SYNTHESIS AND MOLECULAR-STRUCTURE OF BA5(MU-5-OH)[MU-3-OCH(CF3)2]4[MU-2-OCH(CF3)2]4 [OCH(CF3)2](THF)4(H2O) - THF - A SOURCE OF BARIUM FLUORIDE

The reaction between metallic barium and fluoroisopropanol or alcoholysis of [Ba(OPr(i))2] produces a pentanuclear fluoroalkoxide. Its X-ray structure determination showed its formulation to correspond to Ba5(mu5-OH)]mu3-OCH(CF3)2]4[mu2-OCH(CF3)2]4 [OCH(CF3)2](THF)4(H2O).THF. The metallic core is based on a square pyramid encapsulating an hydroxo ligand. In addition to the barium-alkoxide bonds [2.53(3)-2.86(3) angstrom] neutral O-donors, four THF [2.82(2)-2.86(3) angstrom] and one H2O [2.79(3) angstrom] and secondary barium-fluorine interactions [2.99(2)-3.31(2) angstrom] ensure high coordination numbers, from 9 to 11 for the metal centers. Hydrogen bonding between the apical fluoroisopropoxide, the water molecule and one THF molecule, non-bonded to a metal center, accounts for the stability of the hydrate and illustrates the Lewis acidity of fluoroalkoxides. Thermal decomposition leads to BaF2.