Synthesis and Molecular Structures of Hydrotris(dimethylpyrazolyl)borate Complexes of the Lanthanides

• Published in: Inorganic chemistry Vol. 35; no. 1; pp. 76 - 81
• Main Authors: Liu, Sung-Ying, Maunder, Graham H, Sella, Andrea, Stevenson, Maya, Tocher, Derek A
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 03.01.1996
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic941469w

The reaction of lanthanide triflates with 2 equiv of potassium hydrotris(dimethylpyrazolyl)borate (TpMe2 ) gives good yields of complexes of composition Ln(TpMe2 )2OTf. For La (2), Ce (3), Pr (4), and Nd (5) the complexes are seven-coordinate in the solid state with the triflate group coordinated to the metal in unidentate fashion. Complex 5 crystallizes in the monoclinic space group P21/c with a = 17.629(3) Å, b = 12.740(2) Å, c = 18.163(3) Å, β = 107.35(1)°, V = 3893(1) Å3, Z = 4, and R w = 0.0458. For the complexes of Y (1), Sm (6), Eu (7), Gd (8), Dy (9), Ho (10), and Yb (11), the smaller size of the metal ion leads to ejection of the triflate from the coordination sphere and the complexes are ionic in the solid state with a six-coordinate metal center. Complex 11 crystallizes in the monoclinic space group C2/m with a = 16.593(7) Å, b = 13.671(5) Å, c = 8.746(2) Å, β = 91.66(3)°, V = 1983(1) Å3, Z = 2, and R w = 0.0416. In solution, however, complex 6 adopts a seven-coordinate molecular structure with the triflate ion within the first coordination sphere.