Insertion of dimethylsilanone into a Ln-N bond and X-ray crystal structure of the insertion product [MeCpDy(η2-PzMe2)(μ-η1:η2-OSiMe2PzMe2)]

Reaction of MeCp 3 Ln(MeCp = COLLABCH 3 C 5 H 4 , Ln = Nd, Gd, Dy) with two equivalents of HPzMe 2 (HPzMe 2 = 3,5-dimethylpyrazole) in THF at room temperature yielded complexes [MeCpLn(PzMe 2 ) 2 ] [Ln-Nd( 1 ), Gd( 2 ), Dy( 3 )], which have been characterized by elemental analysis, IR and MS spectra. The new complexes react with dimethylsilicone grease to give the dimethylsilanone insertion products: [MeCpLn( η 2 -PzMe 2 )( μ-η 1 : η 2 -OSiMe 2 PzMe 2 )] 2 [Nd( 4 ), Gd( 5 ), Dy( 6 )]. The complex 6 has been structurally characterized by X-ray crystallography. 6 crystallizes in the space group P 2 1 / n with unit cell dimensions a =12.066(5), b =11.601(2), c =15.307(3) A, β = 105.84(3)°, V = 2061(1) A 3 , and Z =2 for D Caled =1.63 g cm −3 . Least-squares refinement on the basis of 2930 observed reflections were allowed to reach a final R value of 0.031. The molecule is centrosymmetric dimer in which each dysprosium is coordinated by one methylcyclopentadienyl group, two bridging oxygens, two nitrogens of the chelating PzMe 2 ligand and one nitrogen atom of the bridging PzMe 2 ligand to form a distorted octahedron. The Dy-N(bridging) and Si-N bond lengths are 2.454(5) and 1.803(5) A, respectively. The average Dy-C(ring), Dy-0 and Dy-N(chelating) distances are 2.684(16), 2.294(10), and 2.344(25) A, respectively.