321，310，311，325nm处出现新的最大吸收峰。流动注射与火焰原子吸收联用分析结果表明DTC-TETA对铜、镉、镍、锌等重金属离子的络合能力强于二乙基二硫代氨基甲酸钠（DDTC）。

A sodion triethylenetetrarnine-bisdithiocarbamate（DTC-TETA） and its complexes with heavy metal ions were investigated by FTIR, UV, FAAS and elemental analysis, respectively. The FTIR spectrum of DTC-TETA showed strong absorption peaks at 1 461-1 388 cm^-1 and 1 174-996 cm^-1 which were attributed to partly double bonds of C=N and C=S , respectively. The UV spectrum of DTC-TETA had two absorption peaks at 265 and 290 urn, assigned to π-π＇ transition of N…C…S radical and nonbonding electron n-π＇ transition of S…C…S radical to conjugated system, respectively. The elemental analysis results demonstrated that the mol ratio of C, H, N and S in DTC-TETA was about 2 ： 4 ： 1 ： 1. As for UV spectrum of its complexes with Cu（ Ⅱ）, CA（ Ⅱ ）, Zn（ Ⅱ ） and Ni（Ⅱ）, there were four new absorption peaks at 321, 310, 311 and 325 nm, respectively. Coupled to flow-injection, FAAS determination showed that the complexation performance of Cu^2＋ , Cd^2＋ , Ni^2＋ and Zn^2＋ complexes of DTC-TETA was better than that of sodium diethyldithiocarbamate （DDTC）.