A Modular Programmable Inorganic Cluster Discovery Robot for the Discovery and Synthesis of Polyoxometalates
<p>The exploration of complex multi-component chemical reactions leading to new clusters, where discovery requires both molecular self-assembly and crystallization, is a major challenge. This is because the systematic approach required for an experimental search is limited when the number of parameters in a chemical space becomes too large, restricting both exploration, and reproducibility. Herein, we present a synthetic strategy to systematically search a very large set of potential reactions, using an inexpensive, high-throughput platform; modular in terms of both hardware and software, and capable of running multiple reactions with in-line analysis; for the automation of inorganic and materials chemistry. The platform has been used to explore several inorganic chemical spaces to discover new, and reproduce known, tungsten-based, mixed transition-metal polyoxometalate clusters, giving a digital code allowing the easy repeat synthesis of the clusters. Among the many species identified in this work, most significantly is the discovery of a novel, purely inorganic W<sub>24</sub>Fe<sup>III</sup>-superoxide cluster formed under ambient conditions. The Modular Wheel Platform (MWP) was then employed to undertake two chemical space explorations producing compounds [1-4]: (C<sub>2</sub>H<sub>8</sub>N)<sub>10</sub>Na<sub>2</sub>[H<sub>6</sub>Fe(O<sub>2</sub>)W<sub>24</sub>O<sub>82</sub>(H<sub>2</sub>O)<sub>25</sub>] (1, {W<sub>24</sub>Fe}), (C<sub>2</sub>H<sub>8</sub>N)<sub>72</sub>Na<sub>16</sub>[H<sub>16</sub>Co<sub>8</sub>W<sub>200</sub>O<sub>660</sub>(H<sub>2</sub>O)<sub>40</sub>] (2, {W<sub>200</sub>Co<sub>8</sub>}), (C<sub>2</sub>H<sub>8</sub>N)<sub>72</sub>Na<sub>16</sub>[H<sub>16</sub>Ni<sub>8</sub>W<sub>200 </sub>O<sub>660-</sub>(H<sub>2</sub>O)<sub>40</sub>] (3, {W<sub>200</sub>Ni<sub>8</sub>}) and (C<sub>2</sub>H<sub>8</sub>N)<sub>14</sub>[H<sub>26</sub>W<sub>34</sub>V<sub>4</sub>O<sub>130</sub>] (4, {W<sub>34</sub>V<sub>4</sub>}), along with many other known species, for example simple Keggin clusters and 1D {W<sub>11</sub>M<sup>2+</sup>} chains. <b></b></p>