Synthesis of asymmetric supramolecular compounds using a Ni(0) catalysed homo-coupling approach

The synthesis and characterisation of a series of dinuclear ruthenium and osmium polypyridyl metal complexes based on the bridging ligands [5-(5′-bipyridin-2′,2′-yl)-3-(pyridin-2-yl)]-1,2,4-triazole (Hpytr-bipy), 2,2′-bis(pyridin-2′yl)-5,5′-bis(pyridin-3′-yl) (bipy-bipy) and 5,5′-bis(pyridin-2′-yl)-3,3′-bis(1,2,4-triazole) (Hpytr-Hpytr) are reported. The dinuclear complexes have been synthesised via a Ni(0) catalysed cross-coupling reaction from brominated precursors. With this approach a mixture of three products is obtained, which are separated by chromatographic methods. The compounds obtained are characterised by elemental analysis, 1H NMR, absorption and emission spectroscopy. The synthetic approach developed offers a new route to asymmetric multinuclear supramolecular structures that is complimentary to the complexes as ligands/complexes as metal approaches.