Macrocyclic ligands bearing two 3-(Hydroxy)-2-pyridinone moieties as side-arms. Conformational studies, synthesis, crystal structure, and alkali and alkaline earth complex formation
Macrocyclic ligands bearing two 3-(Hydroxy)-2-pyridinone moieties as side-arms. Conformational studies, synthesis, crystal structure, and alkali and alkaline earth complex formation
复制标题
DOI：
10.1039/b411165f
复制
发表时间：
2004-01-01
影响因子：
3.3
通讯作者：
Zappia, G
中科院分区：
文献类型：
--
作者：
Ambrosi, G;Dapporto, P;Zappia, G
报道了新的四氮杂大环4（N），10（N）-双[ 2-（3-羟基-2-氧代-2-H-吡啶-1-基）乙基]-1，7-二甲基-1，4，7，10-四氮杂环十二烷（L1）的合成与表征。L1显示两个3-（羟基）-1-（羰基亚甲基）-2（1H）-吡啶酮（HPO）部分连接到作为侧臂的大环碱4，7-二甲基-1，4，7，10-四氮杂环十二烷上.报道了L1与结构相似的配体4-（N），10-（N）-双[ 2-（3-羟基-2-氧代-2H-吡啶-1-基）乙酰胺基]-1，7-二甲基-1，4，7，10-四氮杂环十二烷（L2）的酸碱性质和对碱金属、碱土金属离子的配位性质。L2结合所研究的所有金属离子形成稳定的单核络合物，而L1仅结合一些稳定常数低于L2的碱土金属离子。这两种化合物都显示出相对于碱土金属系列对Mg（II）离子的选择性。结合区域由两个HPO基团的四个会聚氧原子形成。L2似乎是一个更有效的配体在硬金属离子的配位，因为两个HPO结合基团被迫由大环骨架留在大环的同一部分，而这种构象是不利的L1。这些数据得到了对两种配体进行的分子动力学（MD）模拟和[ H（2）L1]（ClO 4）（2）物质的晶体结构的支持，该晶体结构显示两个侧臂与大环相反。研究了pH和金属离子配位对两种配体的紫外-维斯吸收和荧光发射性质的影响，强调了酸碱反应以及金属离子配位时光学性质的变化。
The synthesis and characterization of the new tetraazamacrocycle 4( N), 10( N)- bis[ 2-( 3- hydroxy- 2- oxo- 2-H-pyridin-1- yl) ethyl]- 1,7- dimethyl- 1,4,7,10- tetraazacyclododecane ( L1) is reported. L1 shows two 3-( hydroxy)- 1-( carbonylmethylen)- 2( 1H)- pyridinone ( HPO) moieties linked to the macrocyclic base 4,7- dimethyl- 1,4,7,10- tetrazacyclododecane, as side- arms. The acid - base and coordination properties towards alkali, alkaline earth ions of L1 together with those of the structurally similar ligand 4-( N), 10-( N)- bis[ 2-( 3-hydroxy- 2- oxo- 2H- pyridin- 1- yl) acetamido]- 1,7- dimethyl- 1,4,7,10- tetraazacyclododecane ( L2) are reported. L2 binds all the metal ions investigated forming stable mono- nuclear complexes, while L1 binds only some alkaline earth ions with stability constants lower than those of L2. Both compounds show selectivity towards the Mg( II) ion with respect to the alkaline earth series. The binding area is formed by the four converging oxygen atoms of the two HPO groups. L2 appears to be a more efficient ligand in the coordination of hard metal ions because the two HPO binding groups are forced by the macrocyclic skeleton to stay on the same part of the macrocyclic ring, while this conformation is unfavourable for L1. These data are supported by molecular dynamics ( MD) simulations performed on both ligands and by the crystal structure of the [ H(2)L1]( ClO4) (2) species which shows the two side- arms displaced opposite to the macrocyclic ring. The effects of pH and metal ion coordination on the UV- Vis absorption and fluorescence emission properties of both ligands were investigated, highlighting that the optical properties changes in acid - base reactions as well as in the coordination of metal ions.