Coordination Chemistry of Anticrowns. Synthesis and Structures of Complexes of the Perfluorinated Three‐Mercury Anticrown ( o ‐C 6 F 4 Hg) 3 with Monohalogenobenzenes

The paper reports the reactions of the perfluorinated three‐mercury anticrown ( o ‐C 6 F 4 Hg) 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 ‐C 6 F 4 Hg) 3 ](C 6 H 5 F)}. 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 ‐C 6 F 4 Hg) 3 ] 2 (C 6 H 5 X) 4 }, (X = Cl, Br), containing four halogenobenzene molecules per two molecules of 1 . The complexes include two monomeric {[( o ‐C 6 F 4 Hg) 3 ](C 6 H 5 X) 2 } fragments connected with one another by two bridging η 1 coordinated halogen atoms of the halogenobenzene ligands. The halogen atoms of two other halogenobenzene species are η 3 coordinated each with the Hg centers of the neighboring molecule of 1 . The reaction of iodobenzene with 1 affords a 3:1 complex, {[( o ‐C 6 F 4 Hg) 3 ](C 6 H 5 I) 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 .