om8b00212_si_001.xyz (165.31 kB)
Reactivity of Tuck-over Titanium Oxo Complexes with Isocyanides
dataset
posted on 2018-06-22, 18:50 authored by María Gómez-Pantoja, Juan. I. González-Pérez, Avelino Martín, Miguel Mena, Cristina Santamaría, Manuel TempradoThe reactivity of
the “tuck-over” species [Ti2(η5-C5Me5)(CH2Ph)3(μ-η5-C5Me4CH2-κC)(μ-O)]
(1) and [Ti2(η5-C5Me5)(CH2CMe3)(μ-η5-C5Me4CH2-κC)(μ-CH2CMe2CH2)(μ-O)] (2) toward isocyanides has been
examined both synthetically and theoretically. Treatment of 1 with the isocyanides RNC, R = Me3SiCH2, 2,6-Me2C6H3, tBu, iPr, leads to a series of η2-iminoacyl species (3–6) where the
molecule of isocyanide inserts into one of the terminal metal–alkyl
bonds. The analogous reaction of the “tuck-over” metallacycle
species 2 with 2,6-Me2C6H3NC and tBuNC results in the initial insertion of
one isocyanide into the terminal Ti–alkyl bond to form the
iminoacyl complexes 7 and 8, followed by
a second insertion into the metallacycle moiety to generate 9, in the case of tert-butylisocyanide. DFT
calculations support the selective reactivity observed experimentally
with a kinetic and thermodynamic preference for RNC insertion on the
terminal alkyl groups bound to both metallic centers over the alternative
insertion on the “tuck-over” ligand.