Ziółkowska A, Szynkiewicz N, Pikies J, Ponikiewski Ł. Solvent Impact on the Diversity of Products in the Reaction of Lithium Diphenylphosphide and a Ti(III) Complex Supported by a
tBu
2P-P(SiMe
3) Ligand.
Inorg Chem 2020;
59:11305-11315. [PMID:
32799493 PMCID:
PMC7458418 DOI:
10.1021/acs.inorgchem.0c00824]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present two important trends in the reactivity of the titanium complex [MeNacNacTi(Cl){η2-P(SiMe3)-PtBu2}] (MeNacNac- = [Ar]NC(Me)CHC(Me)N[Ar]; Ar = 2,6-iPr2Ph) with nucleophilic reagents RLi (R = Ph2P, tBuO, (Me3Si)2N, and tBu2N) 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 [MeNacNacTi(R){η2-P-PtBu2}] (1 for R = PPh2), via the elimination of Me3SiR to afford Ti(III) complex [MeNacNacTi(Cl){η2-P-PtBu2}]-[Li(12-crown-4)2]+ (2), and via 2e- reduction process to afford new ionic complex [{ArNC(Me)CHC(Me)}Ti═NAr{η1-P(SiMe3)-PtBu2}]-[Li(12-crown-4)2]+ (3). Quite differently, the complex [MeNacNacTi(Cl){η2-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]+·(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.
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