Dinuclear Dysprosium and Ytterbium Complexes Incorporating N,N‐Bis(pyrrolyl‐α‐methyl)‐N‐methylamine Ligand: Syntheses and Structures

Reaction of DyCl3 with two equivalents of NaN(SiMe3)2 in THF yielded {Dy(μ-Cl)[N(SiMe3)2]2(THF)}2 (1). X-ray crystal structure analysis revealed that 1 is a centrosymmetric dimer with asymmetrically bridging chloride ligands. The metal coordination arrangement can be best described as distorted trigonal bipyramid. The bond lengths of Ln–Cl and Ln–N showed a decreasing trend with the contraction of the size of Ln3+. Treatment of N,N-bis(pyrrolyl-α-methyl)-N-methylamine (H2dpma) with 1 and known compound {Yb(μ-Cl)[N(SiMe3)2]2(THF)}2, respectively, led to the formations of [Dy(μ-Cl)(dpma)(THF)2]2 (2) and {Yb(μ-Cl)[N(SiMe3)2]2(THF)}2 (3). Compounds 2 and 3 were fully characterized by single-crystal X-ray crystallography, elemental analysis, and 1H NMR spectroscopy. Structure determination indicated that 2 and 3 exhibit as centrosymmetric dimers with asymmetrically bridging chloride ligands. One pot reactions involving LnCl3 (Ln = Dy and Yb), LiN(SiMe3)2, and H2dpma were explored and desired products 2 and 3 were not yielded, which indicated that 1 and {Yb(μ-Cl)[N(SiMe3)2]2(THF)}2 are the demanding precursors to synthesize Dysprosium and Ytterbium complexes supported by dpma2– ligand. Compounds 2 and 3 are the first reported lanthanide complexes chelated by dpma2– ligand.