UNUSUAL COORDINATION MODES OF MULTIDENTATE LIGANDS - CRYSTAL-STRUCTURE OF [((TMHD)(3)Y)(2)(HMTETA)] [TMHD = (BUCOCHCOBUT)-C-T AND HMTETA = ME2N(CH2CH2NME)(2)CH2CH2NME2]

The reaction of the hydrated lanthanide metal beta-diketonate complexe s [Ln(tmhd)(3)(H2O)] (tmhd = (BuCOCHCOBut)-C-t) with hexamethyltriethy lenetetramine (hmteta = Me2N(CH2CH2NMe)(2)CH2CH2 NMe2) in n-hexane at room temperature yields the anhydrous, bridged dimeric complexes, [{(t mhd)(3)Ln}(2)(hmteta)],where Ln=Gd 1 or Y 2. An nitrogen atoms of the hmteta ligand are utilised in bonding to the yttrium centres. The comp lexes are air and moisture stable, and more importantly both have good volatility, thermal stability, and mass transport properties as demon strated by sublimation, differential scanning calorimetry (DSC) and th ermal gravimetric analysis (TGA), thus making them potential precursor s for MOCVD application. (C) 1998 Published by Elsevier Science Ltd. A ll rights reserved.