A Novel Coordination Mode of 7-Methyl-7-sila-nido-undecaborate(1-).

B-N-M bridges, resulting from the activation of two B,H units, are present in the anion [Nb(MeSiB(10)H(8))(µ-NMe(2))(2)Br(3)](-) (see structure depicted). Thus, this is an example for a hitherto unknown coordination mode in the chemistry of heteroborane clusters.