Anionic Complexes of the Perfluorinated Three-Mercury Anticrown (o,o'-C6F4C6F4Hg)3. Dependence of the Anion Coordination Type on Counter-Cation in Case of Chloride and Bromide Anions

The interaction of the macrocycle (o,o '-C6F4C6F4Hg)(3) (1) containing three mercury centres with arylphosphonium salts ([Ph4P]Cl or [Ph4P]Br) yields halide complexes, [Ph4P]{[(o,o '-C6F4C6F4Hg)(3)](eta(1):eta(1)-X)} (X=Cl, Br) having infinite polymer chain structure in the crystal. In both adducts, the halide anion is situated outside of the cavity of the three-mercury anticrown 1 and bridged by two mercury centres of neighbouring anticrown moieties. At the same time, when mercuracycle 1 interacts with tetraalkylammonium salts ([(Bu4N)-Bu-n]Cl or [(Bu4N)-Bu-n]Br), then the discrete 1 : 1 complexes [(Bu4N)-Bu-n]{[(o,o '-C6F4C6F4Hg)(3)](eta(3)-X)} (X=Cl, Br) of completely different structure are formed. In these halide complexes the anion is located inside the cavity of macrocycle 1 and coordinates the three mercury atoms symmetrically. The synthesized halide complexes [(Bu4N)-Bu-n]{[(o,o '-C6F4C6F4Hg)(3)](eta(3)-X)} (X=Cl, Br) are the first example of complexes of the macrocycle 1 where it behaves as anticrown.