Reactivity of tetrel functionalized heptapnictogen clusters towards heteroallenes

Despite being known for decades, the solution-state molecular chemistry of heptapnictogen ([Pn(7)](3-); Pn = P, As) clusters is not well established. Here we study heavy element derivatives of tetrel functionalized heptapnictogen clusters towards heteroallene capture, specifically isocyanates, an isothiocyanate and CO2 are probed. Clusters (Me3Ge)(3)P-7 (1), (Et3Ge)(3)P-7 (2), ((Bu3Sn)-Bu-n)(3)P-7 (3), and (Me3Si)(3)As-7 (4) were all found to capture isocyanates between all three of their tetrel-pnictogen bonds. In the case of phenyl isocyanate insertion, tetrel coordination at the isocyanate nitrogen atoms is preferred, while in the case of p-toluenesulfonyl isocyanate insertion, tetrel coordination at oxygen is preferred. Furthermore, the reaction of (Me3Si)(3)P-7 with CO2 gave NMR spectra consistent with the capture of the greenhouse gas. Heteroallene insertion at these clusters was also studied using density functional theory.

Automated summary

The solution-state molecular chemistry of heptapnictogen clusters has not been well established. We investigated the heteroallene capture ability of heavy element derivatives of tetrel functionalized heptapnictogen clusters towards isocyanates and CO2. The experimental results showed that these clusters could capture isocyanates through their tetrel-pnictogen bonds, with different preferences for coordinating with nitrogen or oxygen atoms. This study also used density functional theory to explore the heteroallene insertion at these clusters.