Synthesis, supramolecular isomerism, and photoluminescence of scandium(iii) complexes with a tetrafluoroterephthalate ligand

Here we present a new family of seven Sc(iii) complexes with a tetrafluoroterephthalate ligand (tFBDC2−), having non-polymeric and polymeric 2D and 3D structures. These complexes are characterized by SC XRD, PXRD, FT-IR, elemental analysis, and TGA. Among these complexes, 3D coordination polymers [Sc(H2O)(tFBDC)1.5]·H2O (1), [Sc2(H2O)2(tFBDC)3]·2H2O (2), and [Sc(H2O)(tFBDC)1.5]·4H2O (3) are supramolecular isomers. Complex 1 is obtained as a phase pure material, while 2 and 3 are found as admixtures. The reaction of Sc(CF3SO3)3 with H2tFBDC in the presence of NH3 as a base produces layered coordination polymer [Sc(H2O)(OH)(tFBDC)] (4). Complexes (NH4)[Sc(H2O)4(tFBDC)2]·5H2O (5), [K(H2O)2Sc(H2O)4(tFBDC)2]·3H2O (6) and [Cs(H2O)4Sc(H2O)4(tFBDC)2]·0.5H2O (7) based on the same [Sc(H2O)4(tFBDC)2]− anionic unit are obtained by precipitation with NH3, KOH or CsOH. Coordination polymers 1 and 4 are stable in an aqueous solution in the range of pH 2-12. Solid complexes 1, 4-7 show ligand-centred purple/blue photoluminescence, with 1 and 4 having high quantum yields of 28 and 34% at room temperature. © The Royal Society of Chemistry