Reaction of a monomeric titanium hydride with dioxygen does not produce a stable titanium hydroperoxide

Terminal Titanyl Complexes of Tri- and Tetrametaphosphate: Synthesis, Structures, and Reactivity with Hydrogen Peroxide

“…6,48 It is instead believed that titanium(IV) hydroperoxo species play the active role in substrate oxidation within heterogeneous systems, 10,43,49 and therefore the preparation of well-defined titanium hydroperoxo complexes has been targeted by synthetic chemists. 50 We were unable to observe a stable titanium(IV) hydroperoxo complex, and 1 and 2 did not show any signs of catalytic activity toward organic substrates in the presence of H 2 O 2 (see section 13 in the Supporting Information for experimental details). Both results are likely due to the rapid conversion of 1 and 2 to 3 and 4, respectively, upon addition of H 2 O 2 without a long-lived hydroperoxo intermediate for interception by a substrate.…”

“…6,48 It is instead believed that titanium(IV) hydroperoxo species play the active role in substrate oxidation within heterogeneous systems, 10,43,49 and therefore the preparation of well-defined titanium hydroperoxo complexes has been targeted by synthetic chemists. 50 We were unable to observe a stable titanium(IV) hydroperoxo complex, and 1 and 2 did not show any signs of catalytic activity toward organic substrates in the presence of We did, however, test the ability of 3 and 4 to behave as stoichiometric oxidants towards phosphorus(III) compounds and sulfides. Treatment of 3 with P(OMe) 3 , PPh 3 and SMe 2 at ambient temperature resulted in the formation of the corresponding organic oxide as well as clean regeneration of 1 as determined by 31 12 were prepared as previously reported.…”

“…Examples of molecular peroxotitanium­(IV) complexes that serve as oxidants toward organic substrates are rare due to the well-documented stability of the titanium–peroxo structural unit and, therefore, its corresponding lack of oxidizing capacity. , It is instead believed that titanium­(IV) hydroperoxo species play the active role in substrate oxidation within heterogeneous systems, ,, and therefore the preparation of well-defined titanium hydroperoxo complexes has been targeted by synthetic chemists …”

Synthesis and Structure of Titanium(III) Bis(decamethyltitanocene) Oxide

“…21 It could be of relevance that the Ti(IV) hydride [(DIPPO) 3 TiH(PMe 3 )] (DIPPO = 2,6diisopropylphenyloxide) reacts with dioxygen to give [{(DIP-PO) 3 Ti} 2 O] and not the expected hydroperoxide. 25 However, in view of the reported low stability of E 12 the less sterically hindered compound [Cp* 2 Ti(O 2 )] should be even more reactive and capable of reacting further with an initial overwhelming [Cp* 2 Ti] to give, for example, [{Cp* 2 Ti(μ-O)} 2 ] similar to B1 and B2 (Chart 1). The oxygen bonded in such a rather stable titanocene compound could be released only slowly by [Cp* 2 TiH] to give 1.…”

“…Consecutive conversion of the suggested peroxide [Cp* 2 Ti(O 2 )] to 1 could be induced by interaction with [Cp* 2 TiH], which was generated together with [Cp*Ti(C 5 Me 4 CH 2 )] by disproportionation of [Cp* 2 Ti] during the first week of aging . It could be of relevance that the Ti(IV) hydride [(DIPPO) 3 TiH(PMe 3 )] (DIPPO = 2,6-diisopropylphenyloxide) reacts with dioxygen to give [{(DIPPO) 3 Ti} 2 O] and not the expected hydroperoxide . However, in view of the reported low stability of E the less sterically hindered compound [Cp* 2 Ti(O 2 )] should be even more reactive and capable of reacting further with an initial overwhelming [Cp* 2 Ti] to give, for example, [{Cp* 2 Ti(μ-O)} 2 ] similar to B1 and B2 (Chart ).…”