Publication
The reaction of hydrated lanthanide hexafluoroacetylacetonates, [Ln(hfa)(3)(H2O)(2)], with 1,4-disubstituted benzenes afforded a new series of one-dimensional coordination polymers Ln(hfa)(3)(Q), where Ln = Eu, Gd, Tb, and Lu and Q = 1,4-diacetylbenzene (acbz), 1,4-diacetoxybenzene (acetbz), or 1,4-dimethyltherephtalate (dmtph). X-ray single crystal analyses reveal Ln(hfa)(3)(acbz) (Ln = Eu, Gd, Tb) consisting of zigzag polymeric chains with Ln Ln Ln angles equal to 128 degrees, while the arrays are more linear in [Eu(hfa)(3)(acetbz)infinity and Eu(hfa)(3)(dmtph), with Ln Ln Ln angles of 165 degrees and 180 degrees, respectively. In all structures, Ln(III) ions are 8-coordinate and lie in distorted square-antiprismatic environments. The coordination polymers are thermally stable up to 180-210 degrees C under a nitrogen atmosphere. Their volatility has been tested in vacuum sublimation experiments at 200-250 degrees C and 10(-2) Torr: the metal organic frameworks with acetbz and dmtph can be quantitatively sublimed, while Ln(hfa)(3)(acbz) undergoes thermal decomposition. The triplet state energies of the ancillary ligands, 21 600 (acetbz), 22 840 (acbz), and 24 500 (dmtph) cm(-1), lie in an ideal range for sensitizing the luminescence of Eu-III and/or Tb-III. As a result, all of the Ln(hfa)(3)(Q) polymers display bright red or green luminescence due to the characteristic D-5(0)-> F-7(J)(J=0-4) or D-5(4) -> F-7(J) (J=6-0) transitions, respectively. Absolute quantum yields reach 51(Eu) and 56(Tb) % for the frameworks built from dmtph. Thin films of Eu(hfa)(3)(Q) with 100-170 nm thickness can be obtained by thermal evaporation (P