| Reaction of 3-pentanone with 1 equiv of pyrrole in anhydrous ethanol yielded (C4H2NH)4(CEt2)4 (1) in 42.7% yield. Treatment of [(Me3Si)2N]3Ln(μ-Cl)Li(THF)3 (Ln = Sm, Nd, Gd) with 1/2 equiv of 1 in toluene under refluxing for 48 hours, after recrystallization from hexane, gave novel nine coordinate and dinuclear rare-earth metal complexes [η5:η1:η5:η1-Et8(C4H2N)4]{Sm[N(SiMe3)2]}2 (2) in 52% yield; [η5:η1:η5:η1-Et8(C4H2N)4]{Nd[N(SiMe3)2]}2 (3) in 57% yield; [η5:η1:η5:η1-Et8(C4H2N)4]{Gd[N(SiMe3)2]}2 (4) in 53% yield, respectively. All the complexes were fully characterized by elemental and spectroscopic analyses. The structures of complexes 2, 3, 4 were determined by X-ray diffraction.At the same time, We have studied the catalytic activity of the above organolanthanide complexes as hydrophosphonylation of acetophenone catalysts. The results showed that all organolanthanide complexes exhibited high catalytic activity and selectivity on hydrophosphonylation of acetophenone. Moreover, the temperature, time, solvents, and catalyst loading affected the catalytic activities of the reactions. All the above-mentioned conditions are optimized and we put forward possible catalytic mechanisms. |
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