Synthesis and reactivity of Ta(III) halide γ-picoline adducts. Formation of Ta(IV) β-diketonate and carboxylate, and Ta(III) alkoxide

Abstract

Molecular tantalum(III) adducts Ta 2X 6(γ-pic) 4 (X = Ci or Br) have been obtained in high yields by reducing Ta 2X 10 by magnesium in the presence of the ligand. Preliminary results of their reactivity are given. Ta(IV) β-diketonates or carboxylates, Ta 2CI 4(dpm) 4 and Ta 2CI 4( tBuCO) 2 4), 2 tBuCo 2H or oxo derivatives were obtained by treating Ta 2CI 6- (γ-pic) 4 with the weak protonic acids: dipivaloylmethane (dpmH), pivalic acid and acetic respectively. Reactions between Ta 2Cl 6(γ-pic) 4 and LiO tBu led to the formation of the tantalum(III) alkoxide Ta 2CI 2(O tBu) 4. All new derivatives, which are diamagnetic, were characterized by elemental analysis, IR and 1H NMR spectroscopy.