Inorganic Chemistry, Vol.59, No.16, 11305-11315, 2020
Solvent Impact on the Diversity of Products in the Reaction of Lithium Diphenylphosphide and a Ti(III) Complex Supported by a tBu(2)P-P(SiMe3) Ligand
We present two important trends in the reactivity of the titanium complex [(Me)NacNacTi(Cl){eta(2)-P(SiMe3)-PtBu2}] ((Me)NacNac(-) = [Ar]NC(Me)CHC(Me)N[Ar]; Ar = 2,6-iPr(2)Ph) with nucleophilic reagents RLi (R = Ph2P, tBuO, (Me3Si)(2)N, and tBu(2)N) depending on the reaction medium. Reaction in nonpolar solvent (toluene) leads to three main products: via an autoredox process and nucleophilic substitution at the Ti-atom to afford the Ti(IV) complex [(Me)NacNacTi(R){eta(2)-P-PtBu2}] (1 for R = PPh2), via the elimination of Me3SiR to afford Ti(III) complex [(Me)NacNacTi(Cl){eta(2)-P-PtBu2}](-)[Li(12-crown-4)(2)](+) (2), and via 2e(-) reduction process to afford new ionic complex [{ArNC(Me)-CHC(Me)}Ti=NAr{eta(1)-P(SiMe3)-PtBu2]}(-)[Li(12-crown-4)(2)](+) (3). Quite differently, the complex [(Me)NacNacTi(Cl){eta(2)-P(SiMe3)-PtBu2}] reacts with Ph2PLi in THF, unexpectedly yielding two new, four-coordinate Ti(IV) imido complexes 4a [{ArNC(Me) = CHC(H)(Me)-P(PtBu2)}Ti=NAr(Cl)](-) [Li(12-crown-4)(2)](+)-(toluene)(2) and 4b [{ArNC(CH2)CH=C(Me)-P(PtBu2)}Ti=NAr-(Cl)](-)[Li(12-crown-4)(2)](+)center dot(Et2O). Complex 2 dissolved in THF converts to 4a and 4b. 1, 2, 3, 4a, and 4b were characterized by X-ray diffraction. 1, 4a, and 4b were also fully characterized by multinuclear NMR spectroscopy.