RT info:eu-repo/semantics/article
T1 Reactivity with Electrophiles of Imido Groups Supported on Trinuclear Titanium Systems
A1 Caballo González, Jorge
A1 González Moreiras, Mariano
A1 Mena Montoro, Miguel
A1 Pérez Redondo, Adrián
A1 Yélamos Sánchez, Carlos
K1 Química
K1 Chemistry
AB Several trinuclear titanium complexes bearingamido mu-NHR, imido mu-NR, and nitrido mu(n)-N ligands have been prepared by reaction of [{Ti(eta(5)-C5Me5)(mu-NH)}(3)(mu(3)-N)] (1) with 1 equiv of electrophilic reagents ROTf (R = H, Me, SiMe3; OTf = OSO2CF3). Treatment of 1 with triflic acid or methyl triflate in toluene at room temperature affords the precipitation of compounds [Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)(mu-NH)(2)(mu-NH2)(OTf)] (2) or [Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)(mu-NH)(mu-NH2)(mu-NMe)(OTf)](3). Complexes 2 and 3 exhibit a fluxional behavior in solution consisting of proton exchange between mu-NH2 and mu-NH groups, assisted by the triflato ligand, as could be inferred from a dynamic NMR spectroscopy study. Monitoring by NMR spectroscopy the reaction course. of 1 with MeOTf allows the characterization of the methylamido intermediate [Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)(mu-NH)(2)(mu-NHMe)(OTf)] (4), which readily rearranges to give 3 by a proton migration from the NHMe amido group to the NH imido ligands. The treatment of 1 with 1 equiv ofMe3SiOTf produces the stable ionic complex [Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)(mu-NH)(2)(mu-NHSiMe3)][OTf] (5) with a disposition of the nitrogen ligands similar to that of 4. Complex 5 reacts with 1 equiv of [K{N(SiMe3)(2)}] at room temperature to give [Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)(mu-N)(mu-NH)(mu-NHSiMe3)] (6), which at 85 degrees C rearranges to the trimethylsilylimido derivative [Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)(mu-NH)(2)(mu-NHSiMe3)] (7). Treatment of 7 with [K{N(SiMe3)(2)}] affords the potassium derivative [K{(mu(3)-N)(mu(3)-NH)(mu(3)-NiSMe3)Ti-3(eta(C5Me5)-C-5)(3)(mu(3)-N)}] (8), which upon addition of 18-crown-6 leads to the ion pair [K(18-crown-6)] [Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)(mu-NH)(mu-NHSiMe3)] (9). The X-ray crystal structures of2, 5, 6, and 8 have been determined.
SN 0020-1669
YR 2013
FD 2013-10-07
LK http://hdl.handle.net/10017/38427
UL http://hdl.handle.net/10017/38427
LA eng
NO Ministerio de Ciencia e Innovación de España, Comunidad de Madrid, Universidad de Alcalá, Ministerio de Educación y Ciencia de España
DS MINDS@UW
RD 20-abr-2024