ISSN:
1572-901X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Summary The addition of dienes to the system [(Cp2TiCl)2] ∶ LiAlH4∶toluene changes the system so that the complex [Cp2TiAlH4] is quantitatively formed instead of a titanocene hydride — aluminium hydride cluster. The complex [Cp2TiAlH4] is further converted into η3-allyltitanocene derivatives ([Cp2TiA]) if the diene structure is suitable for formation of stable [Cp2TiA] compounds and if the equilibrium [Cp2TiAlH4]+diene⇌[Cp2TiA]+A1H3 is shifted towards the formation of [Cp2TiA] by the excess of diene. All the compounds [Cp2TiA] exhibit high-resolution e.s.r. spectra at g=1.993, showing interaction of the unpaired electron with the cyclopentadienyl and η3-allyl protons. The e.s.r. spectra clearly reveal the presence of alkyl substituents atsyn-1,3-positions of η3-allyl ligand, and show a triplet of multiplets for (η3-allyl)titanocene, doublets of multiplets for (1-alkyl-η3-allyl)titanocenes and single multiplets for (1,3-dialkyl-η3-allyl)-titanocenes. thermal isomerization of (1,3-dimethyl-η3-allyl)-titanocene and (1-methyl-3-ethyl-η3-allyl)titanocene, hitherto considered as the stable Cp2TiA compounds, into (1-alkyl-η3-allyl)titanocenes was confirmed by e.s.r. and electronic absorption spectroscopy as well as by chemical means.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00619015
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