Thermodynamic study of Eu(III) complexation by pyridine monocarboxylates

► Eu(III) picolinates are highly stable over the other two isomers due to chelation. ► The enthalpy change of complexation (ΔHC) of picolinates are found negative. ► Life time measurements by TRFS supported the bidentate nature of picolinate. ► Charge transfer is more pronounced in isonicotinate than in nicotinate. ► The enthalpy change of complexation (ΔHC) of Eu(III) with other two are positive.