Molecular complex formation between some azacrown ethers and 2,4,6-trinitrophenol

The formation of molecular complexes with 1 : 1 stoichiometry between 2,4,6 -trinitrophenol and aza-12-crown-4, aza-15-crown-5 and aza-18-crown-6 in ch loroform solution was investigated spectrophotometrically. The resulting co mplexes were isolated and characterized by microchemical analysis, IR and N MR spectroscopy. The equilibrium constants of the 1 : 1 adducts were evalua ted from the non-linear least-squares fitting of the absorbance-mole ratio data. The overall stability of the 2,4,6-trinitrophenol complexes was found to vary in the order aza-15-crown-5 > aza-18-crown-6 approximate to aza-12 -crown-4. The kinetics of complex formation between 2,4,6-trinitrophenol an d the aza-substituted crown ethers used were investigated and in all cases the results showed the occurrence of an oscillating chemical reaction in so lution.