Study on Syntheses of Cationic Borane a Complexes and Heterolytic Cleavage of a Boron-Hydrogen Bond

New Borane复合体是由Borane-Lewis基地添加剂的协调而合成的，因为它们具有极低的P-接受能力，从而积极地充电金属中心。在复合体被发现的情况下，在中央金属和协调的BH氢原子之间的结合在一起，使其比中性硼复合体更稳定。Furthermore发现，通过与中央中心的协调和化学激活的硼配体极化， [Mn（CO）_4（PR_3）（η^1-BH_3·PMe_3）]^+ （1）和[Cp^*Mo（CO）_3（η ^1-BH_3·PMe_3）]^+ （2），受到相应的硼复合体的保护。一种稀土衍生物， [CpRu（PMe_3_）2（η^1-BH_3·PMe_3）]^+（3），由[CpRu（PMe_3）_2Cl]的氯基结构合成的不饱和物种的有机混合物制备。化合物1和2通过BH清除后将房间温度分离到金属中心，不如通过硼分离。这是一种新颖的反应类型，在一种BH债券上异质地激活了金属，这是一种难以分离的化合物1和2，因为他们的BH异分子清除迅速地进行。在对比之下，由于目前仍在使用富含电子的金属碎片，稀土复合体3是非常稳定的，因为它并不妨碍真空下的BH清除。这很可能是由于金属成分的富含电子的性质而使金属硼连接稳定在金属原子上，并由金属原子中的最适度极化的硼配体引起的。However，追踪水的存在促进了BH异质清除的3。

New borane complexes were synthesized by the coordination of borane-Lewis base adducts, which have extremely low p-accepting ability, to positively charged metal centers. In the complexes obtained, the bonding between the central metal and coordinated BH hydrogen atom has proved to be more stable than in the neutral borane complexes. Furthermore, it was found that the borane ligand was polarized through the coordination to the cationic center and thereby chemically activated.Cationic manganese and molybdenum borane complexes, [Mn(CO)_4(PR_3)(η^1-BH_3・PMe_3)]^+ (1) and [Cp^*Mo(CO)_3(η^1-BH_3・PMe_3)]^+ (2), were obtained by protonation of the corresponding boryl complexes. A ruthenium derivative, [CpRu(PMe_3_)2(η^1-BH_3・PMe_3)]^+(3), was prepared by the borane coordination to the coordinatively unsaturated species generated by the chloride abstruction of [CpRu(PMe_3)_2Cl].Compounds 1 and 2 decompose at room temperature through BH cleavage leaving a hydride onto the metal center, rather than through borane dissociation. This is a novel type of reaction, in which a BH bond is heterolytically activated on metal.It was difficult to isolate compounds 1 and 2 because their BH heterolytic cleavage rapidly proceeds. In contrast, by the use of the cationic yet inherently electron-rich metal fragment, the ruthenium complex 3 has been very stable that it has not undergone the BH cleavage under vacuum. This is probably due to the metal-borane linkage stabilized by the positive charge on the metal atom and modest polarization of the borane ligand caused by the electron-rich nature of the metal fragment. However, the presence of trace water promoted the BH heterolytic cleavage of 3.