Palladium‐Catalyzed Activation of Carbon–Halogen Bonds: Electrostatics‐Controlled Reactivity


We have quantum chemically studied the palladium-mediated activation of C(spn)–X bonds (n = 1–3 X = F, Cl, Br, I) in the archetypal model substrates H3C–CH2–X, H2C=CH–X, and HC≡C–X by a product bare palladium catalyst, making use of relativistic density purposeful principle at ZORA-BLYP/TZ2P. The bond activation reaction barrier decreases, for all sp-hybridized carbon facilities, when the substituent X of the substrate is modified from X = F to I. Activation strain and electricity decomposition analyses expose that the increased reactivity alongside this collection originates from (i) a less destabilizing activation strain due to an intrinsically weaker C(spn)–X bond and (ii) an ever more much more stabilizing electrostatic interaction involving the catalyst and the substrate. The latter is a immediate consequence of the extra diffuse electron density and bigger nuclear charge of the X atom in the C(spn)–X bond when heading from X = F to I, which, in turn, engages in a much more favorable electrostatic attraction with the nucleus and electrons, respectively, of the palladium catalyst.