[{Br2B(η5-C5H4)}Mn(CO)3] – A versatile Precursor for Boron-based Ligands

A range of potential boron-based ligand precursors has been synthesized starting from [{Br2B(eta(5)-C5H4)}Mn(CO)(3)] (1) Via salt elimination reactions. These comprise ligand precursors suitable for the preparation of i) ansa-metallocenes such as [CymB(eta(1)-C5H5)(2)] (2), [CyrnB(1-C9H7)(2)] (3a), and [CymB(3C(9)H(7))(2)] (3b), ii) constrained geometry complexes such as [CymB(Br)N(H)tBu] (5) as well as iii) ansa-diamido complexes such as [CymB{N(H)Ph}(2)](4) and [CymB{N(H)tBu)(2)](6) (Cym =cyrnantrenyl, C5H5 = cyclopentadienyl, C9H7 = indenyl). Furthermore, we present the hydrolysis of 1, leading to the three-fold cymantrenyl-substituted boroxine [(OB(eta(5)-C5H4)}Mn(CO)(3)](3) (7). All new compounds have been characterized by multinuclear NMR spectroscopic techniques and in the case of 1 and 7 by X-ray diffraction analyses.