Reactions of 11-Vertex Rhodathiaboranes with HCl: Synthesis and Reactivity of New Cl-Ligated Clusters CalvoBeatriz MacíasRamón ArtigasMaria Jose LahozFernando J. OroLuis A. 2013 Reactions of [8,8,8-(H)­(PPh<sub>3</sub>)<sub>2</sub>-9-(Py)-<i>nido</i>-8,7-RhSB<sub>9</sub>H<sub>9</sub>] (<b>1</b>), [1,1-(PPh<sub>3</sub>)<sub>2</sub>-3-(Py)-<i>closo</i>-1,2-RhSB<sub>9</sub>H<sub>8</sub>] (<b>2</b>), and [1,1-(CO)­(PPh<sub>3</sub>)-3-(Py)-<i>closo</i>-1,2-RhSB<sub>9</sub>H<sub>8</sub>] (<b>4</b>), where Py = Pyridine, with HCl to give the Cl-ligated clusters, [8,8-(Cl)­(PPh<sub>3</sub>)-9-(Py)-<i>nido</i>-8,7-RhSB<sub>9</sub>H<sub>9</sub>] (<b>3</b>) and [8,8,8-(Cl)­(CO)­(PPh<sub>3</sub>)-9-(Py)-<i>nido</i>-8,7-RhSB<sub>9</sub>H<sub>8</sub>] (<b>5</b>), have recently demonstrated the remarkable <i>nido</i>-to-<i>closo</i> redox flexibility and bifunctional character of this class of 11-vertex rhodathiaboranes. To get a sense of the scope of this chemistry, we report here the reactions of PR<sub>3</sub>-ligated analogues, [8,8,8-(H)­(PR<sub>3</sub>)<sub>2</sub>-9-(Py)-<i>nido</i>-8,7-RhSB<sub>9</sub>H<sub>9</sub>], where PR<sub>3</sub> = PMePh<sub>2</sub> (<b>6</b>), or PPh<sub>3</sub> and PMe<sub>3</sub> (<b>7</b>); and [1,1-(PR<sub>3</sub>)<sub>2</sub>-3-(Py)-<i>closo</i>-1,2-RhSB<sub>9</sub>H<sub>8</sub>], where PR<sub>3</sub> = PPh<sub>3</sub> and PMe<sub>3</sub> (<b>8</b>), PMe<sub>3</sub> (<b>9</b>) or PMe<sub>2</sub>Ph (<b>10</b>), with HCl to give Cl-ligated clusters. The results demonstrate that in contrast to the PPh<sub>3</sub>-ligated compounds, <b>1</b>, <b>2</b>, and <b>3</b>, the reactions with <b>6</b>–<b>10</b> are less selective, giving rise to the formation of mixtures that contain monophosphine species, [8,8-(Cl)­(PR<sub>3</sub>)-9-(Py)-<i>nido</i>-8,7-RhSB<sub>9</sub>H<sub>9</sub>], where PR<sub>3</sub> = PMe<sub>3</sub> (<b>11</b>), PMe<sub>2</sub>Ph (<b>12</b>), or PMePh<sub>2</sub> (<b>15</b>), and bis-ligated derivatives, [8,8,8-(Cl)­(PR<sub>3</sub>)<sub>2</sub>-9-(Py)-<i>nido</i>-8,7-RhSB<sub>9</sub>H<sub>9</sub>], where PR<sub>3</sub> = PMe<sub>3</sub> (<b>13</b>) or PMe<sub>2</sub>Ph (<b>14</b>). The {RhCl­(PR<sub>3</sub>)}-containing compounds, <b>3</b>, <b>11</b>, <b>12</b>, and <b>15</b>, are formally unsaturated 12 skeletal electron pair (sep) clusters with <i>nido</i>-structures. Density functional theory (DFT) calculations demonstrate that the <i>nido</i>-structure is more stable than the predicted <i>closo</i>-isomers. In addition, studies have been carried out that involve the reactivity of <b>3</b> with Lewis bases. Thus, it is reported that <b>3</b> interacts with MeCN in solution, and it reacts with CO and pyridine to give the corresponding Rh-L adducts, [8,8,8-(Cl)­(L)­(PPh<sub>3</sub>)-9-(Py)-<i>nido</i>-8,7-RhSB<sub>9</sub>H<sub>9</sub>], where L = CO (<b>5</b>) or Py (<b>20</b>). On the other hand, the treatment of <b>3</b> and <b>5</b> with Proton Sponge (PS) promotes the abstraction of HCl, as [PSH]­Cl, from the <i>nido</i>-clusters, and the regeneration of the parent <i>closo</i>-species, completing two new stoichiometric cycles that are driven by Brønsted acid/base chemistry.