Titanium(III) trisamidotriazacyclononane: reactions with C60 and radicals.
The 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.
Barroso
Sónia
S
Centro de Química Estrutural, Complexo Interdisciplinar, Instituto Superior Técnico, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal.
Cui
Jinlan
J
Dias
Alberto R
AR
Duarte
M Teresa
MT
Ferreira
Humberto
H
Henriques
Rui T
RT
Conceição Oliveira
M
M
Ascenso
José R
JR
Martins
Ana M
AM