二乙基二硫代氨基甲酸钠与Cu^2＋、Pb^2＋、Cd^2＋、Ni^2＋的络合性研究

Stability of Cu^(2+),Pb^(2+),Cd^(2+) and Ni^(2+) Complexes of Sodium Diethyldithiocarbamate

在0.01 mol/L硼砂缓冲溶液中,以二乙基二硫代氨基甲酸钠(DDTC)为配体,与Cu2+、Pb2+、Cd2+、N i2+络合,用紫外可见分光光度法测定了金属络合物的吸收光谱,并计算出它们的稳定常数。实验结果表明,DDTC分别在257、282 nm处出现两个最大吸收峰,而Cu2+、Pb2+、Cd2+、N i2+配合物分别在紫外区的304、305、303、321 nm处有最大吸收峰;DDTC与Cu2+、Pb2+、Cd2+、N i2+形成的配合物的稳定常数分别为4.05×1011,2.67×1011,2.14×1011,4.01×1010,其稳定性顺序为:Cu(DDTC)2>Pb(DDTC)2>Cd(DDTC)2>N i(DDTC)2。

The Cu^2＋ , Pb^2＋, Cd^2＋ and Ni^2＋ complexes of sodium diethyldithiocarbamate （ DDTC ） were formed in 0.01 mol/L borax buffer solution and the stability constants of the complexes were measured by spectrophotometric method. The results show that DDTC has two obvious absorption peaks at 257 and 282 nm, while its complexes with Cu^2＋ , Pb^2＋ , Cd^2＋ and Ni^2＋ have another absorption peaks at 304,305,303 and 321 nm, respectively ; the stability constants of Cu^2＋ , Pb^2＋ , Cd^2＋ and Ni^2＋ complexes are 4.05 × 10^11 ,2.67 × 10^11 ,2. 14 × 10^11 and 4.01 × 10^10,respectively. The stability of the complexes has following sequence ： Cu （DDTC） 2 〉 Pb （ DDTC ） 2 〉 Cd （ DDTC ） 2 〉 Ni （DDTC） 2.