LAUSR

Abstract POCOP-pincer ligated palladium hydrocarbyl complexes [2,6-(R2PO)2C6H3]PdR′ have been prepared from the reaction between [2,6-(R2PO)2C6H3]PdCl and R'Li. X-ray crystallographic studies of these complexes show that the Pd–R′ bond becomes shorter when the metal-bound carbon has more s character. Comparing the relative reactivity of these palladium hydrocarbyl (including hydride) complexes toward phenylacetylene suggests that the rate of the C–H exchange process follows a decreasing order of Pd–H > Pd–Csp3 > Pd–Csp2 > Pd–Csp. The palladium phenyl complex [2,6-(R2PO)2C6H3]PdPh is exceptionally slow for the reaction with phenylacetylene, possibly due to a high-energy conformer required for the palladium-carbon bond cleavage.