Abstract
Complexes of ethylenediaminetetraacetamide with Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Mg(II), Ca(II), Ba(II), Zn(II), Cd(II), Hg(II) and La(III) have been prepared as chloride salts (and perchlorate in the case of Cu(II)) and characterised on the basis of microanalytical, spectral, magnetic and conductivity data. The corresponding N-deuterated complexes have also been prepared and their spectral properties have been used in the characterisation of the undeuterated complexes. In aqueous solution the Cu(II) complex behaves as a dibasic acid and ionisation constants for the deprotonation of two amide groups in this complex have been obtained by potentio-metric methods. In addition the conjugate base complex has been isolated from solution. Complexes of the tetramethylester of Edta with Mn(II), Ee(II), Co(II), Ni(II), Cu(II), Cd(II) , Hg(II) and Sn(II) have also been prepared and characterised using the above methods. The reactions between trans-[Co(en)[2]Cl[2]] Cl (en = ethy-lenediamine) and ethylenediaminemonoacetic acid (EdmaH) and its ethyl ester (EdmaEt) have been found to give the products trans- [Co(en)[2]Cl(EdmaH)][2+] and cis-[Co(en)[2]Cl(EdmaEt)][2+] respectively. In the former the amino acid is monodentate and bonded through its carboxylate group to the metal ion while in the latter the amino acid ester behaves as a mono-dentate N-bonded ligand. The kinetics of the Hg(II) promoted acid hydrolysis, in which Cl[-] is replaced by H[2]O, and base hydrolysis, in which Cl[-] is replaced by OH[- ]have been inves- tigated at 25+/-0.1°C in both cases. The hydrolysis of EdmaEt in the presence of some metal ions has also been studied at 25+/-0.1°C and the order in which these metal ions promote ester hydrolysis is Cu(II)>>Co(II)>Ni(II). Finally the synthesis and properties of a number of divalent metal ion (Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)) complexes of the ligand 2-carboethoxy-1,10-phe-nanthroline have been investigated.