名称:
Benzophenone complexes of the lanthanides: Synthesis of [Ln{N(SiMe3)2}3(Ph2CO)] (L = La, Eu, Tb, Yb or Y) and X-ray crystal structure of the terbium complex
摘要:
The four coordinate complexes [LnL3(Ph2CO)] [Ln = La, Eu, Tb, Yb or Y; L = N(SiMe3)2] have been prepared by reaction of [LnL3] with one equivalent of Ph2 CO. The crystal and molecular structure of [TbL3(Ph2CO)] have been determined by X-ray diffraction [monoclinic P2(1)/n; a = 11.738(4), b = 31.425(4), c = 12.729(2) angstrom; beta = 110.16(3)-degrees; Z = 4; R = 0.0437 for 5276 unique reflections]. The complex has a distorted tetrahedral arrangement of ligand atoms around terbium, and Ph2CO is coordinated through oxygen. Spectroscopic (H-1 NMR, C-13 NMR, IR and UV-vis) and analytical data are consistent with this structure for Ln = La, Eu, Yb or Y. Variable temperature H-1 NMR studies of [EuL3(Ph2CO)] show that rotation about the Eu-N bonds is frozen out at 203 K, but there is still rapid rotation about the Eu-O bond at 180 K.