Complexation ability of octaazamacrocyclic ligand toward Co2+, Ni2+, Cu2+ and Zn2+ metal cations: Experimental and theoretical study
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AuthorsPetkovic, B. B.
Sovilj, Sofija P.
Article (Published version)
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The complexation reactions between octaazamacrocyclic ligand N,N',N '',N'"-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane (tpmc) and Co2+, Ni2+, Zn2+ and Cu2+ metal cations have been studied conductometrically in acetonitrile and aqueous solutions. The conductance data exhibit different stoichiometry of the complexes in two studied solutions. In most cases 1:1 (ML) complexes were formed while in some cases 2:1 (M2L) complexes are evident. The stability constants of the resulting 1:1 complexes were determined by computer fitting of the conductance/mole ratio data. Theoretical DFT calculations were used to explain metal binding capability of tpmc ligand and the binding sequences were found to follow the order: Cu2+ >> Ni2+ > Co2+ > Zn2+. The combination of results obtained by this theoretical approach and conductometric study successfully explains sensitivity and selectivity of recently developed tpmc based ISE and could play a guiding role in planning experiments with large... macrocyclic ligands.
Keywords:N,N ',N '',N '''-Tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane (tpmc) / Co2+, Ni2+, Zn2+ and Cu2+ ions / Binding energy / Conductometry / Conformations
Source:Electrochimica Acta, 2013, 89, 680-687
- Pergamon-Elsevier Science Ltd, Oxford