Cyclopentadienyl-diethylcarbamato derivatives of zirconium(IV) and hafnium(IV), [M(C5H5)(O2CNEt2)3]:: synthesis and use as precursors for chemical implantation on a silica surface

Reaction of Mg(C5H5)(2) with the homoleptic diethylcarbamato derivatives of zirconium(rv) or hafnium(Iv), M(O2CNEt2)(4), gave the mixed cyclopentadienyl-diethylcarbamato complexes [M(C5H5)(O2CNEt2)(3)]. These derivatives have also been obtained by reaction of Fe(O2CNEt2)(2) with M(C5H5)(4) in the appropriate stoichiometric ratio. The compound [Zr(C5H5)(O2CNEt2)(3)] crystallizes in the space group P (1) over bar, Z = 2, a = 9.734(4), b = 10.234(2), c = 12.948(6) Angstrom; alpha = 83.41(4), beta = 86.13(4) and gamma = 67.43(3)degrees. On reaction of [Zr(C5H5)(O2CNEt2)(3)] with dehydrated silica, 1 mol of CO2 per zirconium was evolved. The organometallic fragment Zr(C5H5)(O2CNEt2)(2) grafted on silica has been characterized by analytical methods and by CP MAS C-13 NMR spectroscopy.