Borabenzene, sandwich complexes

On treatment with T1C1, alkali metal boratabenzenes afford the corresponding T1 compounds (51). The lower reactivity of these can be essential for some syntheses. Some of the rare cationic borabenzene complexes 35-37 could be made using thallium boratabenzenes as reagents. Similarly, (C4Me4)Co(CO)2I yielded the mixed sandwich complexes 38 and 39 in excellent yields (71). 

One of the most intensely studied boracychc compound is the borabenzene ligand synthesized by Her-berich and coworkers. Bis- and monoborabenzene cobalt sandwich complexes were first obtained by treating cobaltocene with boron trihalides BX3 (R = Cl, Br) or alkyl/arylboron dihalides (R = alkyl, aryl) as outlined in... 

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