Heteroallene Capture and Exchange at Functionalised Heptaphosphane Clusters

Despite being known for decades the chemical reactivity of homoatomic seven‐atom phosphorus clusters towards small molecules remains largely unexplored. Here, we report that neutral tris(silyl) functionalised heptaphosphane (P7(SiR3)3) cages are capable of heteroallene capture between the P−Si bonds of the cluster. A range of isocyanates and an isothiocyanate were investigated. In the case of isocyanates, silyl bonding at oxygen or nitrogen is regioselectively directed by the functional group on the isocyanate and substituents on the silyl moiety. Above all, we find that captured isothiocyanate molecules can be exchanged for isocyanate molecules, indicative of small molecule catch and release. Small molecule catch and release at these Zintl‐derived clusters reveals their potential application as chemical storage materials or as reusable probes. Three equivalents of heteroallene can be captured between the Si−P bonds of Zintl‐derived clusters. Silyl coordination at either the nitrogen or chalcogen of the heteroallene can be controlled by tuning the groups on the silyl moiety or functional groups at the heteroallene. It was also found that one captured small molecule can be exchanged for another, evidencing small molecule catch and release at these clusters.