【摘要】 在001mol·L-1N2羟乙基哌嗪N’2乙磺酸(Hepes),pH74,室温条件下,应用紫外差光谱滴定观察了Gd(Ⅲ),Yb(Ⅲ)与N,N’二(2羟苄基)乙二胺N,N’二乙酸(HBED)的结合。结果表明Gd(Ⅲ),Yb(Ⅲ)与HBED均形成1∶1的配合物,其紫外差光谱均于237和291nm处出现吸收峰,在237nm处配合物GdHBED与YbHBED的摩尔吸光系数分别为ΔεGd=(2252±020)×103cm-1·mol-1·L,ΔεYb=(2715±011)×103cm-1·mol-1·L;配合物GdHBED与YbHBED的条件稳定常数分别为lgKGdHBED=1356±028,lgKYbHBED=1606±003,符合线性自由能关系。更多还原

【Abstract】 In 0.01 mol·L~-1 Hepes, pH 7.4 and at room temperature the binding of HBED with Gd(Ⅲ) or Yb(Ⅲ) was monitored by UV difference spectrum. The results show that the molar ratio of the complexes is most likely 1∶1. Gd-HBED or Yb-HBED complex produced peaks at 237 nm and 291 nm. The molar absorptivities of Gd-HBED and Yb-HBED at 237 nm are Δε_~Gd = (22.52±0.20)×103 cm~-1 ·mol~-1 ·L, Δε_~Yb =(27.15±0.11)×103 cm~-1 ·mol~-1 ·L, respectively. The conditional equilibrium constants for the complexes were measured to be lgK_~Gd-HBED =13.56±0.28 and lgK_~Yb-HBED =16.06±0.03. A linear free energy relationship for the complexes of Yb(Ⅲ) and Gd(Ⅲ) has been established by using equilibrium data on 18 complexes. The HBED binding constants for ~Yb(Ⅲ) and Gd (Ⅲ) are in agreement with the linear free energy relationship.更多还原