SYNTHESIS AND STUDIES OF THE Ln-N BOND INSERTION OF METHYLCYCLOPENTADIENYL LANTHANIDE PYRAZOLATES

摘要

Reaction of (C_5H_4Me)_3Ln with twoequivalents of 3,5-dimethylpyrazole (UpzMe_2) in THFat room temperature yielded complexesRC_5H_4Me)Ln(PZMe_2)_2]_2 [Ln = Sm (I), Tb (2)].Complexes (1) and (2) react with dimethylsiliconegrease to give the insertion products[(C_5R_4Me)Ln(PzMe_2)(OsiMe_2PzMe)]_2 [Ln = Sm (3), Tb(4)]. The results show that the dimethylsilanoneinsertion only occurs for the bridging Ln-N bond ofmethylcyclopentadienyllanthanide pyrazolates. Allcomplexes were characterized by elemental analyses, IRspectra and mass spectra. X-ray diffraction revealscomplex (4) to be a centrosymmetric dimer in which eachterbium atom is coordinated by onemethylcyclopentadienyl group, two bridging oxygenatoms and three nitrogen atoms, two from the chelatingPzMe_2 ligand and one from the bridgingdimethylpyrazolyl group to form a distorted octahedron.The average Tb-C and Tb-O distances are 2.700(4) and2.318(3)A, respectively. The Tb-N distances are2.331(4), 2.390(4) and 2.464(4) A.