Monomerisation of [Rh2(1,3-bis-(diphenylphosphino)-propane)2(µ2-Cl)2] detected by pulsed gradient spin echo spectroscopy and 31P NMR monitoring of metathesis experiments

A pulsed gradient spin echo experiment on [Rh2(1,3-bis-(diphenylphosphino)-propane)2(µ2-Cl)2] complex has been conducted in order to shed light on the supposed monomerisation process of [Rh2(diphosphine)2(µ2-Cl)2] complexes in solution. Such a process should generate a 14-electron [Rh(diphosphine)Cl] complex, which has only been postulated to date. Metathesis experiments on [Rh2(1,3-bis-(diphenylphosphino)-propane)2(µ2-Cl)2] and [Rh2(bis[2-(diphenylphosphino)phenyl]ether)2(µ2-Cl)2] complexes, analysed by 31P NMR, reveal that monomerisation of [Rh2(diphosphine)2(µ2-Cl)2] complexes is not restricted to the case of 1,3-bis-(diphenylphosphino)propane.