Reactivity and electrochemical properties of the d8–d8 Pd2(dppm)2(Cl)2(Me)2 towards MeI

The title dimer reacts with MeI or KI to form [Pd2(dppm)2(μ-I)(Me)2]I. The latter has been characterized from X-ray crystallography, and exhibits a A-frame structure with a Pd⋯Pd separation of 3.061 Å. The 4-electron reduction of the d8–d8 title starting material Pd2(dppm)2(Cl)2(Me)2 and resulting [Pd2(dppm)2(μ-I)(Me)2]I product in the presence of dppm, produces the known Pd2(dppm)3 dimer. The presence of intermediates such as the d9–d9 ‘Pd2(dppm)2(Me)2’ and d10–d10 ‘Pd2(dppm)2(I)n n−’ species are suspected, and 31P NMR indicates evidence for the relatively unstable mononuclear Pd(dppm)(Me)2 complex. The reductive electrolysis of both d8–d8 dimers in the presence of an excess of MeI leads to an increase in Pd(dppm)(Me)2 concentration.