Probing the Intrinisic Structure and Dynamics of Aminoborane Coordination at Late Transition Metal Centers: Mono(σ-BH) Binding in [CpRu(PR3)2(H2BNCy2)]+

Aminoboranes, H2BNRR′, represent the monomeric building blocks from which novel polymeric materials can be constructed via metal-mediated processes. The fundamental capabilities of these compounds to interact with metal centers have been probed through the coordination of H2BNCy2 at 16-electron [CpRu(PR3)2]+ fragments. In contrast to the side-on binding of isoelectronic alkene donors, an alternative mono(σ-BH) mode of aminoborane ligation is established for H2BNCy2, with binding energies only ∼8 kcal mol–1 greater than those for analogous dinitrogen complexes. Variations in ground-state structure and exchange dynamics as a function of the phosphine ancillary ligand set are consistent with chemically significant back-bonding into an orbital of B–H σ* character.氨基硼烷（Aminoboranes，通式为H2BNRR′）是一类单体结构单元，可通过金属介导过程构建新型聚合材料。此前，科研人员通过将H2BNCy2与16电子[CpRu(PR3)2]+片段配位，对这类化合物与金属中心相互作用的基本能力进行了探究。与等电子烯烃给体的侧基结合模式不同，H2BNCy2采取了独特的单(σ-BH)配位模式，其结合能仅比同类二氮配合物的结合能高约8 kcal mol–1。基态结构与交换动力学随膦辅助配体体系的变化规律，与发生在B-H σ*轨道上的显著化学反馈成键作用相一致。