Lanthanide coordination polymers based on flexible ligands derived from iminodiacetic acid. (15th September 2019) - Puentes, Roberto
Graphical abstract: Two flexible ligands derived from iminodiacetic acid, N-methyliminodiacetic acid and N-(2-hydroxyethyl)iminodiacetic acid have been used as ligands towards lanthanide ions. Polymeric cationic networks have been prepared and fully characterized. The influence of the substitution on N atom in the ligand is discussed. Abstract: Two flexible ligands derived from iminodiacetic acid, N-methlyiminodiacetic acid (H2 mida) and N-(2-hydroxyethyl)iminodiacetic acid (H2 hida) have been used as ligands towards lanthanide ions. Potentiometric studies (25.0 °C, 0.50 mol L −1 Me4 NCl) revealed the predominance of stable species at acidic pH values. With this information, the synthesis of the coordination compounds was afforded in aqueous solution and the polymeric solids [Sm(Hmida)2 (H2 O)2 ]ClO4 ·1/6NaClO4 ·9H2 O and [Ln(hida)(H2 O)2 ](F3 CSO3 )·H2 O (Ln = Ho, Yb) were prepared and characterized. The samarium compound consists of a cationic 2D polymeric structure in which the ligand is protonated in the N atom, preventing coordination to the central atom. The structure presents channels along one crystallographic direction. Ho and Yb coordination compounds are isostructural. A 2D polymeric cationic network is also observed. In this case, the additional hydroxyethyl group and the unprotonated N atom participate in the coordination.