Department of Chemistry, University of California at Berkeley, Berkeley, California 94720-1460, USA.
J Am Chem Soc. 2011 May 25;133(20):7942-56. doi: 10.1021/ja201511u. Epub 2011 May 4.
Several linear, hexa- and tetradentate ligands incorporating a combination of 2,3-dihydroxy-terephthalamide (TAM) and hydroxypyridinone-amide (HOPO) moieties have been developed as uranyl chelating agents. Crystallographic analysis of several {UO(2)[TAM(HOPO)(2)]}(2-) complexes revealed a variable and crowded coordination geometry about the uranyl center. The TAM moiety dominates the bonding in hexadenate complexes, with linker rigidity dictating the equality of equatorial U-O bonding. Hexadentate TAM(HOPO)(2) ligands demonstrated slow binding kinetics with uranyl affinities on average 6 orders of magnitude greater than those of similarly linked bis-HOPO ligands. Study of tetradentate TAM(HOPO) ligands revealed that the high uranyl affinity stems primarily from the presence of the TAM moiety and only marginally from increased ligand denticity. Uranyl affinities of TAM(HOPO)(2) ligands were within experimental error, with TAM(o-phen-1,2-HOPO)(2) exhibiting the most consistent uranyl affinity at variable pH.
几种包含 2,3-二羟基对苯二甲酰胺（TAM）和羟吡啶酮酰胺（HOPO）部分组合的线性、六齿和四齿配体已被开发为铀酰螯合剂。对几种{UO（2）[TAM（HOPO）（2）]}（2-）配合物的晶体学分析表明，铀酰中心周围的配位几何形状具有可变性和拥挤性。TAM 部分在六齿配合物中占主导地位，连接体的刚性决定了赤道 U-O 键的平等性。六齿 TAM（HOPO）（2）配体与铀酰的结合动力学较慢，铀酰亲和力平均比类似连接的双 HOPO 配体高 6 个数量级。对四齿 TAM（HOPO）配体的研究表明，高铀酰亲和力主要源于 TAM 部分的存在，而略微增加配体的齿密度。TAM（HOPO）（2）配体的铀酰亲和力在实验误差范围内，TAM（邻-苯-1,2-HOPO）（2）在可变 pH 值下表现出最一致的铀酰亲和力。
