Abstract
The complex formation reactions of [Cu(NTP)(OH
2
)]
4−
(NTP = nitrilo-tris(methyl phosphonic acid)) with some selected bio-relevant ligands containing different functional groups, are investigated. Stoichiometry and stability constants for the complexes formed are reported. The results show that the ternary complexes are formed in a stepwise mechanism whereby NTP binds to copper(II), followed by coordination of amino acid, peptide or DNA. Copper(II) is found to form Cu(NTP)H
n
species with n = 0, 1, 2 or 3. The concentration distribution of the various complex species has been evaluated. The kinetics of base hydrolysis of glycine methyl ester in the presence of copper(II)-NTP complex is studied in aqueous solution at different temperatures. It is proposed that the catalysis of GlyOMe ester occurs by attack of OH
−
ion on the uncoordinated carbonyl carbon atom of the ester group. Activation parameters for the base hydrolysis of the complex [Cu(NTP)NH
2
CH
2
CO
2
Me]
4−
are, ΔH
±
= 9.5 ± 0.3 kJ mol
−1
and ΔS
±
= −179.3 ± 0.9 J K
−1
mol
−1
. These show that catalysis is due to a substantial lowering of ΔH
±
.