The tris-boryl complex [(Me₃P)₃Co(Bcat)₃], obtained by oxidative addition of B₂cat₂ to [(Me₃P)₄Co-Me] via the mono-boryl complex [(Me₃P)₄Co-Bcat], exhibits unique structural and electronic properties. While it is formed in an equilibrium reaction (ΔG ≈ 0 kJ mol^–1) from the intermediate mono-boryl complex [(Me₃P)₄Co-Bcat], it is isolated in the solid state, depending on the temperature of crystallization, as the fac or mer isomer. Further studies reveal that the fac and the mer isomers of [(Me₃P)₃Co(Bcat)₃] are comparable in Gibbs energy and their interconversion is thermodynamically feasible. The mer isomer, comprising an unexpected trans B–Co–B motif, was further studied by means of an AIM analysis of the computed (DFT) and experimental electron densities, giving evidence for appreciable B···B interactions between two of the boryl ligands. The complex mer-[(Me₃P)₃Co(Bcat)₃], featuring three distinct boryl ligands, may, as a limiting case, be described as a diborane(4) complex of [(Me₃P)₃Co-Bcat]. DFT computations suggest that those B···B interactions are crucial for the stability of the trans B–Co–B complex mer-[(Me₃P)₃Co(Bcat)₃].

中文翻译：

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[（Me ₃ P）₃ Co（Bcat）₃ ]：B–B键的平衡氧化加成以及fac -Tris-Boryl和mer -Tris-Boryl配合物之间的相互转化

三-硼配合物[（ME ₃ P）₃的Co（BCAT）₃ ]，通过氧化添加B获得的₂猫₂至[（ME ₃ P）₄共同本人]通过单氧硼配合物[（ME ₃ P）₄ Co-Bcat]，具有独特的结构和电子性能。虽然它在平衡反应（Δ形成ģ ≈0千焦耳摩尔^-1从中间单氧硼配合物）[（ME ₃ P）₄共同BCAT]，它被隔离在固态，这取决于温度结晶，作为FAC或聚体异构体。进一步的研究表明，[（Me ₃ P）₃ Co（Bcat）₃ ]的fac和mer异构体在吉布斯能量上具有可比性，并且它们的相互转化在热力学上是可行的。通过计算（DFT）和实验电子密度的AIM分析，进一步研究了包括一个意外的反式B-Co-B基序的单体异构体，为两个硼基之间明显的B···B相互作用提供了证据。配体。复杂mer -[（Me ₃ P）₃ Co（Bcat）₃]，其特征在于三个不同的硼基配体，在限定情况下，可以描述为[（Me ₃ P）₃ Co-Bcat]的diborane（4）配合物。DFT计算表明，这些B···B相互作用对于反式B–Co–B复合体-[（Me ₃ P）₃ Co（Bcat）₃ ]的稳定性至关重要。