Asymmetric halogeno-bridged complexes of the late transition metals - A computational and experimental study

Metathesis reactions of dinuclear halo-bridged complexes of the late transi tion metals have been studied by NMR. For selected combinations of 15 diffe rent complexes, it has been shown that asymmetric complexes are formed in a dynamic equilibrium. The equilibrium constants have been calculated and th e trends therein are discussed. A theoretical analysis of halo-bridged comp lexes containing (C3H5)MX, (H3P)MX2, [(H3P)(2)MX](+), and (ppy)(2)RhCl frag ments (M = Pd, Pt; X = Cl, Br, I; ppy = anion of 2-phenylpyridine) has been carried out to gain further insight into (i) the influence of the bridging halogen atoms on the equilibrium, (ii) the electron transfer, (iii) the th ermodynamic stability and the dynamic equilibrium behaviour, and (iv) struc tural differences between symmetric and asymmetric halo-bridged complexes.