ic0516156_si_004.pdf (14.75 kB)
Titanium(III) Trisamidotriazacyclononane: Reactions with C60 and Radicals
journal contribution
posted on 2006-05-01, 00:00 authored by Sónia Barroso, Jinlan Cui, Alberto R. Dias, M. Teresa Duarte, Humberto Ferreira, Rui T. Henriques, M. Conceição Oliveira, José R. Ascenso, Ana M. MartinsThe reaction of titanium trisamidotriazacyclononane, [Ti{N(Ph)SiMe2}3tacn] (1), with C60 led to the synthesis of
[Ti{N(Ph)SiMe2}3tacn]C60 (2) in high yield. Treatment of 2 with PhCH2Br led to the formation of [Ti{N(Ph)SiMe2}3tacn]Br and the radical PhCH2C60 (3). The reaction of CH3I with 1 gives two products. One is [Ti{N(Ph)SiMe2}3tacn]I (4), which results from the oxidation of 1 by an I radical. The other product, 5, resulting from a multistep
reaction scheme that involves redox and nucleophilic reactions, presents an imido ligand formed by ligand
rearrangement upon C−N bond cleavage. In solution, an exchange process that corresponds to a reversible 1,3-silyl shift between two Ti-bonded N atoms leads to isomers 5a and 5b. This equilibrium transforms an imido
(TiNPh) into an amido ligand (Ti{NPh}SiMe2CH2Ph) with concomitant generation of an anionic moiety in the originally
neutral triazacyclononane ring. In solution, either 5a or 5b displays additional fluxional processes that consist of its
corresponding racemization processes.