Borylene bridging

Complexes with Carbene/Borylene Bridging Ligands... 

Fig. 4. Structure of selected bridged borylene complexes in the crystal.

Boron compounds, subvalent, 193-194 Boron-containing compounds, See also Diboron compounds Boryl complexes, 165 Borylene complexes bridged, 166-176 molecular structure data, 172 reactivity, 170-171 spectroscopic and structural aspects, 172-176... 

Already in 1995 we obtained the first bridged borylene complexes 11a, d from the unusual reaction of l,2-dihalodiboranes(4) with K[CpMn(CO)2H] (Equation 3). Although this synthesis was recently extended to further examples lib, c and also to the rhenium analogue lie we aimed at a more general access to this interesting class of compounds. 

The preparation and characterization of the first bridged borylene compounds was described in 1995 by Braunschweig. The compounds obtained were [/t-B(NMe2) (Y CsHs)Mn(CO)2 2] 21, [/t-B(NMe2) (Y ... 

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... 

The bridging borylene complexes (V, VI) are of some special relevance since they represent the first structurally authentic examples for the stabilization of the borylene ligand -BR in the coordination sphere of a transition metal. Species where the borylene unit adopts a bridging position between two metals represent the most numerous and well-studied class of these compounds. 

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