583050-39-9Relevant articles and documents
Synthesis and reactivity of hydridotris(1-pyrazolyl)borate tungsten(VI) amido alkylidyne complexes
Doufou, Percy,Abboud, Khalil A.,Boncella, James M.
, p. 103 - 112 (2003)
The synthesis of a series of tungsten(VI) amido alkylidyne complexes containing the chelating ligands Tp (hydridotris(1-pyrazolyl)borate) and Tp′ (hydridotris(3,5-dimethyl-1-pyrazolyl)borate) is described. Complexes of general formula, TpW(CC(CH3)3)(Cl)(NHR) [R=C6H5, 4-Br-C6H4, 3,5-(CF3)2C6H3, H], (3-6), were formed by reaction of TpW(CC(CH3)3)(Cl)2 with the appropriate amide [M][NHR] (M=Li, K). In presence of excess [Li][NHPh], TpW(CC(CH3)3)(NHPh)2 (7) was isolated. Sub-stoichiometric quantities of H2O or HCl were found to catalyze the tautomerization of 3 to the corresponding imido alkylidene. Reaction of excess H2O with 3 produced significant amounts of TpW(O)(CHC(CH3)3)(Cl) (10) and TpW(O)(CC(CH3)3)(Cl) (11) along with tautomerization. Attempted acid catalyzed tautomerizations of 4 and 5 with HCl resulted in loss of the amido ligands and recovery of TpW(CC(CH3)3)(Cl)2. The complex Tp′W(CC(CH3)3)(Cl)(NHPh) (8), was synthesized by reaction of (CH3)3SiN(H)Ph with (DME)W(CC(CH3)3)(Cl)3 followed by addition of KTp′. X-ray crystal structures have been obtained for compounds 7 and 8 and show that the amido groups are syn with respect to the neopentylidyne ligand probably due to the steric demands of the chelating Tp and Tp′ ligands.
