Synthesis of a new triazine derived macrocycle and a thermodynamic study of its complexes with some transition and heavy metal ions in acetonitrile solution

A synthetic procedure has been developed for the preparation of a new triazine derived macrocycle (13,29-diphenyl-4,7,20,23-tetraoxa-1,10,12,14,16,17,26,28,30,32-decaaza[10,10](2,6)triazinophane). The formation of some transition and heavy metal complexes with the macrocycle was investigated in acetonitrile solution conductometrically at different temperatures. The formation constants of the resulting 1:1 complexes were determined from the molar conductance-mole ratio data and found to vary in the sequence Hg > Pb+ > Cd ~ Ag > Cu > Tl > Co > Ni > Zn. The enthalpy and entropy of complexation reactions were determined from the temperature dependence of the formation constants. In all cases, the complexes were found to be enthalpy stabilized but entropy destabilized.