The Impact Of The Alkali Metal Ion On The Crystal Structure And (Mechano)Luminescence Of Terbium(Iii) Tetrakis(Beta-Diketonates)

The novel terbium(III) tetrakis(beta-diketonates) M[TbL4] with different alkali metal counterions (Na, K, Cs) based on functionalized trifluoromethylated beta-diketonate are reported. An efficient approach to alkali metal beta-diketonates ML (M = Na, K, Cs) is proposed, which does not require the alkaline media promoting the destruction of 1,3-dicarbonyl compounds. The transformation of lithium beta-diketonate LiL into the corresponding alkali metal beta-diketonate ML has been achieved under mild conditions using alkali metal fluorides. Organic ligand generates the multiplicity of coordination modes through a diketonate fragment, methoxy group and trifluoromethyl substituent. The alkali metal ion changes the geometry of coordination environment of the terbium(III) ion and affects the crystal packing of complexes. The additional coordination centers in the ligand coupled with a small atomic radius of sodium ion resulted in a construction of a rare example of discrete lanthanide tetrakis(beta-diketonate) Na[TbL4]. Moreover, this complex exhibited bright luminescence and mechanoluminescence in contrast to polymeric Tb-III tetrakis(beta-diketonates) with K and Cs.