Etude des composés d'addition des acides de L EWIS XIX. Sur les composés formés par les 2‐ et 4‐hydroxyacétophénones avec TiCl 4 et ZnCl 2

The preparation of complex compounds between ZnCl 2 or TiCl 4 and p ‐hydroxy‐, o ‐hydroxy‐ and hydroxy‐2‐methyl‐5‐acetophenone is described. Some of these compounds have been isolated as intermediate complexes of Fries rearrangements catalyzed by TiCl 4 . ZnCl 2 forms addition compounds whereas with TiCl 4 elimination of HCl occurs. The IR, absorption spectra are examined and prodable structures proposed for the compounds. The electronic acceptor group ‐OTiCl 2 is found to be weaker than TiCl 4 and about as strong ZnCl 2 when dative bonds are formed.