The catalytic system [(Cp 2 TiCl) 2 ]:LiAlH 4 in aromatic solvents, Part II. Formation of η 3 -allyltitanocene derivatives in the presence of dienes — their structure and e.s.r. spectra

摘要: The addition of dienes to the system [(Cp2TiCl)2] ∶ LiAlH4∶toluene changes so that complex [Cp2TiAlH4] is quantitatively formed instead a titanocene hydride — aluminium cluster. further converted into η3-allyltitanocene derivatives ([Cp2TiA]) if diene structure suitable for formation stable [Cp2TiA] compounds and equilibrium [Cp2TiAlH4]+diene⇌[Cp2TiA]+A1H3 shifted towards by excess diene. All exhibit high-resolution e.s.r. spectra at g=1.993, showing interaction unpaired electron with cyclopentadienyl η3-allyl protons. clearly reveal presence alkyl substituents atsyn-1,3-positions ligand, show triplet multiplets (η3-allyl)titanocene, doublets (1-alkyl-η3-allyl)titanocenes single (1,3-dialkyl-η3-allyl)-titanocenes. thermal isomerization (1,3-dimethyl-η3-allyl)-titanocene (1-methyl-3-ethyl-η3-allyl)titanocene, hitherto considered as Cp2TiA compounds, was confirmed electronic absorption spectroscopy well chemical means.