Strukturchemie Titan-Organischer Verbindungen: Die Struktur von Bis(π-cyclopentadienyl)bis(trifluormethansulfonato)-titan(IV)

Metallocene bis(perfluoroalkanesulfonate)s as air-stable cationic Lewis acids

“…The large molar conductivity values are consistent with complete ionization into a 1:2 electrolyte [15]. 3 and Y(OTf) 3 (g zz = 2.0349, DE = 0.85 eV). Since Lewis acids with the DE value larger than 0.88 were presumed to be capable for inducing carbon-carbon bond-forming reactions [16b], it is reasonably expected that the Lewis acidity of 2a and 2b is high enough to trigger synthetically useful reactions.…”

“…Cationic group 4 metallocene compounds, which have attracted increasing attention recently [2], represent a typical example. The metallocene bis(triflate) complexes of zirconium and titanium Cp 2 M(OTf) 2 (Cp = C 5 H 5 , Tf = CF 3 SO 2 ) were initially obtained by treatment of Cp 2 MCl 2 with AgOTf [3] and later from Cp 2 ZrMe 2 and TfOH [4]. These complexes were successfully employed as catalysts for Diels-Alder reaction [5], Mukaiyama-Aldol reaction [6], HosomiSakurai reaction [6a,7], [3+2] nitrone-olefin cycloaddition reaction [8], and glycosylation [9].…”

Metallocene and Organo-main Group Trifluoromethanesulfonates

“…Yield: 86%, orange microcrystalline powder; previously reported [6]. 1 Cp 2 ZrðOSO 2 CF 3 Þ 2 : Ag(OSO 2 CF 3 ) (1050 mg, 4.09 mmol) was dissolved in benzene (20 ml) and added to a solution of Cp 2 ZrCl 2 (570 mg, 1.95 mmol) in benzene (60 ml).…”

“…As the solid state structure of Cp 2 Ti(CF 3 SO 3 ) 2 is known from an X-ray crystal structure [6], its IR spectrum (Figure 1b) can be assumed to be that of a covalently bonded monodentate ligand. Five major bands are observed for this compound ( Table 2).…”

“…The first organotitanium-triflate derivatives were reported by Doyle and Tobias [5] in 1967, who synthesized [Cp 2 Ti(acac) + ](OSO 2 CF 3 ) ) by the addition of acetylacetone to a solution of Cp 2 TiCl 2 and Ag(OSO 2 CF 3 ) in water. Thewalt and Klein [6] subsequently synthesized Cp 2 Ti(OSO 2 CF 3 ) 2 by the addition of Ag(OSO 2 CF 3 ) to a solution of Cp 2 TiCl 2 in anhydrous tetrahydrofuran. The product was characterized by X-ray crystallography and shows an approximately tetrahedral coordination about titanium, with two covalently bound (monodentate) triflate ligands.…”