Coordination Chemistry of Anticrowns. Synthesis and Structures of Complexes of the Perfluorinated Three‐Mercury Anticrown (o‐C6F4Hg)3 with Monohalogenobenzenes.

The paper reports the reactions of the perfluorinated three‐mercury anticrown (o‐C6F4Hg)3 (1) with monohalogenobenzenes. It has been found that the interaction of 1 with fluorobenzene gives two 1:1 complexes 2 and 3, differing in their structures. Complex 2 forms in the crystal extended binary stacks wherein the molecules of 1 alternate with the halogenobenzene species, while complex 3 consists of the cofacial dimers formed from the corresponding monomeric units {[(o‐C6F4Hg)3](C6H5F)}. Each fluorobenzene molecule in both adducts is bonded to 1 by its phenyl ring through secondary π‐Hg–C interactions, whereas the fluorine atom is coordinated with one of the Hg sites of 1. Analogous types of bonding are realized in the chlorobenzene and bromobenzene complexes, {[(o‐C6F4Hg)3]2(C6H5X)4}, (X = Cl, Br), containing four halogenobenzene molecules per two molecules of 1. The complexes include two monomeric {[(o‐C6F4Hg)3](C6H5X)2} fragments connected with one another by two bridging η1 coordinated halogen atoms of the halogenobenzene ligands. The halogen atoms of two other halogenobenzene species are η3 coordinated each with the Hg centers of the neighboring molecule of 1. The reaction of iodobenzene with 1 affords a 3:1 complex, {[(o‐C6F4Hg)3](C6H5I)3}, which is unstable and readily transformed into the corresponding 1:1 adduct. Both compounds form in the crystal extended stacks wherein each sandwiched iodobenzene molecule is coordinated via the iodine atom with the adjacent molecule(s) of 1. [ABSTRACT FROM AUTHOR]