DIORGANOGALLIUM BETA-DIKETONATES AND THEIR LEWIS ACID-BASE ADDUCTS - CRYSTAL AND MOLECULAR-STRUCTURES OF MES(2)GA(HFAC) AND ME2GA(HFAC)CENTER-DOT-NC5H5

Compounds of the type R2Ga(bdk) (R = Me, Et, Mes (mesityl); bdk = 2,4- pentanedionato (acac); 1,1,1-trifluoro-2,4-pentanedionato (tfac), 1,1, 1,5,5,5-hexafluoro-2,4-penatedionato (hfac), 2,2,6,6-tetramethyl-3,5-h eptanedionato (tmhd)) have been prepared by multiple routes, including hydrocarbon elimination, metathesis, and ligand redistribution reacti ons, and fully characterized by elemental analyses, cryoscopic molecul ar weight studies in benzene, and IR and multinuclear NMR spectroscopi c studies. An X-ray structural study of Mes(2)Ga(hfac) demonstrated fo ur-coordinate gallium with sigma bonds to the two mesityl rings and to the two oxygen atoms of the beta-diketonate ligand. The Lewis aciditi es of the diorganogallium beta-diketonate derivatives toward NMe3 and/ or pyridine were also-investigated. Two adducts, Me2Ga(hfac). NMe and Me2Ga(hfac). py, were stable to dissociation at room temperature and t hus were fully characterized by elemental analysis, cryoscopic molecul ar weight studies in benzene, vapor pressure-temperature studies, and IR and multinuclear NMR (including variable temperature) spectroscopic studies. The compound Me2Ga(hfac). py was also characterized by an X- ray structural study. The structure involved five-coordinate gallium w ith one Ga-N, two (inequivalent) Ga-O, and two Ga-C bonds.