Structure and Gas-Phase Thermochemistry of a Pd/Cu Complex: Studies on a Model for Transmetalation Transition States

A heterobimetallic Pd­(II)/Cu­(I) complex
was prepared and characterized
by X-ray diffraction analysis. The crystal structure shows a remarkably
short Pd–Cu bond and a trigonal ipso carbon atom. The Pd–Cu
interaction, as determined by energy-resolved collision-induced dissociation
cross-section experiments, models the net stabilizing energy of the
Pd–Cu interaction in the transition state of the transmetalation
step in Pd/Cu-catalyzed cross-coupling reactions. The bonding situation
in the bimetallic dinuclear complex has been studied by atoms-in-molecules
analysis.