Enthalpy and entropy studies with some copper(II) bis(diamine) complexes and some comments on solvation energy and gas-phase enthalpies

Linear relations were tested between heat of Cu2+ alkylamine chelate formation in aq. soln., ΔHaq, and energy of the principal d-d transition, ν(d-d), and between ΔHaq and entropy of chelate formation. Monoalkyl- and C-alkylethylenediamine complexes fit the linear relation well, but N-bonded dialkylethylenediamine complexes deviated considerably, probably due to release of a greater no. of H2O mols. in their formation. Values for the gas phase heats of chelation ΔHg were estd. and discussed. New values of heats and entropies of Cu(H2O)62+ [14946-74-8] deaquation by N,N'-diethylethylenediamine and N,N-diethylethylenediamine and ν values for methylethylenediamine complexes are reported.