ElectroNick commenced with a study into using cobalt electrocatalysts to create cobalt–carbon bonds, which could then transfer the organic group onto a nickel catalyst that would be key to forging novel carbon–carbon bonds. However, when we reduced the Co(II) species, adding an electron from the electrical curcuit to generate a Co(I) intermediate, we found these new Co(I) compounds were very unstable to decomposition, which would not be productive in our desired transformation. To understand this decomposition event, we used advanced electronalytical techniques to study the rate of the reaction. Changing the ligand bound to Co(I), we surveyed how small differences affected this decomposition rate, collecting large data sets to correlate with structural features of the ligand. In doing so, we developed a mechanism for the undesired decomposition pathway, and gained insight in how to avoid it.
With that in hand, we used the same toolkit to understand how the Co(I) would react productively with organic molecules, developing understanding on how, of many possibilities, the Co(I) would add into a carbon–bromine bond (oxidative addition). This strategy of combining electroanalytical techniques with statistical modeling to understand these processes represents a significant advance in building methods to interrogate reactivity, and we have expanded its use to investigating reactivity with alternative substrates and nickel complexes. Finally, the statisical modeling techniques were utilized to understand intricate interactions which drive selectivity in a new palladium catalyzed transformation, forging new carbon–nitrogen and carbon–oxygen bonds towards pharmaceutical targets.
In the outgoing phase of ElectroNick, the project developed new tools combining electroanalytical techniques with statistical modeling to interrogate reaction mechanisms. Our results uncovered how Co(I) complexes add into a carbon–bromine bond through a specific oxidative addition mechanism. In an extension to that study, we have investigated how Co(I) complexes with different ligand scaffolds can change the mechanism of activation of the substrate to alternative processes, including the transfer of an electron into the carbon–bromine bond (concerted dissociative electron transfer). Additionally, we expand our studies beyond the confines of Co(I) complexes to include other transition metals. In doing so, we have formulated a platform to globally understand and predict reactivity between metals and organic molecules that can be used to design new reactions for pharmaceutical and agrochemical synthesis.
With knowledge of how these reactions occur mechanistically, we have sought to develop new carbon–carbon and carbon–heteroatom bond forming reactions using the combination of electrochemistry and nickel catalysis. The ElectroNick project has realized early studies indicating that the functionalization of simple carbon–hydrogen bonds can be achieved by these techniques, and work to expand these principles to transformative new reactions remains ongoing within the research groups.
Altogther, ElectroNick has thus far afforded four open access publications in scientific journals, was presented at two interantional conferences and eight invited seminars, and been disseminated to the wider public through social media, video clips and outreach activities.
