Synthesis, Characterization, and Computational Studies of 6-(RR'N)-nido-5,7-C_2B_8H_(11): A Polyborane Cluster with a Cage-Boron Having an Exopolyhedral Dative Boron-Nitrogen Double Bond

摘要

The reactions of the arachno-4,6-C_2B_7H_(13) carborane with the secondary and primary amines, Me_2NHBH_3 and ~tBuNH_2BH_3, in ionic liquid media result in both boron-insertion into the cage at a position across the two cage-carbons and additional hydrogen-elimination via the reaction of a hydridic B-H with a protonic amine N-H hydrogen to produce the 6-(RR'N)-nido-5,7-C_2B_8H_(11) carboranes. Computational characterizations of these compounds and the previously reported 6-CIC_6H_4-9-(RR'N)-nido-6-NB_9H_(10) azaboranes indicate that the amine-nitrogens form unique exopolyhedral dative B=N double bonds with a cage-boron.