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

Reaction of DyCl 3 with two equivalents of NaN(SiMe 3 ) 2 in THF yielded {Dy(μ‐Cl)[N(SiMe 3 ) 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 Ln 3+ . Treatment of N , N ‐bis(pyrrolyl‐α‐methyl)‐ N ‐methylamine (H 2 dpma) with 1 and known compound {Yb(μ‐Cl)[N(SiMe 3 ) 2 ] 2 (THF)} 2 , respectively, led to the formations of [Dy(μ‐Cl)(dpma)(THF) 2 ] 2 ( 2 ) and {Yb(μ‐Cl)[N(SiMe 3 ) 2 ] 2 (THF)} 2 ( 3 ). Compounds 2 and 3 were fully characterized by single‐crystal X‐ray crystallography, elemental analysis, and 1 H NMR spectroscopy. Structure determination indicated that 2 and 3 exhibit as centrosymmetric dimers with asymmetrically bridging chloride ligands. One pot reactions involving Ln Cl 3 ( Ln = Dy and Yb), LiN(SiMe 3 ) 2 , and H 2 dpma were explored and desired products 2 and 3 were not yielded, which indicated that 1 and {Yb(μ‐Cl)[N(SiMe 3 ) 2 ] 2 (THF)} 2 are the demanding precursors to synthesize Dysprosium and Ytterbium complexes supported by dpma 2– ligand. Compounds 2 and 3 are the first reported lanthanide complexes chelated by dpma 2– ligand.