MONOMERIC STRONTIUM AND BARIUM BETA-DIKETONATE ADDUCTS WITH POLYETHERS - THE X-RAY CRYSTAL-STRUCTURES OF [SR(PH2ACAC)2(TETRAGLYME)] AND [BA(THD)2(TETRAGLYME)]

The reaction of the ethanol solvated strontium ethoxide [Sr(OEt)2(EtOH)4]infinity with the beta-diketonate thd-H in the presence of tetraglyme in hexane at ambient temperature yields [Sr(thd)2(tetraglyme)] (1); while the analogous reaction of the in situ prepared [Sr(tfa)2]infinity and triglyme produces [Sr(tfa)2(triglyme)] (2). Reaction of [Sr(Ph2acac)2]infinity with tetraglyme yields [Sr(Ph2acac)2(tetraglyme)] (3). The corresponding barium complex [Ba(OEt)2(EtOH)4]infinity also reacts rapidly with thd-H and tetraglyme in hexane to yield the glyme-chelated monomeric complex [Ba(thd)2(tetraglyme)] (4). These complexes are all monomeric and have been characterized by IR, H-1 and C-13 NMR spectroscopy, microanalysis, mass spectrometry, and in selected cases TGA and DSC. The X-ray structures of [Sr(Ph2acac)2(tetraglyme)] (3) and [Ba(thd)2(tetraglyme)] (4) reveal that they are monomeric with similar nine-coordinate metal centres. The tetraglyme coordinates via all its available oxygen atoms which wrap in a meridional plane and the two beta-diketonates are positioned on either side of this plane.