Reactivity at the beta-diketiminate ligand Nacnac(-) on titanium(IV) (Nacnac(-) = [Ar]NC(CH3)CHC(CH3)N[Ar], Ar=2,6-[CH(CH3)(2)](2)C6H3). Dilmine-alkoxo and bis-anilido ligands stemming from the Nacnac(-) skeleton

摘要

The reaction of ketene OCCPh2 with the four-coordinate titanium(IV) imide (L-1)Ti=NAr(OTf) (L-1(-) = [Ar]NC(CH3)-CHC(CH3)N[Ar], Ar = 2,6-[CH(CH3)(2)](2)C6H3) affords the tripodal dimine-alkoxo complex (L-2)Ti=NAr(OTf) (L-2(-) = [Ar]NC(CH3)CHC(O)=CPh2C(CH3)N[Ar]). Complex (L-2)Ti=NAr(OTf) forms from electrophilic attack of the beta-carbon of the ketene on the gamma-carbon of the Nacnac(-) NCCgammaCN ring. On the contrary, nucleophiles such as LiR (R- = Me, (CH2Bu)-Bu-t, and CH2SiMe3) deprotonate cleanly in OEt2 the methyl group of the beta-carbon on the former Nacnac(-) backbone to yield the etherate complex (L-3)Ti=NAr(OEt2), a complex that is now supported by a chelate bis-anilido ligand (L-3(2-) = [Ar]NC(CH3)CHC(CH2)N[Ar]). In the absence of electrophiles or nucleophiles, the robust (L,)Ti=NAr(OTf) template was found to form simple adducts with Lewis bases such as (CNBu)-Bu-t or NCCH2(2,4,6-Me3C6H2). Complexes (L-2)Ti=NAr(OTf), (L-3)Ti=NAr(OEt2), and the adducts (L-1)Ti=NAr(OTf)(XY) [XY = (CNBu)-Bu-t and NCCH2(2,4,6-Me3C6H2)] were structurally characterized by single-crystal X-ray diffraction studies. [References: 74]