RT info:eu-repo/semantics/article T1 Oxo and imido/imido exchange and C-H activation reactions based on pentamethylcylopentadienyl imido tantalum complexes A1 Royo Gracia, Pascual A1 Sánchez-Nieves Fernández, Javier K1 Oxo/imido imido/imido exchange K1 C-H activation K1 Cyclopentadienyl imido tantalum complexes K1 Ciencia K1 Química inorgánica K1 Science K1 Chemistry, inorganic AB Reactions of [TaCp*Cl4] with two, three and four equivalents of LiNHtBu give the halo- and amido-imido complexes[TaCp*Cl2(NtBu)] (1a), [TaCp*Cl(NtBu)(NHtBu)] (2) and [TaCp*(NtBu)(NHtBu)2] (3), respectively. The related complex[TaCp*Cl2{N(2,6-Me2C6H3)}] (1b) is prepared by a similar reaction using two equivalents of Li[NH(2,6-Me2C6H3)]. Complex 3can be transformed into 2 and further into 1a by reaction with SiClMe3. Complex 1a reacts with CNtBu to give the 18-electronadduct [TaCp*Cl2(NtBu)(CNtBu)] (4) whereas addition of excess CN(2,6-Me2C6H3) results in reductive elimination of thecarbodiimide tBuN C N(2,6-Me2C6H3) (5) to give [TaCp*Cl2{CN(2,6-Me2C6H3)}3]. However complex 1b does not react with anyof the isocyanide ligands. Both complexes 1a and 1b react with PhCHO undergoing imido/oxo exchange to give the iminesPhCH NR (R=tBu, 2,6-Me2C6H3 (6)) and dimeric [TaCp*Cl2(O)]2 or trimeric [(TaCp*Cl)3(m2-Cl)(m2-O)3(m3-O)] oxo-complexes,whereas only 1a reacts with CO2, PhCH NR% (R%=Ph, Me) and (2,6-Me2C6H3)N C NtBu producing tBuN CO, PhCH NtBuand tBuN C NtBu, respectively and the corresponding oxo or imido tantalum derivative. None of the complexes reacts withCO or NCR (R=Me, Ph). The complex [TaCp*Me(NtBu)(NHtBu)] activates C–H bonds when heated in benzene and tolueneaffording [TaCp*Ph(NtBu)(NHtBu)] (7) and a mixture of [TaCp*(m-MeC6H4)(NtBu)(NHtBu)] 8a and [TaCp*(pMeC6H4)(NtBu)(NHtBu)] (8b). All of the reported organic compounds and tantalum complexes were characterized by 1H- and 13C-NMR spectroscopy PB Elsevier SN 0022-328X YR 2000 FD 2000 LK http://hdl.handle.net/10017/4209 UL http://hdl.handle.net/10017/4209 LA eng NO The authors acknowledge DGICYT (project PB97-0776) for financial support and J.S.N. acknowledges MEC for a fellowship. DS MINDS@UW RD 29-mar-2024