Interaction Modes of Titanium Tetrachloride with the Carbonyl Functionality

Mesityl aldehyde binds TiCl 4 leading to the first structurally characterized TiCl 4 ‐aldehyde adduct, cis ‐[(MesCHO) 2 TiCl 4 ] (Mes = 2,4,6‐Me 3 C 6 H 2 ) ( 1 ), which contains a pseudooctahedral titanium and two aldehyde carbonyl groups in a cis arrangement. However, in the case of 1:1 TiCl 4 –acetone adduct [(Me 2 CO)TiCl 3 ) 2 (μ‐Cl) 2 ] ( 3 ) the solid‐state structure of this acid‐base complex is that of a chloro‐bridged dimer. Both kinds of structures were suggested for the products [{(PhCOMe)TiCl 3 } 2 (μ‐Cl) 2 ] ( 4 ) and [ cis ‐(PhCOMe) 2 TiCl 4 ] ( 5 ) formed by the reaction of TiCl 4 with acetophenone in 1:1 and 1:2 molar ratio. Thioesters behave like acetone in that they give adducts 8 and 9 with TiCl 4 , where 9 , [{(PhSC(Me)O)TiCl 3 } 2 (μ‐Cl) 2 ], exhibits a solid‐state dimeric structure like 3 . The bidentate bonding mode of the chiral propionyloxazolidone 12 with TiCl 4 was revealed by an X‐ray analysis of 13 .