Synthesis and Solid-State Structures of Pyrazolylmethane Complexes of the Rare Earths

In this paper, we report the first examples of trispyrazolylmethane complexes of rare earths. Reaction of LnCl3 with
Tpm* (tris(3,5-dimethylpyrazolyl)methane) in THF or acetonitrile gives good yields of the [Ln(Tpm*)Cl3] (Ln = Y,
Ce, Nd, Sm, Gd, Yb). Tpm* adducts of the lanthanide triflates [Ln(Tpm*)(OTf)3(THF)] (Ln = Y, Ho, Dy) may also
be prepared. The X-ray crystal structures of [Y(Tpm*)Cl3], [Sm(Tpm*)Cl3(THF)], and [Ln(Tpm*)(OTf)3(THF)] (Ln =
Y, Ho) are reported. The halide/triflate complexes may be used to prepare the aryloxide complexes [Ln(Tpm*)(OArMe2)3] (Ln = Y, Nd, Sm, Yb; ArMe2 = C6H3-2,6-(CH3)2), which are fluxional in solution as a result of interactions
between the Tpm* and the aryloxide groups. The structures of the Nd and Sm complexes have been determined.
Finally, the reaction of [Nd(BH4)3(THF)3] with Tpm* in THF results in the displacement of two THF molecules to
give [Nd(Tpm*)(BH4)3(THF)]. Infrared spectra are consistent with tridentate borohydride coordination. The X-ray
structures of these compounds indicate that the Tpm* ligand is less strongly bound than its anionic trispyrazolylborate
analogues.

本研究首次报道了稀土元素的三吡唑甲烷（trispyrazolylmethane）配合物。将氯化稀土（LnCl₃）与Tpm*（三(3,5-二甲基吡唑基)甲烷）在四氢呋喃（THF）或乙腈中反应，可高产率得到[Ln(Tpm*)Cl₃]（其中Ln=钇(Y)、铈(Ce)、钕(Nd)、钐(Sm)、钆(Gd)、镱(Yb)）。此外，还可制备三氟甲磺酸盐（triflate）类稀土的Tpm*加合物[Ln(Tpm*)(OTf)₃(THF)]（Ln=Y、钬(Ho)、镝(Dy)）。本文报道了[Y(Tpm*)Cl₃]、[Sm(Tpm*)Cl₃(THF)]以及[Ln(Tpm*)(OTf)₃(THF)]（Ln=Y、Ho）的X射线晶体结构。该卤化物/三氟甲磺酸盐配合物可用于合成芳氧基配合物[Ln(Tpm*)(OArMe₂)₃]（Ln=Y、Nd、Sm、Yb；ArMe₂=C₆H₃-2,6-(CH₃)₂），这类配合物在溶液中呈现流变行为，其成因是Tpm*配体与芳氧基基团之间的相互作用。已测定了钕和钐配合物的晶体结构。最后，将[Nd(BH₄)₃(THF)₃]与Tpm*在四氢呋喃（THF）中反应，可置换出两个四氢呋喃分子，得到[Nd(Tpm*)(BH₄)₃(THF)]。红外光谱结果与三齿配位的硼氢化物（borohydride）配位模式相符。该类化合物的X射线晶体结构表明，Tpm*配体的配位强度弱于其阴离子型三吡唑硼烷类似物。