The X-ray crystal and molecular structure of [Ba(TDFND)2.tetraglyme], the first molten barium precursor for MOCVD applications


  • [Ba(TDFND)2.tetraglyme] is 2,5,8,11,14-pentaoxapentadecane-bis (1′,1′,1′,2′,2′,3′, 3′,7′,7′,8′,8′,9′,9′,9′-tetradecafluorononane-4′,6′-dionato)barium(II). Full bond lengths and angles, atomic co-ordinates, isotropic temperature factors are available form the Cambridge Crystallographic Data Centre. For ordering instructions see Notes for Contributors.


At 150 K [Ba(TDFND)2, tetraglyme] crystallises in the P1/c space group with a = 17.15(2) Å b = 10.735(5) Å, c = 22.830(7) A, β = 97.56 (7)°, V = 4165 (5) Å3, Z=4. R1 = 0.0435, wR2 = 0.1079. The barium atom is nine-co-ordinate, with binding to all the O atoms. The two BaTDFND rings are planar but tilted by 26° from being co-planar. The five O atoms of the tetraglyme ligand are also essentially co-planar, but this plane subtends angles of 88.8(1)° and 67.4(1)° to the two BaTDFND planes. The Ba[BOND]O (TDFND) bond lengths are longer than for other related compounds, but the Ba[BOND]O (tetraglyme) bond lengths are similar to those in [Ba(HFA)2.tetraglyme] (HFA [TRIPLE BOND] CF3C(O)CHC(O)CF3). The low melting point and the fact that [Ba(TDFND)2.tetraglyme], alone of barium complexes of this kind, can be evaporated without decomposition at 1 atm are attributed to lower intermolecular forces for this compound and to its greater thermal stability.