Synthesis of Tridentate Poly-amine Ligands and Determination of Stability Constants of Transition Metal Complexes
Analytical Science and Technology / Analytical Science and Technology, (P)1225-0163; (E)2288-8985
2002, v.15 no.2, pp.135-141
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(2002). Synthesis of Tridentate Poly-amine Ligands and Determination of Stability Constants of Transition Metal Complexes. , 15(2), 135-141.
Abstract
The new tridentate poly-amine ligands, N,N-Bis(2-amino-ethyl)-methyl amine${\cdot}$2HBr (BAMA${\cdot}$2HBr), N,N-Bis(2-amino-ethyl)-ethylamine${\cdot}$2HBr (BAEA${\cdot}$2HBr), N,N-Bis(2-amino-ethyl)-propylamine${\cdot}$2HBr (BAPA${\cdot}$2HBr) and N,N-Bis(2-amino-ethyl)-butylamine${\cdot}$2HBr (BABA${\cdot}$2HBr) were synthesized as their dihydrobromic-salt and characterized by EA, IR, NMR and Mass spectroscopy. The protonation constants of the ligands and stability constants of transition metal(II) complexes were determined in aqueous solutions by potentiometry and compared with diethylenetriamine. Stability constants for transition metal complexes of ligands are in the order of BAMA < BAEA < BAPA > BABA. The larger value of stability constants of BAPA compared to these BABA, may be attributed to the more distorted structure of the complex due to the increased steric crowding caused by the presence of the bulky N-butyl group.
- keywords
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protonation constants,
stability constants,
potentiometry