Several tetracationic N,N'-bipyridinium-based [2]catenanes and cycloph
anes have been synthesised containing, as part of the overall structur
e, the cation chelating 2,2'-bipyridyl (bipy) subunit. The metal bindi
ng unit is used to generate photoactive ruthenium(II) and osmium(II) a
ssemblies, and a potential site for further metal cluster formation. (
C) 1997 Elsevier Science Ltd.