Monocyclopentadienyl titanium complexes supported by functionalized Shiff Base ligands

Abstract

The titanium derivatives [TiCp * Me(κ3-ONO–OOCPhNCHPhO)] (1), [TiCp * Me(κ3-ONO–OCH2PhNCHPhO)] (2) and [TiCp * Me(κ3-ONS–SPhNCHPhO)] (3) have been synthesized by reaction of [TiCp * Me3] (Cp* = η5-C5Me5) with 2-(salicylideneamino)benzoic acid, 2-(hydroxybenzyl)salicylideneamino or 2-(salicylideneamino)thiophenol, respectively, in a 1:1 M ratio. The reaction of [TiCp * Me3] with and 2-(salicylideneamino)thiophenol in 1:2 M ratio yields the titanium compound [TiCp * Me(κ3-ONS–SPhNCHPhO)(κ1-O-PhCHNHPhS)] (5) Complexes 1, 2 and 3 react with tBuNC to yield the iminoacyl-containing compounds [TiCp * (η2-CN–MeCNtBu)(κ3-ONO–OOCPhNCHPhO)] (6), [TiCp * (η2-CN–MeCNtBu)(κ3-ONO–OCH2PhNCHPhO)] (7) and [TiCp * (η2-CN–MeCNtBu)(κ3-ONS–SPhNCHPhO)] (8). Compounds 7 and 8 can be protonated with triflic acid to yield the aminocarbene derivatives (9) and (10), respectively. Moreover, the reaction of complexes 1–3 with triflic acid renders the corresponding triflate compounds [TiCp * (κ3-ONO–OOCPhNCHPhO)(OTf)] (11), [TiCp * (κ3-ONO–OCH2PhNCHPhO)(OTf)] (12) and [TiCp * (κ3-ONS–SPhNCHPhO)(OTf)] (13). The reaction of 1 or 2 with B(C6F5)3 in a 1:1 M ratio yields the carboxylate adduct [TiCp * Me(κ3-ONO–OOCPhNCHPhO·B(C6F5)3)] (14) or the cationic derivative. [TiCp * (κ3-ONO–OCH2PhNCHPhO)]2[MeB(C6F5)3)]2 (15), respectively. The molecular structures of complexes 2, 5, 6, 13 and 15 have been established by X-ray diffraction methods.