Authors: Guido Bussoli | Alberto Boccalini | Marco Bortoluzzi | Cristiana Cesari | Maria Carmela Iapalucci | Tiziana Funaioli | Giorgia Scorzoni | Stefano Zacchini | Silvia Ruggieri | Cristina Femoni
Source: Nanoscale (article, 2024-01-01)
Field: Materials Science — Materials Chemistry

Atomically precise rhodium–indium carbonyl nanoclusters: synthesis, characterization, crystal structure and electron-sponge features In this paper we present the investigation of the reactivity of [Rh<sub>7</sub>(CO)<sub>16</sub>]<sup>3-</sup> with InCl<sub>3</sub>, with the aim of expanding the more general study that allowed us to obtain, among other species, the icosahedral [Rh<sub>12</sub>E(CO)<sub>27</sub>]<sup><i>n</i>-</sup> (<i>n</i> = 4 when E = Ge or Sn; <i>n</i> = 3 when E = Sb or Bi) family of clusters. Indeed, the study resulted in the isolation and characterization of the analogous In-centred icosahedral [Rh<sub>12</sub>In(CO)<sub>28</sub>]<sup>3-</sup> nanocluster (1), which is isoelectronic and isostructural with the [Rh<sub>12</sub>E(CO)<sub>27</sub>]<sup><i>n</i>-</sup> congeners. During the course of the reaction two more new species, namely the octahedral [Rh<sub>6</sub>(CO)<sub>15</sub>InCl<sub>3</sub>]<sup>2-</sup> (2) and the dimeric [{Rh<sub>6</sub>(CO)<sub>15</sub>InCl<sub>2</sub>}<sub>2</sub>]<sup>2-</sup> (3) have also been identified. The reaction between [Rh<sub>7</sub>(CO)<sub>16</sub>]<sup>3-</sup> and InCl<sub>3</sub> proved to be poorly selective; nevertheless, by fine tuning some reaction parameters it was possible to drive the reaction more towards one product or the other. Alternatively, [Rh<sub>6</sub>(CO)<sub>15</sub>InCl<sub>3</sub>]<sup>2-</sup> can be more selectively prepared by reacting either [Rh<sub>5</sub>(CO)<sub>15</sub>]<sup>-</sup> or, less efficiently, [Rh<sub>6</sub>(CO)<sub>15</sub>]<sup>2-</sup> with InCl<sub>3</sub>. As for the dimeric [{Rh<sub>6</sub>(CO)<sub>15</sub>InCl<sub>2</sub>}<sub>2</sub>]<sup>2-</sup> species, this was only isolated by carrying out the reaction with [Rh<sub>7</sub>(CO)<sub>16</sub>]<sup>3-</sup> under inert atmosphere, as opposed to under CO. All clusters were characterized by IR spectroscopy and ESI-MS, and their molecular structures were fully established by single-crystal X-ray diffraction studies. The [Rh<sub>12</sub>In(CO)<sub>28</sub>]<sup>3-</sup> species was also analysed by EDS <i>via</i> SEM, and further investigated through <i>in situ</i> infrared spectroelectrochemistry and CV experiments to check its multivalence nature. Indeed, [Rh<sub>12</sub>In(CO)<sub>28</sub>]<sup>3-</sup> can reversibly undergo two monoelectronic oxidation and one bi-electronic reduction processes, behaving like an electron sponge and, thus, giving rise to the further [Rh<sub>12</sub>In(CO)<sub>28</sub>]<sup><i>n</i>-</sup> derivatives (<i>n</i> = 1, 2 and 5). These results parallel the findings for the [Rh<sub>12</sub>E(CO)<sub>27</sub>]<sup><i>n</i>-</sup> series. The geometry variations of the metal framework associated with the changes in the cluster negative charge were investigated by means of DFT calculations. Nanoclusters ; Characterization (materials science) ; Rhodium ; Materials science ; Indium ; Nanotechnology ; Sponge ; Crystal structure ; Crystallography ; Chemistry ; Optoelectronics ; Organic chemistry ; Catalysis ; Geology Nanocluster Synthesis and Applications ; Advanced Chemical Physics Studies ; Catalytic Processes in Materials Science