59731-85-0Relevant articles and documents
An insight into the extraction of transition metal ions by picolinamides associated with intramolecular hydrogen bonding and rotational isomerization
Li, Yan,Jia, Yiming,Wang, Zhenwen,Li, Xianghui,Feng, Wen,Deng, Pengchi,Yuan, Lihua
, p. 29702 - 29714 (2014/08/05)
The clear connection between molecular structures of N-substituted picolinamides and extraction behaviour has been rationalized by highlighting the relationship between intramolecular hydrogen bonding and rotational isomerism. To this aim aromatic pyridine-2,6-dicarboxamides 1a-1c with N-substitution and their analogues 3a and 3b containing intramolecular hydrogen bonds were designed and synthesized. The results from the liquid-liquid extraction towards some representative transition metal picrates including Ag+, Hg 2+, Pb2+, Cd2+, Zn2+, Cu 2+, Co2+ and Ni2+ salts demonstrated that the higher selectivity and efficiency towards Hg2+ (88.6-95.4%) over other metal cations stem mainly from N-substitution via disruption of intramolecular H-bonding. X-ray structural analysis, and ordinary and variable-temperature proton and carbon NMR experiments provided supporting information for expounding the difference in extraction ability among these ligands, particularly the importance of N-substitution that leads to the formation of rotamers affecting the extraction process.
