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

## TL;DR

This paper compares nickel and copper in C–H activation reactions using electronic descriptors to predict and explain reactivity trends in metal-carbenoid catalysts.

## Contribution

A descriptor-based framework using CDFT is introduced to unify and predict reactivity trends in nickel and copper carbenoid chemistry.

## Key findings

- PGCDD descriptor shows strong predictive power for activation barriers in Ni and Cu carbenoids.
- Excited-state corrections via SSDD improve correlation with computed reaction barriers.
- Mesomeric effects from halogen substituents are critical for electronic interpretation of reactivity.

## Abstract

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.