Side-on coordination mode of a pyrazolyl group in the structure of a divalent [Sm{B(3-Mepz)4}2] complex (3-Mepz is 3-methylpyrazol-1-yl).
The discovery of polypyrazolylborate ligands allowed the development of various chemical fields and these ligands are an alternative to cyclopentadienyl, because both ligands have the same charge and donate the same number of electrons, as well as adopting the same facial geometry. Easy control of the bulkiness of polypyrazolylborate ligands is possible by modification of the substituents in the 3- and 5-positions of the pyrazolyl rings. The title complex, bis[tetrakis(3-methyl-1H-pyrazol-1-yl)borato]samarium(II), [Sm(C16H20BN8)2], was synthesized from the reaction of SmI2with potassium tetrakis(3-methyl-1H-pyrazol-1-yl)borate, denoted K[B(3-Mepz)4], in tetrahydrofuran. The X-ray structure analysis revealed an unusual side-on coordination mode of a 3-methylpyrazolyl group through an N=N group in the B(3-Mepz)4ligand. The distortion is defined by the B-N-N-Sm torsion angle [85.5 (4)°]. This is in contrast to the structure of the similar divalent samarium complex [Sm(TpMe2is tris(3,5-dimethylpyrazol-1-yl)borate], which displays normal κ3-bonding modes of the TpMe2ligands.
Division of Chemistry and Materials Science, Graduate School of Engineering, Nagasaki University, Bunkyo-machi 1-14, Nagasaki 852-8521, Japan.
Yasuhiro
Y
Arikawa
Graduate School of Science and Technology, Nagasaki University, Bunkyo-machi 1-14, Nagasaki 852-8521, Japan.
Kei Ichiro
KI
Inada
Department of Applied Chemistry, Faculty of Engineering, Nagasaki University, Bunkyo-machi 1-14, Nagasaki 852-8521, Japan.
Masayoshi
M
Onishi
crystal structure; divalent; samarium; scorpionate; side-on interaction; tetrakis(3-methylpyrazolyl)borate