Creation of Substitution Labile Pyrazolylborate Metal Complexes

(1)制备了Bis[dihydrobis(3，5-bis(trifluoromethyl)pyrazolyl)borate]cobalt，并用X-射线单晶分析确定了其结构。钴中心以方形平面的方式配位到四个吡唑基，并在轴向位置与两个B-H基团配位，形成完全扭曲的八面体构型。这与已知的未取代和3，5-二甲基取代的吡唑基硼酸盐衍生物形成了鲜明的对比。(2)合成了Bis(triphenylphosphine)[dihydrobis(3，5-R_2-pyrazolyl)borate]ruthenium氢化物(R=H，Me，Cf_3)，并用X-射线单晶衍射法确定了它们的结构。根据与CO的反应活性，估算了相互作用强度的大小顺序为：Me&Gt；H*Cf_3。(3)合成了双(三苯基膦)[二氢双(3，5-R_2-吡唑基)硼酸盐]Rh配合物(R=H，Me，CF_3)，并通过X-射线晶体分析确定了其结构。四个吡唑基以方形平面图的方式配位于Rg中心。(4)合成了Eta、3-烯丙基和indenyl[hydrotris(3，5-R_2-pyrazolyl)borate]palladium(R=H，Me，Cf_3)配合物，并用X-射线单晶分析确定了它们的结构。用核磁共振波谱研究了它们在溶液中的流动行为。

(1) Bis[dihydrobis(3,5-bis(trifluoromethyl)pyrazolyl)borate]cobalt was prepared and the structure was determined by X ray crystallographic analysis. The cobalt center is coordinated to four pyrazolyl groups in a square planner manner and to two B-H groups at the axial positions forming totally a distorted octahedral configuration. This is in marked contrast to those of known non-substituted and 3, 5-dimethyl substituted pyrazolylborate derivatives which appear inn a tetrahedral configuration Similar nickel complex having a B-H-M agostic interaction was prepared.(2) Bis(triphenylphosphine)[dihydrobis(3,5-R_2-pyrazolyl)borate]ruthenium hydrides (R=H, Me, CF_3) were prepared and the structures containing a B-H-Ru agostic interaction were determined by X ray crystallography. Based on the reactivity with CO, strength of the agostic interaction was estimated to decrease in the order, Me> H * CF_3.(3) Bis(triphenylphosphine)[dihydrobis(3, 5-R_2-pyrazolyl)borate]rhodium complexes (R=H, Me, CF_3) were prepared and the structures were determined by X ray crystallographic analysis. The rhodium centers are coordinated in a square planner manner to the four pyrazolyl groups. No B-H-Rh agostic interactions were observed in these complexes.(4) eta^3-Allyl and indenyl[hydrotris(3,5-R_2-pyrazolyl)borate]palladium complexes (R=H, Me, CF_3) were prepared and the structures were determined by X ray crystallographic analysis. Their fluxional behavior in solution were studied by NMR spectroscopy.