Gold liquid crystals displaying luminescence in the mesophase and short F...F interactions in the solid state

Rodlike gold(I) complexes, [Au(C6F4OCmH2m+1)(C(triple bond)NC6H4C6H4OCnH2n+1)] (m=2, n=4, 10; m=6, n=10; m=10, n=6, 10), display interesting features. They are liquid crystals and show photoluminescence in the mesophase, as well as in the solid state and in solution. The single-crystal, X-ray diffraction structure of [Au(C6F4OC2H5)(C(triple bond)NC6H4C6H4OC4H9)] confirms its rodlike structure, with a linear coordination around the gold atom, and reveals the absence of any Au...Au interactions (such interactions are often present in luminescent gold complexes). Well-defined, intermolecular Fortho...Fmeta interactions, with remarkably short intermolecular FF distances (2.66 A), are observed; these interactions seem to be responsible for the crystal packing, which consists of an antiparallel arrangement of molecules. Experiments under different conditions support the explanation that the photoluminescence has an intramolecular origin.