Mixed-ligand complex compounds of europium(III) with ortho-methoxybenzoic acid and phosphorus-containing neutral ligands

Luminescent coordination mixed-ligand compounds of europium(III) with ortho-methoxybenzoic acid and phosphorus-containing neutral ligands of the isle-like structure Eu(MOBA)$_3$ $\cdot$ 3H$_2$O and Eu(MOBA)$_3$ $\cdot$ L have been synthesized. MOBA– ortho-methoxybenzoic acid, L—hmpa (hexamethylphosphotriamide), tppo (triphenylphosphinoxide), Et$_6$pa (hexaethylphosphotriamide). Thermal properties of the complex mixed-ligand compounds of europium(III) have been investigated. It has been shown that thermolysis results in the splitting of a neutral ligand molecule proceeding within one stage along with an endothermic effect. The complex compound appeared to be stable up to 280$^\circ$C. The composition and structure of the synthesized complexes have been established. Based on the IR spectroscopy data, it has been demonstrated that in ortho-methoxybenzoates of europium(III) ortho-methoxybenzoic acid is coordinated to a europium(III) ion bidentately.