Popis: |
Four new unsolvated lanthanide bis(alkynylamidinato) amide complexes [c-C3H5–C C–C(NR)2]2LnN(SiMe3)2 (2: Ln = Ce, R = iPr; 3: Ln = Ce, R = Cy; 4: Ln = Nd, R = Cy; 5: Ln = Ho, R = Cy) have been prepared in moderate to good isolated yields (37–67%) via three-component reactions between anhydrous LnCl3 (Ln = Ce, Nd, Ho), Li[c-C3H5–C C–C(NR)2]- (1a: R = iPr, 1b: R = Cy) and KN(SiMe3)2 in a 1:2:1 M ratio in THF. The same compounds were also accessible by amination of the previously reported lanthanide bis(amidinate) chloro precursors [c-C3H5–C C–C(NR)2]2Ln(μ-Cl)2] and [c-C3H5–C C–C(NR)2]2Ho(μ-Cl)2Li(THF)(Et2O) with KN(SiMe3)2. However, this synthetic protocol gave significantly lower yields of 2–5 (17–42%). The molecular structures of 4 and 5 have been authenticated through single-crystal X-ray diffraction. An initial catalytic study showed that the new complexes cannot be reliably employed as precatalysts for hydroamination/cyclization reactions. |