Nickel and Copper in C-H Activation and Carbenoid Chemistry: A Descriptor-Based Comparative Analysis of Transition Metals.

A series of Fischer-type carbenoids of groups 10 and 11, bearing diverse electron-donating and electron-withdrawing substituents, were systematically analyzed using a descriptor-based framework grounded in Conceptual Density Functional Theory (CDFT), assessing whether shared electronic descriptors can rationalize the reaction profiles and reactivity in Ni(II) and Cu(I) complexes in a series of C-H activation reactions. The activation barriers for carbenoid insertion reactions were computed and correlated with reactivity indexes, including the Dual Descriptor and its Grand Canonical extensions based on softness and hardness (SGCDD and PGCDD). Although Ni carbenoids display slightly higher activation barriers than their Cu analogues, both metals exhibit parallel qualitative trends. The PGCDD descriptor showed the strongest predictive capability, yielding high correlations with computed barriers, particularly when refined through excited-state corrections using the Specific State Dual Descriptor (SSDD). Substituent effects especially mesomeric contributions from halogen groups were critically evaluated to establish a coherent electronic interpretation of reactivity. This unified descriptor-based framework provides a transferable methodology for rationalizing C-H activation mechanisms across transition metals, offering valuable insights for the predictive design of metal-carbenoid catalysts.