BH, CH, and BC Bond Activation: The Role of Two Adjacent Agostic Interactions

Abstract

Tuning the nature of the linker in a L~BHR phosphinoborane compound led to the isolation of a ruthenium complex stabilized by two adjacent, δ-C-H and ε-B(sp2)-H, agostic interactions. Such a unique coordination mode stabilizes a 14-electron "RuH2P2" fragment through connected σ-bonds of different polarity, and affords selective B-H, C-H, and B-C bond activation as illustrated by reactivity studies with H2 and boranes.

The Catalytic Dehydrocoupling of Amine–Boranes and Phosphine–Boranes

“…Sabo-Etienne and Alcaraz have recently reported an unusual aminoborane complex exhibiting adjacent agostic B-H and C-H interactions (Fig. 6) [85]. The isolation of aminoborane complexes is of interest mechanistically, as aminoboranes bound to the metal centre have been implicated in dehydrocoupling mechanisms, although often not observed directly (vide infra) [12,70,86].…”

Reversible carbon–boron bond formation at platinum centers through σ-BH complexes

“… 6 In addition, examples of transition metal σ-borane alkyl complexes [M(R)(HBR 2 )] are extremely rare, and those that have been isolated did not show further reactivity involving the formation of carbon–boron bonds. 7 Isolation of this type of compounds might offer an invaluable opportunity for determining the factors that can lead to competitive carbon–boron or carbon–hydrogen coupling products.…”

Mercapto-benzothiazolyl based ruthenium(ii) borate complexes: synthesis and reactivity towards various phosphines

“…However, they are considerably longer than the Ru-B distance 23 as well as in ruthenaborane clusters. 24 The two S,B,S-donor sets in 3 are aligned in fac-arrangements that minimizes the steric repulsion between them.…”