APPROACHES TO HEXANE-SOLUBLE CATIONIC ORGANOMETALLIC LEWIS-ACIDS - SYNTHESIS, STRUCTURE, AND SOLUBILITY OF TITANIUM COMPLEXES OF THE FORMULA [(ETA-5-C5(SI(CH3)3)NH5-N)TI(ACAC)2]+OTF- (N = 2, 3)

Treatment of (1,3-bis(trimethylsilyl)cyclopentadienyl)titanium trichloride with silver triflate (1 equiv) and acetylacetone RCOCH2COR (2 equiv, R = CH3, (t)Bu, CF3) in dichloromethane affords the triflate complexes [(1,3-C5(Si(CH3)3)2H3)Ti(CH3COCHCOCH3)2]+TfO-, [(1,3-C5(Si(CH3)3)2H3)Ti((t)BuCOCHCO(t)Bu)2]+TfO-, and [(1,3-C5(Si(CH3)3)2H3)Ti(CF3COCHCOCF3)2OTf]. Similar reactions using (1,2,4-tris(trimethylsilyl)cyclopentadienyl)titanium trichloride and RCOCH2COR (R = (t)Bu, CF3) give [(1,2,4-C5(Si(CH3)3)3H2)Ti((t)BuCOCHCO(t)Bu)2]+TfO- and [(1,2,4-C5(Si(CH3)3)3H2)Ti(CF3COCHCOCF3)2OTf]. These complexes exhibit modest to excellent solubility in alkane and perfluoroalkane solvents and demonstate that ionic complexes can be solubilized into even the most nonpolar solvents with the appropriate choice of ligands. The ionic versus molecular nature of the complexes has been established through crystal structure determinations for [(1,3-C5(Si(CH3)3)2H3)Ti(CH3COCHCOCH3)2]+TfO- and [(1,3-C5(Si(CH3)3)2H3)Ti(CF3COCHCOCF3)2OTf].