SYNTHESIS, STRUCTURE, AND PHOTOLUMINESCENT PROPERTIES OF LANTHANIDE(III) COMPLEXES WITH A LIGAND BASED ON 1,10-PHENANTHROLINE AND BORNEOL

Abstract

Chiral complexes [Ln((–)-L)2(NO3)3] (Ln = Sm (1), Eu (2), Tb (3)) with an optically active ligand (–)-L containing 1,10-phenanthroline and (–)-borneol moieties and also [Ln((±)-L)2(NO3)3]·1.5MeCN (Ln = Sm (4), Eu (5), Tb (6)) compounds with a racemic ligand (±)-L based on 1,10-phenanthroline and (+)-, (–)-borneol are synthesized. According to single crystal X-ray diffraction data, mononuclear complexes 1-3 are isostructural and crystallize in the non-centrosymmetric space group P43212. The crystal structures of isostructural complexes 4-6 crystallizing in the centrosymmetric space group C2/c contains (+)- and (–)-enantiomeric molecules of the mononuclear complex and MeCN molecules. In complexes 1-6, the (–)-L, (±)-L, and $$\text{NO}_{3}^{-}$$ ligands perform the bidentate chelate function (N4O6 coordination polyhedron of the Ln atom). Complexes 2 and 3 have high quantum yields (φ = 52% and 41%) and long-life luminescence (τ = 1.4 ms and 1.2 ms) in the solid state at 300 K. The luminescence quantum yields of chiral complexes 1-3 are found to several times exceed the quantum yields of racemic complexes 4-6.