Lanthanide anilido complexes stabilized by the 2,6-diisopropylanilido ligand have been synthesized and characterized, and their catalytic activity for hydrophosphonylation reaction was explored. A reaction of anhydrous LnCl3 with 5 equivalents of LiNHPh-iPr2-2,6 in THF generated the heterobimetallic lanthanide–lithium anilido complexes (2,6-iPr2PhNH)5LnLi2(THF)2 [Ln = Sm(1), Nd(2), Y(3)] in good isolated yields. These complexes are well characterized by elemental analysis, IR, NMR (for complex 3) and single-crystal structure determination. Complexes 1–3 are isostructural. In these complexes, the lanthanide metal ion is five-coordinated by five nitrogen atoms from five 2,6-diisopropylanilido ligands to form a distorted trigonal bipyramidal geometry. The lithium ion is coordinated by two nitrogen atoms from two 2,6-diisopropylanilido ligands, and one oxygen atom from a THF molecule. It was found that these simple lanthanide anilido complexes are highly efficient for catalyzing hydrophosphonylation reactions of various aldehydes and unactivated ketones to generate α-hydroxyphosphonates in good to excellent yields (up to 99%) within a short time (5 min for aldehydes, 20 min for ketones). Furthermore, the mechanism of hydrophosphonylation reactions has also been elucidated via1H NMR monitoring of reaction.
稳定的
2,6-二异丙基苯胺配体的
镧系
金属
苯胺复合物已被合成和表征,并探讨了其在
磷化氢化反应中的催化活性。无
水LnCl3与5个等摩尔的LiNHPh-iPr2-2,6在THF中的反应生成了异质双
金属
镧系-
锂苯胺复合物(2,6-iPr2PhNH)5LnLi2(THF)2 [Ln = Sm(1), Nd(2), Y(3)],收率良好。这些复合物通过元素分析、红外光谱、核磁共振(对于复合物3)和单晶结构测定进行了良好的表征。复合物1-3是同构的。在这些复合物中,
镧系
金属离子由来自五个
2,6-二异丙基苯胺配体的五个氮原子协调,形成四面体畸变的三角双锥几何结构。
锂离子则由两个
2,6-二异丙基苯胺配体中的两个氮原子和一个THF分子中的氧原子协调。研究发现,这些简单的
镧系
苯胺复合物在催化各种醛和未活化酮的
磷化氢化反应中具有高效率,能够在短时间内(醛为5分钟,酮为20分钟)生成α-羟基
磷酸酯,收率良好至优异(高达99%)。此外,
磷化氢化反应的机制也通过氢核磁共振监测反应得到了阐明。