九配位钬-三乙四胺六乙酸配合物K3[Ho(TTHA)]·5H2O的合成及分子结构

In this paper, the molecular and crystal structures of the K₃Ho(TTHA)]·5H₂O(TTHA=triethylenete-traminehexaacetic acid)are given. The crystal data are as follows: monoclinic system, P2₁/c space group, a=1.0290(9)nm, b=1.2466(11)nm, c=2.279(2)nm, β=91.322(16)°, V=2.923(5)nm³, Z=4, M=860.67, D_c=1.956gcm^-3, μ=3.217mm^-1, F(000)=1720. The final R₁ and wR₂ are 0.0395 and 0.0796 for 5145 I >2.0σ(I)] unique reflections and 0.0546 and 0.0833 for all 11567 reflections, respectively. In the title complex, the anion Ho(TTHA)]^3- has a nine-coordination structure with distorted tricapped trigonal prism. A TTHA having four N atoms of amido groups and six O atoms of carboxylic groups acts as a enneadentate ligand with four N atoms and five O atoms. In addition, there is a free non-coordinated carboxyl group (-CH₂COO^-) in the complex anion Ho(TTHA)]^3-. The free carboxyl group could be embellished by some biological molecules which have selectivity and affinity to tumor cell. Then the ¹⁶⁶Ho^Ⅲ- TTHA complex may become radioactive anti-tumor drug having targeting function.