Dynamic properties of the fluxional Rh2H(μ-PPh2)2(PPh3)3−1 complex

The rhodium dimer [Rh2H(PPh2)2(PPh3)3]− was prepared from RhCl(PPh3)3 and K4Sn9 in the presence of 2,2,2-cryptand in ethylenediamine/toluene solvent mixtures. The [K(2,2,2-crypt)]+ salt was isolated and characterized via NMR and X-ray diffraction studies. The solid state structure reveals a binuclear, diphenylphosphido-bridged, 32 electron Rh(I)–Rh(I) complex with edge-shared tetrahedral and square planar Rh centers with overall Cs point symmetry. 1-D and 2-D 1H, 31P, and 31P{1H} NMR experiments were used to characterize the complex.