Thanapat Worakul†, Boodsarin Sawatlon,ξ and Panida Surawatanawong*,†,‡

†Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand

ξDepartment of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand

‡Center of Sustainable Energy and Green Materials, Mahidol University, Salaya, Nakhon Pathom 73170, Thailand

*E-mail: panida.sur@mahidol.ac.th

Expanding upon the initial use of nickel complexes to cleave aliphatic C-F bond in the hydrodefluorination of trifluoromethylarene, we employed linear free energy scaling relationships and molecular volcano plots to elucidate the impact of N-heterocyclic carbene and phosphine ligands, as well as metals and additives, on the energy span related to catalytic activity. Our findings revealed that multiple reference states must be essentially considered to fully describe the catalytic activity of the nickel complexes. We introduced the concept of “reference-generalized volcano plots” (RGVPs) as a tool aiding in the selection of the appropriate reference state to determine catalytic activity. Multivariate linear regression analysis using non-energetic descriptors allowed us to uncover the effects of steric and electronic properties on catalytic activity. Specifically, strong electron-donating and small- to moderate-sized ligands are identified as optimal for nickel catalysts. The RGVPs in combination with multivariate linear regression models based on steric and electronic molecular features provide chemical insights into catalytic activity and offer guidance for fine-tuning catalyst properties for hydrodefluorination.