Thermal dehydration of Y(TFA)3(H2O)3: Synthesis and molecular structures of [Y(μ,η~1:η~1-TFA)3(THFXH2O)]_(1∞) · THF and [Y4(μ3-OH)4(μ,η~1:η~1-TFA)6(η~1-TFA) (η~2-TFAXTHF)3(DMSO)(H2O)] · 6THF (TFA = trifluoroacetate)

摘要

In order to obtain a better anhydrous precursor for various applications in materials science and catalysis, thermal dehydration reactions of Y(TFA)3(H2O)3 (TFA = trifluoroacetate) (A) were investigated. Thermal treatment of A at different temperatures under vacuum (5 x 10~(-2) mm) for several hours failed to give totally anhydrous yttrium trifluoroacetate (as indicated by IR), Two different complexes, a partially dehydrated [Y(μ,η~1:η~1-TFA)3(THFXH2O)]_(1∞)·THF (1) and a partially hydrolyzed [Y4(μ3-OH)4(μ,η~1:η~1-TFA)6(η~1-TFA)(η~2-TFAXTHF)3(DMSO)(H2O)] · 6THF (2), were obtained with good and moderate yield, respectively, by crystallization of two different thermally treated batches of A from THF (or THF + DMSO) at room temperature. More efficient dehydration of A could be achieved at 200 °C in a furnace, the obtained anhydrous yttrium tris-trifluoroacetate giving Y(TFA)3(THF)2 (3) on crystallization from THF. All the products were characterized by elemental analyses, FT-IR and ~1H NMR spectroscopy as well as thermo-gravimetric analysis. In addition, single crystal X-ray structures are reported for 1 and 2, which show either a terminal (η~1 and η~2) or bridging (μ,η~1:η~1) bonding behavior of the TFA ligand.