Reactivity of the bridged borylene complex [μ-BCl{η5-C5H4Me)Mn(CO)2}2]

The reactivity of the bridged chloro borylene complex [μ-BCl{(η5-C5H4Me)Mn(CO)2}2] (2a) towards various protic reagents was studied. Reaction of 2a with isopropanol yielded the alkoxy borylene complex [μ-BOiPr{(η5-C5H4Me)Mn(CO)2}2] (3d) in very high yield. A further series of protic reagents HX (X=HS−, BF4−, Co(CO)4−) gave, in the presence of pyridine, the new amino borylene complex [1-(μ-B)-4-H-(NC5H5){(C5H4Me)Mn(CO)2}2] (5a), which represents the product of an unprecedented 1,4-hydroboration of pyridine. Complex 5a was fully characterised in solution by multinuclear NMR studies, in the solid state by X-ray diffraction, and was also subject to DFT-studies.