The simple substitution of a hydrogen atom by a fluorine atom in 1-hexyluracil has an enormous consequence on the solid state structure due to the increment in the π-acidity of the ring.

We report the first gold( iii ) complex with a cytosine derivative since 35 years. In the crystal structure, the complex stacks by reciprocal regium-bonding interactions. These interactions appear to be common in the Cambridge structure database.