Creation of Substitution Labile Pyrazolylborate Metal Complexes

(1)制备了双[二氢双（3,5-二（三氟甲基）吡唑基）硼酸盐]钴，并通过X射线晶体学分析确定了其结构。钴中心与四个吡唑基以正方形规划方式配位，在轴向位置与两个B-H基配位，形成完全扭曲的八面体构型。这与已知的非取代和3,5 -二甲基取代吡唑硼酸酯衍生物形成鲜明对比，它们以四面体结构出现，类似的镍配合物具有B-H-M相互作用。(2)制备了双（三苯基膦）[二氢双（3,5- r_2 -吡唑基）硼酸盐]钌氢化物（R=H, Me, CF_3），并用X射线晶体学对其结构进行了表征。根据与CO的反应性，估算出有机相互作用的强度按Me> H * CF_3的顺序递减。(3)制备了双（三苯基膦）[二氢双（3,5 - r_2 -吡唑基）硼酸盐]铑配合物（R=H, Me, CF_3），并通过X射线晶体学分析对其结构进行了表征。铑的中心以方形规划的方式与四个吡唑基协调。在这些配合物中没有观察到B-H-Rh的相互作用。(4)制备了eta^3-烯丙基和茚基[氢化（3,5- r_2 -吡唑基）硼酸盐]钯配合物（R=H, Me, CF_3），并通过X射线晶体学分析对其结构进行了表征。用核磁共振波谱法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.