Palladium monophosphine Pd(PPh 3 ): is it really accessible in solution?

Catalyst speciation is a ubiquitous theme in homogeneous catalysis. Employing realistic models based on an explicit solvent representation and ab initio molecular dynamics simulations we addressed the issue of solvent coordination in the Pd-PPh3 system. We show the accessibility of species such as (Sol)Pd(PPh3), (Sol)Pd(PPh3)2, (Sol)2Pd(PPh3) (where Sol is a solvent molecule). Importantly, we demonstrate that the bare monophosphine Pd(PPh3) species, often depicted in catalytic cycles, is actually not accessible in solution.