Efficacy analysis of compartmentalization for ambient CH 4 activation mediated by a Rh II metalloradical in a nanowire array electrode

• Published in: Chemical science (Cambridge) Vol. 12; no. 5; pp. 1818 - 1825
• Main Authors: Natinsky, Benjamin S., Jolly, Brandon J., Dumas, David M., Liu, Chong
• Format: Journal Article
• Language: English
• Published: 11.02.2021
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/D0SC05700B

Compartmentalization is a viable approach for ensuring the turnover of a solution cascade reaction with ephemeral intermediates, which may otherwise deactivate in the bulk solution. In biochemistry or enzyme-relevant cascade reactions, extensive models have been constructed to quantitatively analyze the efficacy of compartmentalization. Nonetheless, the application of compartmentalization and its quantitative analysis in non-biochemical reactions is seldom performed, leaving much uncertainty about whether compartmentalization remains effective for non-biochemical reactions, such as organometallic, cascade reactions. Here, we report our exemplary efficacy analysis of compartmentalization in our previously reported cascade reaction for ambient CH 4 -to-CH 3 OH conversion, mediated by an O 2 -deactivated Rh II metalloradical with O 2 as the terminal oxidant in a Si nanowire array electrode. We experimentally identified and quantified the key reaction intermediates, including the Rh II metalloradical and reactive oxygen species (ROS) from O 2 . Based on such findings, we experimentally determined that the nanowire array enables about 81% of the generated ephemeral intermediate Rh II metalloradical in air, to be utilized towards CH 3 OH formation, which is 0% in a homogeneous solution. Such an experimentally determined value was satisfactorily consistent with the results from our semi-quantitative kinetic model. The consistency suggests that the reported CH 4 -to-CH 3 OH conversion surprisingly possesses minimal unforeseen side reactions, and is favorably efficient as a compartmentalized cascade reaction. Our quantitative evaluation of the reaction efficacy offers design insights and caveats into application of nanomaterials to achieve spatially controlled organometallic cascade reactions.