Stoichiometry and structure of Al(C2H5)(3-n)Cl-n/C6H5COOC2H5 complexes (n=0-2)

Ethyl benzoate (EB) complexes of triethylaluminium (TEA), diethylaluminium chloride (DEAC), and ethylaluminium dichloride (EADC), in heptane solution have been studied with in situ FTIR spectroscopy. Complexation is only through the carbonyl oxygen. No evidence of either oxygen complexation is seen in any of the spectra. EB and TEA form a 1:1 complex at all TEA/EB ratios. EB also forms 1:1 complexes with DEAC and EADC at equimolar Al/EB ratios and with excess EB. With excess DEAC or EADC, complexes with more than one Al entity seem to form, where the Al entities are linked together by chlorine bridges. The strength of the Al-EB bond increases with increasing number of chlorine ligands on Al, but in mixtures of TEA and DEAC, EB complexation to TEA is preferred. (C) 1997 Elsevier Science B.V.