Zirconium and hafnium complexes with (allylsilyl)(η amidosilyl) η5 cyclopentadienyl ligands: synthesis, structure and reactivity

Is observed that the degree of contamination of the mixture influences for potentials of the three specimens contaminated with 2, 3 and 4% of NaCl are under -500 mV from the

To a solution of this diastereomeric mixture (31.19 mmol) in acetone at 273 K was added the O-Ethylxanthic acid potassium salt (46.78 mmol) and the reaction was stirred at

The turbid yellow supernatant was removed and the black solid was washed twice with 9 mL of acetone and twice with 9 mL of THF, isolating it by means of centrifugation for 5 min at

The reaction mixture was diluted with AcOEt (50 mL) and washed with water (3 × 50 mL), dried (Na 2 SO 4 ) and concentrated in vacuo and the crude mixture was purificated by

The organic layer was separated, dried with MgSO 4 , the solvent evaporated to dryness and the residue purified by column chromatography (SiO 2 : DCM). The solvent

The removal of the solvent under vacuum conditions afforded a crude product, which was purified with a flash chromatography column on silica gel (20 % t-BuOMe/hexanes) to yield 40 mg

After filtration of the drying agent, the solvent was removed under reduced pressure, and the residue purified by column chromatography on silica gel (eluent: heptane/ethyl

The crude mixture was concentrated under reduced pressure and the crude solid was purified by column chromatography on silica gel eluted with CHCl 3 /MeOH (10:1), affording 2.4 g