Acid activation of titanium alkoxide systems – Structural characterisation of Ti(IV) sulfonyl-imide complexes

Treatment of [Ti(OiPr)4] with the sulfonyl-imine systems Tos2NH ([(p-Me-C6H4SO2)2NH]) and Tf2NH ([(CF3SO2)2NH]) results in the formation of the new Lewis acidic titanium sulfonyl-imide complexes [Ti(OiPr)2(O,O′-Tos2N)2] (1) and [Ti(OiPr)2(HOiPr)2(O-Tf2N)2] (2), respectively. The molecular structures of the complexes have been determined by single crystal X-ray diffraction. The reaction of [Ti(OiPr)3(OAr)] (Ar = 2,6-di-tert-butyl-4-methyl phenyl) with Tf2NH results in the formation of the dimeric complex [Ti(OiPr)3(O,O′-Tf2N)]2 (3), which has also been structurally characterised. The ability of the complexes to catalyst the Friedel–Crafts acylation of anisole has also been assessed.

Graphical abstractThe structurally characterised titanium sulfonyl-imide complexes [Ti(OiPr)2(O,O′-Tos2N)2] (1) and [Ti(OiPr)2(HOiPr)2(O-Tf2N)2] (2) have been synthesised from the reaction of [Ti(OiPr)4] with the N–H acids Tos2NH and Tf2NH, respectively. The dimeric complex [Ti(OiPr)3(O,O′-Tf2N)]2 (3), has also been synthesised and structurally characterised and the ability of the complexes (1–3) to catalyst the Friedel–Crafts acylation of anisole has been assessed.Figure optionsDownload full-size imageDownload as PowerPoint slide