Borylene semi-bridging

The reactivity of the aminoborylene complexes 1 and 2 under thermal conditions leads to the formation of semi-bridged borylene or bis-borylene complexes (vide infra). The photochemical transfer of the borylene ligand is useful for the preparation of borirenes [23], turned out to be an alternative for the synthesis of 1, and was also used for the synthesis of the first half-sandwich borylene complex [(775-C5H5)(OC)3V=B=N(SiMe3)2] (5) [24] (Scheme 4). In the crystal, the borylene ligand adopts the expected linear geometry (V-B-N 177.9(4)°) and the B-N bond (137.8(7) pm) is... 

Scheme 20 Synthesis of the semi-bridging borylene complexes 48 and 49...

Until very recently, the formation of the semi-bridging borylene compounds 48 and 49 represented the only instance of clean thermal, i.e., non-photolytic, reactivity of the terminal borylene complexes 1 and 2. Interestingly, however, an unprecedented metal-to-metal borylene transfer occurred from [(OC)5M=BN(SiMe3)2] (M = Cr, 1 M = W, 2) to [RhCl(CO)2]2 at room temperature, yielding the tetranuclear bis(borylene) complex [Rh4 /x-BN(SiMe3)2 2Cl4(/x-CO)(CO)4] (50) (Scheme 21) [74]. 

Synthesis and Reactivity of Semi-bridging Borylene Complexes [79] ... 

Synthesis and Characterization of Semi-Bridging Molybdenum Borylene Complexes [87] ... 

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