Unfairly Forgotten Member of the Iodocarborane Family: Synthesis and Structural Characterization of 8-Iodo-1,2-dicarba-<i>closo</i>-dodecaborane, Its Precursors, and Derivatives.

8-Iodo-1,2-dicarba-<i>closo</i>-dodecaborane (<b>7</b>) was prepared in three steps starting from decaborane-14 with 20% overall yield. In the presence of nucleophiles, compound <b>7</b> undergoes selective removal of the boron vertex in the position para to the iodine substituent to form the anionic <i>nido</i>-carborane 1-iodo-7,8-dicarba-<i>nido</i>-undecaborate. Capping of the corresponding dicarbollide dianion with BI₃ led to formation of the new carborane, 3,10-diiodo-1,2-dicarba-<i>closo</i>-dodecaborane (<b>15</b>). The same dicarbollide dianion reacts with cobalt and nickel acetylacetonates in anhydrous tetrahydrofuran to form the corresponding bis­(dicarbollide) complexes with excellent yields. All compounds were characterized by multinuclear NMR and high-resolution mass spectroscopy. Structures of 2-iododecaborane (<b>2</b>), 8-iodo-1,2-dicarba-<i>closo</i>-dodecaborane (<b>7</b>), 1-ethoxycarbonyl-8-iodo-1,2-dicarba-<i>closo</i>-dodecaborane (<b>10</b>), cesium 1-iodo-7,8-dicarba-<i>nido</i>-undecaborate (<b>13</b>), 3,10-diiodo-1,2-dicarba-<i>closo</i>-dodecaborane (<b>15</b>), and cesium 3,3′-<i>commo</i>-(10-iodo-1,2-dicarba-3-cobalta-<i>closo</i>-dodecaborane)-(10′-iodo-1′,2′-dicarba-3′-cobalta-<i>closo</i>-dodecaborane) (<b>16</b>) were established by X-ray analysis of single crystals