A Strongly Luminescent Organic-Solvent-Soluble Salt of the Tris(dipicolinato)europium(III) Trianion

The tetraethylammonium salt of the [Eu(dipic) 3 ] 3- (dipic = 2,6-pyridinedicarboxylate) complex anion, tris(tetraethylammonium) tris(2,6-pyridinedicarboxylato-N,O,O)europium(III) tetrahydrate, (C 8 H 20 N) 3 [Eu(C 7 H 3 NO 4 ) 3 ].4H 2 O, forms monoclinic crystals. The lattice contains alternating columns of the Δ and Λ enantiomeric forms of the trianion, with the water molecules hydrogen bonded to the uncoordinated O atoms of the carboxylate groups and the tetraethylammonium cations forming columns, presumably to optimize electrostatic attractions.