Intramolecular Scrambling of Aryl Groups in Organopalladium Complexes [ArPd(PPh3)2]+: From Solution to the Gas Phase, Back Again, and In-Between

Gas-phase experiments are used to probe the intramolecular scrambling of aryl groups between palladium and phosphorus in organopalladium complexes, [ArPd(PPh3)(2)](+), generated by means of electrospray ionization (ESI). To this aim, ESI mass spectrometry, including tandem mass spectrometric experiments, were carried out on deuterated, non-deuterated, and substituted [ArPd(PPh3)(2)](+) complexes. The fragment ions obtained from the deuterated parent ions clearly show the occurrence of intramolecular scrambling between the aryl group bound to palladium and the phenyl groups of the phosphine in the gas phase. Fragmentation pathways, supported by a statistical model, are proposed to explain these migrations and the implications for the condensed-phase chemistry are probed experimentally by using ESI mass spectrometry.