Luminescent gold(I) macrocycles with diphosphine and 4,4′-bipyridyl ligands

The complexes [{-Ph2P(CH2)(n)PPh2AuNC5H4C5H4NAu-}(x)](2x+) [CF3CO2-](2x) (n=1-6) were prepared as colourless, air- stable solids by reaction of silver trifluoroacetate with the corresponding precursor complex [(CH2)(n)(Ph2PAuCl)(2)], and subsequent treatment of the products [(CH2)(n)(Ph2PAuO2CCF3)(2)] with 4,4'-bipyridyl. The complexes are suggested to exist in solution as an equilibrium mixture of linear oligomers and cyclic complexes. When n=1, 3 or 5 the cationic complexes were shown to exist as 26-, 30- and 34-membered macrocyclic rings respectively; only when n=1 are there significant intramolecular Au . . . Au contacts of 3.106(1) and 3.084(1) Angstrom. Some of the complexes are strongly emissive at room temperature in solution and in the solid state.