Synthesis, X-ray structures, and characterization of hexafluoro-iso-propoxide group 3 and lanthanide precursors

A series of hydrated hexafluoro-iso-propoxide (hfip) lanthanide complexes was synthesized from the amide-alkoxide exchange reaction of the lanthanide bis-trimethylsilyl amide dissolved in toluene and an excess amount of H-hfip. The products were isolated and identified by single crystal X-ray diffraction as: [cis-(H2O)2(hfip)2Ln(μ-hfip)]2 (Ln = Ce, Pr, Nd, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y), [trans-(H2O)2(hfip)2Sc(μ-hfip)]2 (Sc), [(H2O)2(hfip)2La2(μ-hfip)3(μ3-OH)]2 (La-OH), and [(H2O)(hfip)2Sc(μ-hfip)(μ-OH)(μ3-OH)Sc(H2O)(hfip)]2 (Sc-OH). All species were found to have bound H2O molecules thought to be present in the hfip. For the non-oxo species, dinuclear species were formed with one bridging and two terminal hfip ligands. The waters were cis-oriented for all samples but the smallest derivative, Sc, where they were located in trans arrangement. Oxo species were formed by ‘aged’ hfip and generated tetranuclear species (La-OH and Sc-OH) that possessed different ligand sets. Initial efforts to determine these compounds utility for LnF3 nanomaterial production were undertaken using amine solvent in solvothermal (SOLVO) or solution precipitation (SPPT) routes. LnF3 phases were noted but often this was mixed with the Ln(O,F) or Ln2O3 phases.

Graphical AbstractA series of lanthanide complexes containing the fluorinated alkoxide, hexafluoro-iso-propoxide (hfip) was synthesized from the amide-alkoxide exchange reaction yielding: [cis-(H2O)2(hfip)2Ln(μ-hfip)]2 (shown), [trans-(H2O)2(hfip)2Sc(μ-hfip)]2, [(H2O)2(hfip)2La2(μ-hfip)3(μ3-OH)]2, and [(H2O)(hfip)2Sc(μ-hfip)(μ-OH)(μ3-OH)Sc(H2O)(hfip)]2. The majority of the SOLVO and SPPT products isolated were identified by PXRD after thermal 650 °C in air, yielded the LnF3 phase but often this was mixed with the Ln(O,F) or Ln2O3 phases.Figure optionsDownload as PowerPoint slide