Synthesis and thermolysis of Cp*(C5Me4CH2)TiR complexes

Substitution of the chloride in Cp*FvTiCl with MR (Fv = C5Me4CH2; R = Me, CH2SiMe3, CH2CMe3, CH = CH2, M = Li; R = CH2Ph, M = K; R = C3H5, M = MgCl; R = Ph, M = Na . NaCl) gives Cp*FvTiR. NMR spectroscopic evidence points towards a series of structurally related compounds with a bent-sandwich geometry. The substituent R is positioned in the wedge, midway below the exocyclic methylene group and a neighbouring methyl group of the fulvene. Thermolysis of Cp*FvTiR gives, dependent on the substituent R, reduction to Cp*FvTi (R = CH2Ph) or the double ring metallated Cp*[C5Me3(CH2)(2)]Ti (R = CH2XMe3, X = C, Si) or Cp*FvTiCH=CHMe (R = eta(3)-C3H5)

Early-transition-metal ketenimine complexes:Synthesis, reactivity, and structure of ketenimine-containing titanocene and zirconocene complexes

Reaction of Cp2M(PMe3)(2) complexes (M = Ti, Zr; Cp = eta(5)-C5H5) with the N-(p-tolyl)-diphenylketenimine Ph'N=C=CPh2 (Ph' = p-MeC6H4) in a 1:1 molar ratio affords the ketenimine-containing metallocene derivatives Cp2M(eta(2)-(C,N)-Ph'N=C=CPh2)(PMe3) (M = Ti (1); Zr (2)). The ketenimine ligand reacts in the same way with the ''Cp*M-2'' species (Cp* = eta(5)-C5Me5) generated from the reduction of the corresponding Cp*2MCl2 complexes with (LiBu)-Bu-t (1:2 molar ratio) to give the related complexes Cp*M-2(eta(2)-(C,N)-Ph'N=C=CPh2) (M = Ti (3); Zr (4)). The molecular structure of 3 shows a titanium atom bonded to two eta(5)-cyclopentadienyl rings and a eta(2)-(C,N)-bonded ketenimine ligand. Reaction of ''Cp*Ti-2'' with the ketenimine ligand in a 1:2 molar ratio gives 1,1,5,5-tetraphenyl-3-(p-tolyl)-2-(p-toluidino)-3-aza-1,4-pentadiene, which probably results from the coupling, followed by hydrolysis, of two ketenimine molecules coordinated to one titanocene moiety. Protonation of 3 with Et3NHCl or H2O (1:1 molar ratio) affords the intermediate species Cp*Ti-2(X)(eta(2)-(C,N)-Ph'N=C(H)=CPh2) (X = Cl (5); OH (6)), which on hydrolysis evolves to give the enamine Ph'N(H)-CH=CPh2 as the final product. Finally, 3 reacts reversibly with H-2 to give the hydride enamidate complex Cp*Ti-2(H)(eta(1)-Ph'N-CH=CPh2) (7). The structures of the different compounds have been determined by IR and NMR spectroscopic methods

Titanium dichloro, bis(carbyl), aryne, and alkylidene complexes stabilized by linked cyclopentadienyl-amido auxiliary ligands

Thermal decomposition of the carbyl compounds {C5H4(CH2)(2)NR}TiR'(2) proceeds through alpha- and beta-H elimination to give stable aryne, alkylidene, and olefin. complexes in the presence of PMe3. Reaction of the dibenzyl compound {C5H4(CH2)(2)N-t-Bu}Ti(CH2Ph)(2) with B(C6F5)(3) gives the cationic [{C5H4(CH2)(2)N-t-Bu}TiCH2Ph](+), which is an active catalyst for the polymerization of ethene and propene